local awful = require("awful")
local gears = require("gears")
local wibox = require("wibox")
local gcolor = require("gears.color")
local beautiful = require("beautiful")

local mylayout = {}

mylayout.name = "mstab"

local tabbar_ontop = beautiful.mstab_bar_ontop or false
local tabbar_padding = beautiful.mstab_bar_padding or "default"
local border_radius = beautiful.mstab_border_radius or beautiful.border_radius or 0
local tabbar_position = beautiful.mstab_tabbar_position or beautiful.tabbar_position or "top"

local bar_style = beautiful.mstab_tabbar_style or beautiful.tabbar_style or "default"
local bar = require(tostring(...):match(".*bling") .. ".widget.tabbar." .. bar_style)
local tabbar_size = bar.size or beautiful.mstab_bar_height or beautiful.tabbar_size or 40
local dont_resize_slaves = beautiful.mstab_dont_resize_slaves or false

-- The top_idx is the idx of the slave clients (excluding all master clients)
-- that should be on top of all other slave clients ("the focused slave")
-- by creating a variable outside of the arrange function, this layout can "remember" that client
-- by creating it as a new property of every tag, this layout can be active on different tags and
-- still have different "focused slave clients"
for idx, tag in ipairs(root.tags()) do
  tag.top_idx = 1
end

-- Haven't found a signal that is emitted when a new tag is added. That should work though
-- since you can't use a layout on a tag that you haven't selected previously
tag.connect_signal("property::selected", function(t)
  if not t.top_idx then t.top_idx = 1 end
end)

function update_tabbar(clients, t, top_idx, area, master_area_width, slave_area_width)
  local s = t.screen

  -- create the list of clients for the tabbar
  local clientlist = bar.layout()
  for idx, c in ipairs(clients) do
    -- focus with right click, kill with mid click, minimize with left click
    local buttons = gears.table.join(
      awful.button({}, 1, function()
        c:raise()
        client.focus = c
      end),
      awful.button({}, 2, function() c:kill() end),
      awful.button({}, 3, function() c.minimized = true end)
    )
    local client_box = bar.create(c, (idx == top_idx), buttons)
    clientlist:add(client_box)
  end

  -- if no tabbar exists, create one
  if not s.tabbar then
    s.tabbar = wibox({
      ontop = tabbar_ontop,
      shape = function(cr, width, height) gears.shape.rounded_rect(cr, width, height, border_radius) end,
      bg = bar.bg_normal,
      visible = true,
    })

    -- Change visibility of the tab bar when layout, selected tag or number of clients (visible, master, slave) changes
    local function adjust_visiblity(t)
      s.tabbar.visible = (#t:clients() - t.master_count > 1) and (t.layout.name == mylayout.name)
    end

    tag.connect_signal("property::selected", function(t) adjust_visiblity(t) end)
    tag.connect_signal("property::layout", function(t, layout) adjust_visiblity(t) end)
    tag.connect_signal("tagged", function(t, c) adjust_visiblity(t) end)
    tag.connect_signal("untagged", function(t, c) adjust_visiblity(t) end)
    tag.connect_signal("property::master_count", function(t) adjust_visiblity(t) end)
    client.connect_signal("property::minimized", function(c)
      local t = c.first_tag
      adjust_visiblity(t)
    end)
  end

  -- update the tabbar size and position (to support gap size change on the fly)
  if tabbar_position == "top" then
    s.tabbar.x = area.x + master_area_width + t.gap
    s.tabbar.y = area.y + t.gap
    s.tabbar.width = slave_area_width - 2 * t.gap
    s.tabbar.height = tabbar_size
  elseif tabbar_position == "bottom" then
    s.tabbar.x = area.x + master_area_width + t.gap
    s.tabbar.y = area.y + area.height - tabbar_size - t.gap
    s.tabbar.width = slave_area_width - 2 * t.gap
    s.tabbar.height = tabbar_size
  elseif tabbar_position == "left" then
    s.tabbar.x = area.x + master_area_width + t.gap
    s.tabbar.y = area.y + t.gap
    s.tabbar.width = tabbar_size
    s.tabbar.height = area.height - 2 * t.gap
  elseif tabbar_position == "right" then
    s.tabbar.x = area.x + master_area_width + slave_area_width - tabbar_size - t.gap
    s.tabbar.y = area.y + t.gap
    s.tabbar.width = tabbar_size
    s.tabbar.height = area.height - 2 * t.gap
  end

