--[[
This file is part of mpv.

mpv is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

mpv is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
]]--

local assdraw = require 'mp.assdraw'
local msg = require 'mp.msg'
local opt = require 'mp.options'
local utils = require 'mp.utils'

--
-- Parameters
--
-- default user option values
-- do not touch, change them in osc.conf
local user_opts = {
    showwindowed = true,        -- show OSC when windowed?
    showfullscreen = true,      -- show OSC when fullscreen?
    scalewindowed = 1,          -- scaling of the controller when windowed
    scalefullscreen = 1,        -- scaling of the controller when fullscreen
    scaleforcedwindow = 2,      -- scaling when rendered on a forced window
    vidscale = true,            -- scale the controller with the video?
    valign = 0.8,               -- vertical alignment, -1 (top) to 1 (bottom)
    halign = 0,                 -- horizontal alignment, -1 (left) to 1 (right)
    barmargin = 0,              -- vertical margin of top/bottombar
    boxalpha = 80,              -- alpha of the background box,
                                -- 0 (opaque) to 255 (fully transparent)
    hidetimeout = 500,          -- duration in ms until the OSC hides if no
                                -- mouse movement. enforced non-negative for the
                                -- user, but internally negative is "always-on".
    fadeduration = 200,         -- duration of fade out in ms, 0 = no fade
    deadzonesize = 0.5,         -- size of deadzone
    minmousemove = 0,           -- minimum amount of pixels the mouse has to
                                -- move between ticks to make the OSC show up
    layout = "bottombar",
    seekbarstyle = "diamond",       -- bar, diamond or knob
    seekbarhandlesize = 0.6,    -- size ratio of the diamond and knob handle
    tooltipborder = 1,          -- border of tooltip in bottom/topbar
    timetotal = false,          -- display total time instead of remaining time?
    timems = false,             -- display timecodes with milliseconds?
    visibility = "auto",        -- only used at init to set visibility_mode(...)
    boxmaxchars = 80,           -- title crop threshold for box layout
    boxvideo = false,           -- apply osc_param.video_margins to video
}

-- read options from config and command-line
opt.read_options(user_opts, "osc", function(list) update_options(list) end)

local osc_param = { -- calculated by osc_init()
    playresy = 0,                           -- canvas size Y
    playresx = 0,                           -- canvas size X
    display_aspect = 1,
    unscaled_y = 0,
    areas = {},
    video_margins = {
        l = 0, r = 0, t = 0, b = 0,         -- left/right/top/bottom
    },
}

local osc_styles = {
    bigButtons = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs50\\fnmpv-osd-symbols}",
    smallButtonsL = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs19\\fnmpv-osd-symbols}",
    smallButtonsLlabel = "{\\fscx105\\fscy105\\fn" .. mp.get_property("options/osd-font") .. "}",
    smallButtonsR = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs30\\fnmpv-osd-symbols}",
    topButtons = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs12\\fnmpv-osd-symbols}",

    elementDown = "{\\1c&H999999}",
    timecodes = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs20}",
    vidtitle = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs12\\q2}",
    box = "{\\rDefault\\blur0\\bord1\\1c&H000000\\3c&HFFFFFF}",

    topButtonsBar = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs18\\fnmpv-osd-symbols}",
    smallButtonsBar = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs28\\fnmpv-osd-symbols}",
    timecodesBar = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs27}",
    timePosBar = "{\\blur0\\bord".. user_opts.tooltipborder .."\\1c&HFFFFFF\\3c&H000000\\fs30}",
    vidtitleBar = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs18\\q2}",

    wcButtons = "{\\1c&HFFFFFF\\fs24\\fnmpv-osd-symbols}",
    wcTitle = "{\\1c&HFFFFFF\\fs24\\q2}",
    wcBar = "{\\1c&H000000}",
}

-- internal states, do not touch
local state = {
    showtime,                               -- time of last invocation (last mouse move)
    osc_visible = false,
    anistart,                               -- time when the animation started
    anitype,                                -- current type of animation
    animation,                              -- current animation alpha
    mouse_down_counter = 0,                 -- used for softrepeat
    active_element = nil,                   -- nil = none, 0 = background, 1+ = see elements[]
    active_event_source = nil,              -- the "button" that issued the current event
    rightTC_trem = not user_opts.timetotal, -- if the right timecode should display total or remaining time
    tc_ms = user_opts.timems,               -- Should the timecodes display their time with milliseconds
    mp_screen_sizeX, mp_screen_sizeY,       -- last screen-resolution, to detect resolution changes to issue reINITs
    initREQ = false,                        -- is a re-init request pending?
    last_mouseX, last_mouseY,               -- last mouse position, to detect significant mouse movement
    mouse_in_window = false,
    message_text,
    message_hide_timer,
    fullscreen = false,
    tick_timer = nil,
    tick_last_time = 0,                     -- when the last tick() was run
    hide_timer = nil,
    cache_state = nil,
    idle = false,
    enabled = true,
    input_enabled = true,
    showhide_enabled = false,
    dmx_cache = 0,
    using_video_margins = false,
    border = true,
    maximized = false,
    osd = mp.create_osd_overlay("ass-events"),
    start,
    finish,
    title,
    volume = 0,
}

local window_control_box_width = 80
local tick_delay = 0.03

local is_december = os.date("*t").month == 12

--
-- Helperfunctions
--

function set_osd(res_x, res_y, text)
    if state.osd.res_x == res_x and
       state.osd.res_y == res_y and
       state.osd.data == text then
        return
    end
    state.osd.res_x = res_x
    state.osd.res_y = res_y
    state.osd.data = text
    state.osd.z = 1000
    state.osd:update()
end

local margins_opts = {
    {"l", "video-margin-ratio-left"},
    {"r", "video-margin-ratio-right"},
    {"t", "video-margin-ratio-top"},
    {"b", "video-margin-ratio-bottom"},
}

-- scale factor for translating between real and virtual ASS coordinates
function get_virt_scale_factor()
    local w, h = mp.get_osd_size()
    if w <= 0 or h <= 0 then
        return 0, 0
    end
    return osc_param.playresx / w, osc_param.playresy / h
end

-- return mouse position in virtual ASS coordinates (playresx/y)
function get_virt_mouse_pos()
    if state.mouse_in_window then
        local sx, sy = get_virt_scale_factor()
        local x, y = mp.get_mouse_pos()
        return x * sx, y * sy
    else
        return -1, -1
    end
end

function set_virt_mouse_area(x0, y0, x1, y1, name)
    local sx, sy = get_virt_scale_factor()
    mp.set_mouse_area(x0 / sx, y0 / sy, x1 / sx, y1 / sy, name)
end

function scale_value(x0, x1, y0, y1, val)
    local m = (y1 - y0) / (x1 - x0)
    local b = y0 - (m * x0)
    return (m * val) + b
end

-- returns hitbox spanning coordinates (top left, bottom right corner)
-- according to alignment
function get_hitbox_coords(x, y, an, w, h)

    local alignments = {
      [1] = function () return x, y-h, x+w, y end,
      [2] = function () return x-(w/2), y-h, x+(w/2), y end,
      [3] = function () return x-w, y-h, x, y end,

      [4] = function () return x, y-(h/2), x+w, y+(h/2) end,
      [5] = function () return x-(w/2), y-(h/2), x+(w/2), y+(h/2) end,
      [6] = function () return x-w, y-(h/2), x, y+(h/2) end,

      [7] = function () return x, y, x+w, y+h end,
      [8] = function () return x-(w/2), y, x+(w/2), y+h end,
      [9] = function () return x-w, y, x, y+h end,
    }

    return alignments[an]()
end

function get_hitbox_coords_geo(geometry)
    return get_hitbox_coords(geometry.x, geometry.y, geometry.an,
        geometry.w, geometry.h)
end

function get_element_hitbox(element)
    return element.hitbox.x1, element.hitbox.y1,
        element.hitbox.x2, element.hitbox.y2
end

function mouse_hit(element)
    return mouse_hit_coords(get_element_hitbox(element))
end

function mouse_hit_coords(bX1, bY1, bX2, bY2)
    local mX, mY = get_virt_mouse_pos()
    return (mX >= bX1 and mX <= bX2 and mY >= bY1 and mY <= bY2)
end

function limit_range(min, max, val)
    if val > max then
        val = max
    elseif val < min then
        val = min
    end
    return val
end

-- translate value into element coordinates
function get_slider_ele_pos_for(element, val)

    local ele_pos = scale_value(
        element.slider.min.value, element.slider.max.value,
        element.slider.min.ele_pos, element.slider.max.ele_pos,
        val)

    return limit_range(
        element.slider.min.ele_pos, element.slider.max.ele_pos,
        ele_pos)
end

