local Easing = require('common.easings');

local backgroundImage = gfx.CreateSkinImage("song_select/bg.png", 1)
local songPlateBg = gfx.CreateSkinImage("song_select/plate/bg.png", 1)
local songPlateBottomBarOverlayImage = gfx.CreateSkinImage("song_select/plate/bottom_bar_overlay.png", 1)

local cursorImage = gfx.CreateSkinImage("song_select/cursor.png", 1)

local defaultJacketImage = gfx.CreateSkinImage("song_select/loading.png", 0)

local difficultyLabelImages = {
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/novice.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/advanced.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/exhaust.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/maximum.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/infinite.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/gravity.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/heavenly.png", 1),
    gfx.CreateSkinImage("song_select/plate/difficulty_labels/vivid.png", 1),
}

local badgeImages = {
    gfx.CreateSkinImage("song_select/medal/nomedal.png", 1),
    gfx.CreateSkinImage("song_select/medal/played.png", 1),
    gfx.CreateSkinImage("song_select/medal/clear.png", 1),
    gfx.CreateSkinImage("song_select/medal/hard.png", 1),
    gfx.CreateSkinImage("song_select/medal/uc.png", 1),
    gfx.CreateSkinImage("song_select/medal/puc.png", 1),
}

game.LoadSkinSample('song_wheel/cursor_change.wav');

local difficultyNumbers;

local resx, resy = game.GetResolution()
local desw, desh;
local scale;

local songPlateHeight = 172;

local selectedIndex = 1;
local selectedDifficulty = 1;

local jacketCache = {}

local transitionScrollScale = 0;
local transitionScrollOffsetY = 0;
local scrollingUp = false;

function resetLayoutInformation()
    resx, resy = game.GetResolution()
    desw = 1080
    desh = 1920
    scale = resx / desw
end

function load_number_image(path)
    local images = {}
    for i = 0, 9 do
        images[i + 1] = gfx.CreateSkinImage(string.format("%s/%d.png", path, i), 0)
    end
    return images
end

function draw_number(x, y, alpha, num, digits, images, is_dim, scale, kern)
    scale = scale or 1;
	kern = kern or 1;
	local tw, th = gfx.ImageSize(images[1])
	tw = tw * scale;
	th = th * scale;
    x = x + (tw * (digits - 1)) / 2
    y = y - th / 2
    for i = 1, digits do
        local mul = 10 ^ (i - 1)
        local digit = math.floor(num / mul) % 10
        local a = alpha
        if is_dim and num < mul then
            a = 0.4
        end
        gfx.BeginPath()
        gfx.ImageRect(x, y, tw, th, images[digit + 1], a, 0)
        x = x - (tw * kern)
    end
end

function getCorrectedIndex(from, offset) 
	total = #songwheel.songs;

	index = from + offset;

	if index < 1 then
		index = total + (from+offset) -- this only happens if the offset is negative
	end;

	if index > total then
		indexesUntilEnd = total - from;
		index = offset - indexesUntilEnd -- this only happens if the offset is positive
	end;

	return index;
end;

function getJacketImage(song)
    if not jacketCache[song.id] then
        jacketCache[song.id] = gfx.CreateImage(song.difficulties[1].jacketPath, 0)
    end

    return jacketCache[song.id];
end

function drawBackground()
    gfx.BeginPath()
    gfx.ImageRect(0, 0, desw, desh, backgroundImage, 1, 0)
end

function drawSong(song, y)
    local songX = desw/2+28
    local selectedSongDifficulty = song.difficulties[selectedDifficulty]
    local bestScore = selectedSongDifficulty.scores[1] or nil;

    -- Draw the bg for the song plate
    gfx.BeginPath()
    gfx.ImageRect(songX, y, 515, 172, songPlateBg, 1, 0)
    
    -- Draw jacket
    local jacketImage = getJacketImage(song);
    gfx.BeginPath()
    gfx.ImageRect(songX+4, y+4, 163, 163, jacketImage or defaultJacketImage, 1, 0)