  -- update clientlist
  s.tabbar:setup({ layout = wibox.layout.flex.horizontal, clientlist })
end

function mylayout.arrange(p)
  local area = p.workarea
  local t = p.tag or screen[p.screen].selected_tag
  local s = t.screen
  local mwfact = t.master_width_factor
  local nmaster = math.min(t.master_count, #p.clients)
  local nslaves = #p.clients - nmaster

  local master_area_width = area.width * mwfact
  local slave_area_width = area.width - master_area_width

  -- "default" means that it uses standard useless gap size
  if tabbar_padding == "default" then tabbar_padding = 2 * t.gap end

  -- Special case: No masters -> full screen slave width
  if nmaster == 0 then
    master_area_width = 1
    slave_area_width = area.width
  end

  -- Special case: One or zero slaves -> no tabbar (essentially tile right)
  if nslaves <= 1 then
    -- since update_tabbar isnt called that way we have to hide it manually
    if s.tabbar then s.tabbar.visible = false end
    -- otherwise just do tile right
    awful.layout.suit.tile.right.arrange(p)
    return
  end

  -- Iterate through masters
  for idx = 1, nmaster do
    local c = p.clients[idx]
    local g = {
      x = area.x,
      y = area.y + (idx - 1) * (area.height / nmaster),
      width = master_area_width,
      height = area.height / nmaster,
    }
    p.geometries[c] = g
  end

  local tabbar_size_change = 0
  local tabbar_width_change = 0
  local tabbar_y_change = 0
  local tabbar_x_change = 0
  if tabbar_position == "top" then
    tabbar_size_change = tabbar_size + tabbar_padding
    tabbar_y_change = tabbar_size + tabbar_padding
  elseif tabbar_position == "bottom" then
    tabbar_size_change = tabbar_size + tabbar_padding
  elseif tabbar_position == "left" then
    tabbar_width_change = tabbar_size + tabbar_padding
    tabbar_x_change = tabbar_size + tabbar_padding
  elseif tabbar_position == "right" then
    tabbar_width_change = tabbar_size + tabbar_padding
  end

  -- Iterate through slaves
  -- (also creates a list of all slave clients for update_tabbar)
  local slave_clients = {}
  for idx = 1, nslaves do
    local c = p.clients[idx + nmaster]
    slave_clients[#slave_clients + 1] = c
    if c == client.focus then t.top_idx = #slave_clients end
    local g = {
      x = area.x + master_area_width + tabbar_x_change,
      y = area.y + tabbar_y_change,
      width = slave_area_width - tabbar_width_change,
      height = area.height - tabbar_size_change,
    }
    if not dont_resize_slaves and idx ~= t.top_idx then
      g = {
        x = area.x + master_area_width + slave_area_width / 4,
        y = area.y + tabbar_size + area.height / 4,
        width = slave_area_width / 2,
        height = area.height / 4 - tabbar_size,
      }
    end
    p.geometries[c] = g
  end

  update_tabbar(slave_clients, t, t.top_idx, area, master_area_width, slave_area_width)
end

local icon_raw = gears.filesystem.get_configuration_dir()
  .. tostring(...):match("^.*bling"):gsub("%.", "/")
  .. "/icons/layouts/mstab.png"

local function get_icon()
  if icon_raw ~= nil then
    return gcolor.recolor_image(icon_raw, beautiful.fg_normal)
  else
    return nil
  end
end

return { layout = mylayout, icon_raw = icon_raw, get_icon = get_icon }
