-- youtube-upnext.lua
--
-- Fetch upnext/recommended videos from youtube
-- This is forked/based on https://github.com/jgreco/mpv-youtube-quality
--
-- Diplays a menu that lets you load the upnext/recommended video from youtube
-- that appear on the right side on the youtube website.
-- If auto_add is set to true (default), the 'up next' video is automatically
-- appended to the current playlist
--
-- Bound to ctrl-u by default.
--
-- Requires wget/wget.exe in PATH. On Windows you may need to set check_certificate
-- to false, otherwise wget.exe might not be able to download the youtube website.

local mp = require 'mp'
local utils = require 'mp.utils'
local msg = require 'mp.msg'
local assdraw = require 'mp.assdraw'

local opts = {
    --key bindings
    toggle_menu_binding = "ctrl+u",
    up_binding = "UP",
    down_binding = "DOWN",
    select_binding = "ENTER",

    --auto load and add the "upnext" video to the playlist
    auto_add = true,

    --formatting / cursors
    cursor_selected   = "● ",
    cursor_unselected = "○ ",

    --font size scales by window, if false requires larger font and padding sizes
    scale_playlist_by_window=false,

    --playlist ass style overrides inside curly brackets, \keyvalue is one field, extra \ for escape in lua
    --example {\\fnUbuntu\\fs10\\b0\\bord1} equals: font=Ubuntu, size=10, bold=no, border=1
    --read http://docs.aegisub.org/3.2/ASS_Tags/ for reference of tags
    --undeclared tags will use default osd settings
    --these styles will be used for the whole playlist. More specific styling will need to be hacked in
    --
    --(a monospaced font is recommended but not required)
    style_ass_tags = "{\\fnmonospace}",

    --paddings for top left corner
    text_padding_x = 5,
    text_padding_y = 5,

    --other
    menu_timeout = 10,
    youtube_url = "https://www.youtube.com/watch?v=%s",

    -- Fallback Invidious instance, see https://instances.invidio.us/ for alternatives e.g. https://invidious.snopyta.org
    invidious_instance = "https://invidious.xyz",

    -- Keep the width of the window the same when the next video is played
    restore_window_width = false,

    -- On Windows wget.exe may not be able to check SSL certificates for HTTPS, so you can disable checking here
    check_certificate = true,

    -- Use a cookies file
    -- Same as youtube-dl --cookies or wget --load-cookies
    -- If you don't set this, the script may create a cookie file for you
    -- On Windows you need to use a double blackslash or a single fordwardslash
    -- For example "C:\\Users\\Username\\cookies.txt"
    -- Or "C:/Users/Username/cookies.txt"
    cookies = ""
}
(require 'mp.options').read_options(opts, "youtube-upnext")

-- Command line options
if opts.cookies == nil or opts.cookies == "" then
    local raw_options = mp.get_property_native("options/ytdl-raw-options")
    for param, arg in pairs(raw_options) do
        if (param == "cookies") and (arg ~= "") then
            opts.cookies = arg
        end
    end
end

local destroyer = nil
local upnext_cache={}
local prefered_win_width = nil
local last_dheight = nil
local last_dwidth = nil

local function table_size(t)
    local s = 0
    for _, _ in ipairs(t) do
        s = s+1
    end
    return s
end

local function exec(args)
    local ret = utils.subprocess({args = args})
    return ret.status, ret.stdout, ret
end

local function url_encode(s)
    local function repl(x)
        return string.format("%%%02X", string.byte(x))
    end
   return string.gsub(s, "([^0-9a-zA-Z!'()*._~-])", repl)
 end

local function download_upnext(url, post_data)
    local command = {"wget", "-q", "-O", "-"}
    if not opts.check_certificate then
        table.insert(command, "--no-check-certificate")
    end
    if post_data then
        table.insert(command, "--post-data")
        table.insert(command, post_data)
    end
    if opts.cookies then
         table.insert(command, "--load-cookies")
         table.insert(command, opts.cookies)
         table.insert(command, "--save-cookies")
         table.insert(command, opts.cookies)
         table.insert(command, "--keep-session-cookies")
    end
    table.insert(command, url)

    local es, s, _ = exec(command)

    if (es ~= 0) or (s == nil) or (s == "") then
        if es == 5 then
            mp.osd_message("upnext failed: wget does not support HTTPS", 10)
            msg.error("wget is missing certificates, disable check-certificate in userscript options")
        elseif es == -1 or es == 127 or es == 9009 then
            mp.osd_message("upnext failed: wget not found", 10)
            msg.error("wget/ wget.exe is missing. Please install it or put an executable in your PATH")
        else
            mp.osd_message("upnext failed: error=" .. tostring(es), 10)
            msg.error("failed to get upnext list: error=" .. tostring(es))
        end
        return "{}"
    end

