#[cfg(feature = "buddy-alloc")]
mod alloc;
mod sh0rk;
mod sprites;

use fastrand::Rng;
use sh0rk::{
    palette,
    sys::*,
    Direction::{self, *},
    Song, Point, Rect,
};

static mut GAME: Game = Game::new();

struct Game {
    frame_count: u32,
    prev_gamepad: u8,
    rng: Option<Rng>,
    mai_position: Point,
    mara_position: Point,
    mara_frame: u32,
    mara_dir: Direction,
    mara_speed: i32,
    bonk_timer: Option<u8>,
    gate_count: u8,
    gate_pos: Point,

    song: Song<48>,
}

impl Game {
    const fn new() -> Self {
        Self {
            frame_count: 0,
            prev_gamepad: 0,
            rng: None,
            mai_position: Point { x: 76, y: 32 },
            mara_position: Point { x: 32, y: 90 },
            mara_frame: 0,
            mara_dir: Right,
            mara_speed: 0,
            bonk_timer: None,
            gate_count: 4,
            gate_pos: Point { x: 40, y: 64 },
            song: Song::new(sh0rk::CHOPSTICKS),
        }
    }

    fn bonk(&mut self) {
        if self.bonk_timer.is_some() {
            return;
        }

        tone(220 | (40 << 16), 6 | (6 << 8), 50, TONE_TRIANGLE);
        self.bonk_timer = Some(12);
    }

    fn mara_walk(&mut self) {
        if self.mara_speed == 0 {
            return;
        }

        if self.frame_count % 15 == 0 {
            self.mara_frame = if self.mara_frame == 1 { 0 } else { 1 };
        }

        if self.frame_count % 4 == 0 {
            if self.mara_dir == Right && self.mara_position.x >= 144 {
                self.mara_speed = 0;
                self.mara_position.x = 144;
                self.bonk();
            }
            if self.mara_dir == Down && self.mara_position.y >= 120 {
                self.mara_speed = 0;
                self.mara_position.y = 120;
                self.bonk();
            }
            if self.mara_dir == Left && self.mara_position.x <= 0 {
                self.mara_speed = 0;
                self.mara_position.x = 0;
                self.bonk();
            }
            if self.mara_dir == Up && self.mara_position.y <= 64 {
                self.mara_speed = 0;
                self.mara_position.y = 64;
                self.bonk();
            }

            match self.mara_dir {
                Left => self.mara_position.x -= self.mara_speed,
                Right => self.mara_position.x += self.mara_speed,
                Up => self.mara_position.y -= self.mara_speed,
                Down => self.mara_position.y += self.mara_speed,
            };
        }
    }

    fn update(&mut self) {
        self.frame_count += 1;
        self.song.update();

        if let Some(rem) = self.bonk_timer {
            if rem == 0 {
                self.bonk_timer = None;
            } else {
                self.bonk_timer = Some(rem - 1);
            }
        }

        self.mara_speed = 0;

        let gamepad = unsafe { *GAMEPAD1 };
        let just_pressed = gamepad & (gamepad ^ self.prev_gamepad);

        let speed = if just_pressed & BUTTON_2 != 0 { 4 } else { 2 };
        if just_pressed & BUTTON_1 != 0 {
            self.song.pause();
        }

        if gamepad & BUTTON_UP != 0 {
            self.mara_dir = Up;
            self.mara_speed = speed;
        }

        if gamepad & BUTTON_DOWN != 0 {
            self.mara_dir = Down;
            self.mara_speed = speed;
        }

        if gamepad & BUTTON_LEFT != 0 {
            self.mara_dir = Left;
            self.mara_speed = speed;
        }

        if gamepad & BUTTON_RIGHT != 0 {
            self.mara_dir = Right;
            self.mara_speed = speed;
        }
        self.prev_gamepad = gamepad;

        self.mara_walk();

        let player = Rect {
            base: self.mara_position.clone(),
            width: 16,
            height: 16,
        };
        let gate = Rect {
            base: self.gate_pos.clone(),
            width: 12,
            height: 4 * self.gate_count as i32,
        };
        if player.collides(&gate) {
            self.mara_speed = 0;
            match self.mara_dir {
                Right => self.mara_position = self.mara_position.add((-2, 0)),
                Left => self.mara_position = self.mara_position.add((2, 0)),
                Up => self.mara_position = self.mara_position.add((0, 2)),
                Down => self.mara_position = self.mara_position.add((0, -2)),
            };
            self.bonk();
        }

        // draw
        for i in 0..self.gate_count {
            let mut gate = self.gate_pos.clone();
            gate.y = gate.y + (sprites::GATE.height * i as u32) as i32;
            sprites::GATE.draw(gate, 0);
        }
        palette::set_draw_color(4);
        line(
            self.gate_pos.x + 1,
            self.gate_pos.y - 1,
            self.gate_pos.x + 10,
            self.gate_pos.y - 1,
        );

        palette::set_draw_color(2);
        text("Mara: Sh0rk of\nJustice 2", 10, 10);
        palette::set_draw_color(4);
        text("From Within, 2022", 10, 144);

        sprites::MAI.draw(self.mai_position, 0);
        sprites::MARA.draw(self.mara_dir, self.mara_frame, self.mara_position, 0);
    }
}

#[no_mangle]
unsafe fn start() {
    palette::en4();
    GAME.rng = Some(Rng::with_seed(420));
}

#[no_mangle]
unsafe fn update() {
    GAME.update();
}