--[[
mpv dynaudnorm filter with visual feedback.

Copyright 2016 Avi Halachmi ( https://github.com/avih )
Copyright 2020 Paul B Mahol ( https://github.com/richardpl )
Copyright 2022 dyphire      ( https://github.com/dyphire )
License: public domain

-- Source https://gist.github.com/richardpl/0c8011dc23d7ac7b7831b2e6d680114f

Needs mpv with very recent FFmpeg build.

Default config:
- Enter/exit drcbox keys mode: alt+n
- Toggle dynaudnorm without changing its values: alt+N
- Reset dynaudnorm values: alt+ctrl+n
 
--]]
-- ------ config -------

local options = {
    language = 'eng', -- eng=English, chs=Chinese
    start_keys_enabled = false, -- if true then choose the up/down keys wisely
    key_toggle_bindings = "ALT+n", -- enter/exit drcbox keys mode
    key_toggle_drcbox = "ALT+N", -- toggle dynaudnorm without changing its values
    key_reset_drcbox = "ALT+CTRL+n", -- reset dynaudnorm values

    {keys = {'2', 'w'}, option = {'framelen',     1, 10, 8000,  500,  500 } },
    {keys = {'3', 'e'}, option = {'gausssize',    1,  3,  301,   31,   31 } },
    {keys = {'4', 'r'}, option = {'peak',      0.01,  0,    1, 0.95, 0.95 } },
    {keys = {'5', 't'}, option = {'maxgain',      1,  1,  100,   10,   10 } },
    {keys = {'6', 'y'}, option = {'targetrms', 0.01,  0,    1,    0,    0 } },
    {keys = {'7', 'u'}, option = {'coupling',     1,  0,    1,    1,    1 } },
    {keys = {'8', 'i'}, option = {'correctdc',    1,  0,    1,    0,    0 } },
    {keys = {'9', 'o'}, option = {'compress',   0.1,  0,   30,    0,    0 } },
}

(require 'mp.options').read_options(options)

-- Localization
local language = {
    ['eng'] = {
        msg1 = 'DynAudNorm: ',
        msg2 = 'Key-bindings: ',
        msg3 = 'Reset: ',
    },
    ['chs'] = {
        msg1 = '开/关 dynaudnorm音频处理: ',
        msg2 = '开/关 内置键位绑定: ',
        msg3 = '重置  dynaudnorm音频处理: ',
    }
}

-- apply lang opts
local texts = language[options.language]

local function get_cmd_full()
    f = options[1].option[5]
    g = options[2].option[5]
    p = options[3].option[5]
    m = options[4].option[5]
    r = options[5].option[5]
    n = options[6].option[5]
    c = options[7].option[5]
    s = options[8].option[5]
    return 'no-osd af toggle @dynaudnorm:lavfi=[dynaudnorm=f=' ..
        f .. ':g=' .. g .. ':p=' .. p .. ':m=' .. m .. ':r=' .. r .. ':n=' .. n .. ':c=' .. c .. ':s=' .. s .. ']'
end

local function get_cmd(option)
    return 'no-osd af-command dynaudnorm ' .. option[1] .. ' ' .. option[5]
end

-- these two vars are used globally
local bindings_enabled = start_keys_enabled
local drcbox_enabled = false -- but af is not touched before the dynaudnorm is modified

-- ------ OSD handling -------
local function ass(x)
    return x
end

local function fsize(s) -- 100 is the normal font size
    return ass('{\\fscx' .. s .. '\\fscy' .. s .. '}')
end

local function color(c) -- c is RRGGBB
    return ass('{\\1c&H' .. ss(c, 5, 7) .. ss(c, 3, 5) .. ss(c, 1, 3) .. '&}')
end

function iff(cc, a, b) if cc then return a else return b end end

function ss(s, from, to) return s:sub(from, to - 1) end

local function cnorm() return color('ffffff') end -- white

local function cdis() return color('909090') end -- grey

local function ceq() return iff(drcbox_enabled, color('ffff90'), cdis()) end -- yellow-ish

local function ckeys() return iff(bindings_enabled, color('90FF90'), cdis()) end -- green-ish