-- translates global (mouse) coordinates to value
function get_slider_value_at(element, glob_pos)

    local val = scale_value(
        element.slider.min.glob_pos, element.slider.max.glob_pos,
        element.slider.min.value, element.slider.max.value,
        glob_pos)

    return limit_range(
        element.slider.min.value, element.slider.max.value,
        val)
end

-- get value at current mouse position
function get_slider_value(element)
    return get_slider_value_at(element, get_virt_mouse_pos())
end

function countone(val)
    if not (user_opts.iamaprogrammer) then
        val = val + 1
    end
    return val
end

-- align:  -1 .. +1
-- frame:  size of the containing area
-- obj:    size of the object that should be positioned inside the area
-- margin: min. distance from object to frame (as long as -1 <= align <= +1)
function get_align(align, frame, obj, margin)
    return (frame / 2) + (((frame / 2) - margin - (obj / 2)) * align)
end

-- multiplies two alpha values, formular can probably be improved
function mult_alpha(alphaA, alphaB)
    return 255 - (((1-(alphaA/255)) * (1-(alphaB/255))) * 255)
end

function add_area(name, x1, y1, x2, y2)
    -- create area if needed
    if (osc_param.areas[name] == nil) then
        osc_param.areas[name] = {}
    end
    table.insert(osc_param.areas[name], {x1=x1, y1=y1, x2=x2, y2=y2})
end

function ass_append_alpha(ass, alpha, modifier)
    local ar = {}

    for ai, av in pairs(alpha) do
        av = mult_alpha(av, modifier)
        if state.animation then
            av = mult_alpha(av, state.animation)
        end
        ar[ai] = av
    end

    ass:append(string.format("{\\1a&H%X&\\2a&H%X&\\3a&H%X&\\4a&H%X&}",
               ar[1], ar[2], ar[3], ar[4]))
end

function ass_draw_rr_h_cw(ass, x0, y0, x1, y1, r1, hexagon, r2)
    if hexagon then
        ass:hexagon_cw(x0, y0, x1, y1, r1, r2)
    else
        ass:round_rect_cw(x0, y0, x1, y1, r1, r2)
    end
end

function ass_draw_rr_h_ccw(ass, x0, y0, x1, y1, r1, hexagon, r2)
    if hexagon then
        ass:hexagon_ccw(x0, y0, x1, y1, r1, r2)
    else
        ass:round_rect_ccw(x0, y0, x1, y1, r1, r2)
    end
end


--
-- Tracklist Management
--

local nicetypes = {video = "Video", audio = "Audio", sub = "Subtitle"}

-- updates the OSC internal playlists, should be run each time the track-layout changes
function update_tracklist()
    local tracktable = mp.get_property_native("track-list", {})

    -- by osc_id
    tracks_osc = {}
    tracks_osc.video, tracks_osc.audio, tracks_osc.sub = {}, {}, {}
    -- by mpv_id
    tracks_mpv = {}
    tracks_mpv.video, tracks_mpv.audio, tracks_mpv.sub = {}, {}, {}
    for n = 1, #tracktable do
        if not (tracktable[n].type == "unknown") then
            local type = tracktable[n].type
            local mpv_id = tonumber(tracktable[n].id)

            -- by osc_id
            table.insert(tracks_osc[type], tracktable[n])

            -- by mpv_id
            tracks_mpv[type][mpv_id] = tracktable[n]
            tracks_mpv[type][mpv_id].osc_id = #tracks_osc[type]
        end
    end
end

-- return a nice list of tracks of the given type (video, audio, sub)
function get_tracklist(type)
    local msg = "Available " .. nicetypes[type] .. " Tracks: "
    if #tracks_osc[type] == 0 then
        msg = msg .. "none"
    else
        for n = 1, #tracks_osc[type] do
            local track = tracks_osc[type][n]
            local lang, title, selected = "unknown", "", "○"
            if not(track.lang == nil) then lang = track.lang end
            if not(track.title == nil) then title = track.title end
            if (track.id == tonumber(mp.get_property(type))) then
                selected = "●"
            end
            msg = msg.."\n"..selected.." "..n..": ["..lang.."] "..title
        end
    end
    return msg
end

-- relatively change the track of given <type> by <next> tracks
    --(+1 -> next, -1 -> previous)
function set_track(type, next)
    local current_track_mpv, current_track_osc
    if (mp.get_property(type) == "no") then
        current_track_osc = 0
    else
        current_track_mpv = tonumber(mp.get_property(type))
        current_track_osc = tracks_mpv[type][current_track_mpv].osc_id
    end
    local new_track_osc = (current_track_osc + next) % (#tracks_osc[type] + 1)
    local new_track_mpv
    if new_track_osc == 0 then
        new_track_mpv = "no"
    else
        new_track_mpv = tracks_osc[type][new_track_osc].id
    end

    mp.commandv("set", type, new_track_mpv)

        if (new_track_osc == 0) then
        show_message(nicetypes[type] .. " Track: none")
    else
        show_message(nicetypes[type]  .. " Track: "
            .. new_track_osc .. "/" .. #tracks_osc[type]
            .. " [".. (tracks_osc[type][new_track_osc].lang or "unknown") .."] "
            .. (tracks_osc[type][new_track_osc].title or ""))
    end
end

-- get the currently selected track of <type>, OSC-style counted
function get_track(type)
    local track = mp.get_property(type)
    if track ~= "no" and track ~= nil then
        local tr = tracks_mpv[type][tonumber(track)]
        if tr then
            return tr.osc_id
        end
    end
    return 0
end

--
-- Element Management
--

local elements = {}

function prepare_elements()

    -- remove elements without layout or invisble
    local elements2 = {}
    for n, element in pairs(elements) do
        if not (element.layout == nil) and (element.visible) then
            table.insert(elements2, element)
        end
    end
    elements = elements2

    function elem_compare (a, b)
        return a.layout.layer < b.layout.layer
    end

    table.sort(elements, elem_compare)


    for _,element in pairs(elements) do

        local elem_geo = element.layout.geometry

        -- Calculate the hitbox
        local bX1, bY1, bX2, bY2 = get_hitbox_coords_geo(elem_geo)
        element.hitbox = {x1 = bX1, y1 = bY1, x2 = bX2, y2 = bY2}

        local style_ass = assdraw.ass_new()

        -- prepare static elements
        style_ass:append("{}") -- hack to troll new_event into inserting a \n
        style_ass:new_event()
        style_ass:pos(elem_geo.x, elem_geo.y)
        style_ass:an(elem_geo.an)
        style_ass:append(element.layout.style)

        element.style_ass = style_ass

        local static_ass = assdraw.ass_new()


        if (element.type == "box") then
            --draw box
            static_ass:draw_start()
            ass_draw_rr_h_cw(static_ass, 0, 0, elem_geo.w, elem_geo.h,
                             element.layout.box.radius, element.layout.box.hexagon)
            static_ass:draw_stop()

        elseif (element.type == "slider") then
            --draw static slider parts

            local r1 = 0
            local r2 = 0
            local slider_lo = element.layout.slider
            -- offset between element outline and drag-area
            local foV = slider_lo.border + slider_lo.gap

            -- calculate positions of min and max points
            if (slider_lo.stype ~= "bar") then
                r1 = elem_geo.h / 2
                element.slider.min.ele_pos = elem_geo.h / 2
                element.slider.max.ele_pos = elem_geo.w - (elem_geo.h / 2)
                if (slider_lo.stype == "diamond") then
                    r2 = (elem_geo.h - 2 * slider_lo.border) / 2
                elseif (slider_lo.stype == "knob") then
                    r2 = r1
                end
            else
                element.slider.min.ele_pos =
                    slider_lo.border + slider_lo.gap
                element.slider.max.ele_pos =
                    elem_geo.w - (slider_lo.border + slider_lo.gap)
            end

            element.slider.min.glob_pos =
                element.hitbox.x1 + element.slider.min.ele_pos
            element.slider.max.glob_pos =
                element.hitbox.x1 + element.slider.max.ele_pos

            -- -- --

            static_ass:draw_start()

            -- the box
            ass_draw_rr_h_cw(static_ass, 0, 0, elem_geo.w, elem_geo.h, r1, slider_lo.stype == "diamond")

            -- the "hole"
            ass_draw_rr_h_ccw(static_ass, slider_lo.border, slider_lo.border,
                              elem_geo.w - slider_lo.border, elem_geo.h - slider_lo.border,
                              r2, slider_lo.stype == "diamond")

