local mp = require 'mp'
local msg = require 'mp.msg'
local opt = require 'mp.options'

--script options, set these in script-opts
local o = {
    --change to disable automatic mode switching
    auto = true,

    --profile to call when valid extension is found
    profile = "music",

    --runs this profile when in music mode and a non-audio file is loaded
    --you should essentially put all your defaults that the music profile changed in here
    undo_profile = "",

    --start playback in music mode. This setting is only applied when the player is initially started,
    --changing this option during runtime does nothing.
    --probably only useful if auto is disabled
    enable = false,

    --the script will also enable the following input section when music mode is enabled
    --see the mpv manual for details on sections
    input_section = "music",

    --dispays the metadata of the track on the osd when music mode is on
    --there is also a script message to enable this seperately
    show_metadata = false
}

opt.read_options(o, 'musicmode', function() msg.verbose('options updated') end)

--a music file is one where mpv returns an audio stream or coverart as the first track
local function is_audio_file()
    local track_list = mp.get_property_native("track-list")

    local has_audio = false
    for _, track in ipairs(track_list) do
        if track.type == "audio" then has_audio = true
        elseif not track.albumart and (track["demux-fps"] or 2) > 1 then return false end
    end
    return has_audio
end

local metadata = mp.create_osd_overlay('ass-events')
metadata.hidden = not o.show_metadata

local function update_metadata()
    metadata.data = mp.get_property_osd('filtered-metadata')
    metadata:update()
end

local function enable_metadata()
    metadata.hidden = false
    metadata:update()
end

local function disable_metadata()
    metadata.hidden = true
    metadata:remove()
end

--changes visibility of metadata
local function show_metadata(command)
    if command == "on" or command == nil then
        enable_metadata()
    elseif command == "off" then
        disable_metadata()
    elseif command == "toggle" then
        if metadata.hidden then
            enable_metadata()
        else
            disable_metadata()
        end
    else
        msg.warn('unknown command "' .. command .. '"')
    end
end

--to prevent superfluous loading of profiles the script keeps track of when music mode is enabled
local musicMode = false

--enables music mode
local function activate()
    mp.commandv('apply-profile', o.profile)
    mp.commandv('enable-section', o.input_section, "allow-vo-dragging+allow-hide-cursor")
    mp.osd_message('Music Mode enabled')

    if o.show_metadata then
        show_metadata("on")
    end

    musicMode = true
end

--disables music mode
local function deactivate()
    mp.commandv('apply-profile', o.undo_profile)
    mp.commandv('disable-section', o.input_section)
    mp.osd_message('Music Mode disabled')

    if o.show_metadata then
        show_metadata('off')
    end

    musicMode = false
end

local function main()
    --if the file is an audio file then the music profile is loaded
    if is_audio_file() then
        msg.verbose('audio file, applying profile "' .. o.profile .. '"')
        if not musicMode then
            activate()
        end
    elseif o.undo_profile ~= "" and musicMode then
        msg.verbose('video file, applying undo profile "' .. o.undo_profile .. '"')
        deactivate()
    end
end

--sets music mode from script-message
local function script_message(command)
    if command == "on" or command == nil then
        activate()
    elseif command == "off" then
        deactivate()
    elseif command == "toggle" then
        if musicMode then
            deactivate()
        else
            activate()
        end
    else
        msg.warn('unknown command "' .. command .. '"')
    end
end

local function lock()
    o.auto = false
    msg.info('Music Mode locked')
    mp.osd_message('Music Mode locked')
end

local function unLock()
    o.auto = true
    msg.info('Music Mode unlocked')
    mp.osd_message('Music Mode unlocked')
end

--toggles lock
local function lock_script_message(command)
    if command == "on" or command == nil then
        lock()
    elseif command == "off" then
        unLock()
    elseif command == "toggle" then
        if o.auto then
            lock()
        else
            unLock()
        end
    else
        msg.warn('unknown command "' .. command .. '"')
    end
end

--runs when the file is loaded, if script is locked it will do nothing
local function file_loaded()
    if o.auto then
        main()
    end
end

if o.enable then
    activate()
end

--sets music mode
--accepts arguments: 'on', 'off', 'toggle'
mp.register_script_message('music-mode', script_message)

--stops the script from switching modes on file loads
----accepts arguments: 'on', 'off', 'toggle'
mp.register_script_message('music-mode-lock', lock_script_message)

--shows file metadata on osc
--accepts arguments: 'on' 'off' 'toggle'
mp.register_script_message('show-metadata', show_metadata)

mp.add_hook('on_preloaded', 40, file_loaded)
mp.observe_property('filtered-metadata', 'string', update_metadata)