package asteroids

import rl "vendor:raylib"
import "core:math"
import "core:fmt"

SCREEN_WIDTH : i32 = 1280
SCREEN_HEIGHT : i32 = 720

SCALE: f32 = 0.5
SHIP_W: f32 = 70 * SCALE
SHIP_H: f32 = 100 * SCALE

THRUST_SPEED : f32 = 0.03
ANGULAR_SPEED : f32 = 2.5

Vec2 :: [2]f32

GameState :: struct {
    ship_pos: Vec2,
    ship_angle: f32,
    ship_vel: Vec2,
    dt: f32,
}

rotate_vec2 :: proc(v : Vec2, angle: f32) -> Vec2 {
    return {
        v.x * math.cos(angle) - v.y * math.sin(angle),
        v.x * math.sin(angle) + v.y * math.cos(angle),
    }
}

get_ship_shape :: proc(s : GameState) -> (Vec2, Vec2, Vec2, Vec2) {
    v1 := rotate_vec2({ SHIP_H*0.5,   0},          s.ship_angle) + s.ship_pos
    v2 := rotate_vec2({-SHIP_H*0.5,  -SHIP_W*0.5}, s.ship_angle) + s.ship_pos
    v3 := rotate_vec2({-SHIP_H*0.5*0.5, 0},        s.ship_angle) + s.ship_pos
    v4 := rotate_vec2({-SHIP_H*0.5,   SHIP_W*0.5}, s.ship_angle) + s.ship_pos
    return v1, v2, v3, v4
}

main :: proc() {
    rl.SetTraceLogLevel(.ERROR)
    rl.InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Asteroids")

    s := GameState{{0,0}, -math.PI / 2, {0,0}, rl.GetFrameTime()}
    s.ship_pos = {600, 350}

    bw := f32(SCREEN_WIDTH)
    bh := f32(SCREEN_HEIGHT)

    for !rl.WindowShouldClose() {
        s.dt = rl.GetFrameTime()
        if rl.IsKeyDown(.D) {
            s.ship_angle += ANGULAR_SPEED * s.dt
        }
        if rl.IsKeyDown(.A) {
            s.ship_angle -= ANGULAR_SPEED * s.dt
        }
        if rl.IsKeyDown(.W) {
            s.ship_vel.x += math.cos(s.ship_angle) * THRUST_SPEED * s.dt
            s.ship_vel.y += math.sin(s.ship_angle) * THRUST_SPEED * s.dt
        }

        s.ship_pos += s.ship_vel * (5000 * s.dt)


        if s.ship_pos.x + SHIP_W < 0  { s.ship_pos.x = bw + SHIP_W}
        if s.ship_pos.x - SHIP_W > bw { s.ship_pos.x = SHIP_W}
        if s.ship_pos.y +  < 0  { s.ship_pos.y = bh}
        if s.ship_pos.y > bh { s.ship_pos.y = 0}

        rl.BeginDrawing()
        rl.ClearBackground(rl.BLACK)

        // Draw ship
        v1, v2, v3, v4 := get_ship_shape(s)
        rl.DrawLineEx(v1, v2, 1, rl.WHITE)
        rl.DrawLineEx(v2, v3, 1, rl.WHITE)
        rl.DrawLineEx(v3, v4, 1, rl.WHITE)
        rl.DrawLineEx(v4, v1, 1, rl.WHITE)

        rl.EndDrawing()
    }

    rl.CloseWindow()
}