-- Copyright 2025 David Vazgenovich Shakaryan

local utils = require('mp.utils')

local script_dir = mp.get_script_directory()
local stream_prefix = mp.get_opt('iptv_menu.stream_prefix')

-- font size is in units of osd height, which is scaled to 720
local font_size = 20
local osd = mp.create_osd_overlay('ass-events')
local osd_lines = math.floor((720 / font_size) + 0.5) - 1
local osd_padding = math.floor((720 - (osd_lines * font_size)) / 2)
local osd_cursor_glyph = '{\\p1\\pbo' .. math.floor(font_size / 5) .. '}' ..
	'm 0 0 l ' .. math.ceil(font_size / 32) .. ' 0 ' ..
	math.ceil(font_size / 32) .. ' ' .. font_size ..
	' 0 ' .. font_size .. '{\\p0}'
local osd_bg = mp.create_osd_overlay('ass-events')
osd_bg.z = -1
osd_bg.data = '{\\alpha&H50&\\c&H&\\pos(0,0)}' ..
	'{\\p1}m 0 0 l 9999 0 9999 720 0 720{\\p0}'

local categories = {}
local streams = {}

local depth = 0
local menus = {}
local key_bindings = {}

local function load_json_file(path)
	local f = io.open(script_dir .. '/' .. path, 'r')
	local data = f:read('*all')
	f:close()
	return utils.parse_json(data)
end

local function load_data()
	categories = load_json_file('categories.json')
	for _, v in ipairs(categories) do
		v.type = 'category'
		v.name = v.category_name
	end

	streams = load_json_file('streams.json')
	for _, v in ipairs(streams) do
		v.type = 'stream'
	end
end

local function osd_menu_lines()
	if depth > 1 then
		-- leaves an extra line for padding between titles and options
		return osd_lines - depth
	else
		return osd_lines
	end
end

local function update_osd()
	local out = {}

	if depth > 1 then
		for i = 2, depth do
			local col = '999999'
			if menus[i].search_active then
				col = 'FF00'
			end
			out[#out+1] = '{\\c&H' .. col .. '&} » [' ..
				menus[i].title .. ']{\\c}'
		end
		out[#out+1] = ' ' -- space character for correct line height
	end

	local menu = menus[depth]
	for i = menu.page_pos, math.min(
			menu.page_pos + osd_menu_lines() - 1, #menu.options) do
		local opt = menu.options[i]
		local str = opt.name

		if opt.type == 'category' then
			str = '[' .. str .. ']'
		end

		if i == menu.cursor_pos and not menu.search_active then
			str = '{\\c&HFF00&}* ' .. str .. '{\\c}'
		elseif opt.type == 'category' then
			str = '{\\c&H99DDFF&}' .. str .. '{\\c}'
		end

		out[#out+1] = str
	end

	-- \q2 disables line wrapping
	osd.data = '{\\q2\\fs' .. font_size .. '\\pos(' .. osd_padding ..
		',' .. osd_padding .. ')}' .. table.concat(out, '\\N')
	osd:update()
	osd_bg:update()
end

local function advance_cursor(n, opts)
	local menu = menus[depth]
	local lines = osd_menu_lines()

	local pos = math.max(1, math.min(menu.cursor_pos + n, #menu.options))
	local top = menu.page_pos
	if opts and opts.advance_page then
		top = top + n
	end

	-- move page to keep selected option visible
	if pos < top then
		top = pos
	elseif pos > top + lines - 1 then
		top = pos - lines + 1
	end

	top = math.max(1, math.min(top, #menu.options - lines + 1))

	menu.cursor_pos = pos
	menu.page_pos = top
	update_osd()
end

local function next_option()
	advance_cursor(1)
end

local function prev_option()
	advance_cursor(-1)
end

local function next_page()
	advance_cursor(osd_menu_lines(), {advance_page=true})
end

local function prev_page()
	advance_cursor(-osd_menu_lines(), {advance_page=true})
end

local function first_option()
	advance_cursor(-math.huge)
end

local function last_option()
	advance_cursor(math.huge)
end

local function push_menu(t)
	local menu = {
		options={},
		title=title,
		cursor_pos=1,
		page_pos=1,
	}

	if t then
		for k, v in pairs(t) do
			menu[k] = v
		end
	end

	depth = depth + 1
	menus[depth] = menu
end

local function category_menu_options(category_id)
	local options = {}
	for _, v in ipairs(categories) do
		if tostring(v.parent_id) == category_id then
			options[#options+1] = v
		end
	end
	for _, v in ipairs(streams) do
		if v.category_id == category_id then
			options[#options+1] = v
		end
	end
	return options
end

local function add_category_menu(category_id, category_name)
	push_menu({
		options=category_menu_options(category_id),
		title=category_name,
	})
	update_osd()
end

local function play_stream(stream_id)
	local url = stream_prefix .. stream_id
	mp.commandv('loadfile', url)
end

local function select_option()
	local menu = menus[depth]
	local opt = menu.options[menu.cursor_pos]

	if opt.type == 'category' then
		add_category_menu(opt.category_id, opt.name)
	else
		play_stream(opt.stream_id)
	end
end

local function prev_menu()
	if depth > 1 then
		depth = depth - 1
		update_osd()
	end
end

local function bind_key(key, name, func, opts)
	key_bindings[key] = name
	mp.add_forced_key_binding(key, name, func, opts)
end

