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 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 difficultyNumbers;

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

local selectedIndex = 1;
local selectedDifficulty = 1;

local jacketCache = {}

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 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

    -- 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, 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[song.difficulties[selectedDifficulty].difficulty+1], 1, 0)

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

end

function drawSongList()
    drawSong(songwheel.songs[selectedIndex-2], desh/2-172/2-172*2)
    drawSong(songwheel.songs[selectedIndex-1], desh/2-172/2-172)
    drawSong(songwheel.songs[selectedIndex], desh/2-172/2)
    drawSong(songwheel.songs[selectedIndex+1], desh/2-172/2+172)
    drawSong(songwheel.songs[selectedIndex+2], desh/2-172/2+172*2)
end

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

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

    drawBackground();

    drawSongList()

    gfx.BeginPath();
    gfx.FontSize(18)
    gfx.TextAlign(gfx.TEXT_ALIGN_LEFT + gfx.TEXT_ALIGN_TOP)
    gfx.Text('DELTA: ' .. deltaTime .. ' // SELECTED_INDEX: ' .. selectedIndex .. ' // SELECTED_DIFF: ' .. selectedDifficulty .. ' // #JACKET_CACHE: ' .. #jacketCache, 8, 8);
end

set_index = function(newIndex)
    selectedIndex = newIndex;
end;

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