            -- marker nibbles
            if not (element.slider.markerF == nil) and (slider_lo.gap > 0) then
                local markers = element.slider.markerF()
                for _,marker in pairs(markers) do
                    if (marker > element.slider.min.value) and
                        (marker < element.slider.max.value) then

                        local s = get_slider_ele_pos_for(element, marker)

                        if (slider_lo.gap > 1) then -- draw triangles

                            local a = slider_lo.gap / 0.5 --0.866

                            --top
                            if (slider_lo.nibbles_top) then
                                static_ass:move_to(s - (a/2), slider_lo.border)
                                static_ass:line_to(s + (a/2), slider_lo.border)
                                static_ass:line_to(s, foV)
                            end

                            --bottom
                            if (slider_lo.nibbles_bottom) then
                                static_ass:move_to(s - (a/2),
                                    elem_geo.h - slider_lo.border)
                                static_ass:line_to(s,
                                    elem_geo.h - foV)
                                static_ass:line_to(s + (a/2),
                                    elem_geo.h - slider_lo.border)
                            end

                        else -- draw 2x1px nibbles

                            --top
                            if (slider_lo.nibbles_top) then
                                static_ass:rect_cw(s - 1, slider_lo.border,
                                    s + 1, slider_lo.border + slider_lo.gap);
                            end

                            --bottom
                            if (slider_lo.nibbles_bottom) then
                                static_ass:rect_cw(s - 1,
                                    elem_geo.h -slider_lo.border -slider_lo.gap,
                                    s + 1, elem_geo.h - slider_lo.border);
                            end
                        end
                    end
                end
            end
        end

        element.static_ass = static_ass


        -- if the element is supposed to be disabled,
        -- style it accordingly and kill the eventresponders
        if not (element.enabled) then
            element.layout.alpha[1] = 136
            element.eventresponder = nil
        end
    end
end


--
-- Element Rendering
--

function render_elements(master_ass)

    for n=1, #elements do
        local element = elements[n]

        local style_ass = assdraw.ass_new()
        style_ass:merge(element.style_ass)
        ass_append_alpha(style_ass, element.layout.alpha, 0)

        if element.eventresponder and (state.active_element == n) then

            -- run render event functions
            if not (element.eventresponder.render == nil) then
                element.eventresponder.render(element)
            end

            if mouse_hit(element) then
                -- mouse down styling
                if (element.styledown) then
                    style_ass:append(osc_styles.elementDown)
                end

                if (element.softrepeat) and (state.mouse_down_counter >= 15
                    and state.mouse_down_counter % 5 == 0) then

                    element.eventresponder[state.active_event_source.."_down"](element)
                end
                state.mouse_down_counter = state.mouse_down_counter + 1
            end

        end

        local elem_ass = assdraw.ass_new()

        elem_ass:merge(style_ass)

        if not (element.type == "button") then
            elem_ass:merge(element.static_ass)
        end

        if (element.type == "slider") then

            local slider_lo = element.layout.slider
            local elem_geo = element.layout.geometry
            local s_min = element.slider.min.value
            local s_max = element.slider.max.value

            -- draw pos marker
            local foH, xp
            local pos = element.slider.posF()
            local foV = slider_lo.border + slider_lo.gap
            local innerH = elem_geo.h - (2 * foV)

            if slider_lo.stype ~= "bar" then
                foH = elem_geo.h / 2
            else
                foH = slider_lo.border + slider_lo.gap
            end

            if pos then
                xp = get_slider_ele_pos_for(element, pos)

                if slider_lo.stype ~= "bar" then
                    local r = (user_opts.seekbarhandlesize * innerH) / 2
                    ass_draw_rr_h_cw(elem_ass, xp - r, foH - r,
                                     xp + r, foH + r,
                                     r, slider_lo.stype == "diamond")
                else
                    local h = 0
                    elem_ass:rect_cw(foH, foV, xp, elem_geo.h - foV - h)
                end

                if slider_lo.rtype == "slider" then
                    ass_draw_rr_h_cw(elem_ass, foH - innerH / 6, foH - innerH / 6,
                                     xp, foH + innerH / 6,
                                     innerH / 6, slider_lo.stype == "diamond", 0)
                    ass_draw_rr_h_cw(elem_ass, xp, foH - innerH / 15,
                                     elem_geo.w - foH + innerH / 15, foH + innerH / 15,
                                     0, slider_lo.stype == "diamond", innerH / 15)
                end
            end

            elem_ass:draw_stop()

            -- add tooltip
            if not (element.slider.tooltipF == nil) then

                if mouse_hit(element) then
                    local sliderpos = get_slider_value(element)
                    local tooltiplabel = element.slider.tooltipF(sliderpos)

                    local an = slider_lo.tooltip_an

                    local ty

                    if (an == 2) then
                        ty = element.hitbox.y1 - slider_lo.border
                    else
                        ty = element.hitbox.y1 + elem_geo.h/2
                    end

                    local tx = get_virt_mouse_pos()
                    if (slider_lo.adjust_tooltip) then
                        if (an == 2) then
                            if (sliderpos < (s_min + 3)) then
                                an = an - 1
                            elseif (sliderpos > (s_max - 3)) then
                                an = an + 1
                            end
                        elseif (sliderpos > (s_max-s_min)/2) then
                            an = an + 1
                            tx = tx - 5
                        else
                            an = an - 1
                            tx = tx + 10
                        end
                    end

                    -- tooltip label
                    elem_ass:new_event()
                    elem_ass:pos(tx, ty)
                    elem_ass:an(an)
                    elem_ass:append(slider_lo.tooltip_style)
                    ass_append_alpha(elem_ass, slider_lo.alpha, 0)
                    elem_ass:append(tooltiplabel)

                end
            end

        elseif (element.type == "button") then

            local buttontext
            if type(element.content) == "function" then
                buttontext = element.content() -- function objects
            elseif not (element.content == nil) then
                buttontext = element.content -- text objects
            end

            local maxchars = element.layout.button.maxchars
            if not (maxchars == nil) and (#buttontext > maxchars) then
                local max_ratio = 1.25  -- up to 25% more chars while shrinking
                local limit = math.max(0, math.floor(maxchars * max_ratio) - 3)
                if (#buttontext > limit) then
                    while (#buttontext > limit) do
                        buttontext = buttontext:gsub(".[\128-\191]*$", "")
                    end
                    buttontext = buttontext .. "..."
                end
                local _, nchars2 = buttontext:gsub(".[\128-\191]*", "")
                local stretch = (maxchars/#buttontext)*100
                buttontext = string.format("{\\fscx%f}",
                    (maxchars/#buttontext)*100) .. buttontext
            end

            elem_ass:append(buttontext)
        end

        master_ass:merge(elem_ass)
    end
end

--
-- Message display
--

-- pos is 1 based
function limited_list(prop, pos)
    local proplist = mp.get_property_native(prop, {})
    local count = #proplist
    if count == 0 then
        return count, proplist
    end

    local fs = tonumber(mp.get_property('options/osd-font-size'))
    local max = math.ceil(osc_param.unscaled_y*0.75 / fs)
    if max % 2 == 0 then
        max = max - 1
    end
    local delta = math.ceil(max / 2) - 1
    local begi = math.max(math.min(pos - delta, count - max + 1), 1)
    local endi = math.min(begi + max - 1, count)

    local reslist = {}
    for i=begi, endi do
        local item = proplist[i]
        item.current = (i == pos) and true or nil
        table.insert(reslist, item)
    end
    return count, reslist
end

function show_message(text, duration)

    --print("text: "..text.."   duration: " .. duration)
    if duration == nil then
        duration = tonumber(mp.get_property("options/osd-duration")) / 1000
    elseif not type(duration) == "number" then
        print("duration: " .. duration)
    end

    -- cut the text short, otherwise the following functions
    -- may slow down massively on huge input
    text = string.sub(text, 0, 4000)

    -- replace actual linebreaks with ASS linebreaks
    text = string.gsub(text, "\n", "\\N")

    state.message_text = text

    if not state.message_hide_timer then
        state.message_hide_timer = mp.add_timeout(0, request_tick)
    end
    state.message_hide_timer:kill()
    state.message_hide_timer.timeout = duration
    state.message_hide_timer:resume()
    request_tick()
end

function render_message(ass)
    if state.message_hide_timer and state.message_hide_timer:is_enabled() and
       state.message_text
    then
        local _, lines = string.gsub(state.message_text, "\\N", "")

        local fontsize = tonumber(mp.get_property("options/osd-font-size"))
        local outline = tonumber(mp.get_property("options/osd-border-size"))
        local maxlines = math.ceil(osc_param.unscaled_y*0.75 / fontsize)
        local counterscale = osc_param.playresy / osc_param.unscaled_y

        fontsize = fontsize * counterscale / math.max(0.65 + math.min(lines/maxlines, 1), 1)
        outline = outline * counterscale / math.max(0.75 + math.min(lines/maxlines, 1)/2, 1)

        local style = "{\\bord" .. outline .. "\\fs" .. fontsize .. "}"


        ass:new_event()
        ass:append(style .. state.message_text)
    else
        state.message_text = nil
    end
end

