if SERVER then AddCSLuaFile() end

local math = math
local urllib = url
local ceil = math.ceil
local floor = math.floor
local Round = math.Round
local log = math.log
local pow = math.pow
local format = string.format
local tostring = tostring
local IsValid = IsValid


local utils = {}

---
-- Ceil the given number to the largest power of two.
--
function utils.CeilPower2(n)
	return pow(2, ceil(log(n) / log(2)))
end

---
-- Method for easily grabbing a value from a table without checking that each
-- fragment exists.
--
-- @param tbl Table
-- @param key e.g. "json.key.fragments"
--
function utils.TableLookup( tbl, key )
	local fragments = string.Split(key, '.')
	local value = tbl

	for _, fragment in ipairs(fragments) do
		value = value[fragment]

		if not value then
			return nil
		end
	end

	return value
end

---
-- Formats the number of seconds to a string.
-- e.g. 3612 => 1:00:12
--
function utils.FormatSeconds(sec)
	sec = Round(sec)

	local hours = floor(sec / 3600)
	local minutes = floor((sec % 3600) / 60)
	local seconds = sec % 60

	if hours > 0 then
		return format("%d:%02d:%02d", hours, minutes, seconds)
	else
		return format("%02d:%02d", minutes, seconds)
	end
end

-- https://github.com/xfbs/PiL3/blob/master/18MathLibrary/shuffle.lua
function utils.Shuffle(list)
	-- make and fill array of indices
	local indices = {}
	for i = 1, #list do
		indices[#indices + 1] = i
	end

	-- create shuffled list
	local shuffled = {}
	for i = 1, #list do
		-- get a random index
		local index = math.random(#indices)

		-- get the value
		local value = list[indices[index]]

		-- remove it from the list so it won't be used again
		table.remove(indices, index)

		-- insert into shuffled array
		shuffled[#shuffled + 1] = value
	end

	return shuffled
end

function utils.Retry( func, success, error, maxAttempts )

	maxAttempts = maxAttempts or 3
	local attempts = 1

	local function callback( value )
		if value then
			success( value )
		elseif attempts < maxAttempts then
			attempts = attempts + 1
			func( callback )
		else
			error()
		end
	end

	func( callback )

end

local function setTimeout( func, wait )
	local timerID = tostring( func )
	timer.Create( timerID, wait, 1, func )
	timer.Start( timerID )
	return timerID
end

local function clearTimeout( timerID )
	if timer.Exists( timerID ) then
		timer.Remove( timerID )
	end
end

-- based on underscore.js' _.throttle function
function utils.Throttle( func, wait, options )
	wait = wait or 1
	options = options or {}

	local timeout, args, result
	local previous

	local function later()
		previous = (options.leading == false) and 0 or RealTime()
		timeout = nil
		result = func( unpack(args) )
		if not timeout then
			args = nil
		end
	end

	local function throttled(...)
		local now = RealTime()
		if not previous then
			previous = now
		end

		local remaining = wait - (now - previous)

		args = {...}

		if remaining <= 0 or remaining > wait then
			if timeout then
				clearTimeout(timeout)
				timeout = nil
			end

			previous = now
			result = func( unpack(args) )

			if not timeout then
				args = nil
			end
		elseif not timeout and options.trailing ~= false then
			timeout = setTimeout(later, remaining)
		end

		return result
	end

	return throttled
end

if CLIENT then

	local CeilPower2 = utils.CeilPower2
	local SetDrawColor = surface.SetDrawColor
	local SetMaterial = surface.SetMaterial
	local DrawTexturedRect = surface.DrawTexturedRect
	local DrawRect = surface.DrawRect

	local color_white = color_white
	local RealTime = RealTime

	local HTML_TEX_INTERVAL = 1 / 30 -- throttle UpdateHTMLTexture to ~30fps

	function utils.DrawHTMLPanel( panel, w, h )
		if not (IsValid( panel ) and w and h) then return end

		-- Throttle UpdateHTMLTexture to ~30fps per panel
		local now = RealTime()
		if not panel._mp_nextTexUpdate or now >= panel._mp_nextTexUpdate then
			panel:UpdateHTMLTexture()
			panel._mp_nextTexUpdate = now + HTML_TEX_INTERVAL
		end

		local pw, ph = panel:GetSize()