    -- Draw the overlay for the song plate (that bottom black bar)
    gfx.BeginPath()
    gfx.ImageRect(songX, y, 515, 172, songPlateBottomBarOverlayImage, 1, 0)
    
    -- Draw the difficulty notch background
    gfx.BeginPath()
    gfx.ImageRect(songX, y+95, 83, 74, difficultyLabelImages[selectedSongDifficulty.difficulty+1], 1, 0)

    -- Draw the difficulty level number
    gfx.BeginPath()
    draw_number(songX+30, y+125, 1.0, selectedSongDifficulty.level, 2, difficultyNumbers, false, 0.65, 1)

    -- Draw score badge
    local badgeImage = badgeImages[1];
    if bestScore then
        badgeImage = badgeImages[bestScore.badge+1];
    end


    gfx.BeginPath()
    gfx.ImageRect(songX+282, y+44, 79, 69, badgeImage, 1, 0)
end

function drawSongList()
    local numOfSongsAround = 7; -- How many songs should be up and how many should be down of the selected one


    local i=1;
    while (i <= numOfSongsAround) do
        local songIndex = getCorrectedIndex(selectedIndex, -i)
        drawSong(songwheel.songs[songIndex], desh/2-songPlateHeight/2-songPlateHeight*i + transitionScrollOffsetY)
        i=i+1;
    end;
    
    -- Draw the selected song
    drawSong(songwheel.songs[selectedIndex], desh/2-songPlateHeight/2 + transitionScrollOffsetY)

    i=1;
    while (i <= numOfSongsAround) do
        local songIndex = getCorrectedIndex(selectedIndex, i)
        drawSong(songwheel.songs[songIndex], desh/2-songPlateHeight/2+songPlateHeight*i + transitionScrollOffsetY)
        i=i+1;
    end;
end

function drawCursor()
    gfx.BeginPath()
    gfx.ImageRect(desw/2-14, desh/2-213/2, 555, 213, cursorImage, 1, 0)
end

function tickTransitions(deltaTime)
    if transitionScrollScale < 1 then
        transitionScrollScale = transitionScrollScale + deltaTime / 0.1 -- transition should last for that time in seconds
    else
        transitionScrollScale = 1
    end

    if scrollingUp then 
        transitionScrollOffsetY = Easing.inQuad(1-transitionScrollScale) * songPlateHeight;
    else
        transitionScrollOffsetY = Easing.inQuad(1-transitionScrollScale) * -songPlateHeight;
    end
end

render = function (deltaTime)
    resetLayoutInformation();
    tickTransitions(deltaTime);
    gfx.Scale(scale, scale);

    if not difficultyNumbers then
        difficultyNumbers = load_number_image('diff_num')
    end

    drawBackground();

    drawSongList()
    drawCursor()


    gfx.BeginPath();
    gfx.FontSize(18)
    gfx.TextAlign(gfx.TEXT_ALIGN_LEFT + gfx.TEXT_ALIGN_TOP)
    local debugScrollingUp= "FALSE"
    if scrollingUp then debugScrollingUp = "TRUE" end;
    gfx.Text('DELTA: ' .. deltaTime .. ' // SELECTED_INDEX: ' .. selectedIndex .. ' // SELECTED_DIFF: ' .. selectedDifficulty .. ' // SCROLLING_UP: ' .. debugScrollingUp, 8, 8);
end

set_index = function(newIndex)
    transitionScrollScale = 0;

	scrollingUp = false;
	if ((newIndex > selectedIndex and not (newIndex == #songwheel.songs and selectedIndex == 1)) or (newIndex == 1 and selectedIndex == #songwheel.songs)) then
		scrollingUp = true;
	end;

	game.PlaySample('song_wheel/cursor_change.wav');

    selectedIndex = newIndex;
end;

set_diff = function(newDiff)
    selectedDifficulty = newDiff;
end;