--
-- Initialisation and Layout
--

function new_element(name, type)
    elements[name] = {}
    elements[name].type = type

    -- add default stuff
    elements[name].eventresponder = {}
    elements[name].visible = true
    elements[name].enabled = true
    elements[name].softrepeat = false
    elements[name].styledown = (type == "button")
    elements[name].state = {}

    if (type == "slider") then
        elements[name].slider = {min = {value = 0}, max = {value = 100}}
    end


    return elements[name]
end

function add_layout(name)
    if not (elements[name] == nil) then
        -- new layout
        elements[name].layout = {}

        -- set layout defaults
        elements[name].layout.layer = 50
        elements[name].layout.alpha = {[1] = 0, [2] = 255, [3] = 255, [4] = 255}

        if (elements[name].type == "button") then
            elements[name].layout.button = {
                maxchars = nil,
            }
        elseif (elements[name].type == "slider") then
            -- slider defaults
            elements[name].layout.slider = {
                border = 1,
                gap = 1,
                nibbles_top = true,
                nibbles_bottom = true,
                stype = "slider",
                adjust_tooltip = true,
                tooltip_style = "",
                tooltip_an = 2,
                alpha = {[1] = 0, [2] = 255, [3] = 88, [4] = 255},
            }
        elseif (elements[name].type == "box") then
            elements[name].layout.box = {radius = 0, hexagon = false}
        end

        return elements[name].layout
    else
        msg.error("Can't add_layout to element \""..name.."\", doesn't exist.")
    end
end

--
-- Layouts
--

local layouts = {}

-- Classic box layout
layouts["box"] = function ()

    local osc_geo = {
        w = 550,    -- width
        h = 138,    -- height
        r = 10,     -- corner-radius
        p = 15,     -- padding
    }

    -- make sure the OSC actually fits into the video
    if (osc_param.playresx < (osc_geo.w + (2 * osc_geo.p))) then
        osc_param.playresy = (osc_geo.w+(2*osc_geo.p))/osc_param.display_aspect
        osc_param.playresx = osc_param.playresy * osc_param.display_aspect
    end

    -- position of the controller according to video aspect and valignment
    local posX = math.floor(get_align(user_opts.halign, osc_param.playresx,
        osc_geo.w, 0))
    local posY = math.floor(get_align(user_opts.valign, osc_param.playresy,
        osc_geo.h, 0))

    -- position offset for contents aligned at the borders of the box
    local pos_offsetX = (osc_geo.w - (2*osc_geo.p)) / 2
    local pos_offsetY = (osc_geo.h - (2*osc_geo.p)) / 2

    osc_param.areas = {} -- delete areas

    -- area for active mouse input
    add_area("input", get_hitbox_coords(posX, posY, 5, osc_geo.w, osc_geo.h))

    -- area for show/hide
    local sh_area_y0, sh_area_y1
    if user_opts.valign > 0 then
        -- deadzone above OSC
        sh_area_y0 = get_align(-1 + (2*user_opts.deadzonesize),
            posY - (osc_geo.h / 2), 0, 0)
        sh_area_y1 = osc_param.playresy
    else
        -- deadzone below OSC
        sh_area_y0 = 0
        sh_area_y1 = (posY + (osc_geo.h / 2)) +
            get_align(1 - (2*user_opts.deadzonesize),
            osc_param.playresy - (posY + (osc_geo.h / 2)), 0, 0)
    end
    add_area("showhide", 0, sh_area_y0, osc_param.playresx, sh_area_y1)

    -- fetch values
    local osc_w, osc_h, osc_r, osc_p =
        osc_geo.w, osc_geo.h, osc_geo.r, osc_geo.p

    local lo

    --
    -- Background box
    --

    new_element("bgbox", "box")
    lo = add_layout("bgbox")

    lo.geometry = {x = posX, y = posY, an = 5, w = osc_w, h = osc_h}
    lo.layer = 10
    lo.style = osc_styles.box
    lo.alpha[1] = user_opts.boxalpha
    lo.alpha[3] = user_opts.boxalpha
    lo.box.radius = osc_r

    --
    -- Title row
    --

    local titlerowY = posY - pos_offsetY - 10

    lo = add_layout("title")
    lo.geometry = {x = posX, y = titlerowY, an = 8, w = 496, h = 12}
    lo.style = osc_styles.vidtitle
    lo.button.maxchars = user_opts.boxmaxchars


    --
    -- Big buttons
    --

    local bigbtnrowY = posY - pos_offsetY + 35
    local bigbtndist = 60

    lo = add_layout("playpause")
    lo.geometry =
        {x = posX, y = bigbtnrowY, an = 5, w = 40, h = 40}
    lo.style = osc_styles.bigButtons

    lo = add_layout("ch_prev")
    lo.geometry =
        {x = posX - (bigbtndist * 2), y = bigbtnrowY, an = 5, w = 40, h = 40}
    lo.style = osc_styles.bigButtons

    lo = add_layout("ch_next")
    lo.geometry =
        {x = posX + (bigbtndist * 2), y = bigbtnrowY, an = 5, w = 40, h = 40}
    lo.style = osc_styles.bigButtons

    lo = add_layout("cy_sub")
    lo.geometry =
        {x = posX - pos_offsetX, y = bigbtnrowY, an = 7, w = 70, h = 18}
    lo.style = osc_styles.smallButtonsL

    lo = add_layout("tog_fs")
    lo.geometry =
        {x = posX+pos_offsetX - 25, y = bigbtnrowY, an = 4, w = 25, h = 25}
    lo.style = osc_styles.smallButtonsR

    lo = add_layout("volume")
    lo.geometry =
        {x = posX+pos_offsetX - (25 * 2) - osc_geo.p,
         y = bigbtnrowY, an = 4, w = 25, h = 25}
    lo.style = osc_styles.smallButtonsR

    --
    -- Seekbar
    --

    lo = add_layout("seekbar")
    lo.geometry =
        {x = posX, y = posY+pos_offsetY-22, an = 2, w = pos_offsetX*2, h = 15}
    lo.style = osc_styles.timecodes
    lo.slider.tooltip_style = osc_styles.vidtitle
    lo.slider.stype = user_opts["seekbarstyle"]

    --
    -- Timecodes + Cache
    --

    local bottomrowY = posY + pos_offsetY - 5

    lo = add_layout("tc_left")
    lo.geometry =
        {x = posX - pos_offsetX, y = bottomrowY, an = 4, w = 110, h = 18}
    lo.style = osc_styles.timecodes

    lo = add_layout("tc_right")
    lo.geometry =
        {x = posX + pos_offsetX, y = bottomrowY, an = 6, w = 110, h = 18}
    lo.style = osc_styles.timecodes

    lo = add_layout("cache")
    lo.geometry =
        {x = posX, y = bottomrowY, an = 5, w = 110, h = 18}
    lo.style = osc_styles.timecodes

end

-- slim box layout
layouts["slimbox"] = function ()

    local osc_geo = {
        w = 660,    -- width
        h = 70,     -- height
        r = 10,     -- corner-radius
    }

    -- make sure the OSC actually fits into the video
    if (osc_param.playresx < (osc_geo.w)) then
        osc_param.playresy = (osc_geo.w)/osc_param.display_aspect
        osc_param.playresx = osc_param.playresy * osc_param.display_aspect
    end

    -- position of the controller according to video aspect and valignment
    local posX = math.floor(get_align(user_opts.halign, osc_param.playresx,
        osc_geo.w, 0))
    local posY = math.floor(get_align(user_opts.valign, osc_param.playresy,
        osc_geo.h, 0))

    osc_param.areas = {} -- delete areas

    -- area for active mouse input
    add_area("input", get_hitbox_coords(posX, posY, 5, osc_geo.w, osc_geo.h))