    local consent_pos = s:find('action="https://consent.youtube.com/s"')
    if consent_pos ~= nil then
        -- Accept cookie consent form
        msg.debug("Need to accept cookie consent form")
        s = s:sub(s:find(">", consent_pos + 1, true), s:find("</form", consent_pos + 1, true))

        local post_str = ""
        for k, v in string.gmatch(s, "name=\"([^\"]+)\" value=\"([^\"]*)\"") do
            msg.debug("name=" .. tostring(k) .. " value=".. tostring(v))
            post_str = post_str .. url_encode(k) .. "=" ..  url_encode(v) .. "&"
        end
        msg.debug("post-data=" .. tostring(post_str))
        if opts.cookies == nil or opts.cookies == "" then
            opts.cookies = os.getenv("TEMP") .. "/youtube-upnext.cookies"
            msg.warn("Created a cookies jar file at \"" .. tostring(opts.cookies) ..
                "\". To hide this warning, set a cookies file in the script configuration")
        end
        return download_upnext("https://consent.youtube.com/s", post_str)
    end

    local pos1 = string.find(s, "ytInitialData =", 1, true)
    if pos1 == nil then
        mp.osd_message("upnext failed, no upnext data found err01", 10)
        msg.error("failed to find json position 01: pos1=nil")
        return "{}"
    end
    local pos2 = string.find(s, ";%s*</script>", pos1 + 1)
    if pos2 ~= nil then
        s = string.sub(s, pos1 + 15, pos2 - 1)
        return s
    else
        msg.error("failed to find json position 02")
    end

    mp.osd_message("upnext failed, no upnext data found err03", 10)
    msg.error("failed to get upnext data: pos1=" .. tostring(pos1) .. " pos2=" ..tostring(pos2))
    return "{}"
end

local function get_invidious(url)
    -- convert to invidious API call
    url = string.gsub(url, "https://youtube%.com/watch%?v=", opts.invidious_instance .. "/api/v1/videos/")
    url = string.gsub(url, "https://www%.youtube%.com/watch%?v=", opts.invidious_instance .. "/api/v1/videos/")
    url = string.gsub(url, "https://youtu%.be/", opts.invidious_instance .. "/api/v1/videos/")
    msg.debug("Invidious url:" .. url)

    local command = {"wget", "-q", "-O", "-"}
    if not opts.check_certificate then
        table.insert(command, "--no-check-certificate")
    end
    table.insert(command, url)

    local es, s, _ = exec(command)

    if (es ~= 0) or (s == nil) or (s == "") then
        if es == 5 then
            mp.osd_message("upnext failed: wget does not support HTTPS", 10)
            msg.error("wget is missing certificates, disable check-certificate in userscript options")
        elseif es == -1 or es == 127 or es == 9009 then
            mp.osd_message("upnext failed: wget not found", 10)
            msg.error("wget/ wget.exe is missing. Please install it or put an executable in your PATH")
        else
            mp.osd_message("upnext failed: error=" .. tostring(es), 10)
            msg.error("failed to get invidious: error=" .. tostring(es))
        end
        return {}
    end

    local data, err = utils.parse_json(s)
    if data == nil then
        mp.osd_message("upnext fetch failed (Invidious): JSON decode failed", 10)
        msg.error("parse_json failed (Invidious): " .. err)
        return {}
    end

    if data.recommendedVideos then
        local res = {}
        msg.verbose("wget and json decode succeeded! (Invidious)")
        for i, v in ipairs(data.recommendedVideos) do
            table.insert(res, {
                    index=i,
                    label=v.title .. " - " .. v.author,
                    file=string.format(opts.youtube_url, v.videoId)
                })
        end
        mp.osd_message("upnext fetch from Invidious succeeded", 10)
        return res
    elseif data.error then
        mp.osd_message("upnext fetch failed (Invidious): " .. data.error, 10)
        msg.error("Invidious error: " .. data.error)
    else
        mp.osd_message("upnext: No recommended videos! (Invidious)", 10)
        msg.error("No recommended videos! (Invidious)")
    end

    return {}
end


local function parse_upnext(json_str, current_video_url)
    if json_str == "{}" then
      return {}, 0
    end

    local data, err = utils.parse_json(json_str)

    if data == nil then
        mp.osd_message("upnext failed: JSON decode failed", 10)
        msg.error("parse_json failed: " .. tostring(err))
        msg.debug("Corrupted JSON:\n" .. json_str .. "\n")
        return {}, 0
    end

    local res = {}
    msg.verbose("wget and json decode succeeded!")