local DUR_DEFAULT = 1.5 -- seconds
local osd_timer = nil
-- duration: seconds, or default if missing/nil, or infinite if 0 (or negative)
local function ass_osd(msg, duration) -- empty or missing msg -> just clears the OSD
    duration = duration or DUR_DEFAULT
    if not msg or msg == '' then
        msg = '{}' -- the API ignores empty string, but '{}' works to clean it up
        duration = 0
    end
    mp.set_osd_ass(0, 0, msg)
    if osd_timer then
        osd_timer:kill()
        osd_timer = nil
    end
    if duration > 0 then
        osd_timer = mp.add_timeout(duration, ass_osd) -- ass_osd() clears without a timer
    end
end

function round(num, numDecimalPlaces)
    return tonumber(string.format("%." .. (numDecimalPlaces or 0) .. "f", num))
end

-- some visual messing about
local function updateOSD()
    local msg1 = fsize(70) .. texts.msg1 .. ceq() .. iff(drcbox_enabled, 'On', 'Off')
        .. ' [' .. options.key_toggle_drcbox .. ']' .. cnorm()
    local msg2 = fsize(70)
        .. texts.msg2 .. ckeys() .. iff(bindings_enabled, 'On', 'Off')
        .. ' [' .. options.key_toggle_bindings .. ']' .. cnorm()
    local msg3 = fsize(70)
        .. texts.msg3
        .. ' [' .. options.key_reset_drcbox .. ']'
    local msg4 = ' '

    for i = 1, #options do
        local option = options[i].option[1]
        local value = round(options[i].option[5], 2)
        local default = options[i].option[6]
        local info =
        ceq() .. fsize(50) .. option .. ' ' .. fsize(100)
            .. iff(value ~= default and drcbox_enabled, '', cdis()) .. value .. ceq()
            .. fsize(50) .. ckeys() .. ' [' .. options[i].keys[1] .. '/' .. options[i].keys[2] .. ']'
            .. ceq() .. fsize(100) .. cnorm()

        msg4 = msg4 .. '   ' .. info
    end

    local nlb = '\n' .. ass('{\\an1}') -- new line and "align bottom for next"
    local msg = ass('{\\an1}') .. msg4 .. nlb .. msg3 .. nlb .. msg2 .. nlb .. msg1
    local duration = iff(start_keys_enabled, iff(bindings_enabled and drcbox_enabled, 5, nil)
        , iff(bindings_enabled, 0, nil))
    ass_osd(msg, duration)
end

local function update_key_binding(enable, key, name, fn)
    if enable then
        mp.add_forced_key_binding(key, name, fn, 'repeatable')
    else
        mp.remove_key_binding(name)
    end
end

local function updateAF()
    mp.command(get_cmd_full())
end

local function updateAF_options()
    if not drcbox_enabled then return end
    for i = 1, #options do
        local o = options[i].option
        mp.command(get_cmd(o))
    end
end

local function getBind(option, delta)
    return function() -- onKey
        option[5] = option[5] + delta
        if option[5] > option[4] then
            option[5] = option[4]
        end
        if option[5] < option[3] then
            option[5] = option[3]
        end
        updateAF_options()
        updateOSD()
    end
end

function toggle_drcbox()
    drcbox_enabled = not drcbox_enabled
    updateAF()
    updateOSD()
end

function reset_drcbox()
    for i = 1, #options do
        options[i].option[5] = options[i].option[6]
    end
    updateAF_options()
    updateOSD()
end

local function toggle_bindings(explicit, no_osd)
    bindings_enabled = iff(explicit ~= nil, explicit, not bindings_enabled)
    for i = 1, #options do
        local keys = options[i].keys
        local option = options[i].option[1]
        local delta = options[i].option[2]
        update_key_binding(bindings_enabled, options.key_toggle_drcbox, options.key_toggle_drcbox, toggle_drcbox)
        update_key_binding(bindings_enabled, options.key_reset_drcbox, options.key_reset_drcbox, reset_drcbox)
        update_key_binding(bindings_enabled, keys[1], 'eq' .. keys[1], getBind(options[i].option, delta)) -- up
        update_key_binding(bindings_enabled, keys[2], 'eq' .. keys[2], getBind(options[i].option, -delta)) -- down
    end
    if not no_osd then updateOSD() end
end

mp.add_key_binding(options.key_toggle_bindings, "key_toggle_bindings", toggle_bindings)
if bindings_enabled then toggle_bindings(true, true) end