    -- area for show/hide
    local sh_area_y0, sh_area_y1
    if user_opts.valign > 0 then
        -- deadzone above OSC
        sh_area_y0 = get_align(-1 + (2*user_opts.deadzonesize),
            posY - (osc_geo.h / 2), 0, 0)
        sh_area_y1 = osc_param.playresy
    else
        -- deadzone below OSC
        sh_area_y0 = 0
        sh_area_y1 = (posY + (osc_geo.h / 2)) +
            get_align(1 - (2*user_opts.deadzonesize),
            osc_param.playresy - (posY + (osc_geo.h / 2)), 0, 0)
    end
    add_area("showhide", 0, sh_area_y0, osc_param.playresx, sh_area_y1)

    local lo

    local tc_w, ele_h, inner_w = 100, 20, osc_geo.w - 100

    -- styles
    local styles = {
        box = "{\\rDefault\\blur0\\bord1\\1c&H000000\\3c&HFFFFFF}",
        timecodes = "{\\1c&HFFFFFF\\3c&H000000\\fs20\\bord2\\blur1}",
        tooltip = "{\\1c&HFFFFFF\\3c&H000000\\fs12\\bord1\\blur0.5}",
    }


    new_element("bgbox", "box")
    lo = add_layout("bgbox")

    lo.geometry = {x = posX, y = posY - 1, an = 2, w = inner_w, h = ele_h}
    lo.layer = 10
    lo.style = osc_styles.box
    lo.alpha[1] = user_opts.boxalpha
    lo.alpha[3] = 0
    if not (user_opts["seekbarstyle"] == "bar") then
        lo.box.radius = osc_geo.r
        lo.box.hexagon = user_opts["seekbarstyle"] == "diamond"
    end


    lo = add_layout("seekbar")
    lo.geometry =
        {x = posX, y = posY - 1, an = 2, w = inner_w, h = ele_h}
    lo.style = osc_styles.timecodes
    lo.slider.border = 0
    lo.slider.gap = 1.5
    lo.slider.tooltip_style = styles.tooltip
    lo.slider.stype = user_opts["seekbarstyle"]
    lo.slider.adjust_tooltip = false

    --
    -- Timecodes
    --

    lo = add_layout("tc_left")
    lo.geometry =
        {x = posX - (inner_w/2) + osc_geo.r, y = posY + 1,
        an = 7, w = tc_w, h = ele_h}
    lo.style = styles.timecodes
    lo.alpha[3] = user_opts.boxalpha

    lo = add_layout("tc_right")
    lo.geometry =
        {x = posX + (inner_w/2) - osc_geo.r, y = posY + 1,
        an = 9, w = tc_w, h = ele_h}
    lo.style = styles.timecodes
    lo.alpha[3] = user_opts.boxalpha

    -- Cache

    lo = add_layout("cache")
    lo.geometry =
        {x = posX, y = posY + 1,
        an = 8, w = tc_w, h = ele_h}
    lo.style = styles.timecodes
    lo.alpha[3] = user_opts.boxalpha


end

function bar_layout(direction)
    local osc_geo = {
        x = -2,
        y,
        an = (direction < 0) and 7 or 1,
        w,
        h = 56,
    }

    local padX = 9
    local padY = 3
    local buttonW = 27
    local tcW = (state.tc_ms) and 170 or 110
    local tsW = 90
    local minW = (buttonW + padX)*5 + (tcW + padX)*4 + (tsW + padX)*2

    -- Special topbar handling when window controls are present
    local padwc_l = 0
    local padwc_r = 0

    if ((osc_param.display_aspect > 0) and (osc_param.playresx < minW)) then
        osc_param.playresy = minW / osc_param.display_aspect
        osc_param.playresx = osc_param.playresy * osc_param.display_aspect
    end

    osc_geo.y = direction * (54 + user_opts.barmargin)
    osc_geo.w = osc_param.playresx + 4
    if direction < 0 then
        osc_geo.y = osc_geo.y + osc_param.playresy
    end

    local line1 = osc_geo.y - direction * (9 + padY)
    local line2 = osc_geo.y - direction * (36 + padY)

    osc_param.areas = {}

    add_area("input", get_hitbox_coords(osc_geo.x, osc_geo.y, osc_geo.an,
                                        osc_geo.w, osc_geo.h))

    local sh_area_y0, sh_area_y1
    if direction > 0 then
        -- deadzone below OSC
        sh_area_y0 = user_opts.barmargin
        sh_area_y1 = (osc_geo.y + (osc_geo.h / 2)) +
                     get_align(1 - (2*user_opts.deadzonesize),
                     osc_param.playresy - (osc_geo.y + (osc_geo.h / 2)), 0, 0)
    else
        -- deadzone above OSC
        sh_area_y0 = get_align(-1 + (2*user_opts.deadzonesize),
                               osc_geo.y - (osc_geo.h / 2), 0, 0)
        sh_area_y1 = osc_param.playresy - user_opts.barmargin
    end
    add_area("showhide", 0, sh_area_y0, osc_param.playresx, sh_area_y1)

    local lo, geo

    -- Background bar
    new_element("bgbox", "box")
    lo = add_layout("bgbox")

    lo.geometry = osc_geo
    lo.layer = 10
    lo.style = osc_styles.box
    lo.alpha[1] = user_opts.boxalpha


    geo = { x = osc_geo.x, y = line1, an = 0, w = 0, h = 18 - padY }
    local t_l = geo.x + geo.w + padX

    -- Cache
    geo = { x = osc_geo.x + osc_geo.w - padX, y = geo.y,
            an = 6, w = 150, h = geo.h }
    lo = add_layout("cache")
    lo.geometry = geo
    lo.style = osc_styles.vidtitleBar

    local t_r = geo.x - geo.w - padX*2

    -- Title
    geo = { x = t_l, y = geo.y, an = 4,
            w = t_r - t_l, h = geo.h }
    lo = add_layout("title")
    lo.geometry = geo
    lo.style = string.format("%s{\\clip(%f,%f,%f,%f)}",
        osc_styles.vidtitleBar,
        geo.x, geo.y-geo.h, geo.w, geo.y+geo.h)


    -- Playback control buttons
    geo = { x = osc_geo.x + padX + padwc_l, y = line2, an = 4,
            w = buttonW, h = 36 - padY*2}
    lo = add_layout("playpause")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    geo = { x = geo.x + geo.w + padX, y = geo.y, an = geo.an, w = geo.w, h = geo.h }
    lo = add_layout("ch_prev")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    geo = { x = geo.x + geo.w + padX, y = geo.y, an = geo.an, w = geo.w, h = geo.h }
    lo = add_layout("ch_next")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    -- Left timecode
    geo = { x = geo.x + geo.w + padX + tcW, y = geo.y, an = 6,
            w = tcW, h = geo.h }
    lo = add_layout("tc_left")
    lo.geometry = geo
    lo.style = osc_styles.timecodesBar

    local sb_l = geo.x + padX

    -- Fullscreen button
    geo = { x = osc_geo.x + osc_geo.w - buttonW - padX - padwc_r, y = geo.y, an = 4,
            w = buttonW, h = geo.h }
    lo = add_layout("tog_fs")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    -- Volume
    geo = { x = geo.x - geo.w - padX, y = geo.y, an = geo.an, w = geo.w, h = geo.h }
    lo = add_layout("volume")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    -- Track selection buttons
    geo = { x = geo.x - tsW - padX, y = geo.y, an = geo.an, w = tsW, h = geo.h }
    lo = add_layout("cy_sub")
    lo.geometry = geo
    lo.style = osc_styles.smallButtonsBar

    -- Right timecode
    geo = { x = geo.x - padX - tcW - 10, y = geo.y, an = geo.an,
            w = tcW, h = geo.h }
    lo = add_layout("tc_right")
    lo.geometry = geo
    lo.style = osc_styles.timecodesBar

    local sb_r = geo.x - padX


    -- Seekbar
    geo = { x = sb_l, y = geo.y, an = geo.an,
            w = math.max(0, sb_r - sb_l), h = geo.h }
    new_element("bgbar1", "box")
    lo = add_layout("bgbar1")

    lo.geometry = geo
    lo.layer = 15
    lo.style = osc_styles.timecodesBar
    lo.alpha[1] =
        math.min(255, user_opts.boxalpha + (255 - user_opts.boxalpha)*0.8)
    if not (user_opts["seekbarstyle"] == "bar") then
        lo.box.radius = geo.h / 2
        lo.box.hexagon = user_opts["seekbarstyle"] == "diamond"
    end

    lo = add_layout("seekbar")
    lo.geometry = geo
    lo.style = osc_styles.timecodesBar
    lo.slider.border = 0
    lo.slider.gap = 2
    lo.slider.tooltip_style = osc_styles.timePosBar
    lo.slider.tooltip_an = 5
    lo.slider.stype = user_opts["seekbarstyle"]

    if direction < 0 then
        osc_param.video_margins.b = osc_geo.h / osc_param.playresy
    else
        osc_param.video_margins.t = osc_geo.h / osc_param.playresy
    end
end

layouts["bottombar"] = function()
    bar_layout(-1)
end

layouts["topbar"] = function()
    bar_layout(1)
end

-- Validate string type user options
function validate_user_opts()
    if layouts[user_opts.layout] == nil then
        msg.warn("Invalid setting \""..user_opts.layout.."\" for layout")
        user_opts.layout = "bottombar"
    end

    if user_opts.seekbarstyle ~= "bar" and
       user_opts.seekbarstyle ~= "diamond" and
       user_opts.seekbarstyle ~= "knob" then
        msg.warn("Invalid setting \"" .. user_opts.seekbarstyle
            .. "\" for seekbarstyle")
        user_opts.seekbarstyle = "bar"
    end

end

function update_options(list)
    validate_user_opts()
    request_tick()
    visibility_mode(user_opts.visibility, true)
    request_init()
end

function get_chapter_duration()
    if ((state.start == nil) or (state.finish == nil)) then
        return nil
    else
      return state.finish - state.start
    end
end

