-- Based on: <https://github.com/BlingCorp/bling/blob/master/layout/mstab.lua>
local awful = require("awful")
local gears = require("gears")
local wibox = require("wibox")
local beautiful = require("beautiful")

local mylayout = {}

mylayout.name = "mstab"

local tabbar_disable = beautiful.mstab_bar_disable or false
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 "boxes"
local bar = require("flex.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_visibility()
			local name = awful.layout.getname(awful.layout.get(s))
			s.tabbar.visible = (name == mylayout.name)
		end

		tag.connect_signal("property::selected", adjust_visibility)
		tag.connect_signal("property::layout", adjust_visibility)
		tag.connect_signal("tagged", adjust_visibility)
		tag.connect_signal("untagged", adjust_visibility)
		tag.connect_signal("property::master_count", adjust_visibility)
		client.connect_signal("property::minimized", adjust_visibility)
	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 not tabbar_disable then
		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
	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

	if not tabbar_disable then
		update_tabbar(slave_clients, t, t.top_idx, area, master_area_width, slave_area_width)
	end
end

return mylayout