    local index = 1
    local autoplay_id = nil
    if data.playerOverlays
    and data.playerOverlays.playerOverlayRenderer
    and data.playerOverlays.playerOverlayRenderer.autoplay
    and data.playerOverlays.playerOverlayRenderer.autoplay.playerOverlayAutoplayRenderer then
        local title = data.playerOverlays.playerOverlayRenderer.autoplay.playerOverlayAutoplayRenderer.videoTitle.simpleText
        local video_id = data.playerOverlays.playerOverlayRenderer.autoplay.playerOverlayAutoplayRenderer.videoId
        autoplay_id = video_id
        msg.debug("Found autoplay video")
        table.insert(res, {
            index=index,
            label=title,
            file=string.format(opts.youtube_url, video_id)
        })
        index = index + 1
    end

    if data.playerOverlays
    and data.playerOverlays.playerOverlayRenderer
    and data.playerOverlays.playerOverlayRenderer.endScreen
    and data.playerOverlays.playerOverlayRenderer.endScreen.watchNextEndScreenRenderer
    and data.playerOverlays.playerOverlayRenderer.endScreen.watchNextEndScreenRenderer.results
    then
        local n = table_size(data.playerOverlays.playerOverlayRenderer.endScreen.watchNextEndScreenRenderer.results)
        msg.debug("Found " .. tostring(n) .. " endScreen videos")
        for i, v in ipairs(data.playerOverlays.playerOverlayRenderer.endScreen.watchNextEndScreenRenderer.results) do
            if v.endScreenVideoRenderer
            and v.endScreenVideoRenderer.title
            and v.endScreenVideoRenderer.title.simpleText then
                local title = v.endScreenVideoRenderer.title.simpleText
                local video_id = v.endScreenVideoRenderer.videoId
                if video_id ~= autoplay_id then
                    table.insert(res, {
                        index=index + i,
                        label=title,
                        file=string.format(opts.youtube_url, video_id)
                    })
                end
            end
        end
        index = index + n
    end

    if data.contents
    and data.contents.twoColumnWatchNextResults
    and data.contents.twoColumnWatchNextResults.secondaryResults
    then
        local secondaryResults = data.contents.twoColumnWatchNextResults.secondaryResults
        if secondaryResults.secondaryResults then
            secondaryResults = secondaryResults.secondaryResults
        end
        local n = table_size(secondaryResults.results)
        msg.debug("Found " .. tostring(n) .. " watchNextResults videos")
        for i, v in ipairs(secondaryResults.results) do
            local compactVideoRenderer = nil
            local watchnextindex = index
            if v.compactAutoplayRenderer
            and v.compactAutoplayRenderer
            and v.compactAutoplayRenderer.contents
            and v.compactAutoplayRenderer.contents.compactVideoRenderer then
                compactVideoRenderer = v.compactAutoplayRenderer.contents.compactVideoRenderer
                watchnextindex = 0
            elseif v.compactVideoRenderer then
                compactVideoRenderer = v.compactVideoRenderer
            end
            if compactVideoRenderer
            and compactVideoRenderer.videoId
            and compactVideoRenderer.title
            and compactVideoRenderer.title.simpleText
            then
                local title = compactVideoRenderer.title.simpleText
                local video_id = compactVideoRenderer.videoId
                local video_url = string.format(opts.youtube_url, video_id)
                local duplicate = false
                for _, entry in ipairs(res) do
                    if video_url == entry.file then
                        duplicate = true
                    end
                end
                if not duplicate then
                    table.insert(res, {
                        index=watchnextindex + i,
                        label=title,
                        file=video_url
                    })
                end
            end
        end
    end

    table.sort(res, function(a, b) return a.index < b.index end)

    upnext_cache[current_video_url] = res
    return res, table_size(res)
end


local function load_upnext()
    local url = mp.get_property("path")

    url = string.gsub(url, "ytdl://", "") -- Strip possible ytdl:// prefix.

    if string.find(url, "//youtu.be/") == nil
    and string.find(url, "//www.youtube.co.uk/") == nil
    and string.find(url, "//youtube.com/") == nil
    and string.find(url, "//www.youtube.com/") == nil
    then
        return {}, 0
    end

    -- don't fetch the website if it's already cached
    if upnext_cache[url] ~= nil then
        local res = upnext_cache[url]
        return res, table_size(res)
    end

    local res, n = parse_upnext(download_upnext(url, nil), url)