-- OSC INIT
function osc_init()
    msg.debug("osc_init")

    -- set canvas resolution according to display aspect and scaling setting
    local baseResY = 720
    local display_w, display_h, display_aspect = mp.get_osd_size()
    local scale = 1

    if (mp.get_property("video") == "no") then -- dummy/forced window
        scale = user_opts.scaleforcedwindow
    elseif state.fullscreen then
        scale = user_opts.scalefullscreen
    else
        scale = user_opts.scalewindowed
    end

    if user_opts.vidscale then
        osc_param.unscaled_y = baseResY
    else
        osc_param.unscaled_y = display_h
    end
    osc_param.playresy = osc_param.unscaled_y / scale
    if (display_aspect > 0) then
        osc_param.display_aspect = display_aspect
    end
    osc_param.playresx = osc_param.playresy * osc_param.display_aspect

    -- stop seeking with the slider to prevent skipping files
    state.active_element = nil

    osc_param.video_margins = {l = 0, r = 0, t = 0, b = 0}

    elements = {}

    local ne

    -- title
    ne = new_element("title", "button")

    ne.content = function ()
        local title = state.title
        if (state.title == nil) then title = "" end
        -- escape ASS, and strip newlines and trailing slashes
        title = title:gsub("\\n", " "):gsub("\\$", ""):gsub("{","\\{")
        return not (title == "") and title or "foobar2000"
    end

    -- big buttons

    --playpause
    ne = new_element("playpause", "button")

    ne.content = function ()
        if mp.get_property("pause") == "yes" then
            return ("\238\132\129")
        else
            return ("\238\128\130")
        end
    end
    ne.eventresponder["mbtn_left_up"] =
        function () mp.commandv("script-message", "foobar", "menu", "/Playback/Play or pause") end

    --ch_prev
    ne = new_element("ch_prev", "button")

    ne.enabled = true
    ne.content = "\238\132\132"
    ne.eventresponder["mbtn_left_up"] =
        function ()
            mp.commandv("script-message", "foobar", "menu", "/Playback/Previous")
        end

    --ch_next
    ne = new_element("ch_next", "button")

    ne.enabled = true
    ne.content = "\238\132\133"
    ne.eventresponder["mbtn_left_up"] =
        function ()
            mp.commandv("script-message", "foobar", "menu", "/Playback/Next")
        end

    --
    update_tracklist()

    --cy_sub
    ne = new_element("cy_sub", "button")

    ne.enabled = (#tracks_osc.sub > 0)
    ne.content = function ()
        local sid = "–"
        if not (get_track("sub") == 0) then
            sid = get_track("sub")
        end
        return ("\238\132\135" .. osc_styles.smallButtonsLlabel
            .. " " .. sid .. "/" .. #tracks_osc.sub)
    end
    ne.eventresponder["mbtn_left_up"] =
        function () set_track("sub", 1) end

    --tog_fs
    ne = new_element("tog_fs", "button")
    ne.content = function ()
        if (state.fullscreen) then
           return ("\238\132\137")
        else
           return ("\238\132\136")
        end
    end
    ne.eventresponder["mbtn_left_up"] =
        function () mp.commandv("script-message", "foobar", "menu", "/View/mpv Commands/Toggle fullscreen") end

    --seekbar
    ne = new_element("seekbar", "slider")

    ne.enabled = not (mp.get_property("percent-pos") == nil or mp.get_property("time-pos") == nil)
    ne.slider.posF =
        function ()
        local timepos = mp.get_property_number("time-pos", nil)
        if not ((state.start == nil) or (state.finish == nil) or (timepos == nil)) then
            return 100 * (timepos - state.start) / (state.finish - state.start)
        end
        return nil
        end
    ne.slider.tooltipF = function (pos)
        if not ((state.start == nil) or (state.finish == nil) or (pos == nil)) then
            possec = ((state.finish - state.start) * (pos / 100))
            return mp.format_time(possec)
        else
            return ""
        end
    end
    ne.eventresponder["mouse_move"] = --seeking when mouse is dragged
        function (element)
            -- mouse move events may pile up during seeking and may still get
            -- sent when the user is done seeking, so we need to throw away
            -- identical seeks
            local seekto = get_slider_value(element)
            if (element.state.lastseek == nil) or
                (not (element.state.lastseek == seekto)) then
                    mp.commandv("script-message", "foobar", "seek", (state.finish - state.start) * 0.01 * seekto)
                    element.state.lastseek = seekto
            end
        end
    ne.eventresponder["mbtn_left_down"] = --exact seeks on single clicks
        function (element)
            if not ((state.start == nil) or (state.finish == nil)) then
                mp.commandv("script-message", "foobar", "seek", (state.finish - state.start) * 0.01 * get_slider_value(element))
            end
        end
    ne.eventresponder["reset"] =
        function (element) element.state.lastseek = nil end


    -- tc_left (current pos)
    ne = new_element("tc_left", "button")

    ne.content = function ()
        local ptime = mp.get_property("playback-time")
        if (not (ptime == nil or state.start == nil)) then
            ptime = ptime - state.start
        else
            ptime = 0
        end
        if state.tc_ms then
            return mp.format_time(ptime) .. "." .. string.format("%03d", (ptime * 1000) % 1000)
        else
            return mp.format_time(ptime)
        end
    end
    ne.eventresponder["mbtn_left_down"] = function ()
        state.tc_ms = not state.tc_ms
        request_init()
    end

    -- tc_right (total/remaining time)
    ne = new_element("tc_right", "button")

    ne.visible = (not (state.finish == nil or state.start == nil))
    ne.content = function ()
        local ptime = mp.get_property("playback-time")
        if (ptime == nil) then
            return ""
        end

        if (state.rightTC_trem) then
            if state.tc_ms then
                return "-" .. mp.format_time(state.finish - ptime) .. "." .. string.format("%03d", ((state.finish - ptime) * 1000) % 1000)
            else
                return "-" .. mp.format_time(state.finish - ptime)
            end
        else
            if state.tc_ms then
                return mp.format_time(state.finish - state.start) .. "." .. string.format("%03d", ((state.finish - state.start) * 1000) % 1000)
            else
                return mp.format_time(state.finish - state.start)
            end
        end
    end
    ne.eventresponder["mbtn_left_down"] =
        function () state.rightTC_trem = not state.rightTC_trem end

    -- cache
    ne = new_element("cache", "button")

    ne.content = function ()
        local cache_state = state.cache_state
        if not (cache_state and cache_state["seekable-ranges"] and
            #cache_state["seekable-ranges"] > 0) then
            -- probably not a network stream
            return ""
        end
        local dmx_cache = cache_state and cache_state["cache-duration"]
        local thresh = math.min(state.dmx_cache * 0.05, 5)  -- 5% or 5s
        if dmx_cache and math.abs(dmx_cache - state.dmx_cache) >= thresh then
            state.dmx_cache = dmx_cache
        else
            dmx_cache = state.dmx_cache
        end
        local min = math.floor(dmx_cache / 60)
        local sec = dmx_cache % 60
        return "Cache: " .. (min > 0 and
            string.format("%sm%02.0fs", min, sec) or
            string.format("%3.0fs", dmx_cache))
    end

