# This file defines a World object for keeping track of everything, as well
# as the collision logic.
use ./player.tm
use ./raylib.tm
use ./box.tm

# Return a displacement relative to `a` that will push it out of `b`
func solve_overlap(a_pos:Vector2, a_size:Vector2, b_pos:Vector2, b_size:Vector2 -> Vector2)
    a_left := a_pos.x
    a_right := a_pos.x + a_size.x
    a_top := a_pos.y
    a_bottom := a_pos.y + a_size.y

    b_left := b_pos.x
    b_right := b_pos.x + b_size.x
    b_top := b_pos.y
    b_bottom := b_pos.y + b_size.y

    # Calculate the overlap in each dimension
    overlap_x := (a_right _min_ b_right) - (a_left _max_ b_left)
    overlap_y := (a_bottom _min_ b_bottom) - (a_top _max_ b_top)

    # If either axis is not overlapping, then there is no collision:
    if overlap_x <= 0 or overlap_y <= 0
        return Vector2(0, 0)

    if overlap_x < overlap_y
        if a_right > b_left and a_right < b_right
            return Vector2(-(overlap_x), 0)
        else if a_left < b_right and a_left > b_left
            return Vector2(overlap_x, 0)
    else
        if a_top < b_bottom and a_top > b_top
            return Vector2(0, overlap_y)
        else if a_bottom > b_top and a_bottom < b_bottom
            return Vector2(0, -overlap_y)

    return Vector2(0, 0)

struct World(player:@Player, goal:@Box, boxes:@[@Box], dt_accum=Num32(0.0), won=no)
    DT := (Num32(1.)/Num32(60.))
    STIFFNESS := Num32(0.3)

    func update(w:@World, dt:Num32)
        w.dt_accum += dt
        while w.dt_accum > 0
            w.update_once()
            w.dt_accum -= World.DT

    func update_once(w:@World)
        w.player.update()

        if solve_overlap(w.player.pos, Player.SIZE, w.goal.pos, w.goal.size) != Vector2(0,0)
            w.won = yes

        # Resolve player overlapping with any boxes:
        for i in 3
            for b in w.boxes
                w.player.pos += World.STIFFNESS * solve_overlap(w.player.pos, Player.SIZE, b.pos, b.size)

    func draw(w:@World)
        for b in w.boxes
            b.draw()
        w.goal.draw()
        w.player.draw()

        if w.won
            DrawText(CString("WINNER"), GetScreenWidth()/Int32(2)-Int32(48*3), GetScreenHeight()/Int32(2)-Int32(24), 48, Color(0,0,0))

    func load_map(w:@World, map:Text)
        if map.has("[]")
            map = map.translate({"[]"="#", "@ "="@", "  "=" "})
        w.boxes = @[]
        box_size := Vector2(50., 50.)
        for y,line in map.lines()
            for x,cell in line.split()
                if cell == "#"
                    pos := Vector2((Num32(x)-1) * box_size.x, (Num32(y)-1) * box_size.y)
                    box := @Box(pos, size=box_size, color=Color(0x80,0x80,0x80))
                    w.boxes.insert(box)
                else if cell == "@"
                    pos := Vector2((Num32(x)-1) * box_size.x, (Num32(y)-1) * box_size.y)
                    pos += box_size/Num32(2) - Player.SIZE/Num32(2)
                    w.player = @Player(pos,pos)
                else if cell == "?"
                    pos := Vector2((Num32(x)-1) * box_size.x, (Num32(y)-1) * box_size.y)
                    w.goal.pos = pos