		-- Convert to scalar
		w = w / pw
		h = h / ph

		-- Fix for non-power-of-two html panel size
		pw = CeilPower2(pw)
		ph = CeilPower2(ph)

		SetDrawColor( color_white )

		local mat = panel:GetHTMLMaterial()

		if mat then
			SetMaterial( mat )
			DrawTexturedRect( 0, 0, w * pw, h * ph )
		else
			DrawRect( 0, 0, w * pw, h * ph )
		end
	end

	function utils.ParseHHMMSS( time )
		local tbl = {}

		-- insert fragments in reverse
		for fragment, _ in string.gmatch(time, ":?(%d+)") do
			table.insert(tbl, 1, tonumber(fragment) or 0)
		end

		if #tbl == 0 then
			return nil
		end

		local seconds = 0

		for i = 1, #tbl do
			seconds = seconds + tbl[i] * math.max(60 ^ (i-1), 1)
		end

		return seconds
	end

	---
	-- Attempts to play uri from stream or local file and returns channel in
	-- callback.
	--
	function utils.LoadStreamChannel( uri, options, callback )
		local isLocalFile = false

		-- Play uri from a local file if:
		-- 1. Windows OS and path contains drive letter
		-- 2. Linux or OS X and path starts with a single '/'
		--
		-- We can't check this using file.Exists since GMod only allows checking
		-- within the GMod directory. However, sound.PlayFile will still load
		-- a file from any directory.
		if ( system.IsWindows() and uri:find("^%w:/") ) or
			( not system.IsWindows() and uri:find("^/[^/]") ) then
			isLocalFile = true

			local success, decoded = pcall(urllib.unescape, uri)
			if success then
				uri = decoded
			end
		end

		local playFunc = isLocalFile and sound.PlayFile or sound.PlayURL
		playFunc( uri, options or "noplay", function( channel )
			if IsValid( channel ) then
				callback( channel )
			else
				callback( nil )
			end
		end )
	end

	---
	-- Gathers the Duration from URI
	-- Works only with URIs that lead directly to the video
	do
		-- https://developer.mozilla.org/en-US/docs/Web/API/MediaError
		local ErrorCodes = {
			[1] = "The user canceled the media.", -- MEDIA_ERR_ABORTED
			[2] = "A network error occurred while fetching the media.", -- MEDIA_ERR_NETWORK
			[3] = "An error occurred while decoding the media.", -- MEDIA_ERR_DECODE
			[4] = "The media source is not supported.", -- MEDIA_ERR_SRC_NOT_SUPPORTED
			[5] = "An unknown error occurred.", -- MEDIA_ERR_UNKOWN
		}

		local HTML_Code = [[
			<html><body> <video id="video" src="{@VideoSrc}" preload="metadata"></video>
				<script>
					const video = document.querySelector('video');
					video.onloadedmetadata  = function() { console.log("DURATION:" + video.duration)};
					video.onerror = function() { console.log("ERROR:" + video.error.code ) };
				</script>
			</body></html>
		]]

		function utils.GatherVideoDuration( uri, callback )

			local panel = vgui.Create("HTML")
			panel:SetSize(100,100)
			panel:SetAlpha(0)
			panel:SetMouseInputEnabled(false)

			function panel:ConsoleMessage(msg)
				if MediaPlayer.DEBUG then
					print("MediaPlayer Gathering: ", msg)
				end

				if msg:StartWith("DURATION:") then
					local str_duration = string.sub(msg, 10)

					local duration
					if str_duration == "Infinity" then -- Edgecase from fragmented webm
						duration = math.huge
					else
						local num = tonumber(str_duration)
						if not num then
							callback(false, "Invalid duration: " .. str_duration)
							panel:Remove()
							return
						end
						duration = math.ceil(num)
					end

					callback(true, duration)
					panel:Remove()
				end

				if msg:StartWith("ERROR:") then
					local code = tonumber(string.sub(msg, 7))
					local err = ErrorCodes[code] or ErrorCodes[5]

					callback(false, err)
					panel:Remove()
				end
			end

			panel:SetHTML(HTML_Code:Replace( "{@VideoSrc}", uri ))
		end
	end

end

_G.MediaPlayerUtils = utils