    -- volume
    ne = new_element("volume", "button")

    ne.content = function()
        local volicon = {"\238\132\139", "\238\132\140",
                         "\238\132\141"}
        if state.volume == 0 then
            return "\238\132\138"
        else
            return volicon[math.min(3,math.ceil(state.volume * 3))]
        end
    end
    ne.eventresponder["wheel_up_press"] =
        function ()
            mp.commandv("script-message", "foobar", "menu", "/Playback/Volume/Up")
        end
    ne.eventresponder["wheel_down_press"] =
        function ()
            mp.commandv("script-message", "foobar", "menu", "/Playback/Volume/Down")
        end

    -- load layout
    layouts[user_opts.layout]()

    --do something with the elements
    prepare_elements()

    update_margins()
end

function reset_margins()
    if state.using_video_margins then
        for _, opt in ipairs(margins_opts) do
            mp.set_property_number(opt[2], 0.0)
        end
        state.using_video_margins = false
    end
end

function update_margins()
    local margins = osc_param.video_margins

    -- Don't use margins if it's visible only temporarily.
    if (not state.osc_visible) or (get_hidetimeout() >= 0) then
        margins = {l = 0, r = 0, t = 0, b = 0}
    end

    if user_opts.boxvideo then
        -- check whether any margin option has a non-default value
        local margins_used = false

        if not state.using_video_margins then
            for _, opt in ipairs(margins_opts) do
                if mp.get_property_number(opt[2], 0.0) ~= 0.0 then
                    margins_used = true
                end
            end
        end

        if not margins_used then
            for _, opt in ipairs(margins_opts) do
                local v = margins[opt[1]]
                if (v ~= 0) or state.using_video_margins then
                    mp.set_property_number(opt[2], v)
                    state.using_video_margins = true
                end
            end
        end
    else
        reset_margins()
    end

    utils.shared_script_property_set("osc-margins",
        string.format("%f,%f,%f,%f", margins.l, margins.r, margins.t, margins.b))
end

function shutdown()
    reset_margins()
    utils.shared_script_property_set("osc-margins", nil)
end

--
-- Other important stuff
--


function show_osc()
    -- show when disabled can happen (e.g. mouse_move) due to async/delayed unbinding
    if not state.enabled then return end

    msg.trace("show_osc")
    --remember last time of invocation (mouse move)
    state.showtime = mp.get_time()

    osc_visible(true)

    if (user_opts.fadeduration > 0) then
        state.anitype = nil
    end
end

function hide_osc()
    msg.trace("hide_osc")
    if not state.enabled then
        -- typically hide happens at render() from tick(), but now tick() is
        -- no-op and won't render again to remove the osc, so do that manually.
        state.osc_visible = false
        render_wipe()
    elseif (user_opts.fadeduration > 0) then
        if not(state.osc_visible == false) then
            state.anitype = "out"
            request_tick()
        end
    else
        osc_visible(false)
    end
end

function osc_visible(visible)
    if state.osc_visible ~= visible then
        state.osc_visible = visible
        update_margins()
    end
    request_tick()
end

function pause_state(name, enabled)
    state.paused = enabled
    request_tick()
end

function cache_state(name, st)
    state.cache_state = st
    request_tick()
end

-- Request that tick() is called (which typically re-renders the OSC).
-- The tick is then either executed immediately, or rate-limited if it was
-- called a small time ago.
function request_tick()
    if state.tick_timer == nil then
        state.tick_timer = mp.add_timeout(0, tick)
    end

    if not state.tick_timer:is_enabled() then
        local now = mp.get_time()
        local timeout = tick_delay - (now - state.tick_last_time)
        if timeout < 0 then
            timeout = 0
        end
        state.tick_timer.timeout = timeout
        state.tick_timer:resume()
    end
end

function mouse_leave()
    if get_hidetimeout() >= 0 then
        hide_osc()
    end
    -- reset mouse position
    state.last_mouseX, state.last_mouseY = nil, nil
    state.mouse_in_window = false
end

function request_init()
    state.initREQ = true
    request_tick()
end

-- Like request_init(), but also request an immediate update
function request_init_resize()
    request_init()
    -- ensure immediate update
    state.tick_timer:kill()
    state.tick_timer.timeout = 0
    state.tick_timer:resume()
end

function render_wipe()
    msg.trace("render_wipe()")
    state.osd:remove()
end

function render()
    msg.trace("rendering")
    local current_screen_sizeX, current_screen_sizeY, aspect = mp.get_osd_size()
    local mouseX, mouseY = get_virt_mouse_pos()
    local now = mp.get_time()

    -- check if display changed, if so request reinit
    if not (state.mp_screen_sizeX == current_screen_sizeX
        and state.mp_screen_sizeY == current_screen_sizeY) then

        request_init_resize()

        state.mp_screen_sizeX = current_screen_sizeX
        state.mp_screen_sizeY = current_screen_sizeY
    end

    -- init management
    if state.initREQ then
        osc_init()
        state.initREQ = false

        -- store initial mouse position
        if (state.last_mouseX == nil or state.last_mouseY == nil)
            and not (mouseX == nil or mouseY == nil) then

            state.last_mouseX, state.last_mouseY = mouseX, mouseY
        end
    end


    -- fade animation
    if not(state.anitype == nil) then

        if (state.anistart == nil) then
            state.anistart = now
        end

        if (now < state.anistart + (user_opts.fadeduration/1000)) then

            if (state.anitype == "in") then --fade in
                osc_visible(true)
                state.animation = scale_value(state.anistart,
                    (state.anistart + (user_opts.fadeduration/1000)),
                    255, 0, now)
            elseif (state.anitype == "out") then --fade out
                state.animation = scale_value(state.anistart,
                    (state.anistart + (user_opts.fadeduration/1000)),
                    0, 255, now)
            end

        else
            if (state.anitype == "out") then
                osc_visible(false)
            end
            state.anistart = nil
            state.animation = nil
            state.anitype =  nil
        end
    else
        state.anistart = nil
        state.animation = nil
        state.anitype =  nil
    end

    --mouse show/hide area
    for k,cords in pairs(osc_param.areas["showhide"]) do
        set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "showhide")
    end
    if osc_param.areas["showhide_wc"] then
        for k,cords in pairs(osc_param.areas["showhide_wc"]) do
            set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "showhide_wc")
        end
    else
        set_virt_mouse_area(0, 0, 0, 0, "showhide_wc")
    end
    do_enable_keybindings()

    --mouse input area
    local mouse_over_osc = false

    for _,cords in ipairs(osc_param.areas["input"]) do
        if state.osc_visible then -- activate only when OSC is actually visible
            set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "input")
        end
        if state.osc_visible ~= state.input_enabled then
            if state.osc_visible then
                mp.enable_key_bindings("input")
            else
                mp.disable_key_bindings("input")
            end
            state.input_enabled = state.osc_visible
        end

        if (mouse_hit_coords(cords.x1, cords.y1, cords.x2, cords.y2)) then
            mouse_over_osc = true
        end
    end

    if osc_param.areas["window-controls"] then
        for _,cords in ipairs(osc_param.areas["window-controls"]) do
            if state.osc_visible then -- activate only when OSC is actually visible
                set_virt_mouse_area(cords.x1, cords.y1, cords.x2, cords.y2, "window-controls")
                mp.enable_key_bindings("window-controls")
            else
                mp.disable_key_bindings("window-controls")
            end

            if (mouse_hit_coords(cords.x1, cords.y1, cords.x2, cords.y2)) then
                mouse_over_osc = true
            end
        end
    end

    if osc_param.areas["window-controls-title"] then
        for _,cords in ipairs(osc_param.areas["window-controls-title"]) do
            if (mouse_hit_coords(cords.x1, cords.y1, cords.x2, cords.y2)) then
                mouse_over_osc = true
            end
        end
    end

    -- autohide
    if not (state.showtime == nil) and (get_hidetimeout() >= 0) then
        local timeout = state.showtime + (get_hidetimeout()/1000) - now
        if timeout <= 0 then
            if (state.active_element == nil) and not (mouse_over_osc) then
                hide_osc()
            end
        else
            -- the timer is only used to recheck the state and to possibly run
            -- the code above again
            if not state.hide_timer then
                state.hide_timer = mp.add_timeout(0, tick)
            end
            state.hide_timer.timeout = timeout
            -- re-arm
            state.hide_timer:kill()
            state.hide_timer:resume()
        end
    end


    -- actual rendering
    local ass = assdraw.ass_new()

    -- Messages
    render_message(ass)

    -- actual OSC
    if state.osc_visible then
        render_elements(ass)
    end

    -- submit
    set_osd(osc_param.playresy * osc_param.display_aspect,
            osc_param.playresy, ass.text)
end