    -- Fallback to Invidious API
    if n == 0 and opts.invidious_instance and opts.invidious_instance ~= "" then
        res = get_invidious(url)
        n = table_size(res)
    end

    return res, n
end

local function on_file_loaded(_)
    local url = mp.get_property("path")
    url = string.gsub(url, "ytdl://", "") -- Strip possible ytdl:// prefix.
    if string.find(url, "youtu") ~= nil then
        local upnext, num_upnext = load_upnext()
        if num_upnext > 0 then
            mp.commandv("loadfile", upnext[1].file, "append")
        end
    end
end

local function show_menu()
    mp.osd_message("fetching 'up next' with wget...", 60)

    local upnext, num_upnext = load_upnext()
    if num_upnext == 0 then
        return
    end
    mp.osd_message("", 1)

    local timeout
    local selected = 1
    local function choose_prefix(i)
        if i == selected then
            return opts.cursor_selected
        else
            return opts.cursor_unselected
        end
    end
    local function draw_menu()
        local ass = assdraw.ass_new()

        ass:pos(opts.text_padding_x, opts.text_padding_y)
        ass:append(opts.style_ass_tags)

        for i,v in ipairs(upnext) do
            ass:append(choose_prefix(i)..v.label.."\\N")
        end

      local w, h = mp.get_osd_size()
      if opts.scale_playlist_by_window then w,h = 0, 0 end
      mp.set_osd_ass(w, h, ass.text)
    end
    local function selected_move(amt)
        selected = selected + amt
        if selected < 1 then
            selected = num_upnext
        elseif selected > num_upnext then
            selected = 1
        end
        timeout:kill()
        timeout:resume()
        draw_menu()
    end

    local function destroy()
        timeout:kill()
        mp.set_osd_ass(0,0,"")
        mp.remove_key_binding("move_up")
        mp.remove_key_binding("move_down")
        mp.remove_key_binding("select")
        mp.remove_key_binding("escape")
        destroyer = nil
    end
    timeout = mp.add_periodic_timer(opts.menu_timeout, destroy)
    destroyer = destroy

    mp.add_forced_key_binding(opts.up_binding,     "move_up",   function() selected_move(-1) end, {repeatable=true})
    mp.add_forced_key_binding(opts.down_binding,   "move_down", function() selected_move(1)  end, {repeatable=true})
    mp.add_forced_key_binding(opts.select_binding, "select",    function()
        destroy()
        mp.commandv("loadfile", upnext[selected].file, "replace")
    end)
    mp.add_forced_key_binding(opts.toggle_menu_binding, "escape", destroy)

    draw_menu()
    return
end

local function on_window_scale_changed(_, value)
    if value == nil then
        return
    end
    local dwidth = mp.get_property("dwidth")
    local dheight = mp.get_property("dheight")
    if dwidth ~= nil and dheight ~= nil and dwidth == last_dwidth and dheight == last_dheight then
        -- If video size stayed the same, then the scaling was probably done by the user to we save it
        local current_window_scale = mp.get_property("current-window-scale")
        prefered_win_width = dwidth * current_window_scale
    end
end

local function on_dwidth_change(_, value)
    if value == nil then
        return
    end
    local dwidth = mp.get_property("dwidth")
    local dheight = mp.get_property("dheight")
    if dwidth == nil or dheight == nil then
        return
    end

    -- Save new video size
    last_dwidth = dwidth
    last_dheight = dheight

    if prefered_win_width == nil then
        return
    end
    -- Scale window to prefered width
    local current_window_scale = mp.get_property("current-window-scale")
    local window_width = dwidth * current_window_scale
    local new_scale = current_window_scale
    if prefered_win_width ~= nil and math.abs(prefered_win_width - window_width) > 2 then
        new_scale = prefered_win_width / dwidth
    end

    if new_scale ~= current_window_scale then
        mp.set_property("window-scale", new_scale)
    end
end


-- register script message to show menu
mp.register_script_message("toggle-upnext-menu",
function()
    if destroyer ~= nil then
        destroyer()
    else
        show_menu()
    end
end)

-- keybind to launch menu
mp.add_key_binding(opts.toggle_menu_binding, "upnext-menu", show_menu)

if opts.auto_add then
    mp.register_event("file-loaded", on_file_loaded)
end

if opts.restore_window_width then
    mp.observe_property("current-window-scale", "number", on_window_scale_changed)
    mp.observe_property("dwidth", "number", on_dwidth_change)
end