use argh::FromArgs;
use dungeon::*;
use graphics::*;

struct Game {
	window: Window,
	dungeon: Dungeon,
	// to ensure the most recently-pressed direction key is used:
	current_dir: Option<(Direction, Key)>,
}

impl Game {
	fn new(window: Window) -> Self {
		// Initial game state
		let dungeon = Dungeon::new();
		Self {
			window,
			dungeon,
			current_dir: None,
		}
	}

	fn player_dir(&mut self) -> Option<Direction> {
		const MOVE_KEYS: [(Direction, [Key; 2]); 4] = [
			(Direction::North, [Key::Up, Key::W]),
			(Direction::West, [Key::Left, Key::A]),
			(Direction::South, [Key::Down, Key::S]),
			(Direction::East, [Key::Right, Key::D]),
		];

		// if a key was just pressed, use it for the new direction to move in
		for (dir, keys) in MOVE_KEYS {
			for key in keys {
				if self.window.is_key_pressed(key) {
					self.current_dir = Some((dir, key));
					return Some(dir);
				}
			}
		}
		// otherwise, use existing direction, so long as the key is still down
		match self.current_dir {
			Some((dir, key)) if self.window.is_key_down(key) => return Some(dir),
			_ => self.current_dir = None,
		}
		// otherwise, use any key that is already down
		for (dir, keys) in MOVE_KEYS {
			for key in keys {
				if self.window.is_key_down(key) {
					self.current_dir = Some((dir, key));
					return Some(dir);
				}
			}
		}
		// otherwise, no direction key is pressed, so return None
		None
	}

	fn run(&mut self) {
		// Main game loop
		while self.window.is_open() {
			// Handle keyboard input
			if self.window.is_key_pressed(Key::F3) {
				self.window.toggle_debug();
			}

			let inputs = PlayerInput {
				direction: self.player_dir(),
			};

			// Update game state
			self.dungeon.update(inputs, self.window.delta_time());

			// Draw a single frame
			self.window.draw_frame(&self.dungeon);
		}
	}
}

/// Play a dungeon crawl game
#[derive(FromArgs)]
struct Args {
	/// enable vsync
	#[argh(switch)]
	vsync: bool,
	/// enable verbose logging
	#[argh(switch, short = 'v')]
	verbose: bool,
}

fn main() -> Result<()> {
	// Parse arguments
	let args: Args = argh::from_env();
	// Load the window
	let window = WindowBuilder::new()
		.vsync(args.vsync)
		.verbose(args.verbose)
		.build()?;
	Game::new(window).run();
	Ok(())
}