local function unbind_keys()
	for _, name in pairs(key_bindings) do
		mp.remove_key_binding(name)
	end
	key_bindings = {}
end

local function split_search_text()
	local menu = menus[depth]

	return menu.search_text:sub(1,
			math.max(0, menu.search_text_cursor_pos - 1)),
		menu.search_text:sub(menu.search_text_cursor_pos)
end

local function search_update_osd()
	local bc, ac = split_search_text()
	menus[depth].title = 'Searching: ' .. bc .. osd_cursor_glyph .. ac
	update_osd()
end

local function search_menu_options_build(options, t)
	local menu = menus[depth]

	for _, v in ipairs(options) do
		if not t[v.type] then
			t[v.type] = {}
		end
		t[v.type][#t[v.type]+1] = v

		if v.type == 'category' then
			search_menu_options_build(
				category_menu_options(v.category_id), t)
		end
	end
end

local function search_menu_options(options)
	local t = {}
	search_menu_options_build(options, t)

	local ret = t.category or {}
	if t.stream then
		for _, v in ipairs(t.stream) do
			ret[#ret+1] = v
		end
	end
	return ret
end

local function search_update()
	local menu = menus[depth]

	local matches = {}
	for _, v in ipairs(menu.search_options) do
		if string.find(v.name, menu.search_text, 0, true) then
			matches[#matches+1] = v
		end
	end

	menu.options = matches
	search_update_osd()
end

local function search_input(event)
	local menu = menus[depth]

	if event.event ~= 'down' and event.event ~= 'repeat' then
		return
	end

	local bc, ac = split_search_text()
	menu.search_text = bc .. event.key_text .. ac
	menu.search_text_cursor_pos = menu.search_text_cursor_pos + 1
	search_update()
end

local function search_backspace()
	local menu = menus[depth]

	if menu.search_text_cursor_pos == 1 then
		return
	end

	local bc, ac = split_search_text()
	menu.search_text = bc:sub(1, -2) .. ac
	menu.search_text_cursor_pos = menu.search_text_cursor_pos - 1
	search_update()
end

local function search_delete()
	local menu = menus[depth]

	if menu.search_text_cursor_pos == #menu.search_text + 1 then
		return
	end

	local bc, ac = split_search_text()
	menu.search_text = bc .. ac:sub(2)
	search_update()
end

local function search_cursor_left()
	local menu = menus[depth]

	if menu.search_text_cursor_pos == 1 then
		return
	end

	menu.search_text_cursor_pos = menu.search_text_cursor_pos - 1
	search_update_osd()
end

local function search_cursor_right()
	local menu = menus[depth]

	if menu.search_text_cursor_pos == #menu.search_text + 1 then
		return
	end

	menu.search_text_cursor_pos = menu.search_text_cursor_pos + 1
	search_update_osd()
end

local bind_search_keys
local bind_menu_keys

local function search_start()
	local menu = menus[depth]
	if menu.type == 'search' then
		menu.search_active = true
		menu.search_text_cursor_pos = #menu.search_text + 1
		menu.cursor_pos = 1
		menu.page_pos = 1
		search_update_osd()
	else
		push_menu({
			type='search',
			search_active=true,
			search_options=search_menu_options(menu.options),
			search_text='',
			search_text_cursor_pos=1,
		})
		search_update()
	end

	bind_search_keys()
end

local function search_finish()
	local menu = menus[depth]

	menu.search_active = false
	menu.title = 'Search results: ' .. menu.search_text
	update_osd()
	bind_menu_keys()
end

local function search_cancel()
	menus[depth].search_active = false
	depth = depth - 1
	update_osd()
	bind_menu_keys()
end

function bind_search_keys()
	unbind_keys()

	local r = {repeatable=true}
	bind_key('ANY_UNICODE', 'search-input', search_input, {complex=true})
	bind_key('ENTER', 'finish-search', search_finish)
	bind_key('ESC', 'cancel-search', search_cancel)
	bind_key('BS', 'search-backspace', search_backspace, r)
	bind_key('DEL', 'search-delete', search_delete, r)
	bind_key('LEFT', 'search-cursor-left', search_cursor_left, r)
	bind_key('RIGHT', 'search-cursor-right', search_cursor_right, r)
end

function bind_menu_keys()
	unbind_keys()

	local r = {repeatable=true}
	bind_key('DOWN', 'next-option', next_option, r)
	bind_key('UP', 'prev-option', prev_option, r)
	bind_key('PGDWN', 'next-page', next_page, r)
	bind_key('PGUP', 'prev-page', prev_page, r)
	bind_key('HOME', 'first-option', first_option)
	bind_key('END', 'last-option', last_option)
	bind_key('ENTER', 'select-option', select_option)
	bind_key('BS', 'prev-menu', prev_menu)
	bind_key('/', 'start-search', search_start)
end

local function toggle_menu()
	osd.hidden = not osd.hidden
	osd_bg.hidden = osd.hidden
	osd:update()
	osd_bg:update()

	if osd.hidden then
		unbind_keys()
	elseif menus[depth].search_active then
		bind_search_keys()
	else
		bind_menu_keys()
	end
end

mp.add_forced_key_binding('TAB', 'toggle-menu', toggle_menu)
bind_menu_keys()
load_data()
add_category_menu('0')
update_osd()