--
-- Eventhandling
--

local function element_has_action(element, action)
    return element and element.eventresponder and
        element.eventresponder[action]
end

function process_event(source, what)
    local action = string.format("%s%s", source,
        what and ("_" .. what) or "")

    if what == "down" or what == "press" then

        for n = 1, #elements do

            if mouse_hit(elements[n]) and
                elements[n].eventresponder and
                (elements[n].eventresponder[source .. "_up"] or
                    elements[n].eventresponder[action]) then

                if what == "down" then
                    state.active_element = n
                    state.active_event_source = source
                end
                -- fire the down or press event if the element has one
                if element_has_action(elements[n], action) then
                    elements[n].eventresponder[action](elements[n])
                end

            end
        end

    elseif what == "up" then

        if elements[state.active_element] then
            local n = state.active_element

            if n == 0 then
                --click on background (does not work)
            elseif element_has_action(elements[n], action) and
                mouse_hit(elements[n]) then

                elements[n].eventresponder[action](elements[n])
            end

            --reset active element
            if element_has_action(elements[n], "reset") then
                elements[n].eventresponder["reset"](elements[n])
            end

        end
        state.active_element = nil
        state.mouse_down_counter = 0

    elseif source == "mouse_move" then

        state.mouse_in_window = true

        local mouseX, mouseY = get_virt_mouse_pos()
        if (user_opts.minmousemove == 0) or
            (not ((state.last_mouseX == nil) or (state.last_mouseY == nil)) and
                ((math.abs(mouseX - state.last_mouseX) >= user_opts.minmousemove)
                    or (math.abs(mouseY - state.last_mouseY) >= user_opts.minmousemove)
                )
            ) then
            show_osc()
        end
        state.last_mouseX, state.last_mouseY = mouseX, mouseY

        local n = state.active_element
        if element_has_action(elements[n], action) then
            elements[n].eventresponder[action](elements[n])
        end
        request_tick()
    end
end

-- called by mpv on every frame
function tick()
    if (not state.enabled) then return end

    if (state.idle or mp.get_property("path") == "artwork://") then
        set_osd(osc_param.playresy, osc_param.playresy, "")
    elseif (state.fullscreen and user_opts.showfullscreen)
        or (not state.fullscreen and user_opts.showwindowed) then

        -- render the OSC
        render()
    else
        -- Flush OSD
        set_osd(osc_param.playresy, osc_param.playresy, "")
    end

    state.tick_last_time = mp.get_time()

    if state.anitype ~= nil then
        request_tick()
    end
end

function do_enable_keybindings()
    if state.enabled then
        if not state.showhide_enabled then
            mp.enable_key_bindings("showhide", "allow-vo-dragging+allow-hide-cursor")
            mp.enable_key_bindings("showhide_wc", "allow-vo-dragging+allow-hide-cursor")
        end
        state.showhide_enabled = true
    end
end

function enable_osc(enable)
    state.enabled = enable
    if enable then
        do_enable_keybindings()
    else
        hide_osc() -- acts immediately when state.enabled == false
        if state.showhide_enabled then
            mp.disable_key_bindings("showhide")
            mp.disable_key_bindings("showhide_wc")
        end
        state.showhide_enabled = false
    end
end

validate_user_opts()

mp.register_event("shutdown", shutdown)
mp.register_event("start-file", request_init)
mp.observe_property("track-list", nil, request_init)
mp.observe_property("playlist", nil, request_init)

mp.register_script_message("osc-message", show_message)

mp.register_script_message("foobar", function(cmd, arg1, ...)
    if (cmd == nil) then
        return
    elseif (cmd == "osc-enabled-changed" and (not (arg1 == nil))) then
        if (arg1 == "yes") then
            enable_osc(true)
        elseif (arg1 == "no") then
            enable_osc(false)
        end
    elseif (cmd == "title-changed" and (not(arg1 == nil))) then
        state.title = arg1
    elseif (cmd == "volume-changed" and (not(arg1 == nil))) then
        state.volume = tonumber(arg1)
    elseif (cmd == "start-changed" and (not(arg1 == nil))) then
        state.start = tonumber(arg1)
    elseif (cmd == "finish-changed" and (not(arg1 == nil))) then
        state.finish = tonumber(arg1)
    end
end)

mp.observe_property("fullscreen", "bool",
    function(name, val)
        state.fullscreen = val
        request_init_resize()
    end
)
mp.observe_property("border", "bool",
    function(name, val)
        state.border = val
        request_init_resize()
    end
)
mp.observe_property("window-maximized", "bool",
    function(name, val)
        state.maximized = val
        request_init_resize()
    end
)
mp.observe_property("idle-active", "bool",
    function(name, val)
        state.idle = val
        request_tick()
    end
)
mp.observe_property("pause", "bool", pause_state)
mp.observe_property("demuxer-cache-state", "native", cache_state)
mp.observe_property("vo-configured", "bool", function(name, val)
    request_tick()
end)
mp.observe_property("playback-time", "number", function(name, val)
    request_tick()
end)
mp.observe_property("osd-dimensions", "native", function(name, val)
    -- (we could use the value instead of re-querying it all the time, but then
    --  we might have to worry about property update ordering)
    request_init_resize()
end)

-- mouse show/hide bindings
mp.set_key_bindings({
    {"mouse_move",              function(e) process_event("mouse_move", nil) end},
    {"mouse_leave",             mouse_leave},
}, "showhide", "force")
mp.set_key_bindings({
    {"mouse_move",              function(e) process_event("mouse_move", nil) end},
    {"mouse_leave",             mouse_leave},
}, "showhide_wc", "force")
do_enable_keybindings()

--mouse input bindings
mp.set_key_bindings({
    {"mbtn_left",           function(e) process_event("mbtn_left", "up") end,
                            function(e) process_event("mbtn_left", "down")  end},
    {"shift+mbtn_left",     function(e) process_event("shift+mbtn_left", "up") end,
                            function(e) process_event("shift+mbtn_left", "down")  end},
    {"mbtn_right",          function(e) process_event("mbtn_right", "up") end,
                            function(e) process_event("mbtn_right", "down")  end},
    -- alias to shift_mbtn_left for single-handed mouse use
    {"mbtn_mid",            function(e) process_event("shift+mbtn_left", "up") end,
                            function(e) process_event("shift+mbtn_left", "down")  end},
    {"wheel_up",            function(e) process_event("wheel_up", "press") end},
    {"wheel_down",          function(e) process_event("wheel_down", "press") end},
    {"mbtn_left_dbl",       "ignore"},
    {"shift+mbtn_left_dbl", "ignore"},
    {"mbtn_right_dbl",      "ignore"},
}, "input", "force")
mp.enable_key_bindings("input")

mp.set_key_bindings({
    {"mbtn_left",           function(e) process_event("mbtn_left", "up") end,
                            function(e) process_event("mbtn_left", "down")  end},
}, "window-controls", "force")
mp.enable_key_bindings("window-controls")

function get_hidetimeout()
    if user_opts.visibility == "always" then
        return -1 -- disable autohide
    end
    return user_opts.hidetimeout
end

function always_on(val)
    if state.enabled then
        if val then
            show_osc()
        else
            hide_osc()
        end
    end
end

-- mode can be auto/always/never/cycle
-- the modes only affect internal variables and not stored on its own.
function visibility_mode(mode, no_osd)
    if mode == "cycle" then
        if not state.enabled then
            mode = "auto"
        elseif user_opts.visibility ~= "always" then
            mode = "always"
        else
            mode = "never"
        end
    end

    if mode == "auto" then
        always_on(false)
        enable_osc(true)
    elseif mode == "always" then
        enable_osc(true)
        always_on(true)
    elseif mode == "never" then
        enable_osc(false)
    else
        msg.warn("Ignoring unknown visibility mode '" .. mode .. "'")
        return
    end

    user_opts.visibility = mode

    if not no_osd and tonumber(mp.get_property("osd-level")) >= 1 then
        mp.osd_message("OSC visibility: " .. mode)
    end

    -- Reset the input state on a mode change. The input state will be
    -- recalcuated on the next render cycle, except in 'never' mode where it
    -- will just stay disabled.
    mp.disable_key_bindings("input")
    mp.disable_key_bindings("window-controls")
    state.input_enabled = false

    update_margins()
    request_tick()
end

visibility_mode(user_opts.visibility, true)
mp.register_script_message("osc-visibility", visibility_mode)
mp.add_key_binding(nil, "visibility", function() visibility_mode("cycle") end)

set_virt_mouse_area(0, 0, 0, 0, "input")
set_virt_mouse_area(0, 0, 0, 0, "window-controls")
