import * as constants from '/static/games/rms/constants.js';

export class Gates {
	constructor() {
		this.x = 200;
		this.y = 40;
		this.v_x = 0;
		this.v_y = 0;
		this.a_x = 0;
		this.a_y = 0;
		this.target_x = 200;
		this.target_y = 40;
		this.health = 1;
	}

	radius() {
		return 30;
	}

	choose_position() {
		const [x, y] = random_position();
		this.target_x = x;
		this.target_y = y;
	}

	act(count) {
		const max_accel = (1 - this.health) * 0.75 + 0.25;
		const max_velocity = (1 - this.health) * 5 + 5;
		let dx = this.target_x - this.x;
		let dy = this.target_y - this.y;
		/* If we've arrived (close and stopped) */
		if (Math.sqrt(dx * dx + dy * dy) < max_velocity / max_accel && Math.sqrt(this.v_x * this.v_x + this.v_y * this.v_y) < 0.01) {
			/* Then pick a new target */
			this.choose_position();

		}

		dx = this.target_x - this.x;
		dy = this.target_y - this.y;
		/* if we're close */
		if (Math.sqrt(dx * dx + dy * dy) < max_velocity / max_accel) {
			/* Then slow down */
			const [x, y] = shorten(-this.v_x, -this.v_y, max_accel);
			this.a_x = x;
			this.a_y = y;
		} else {
			/* Otherwise, speed up */
			const [x, y] = shorten(dx, dy, max_accel);
			this.a_x = x;
			this.a_y = y;
		}

		/* If we're going too fast */
		if (Math.sqrt(this.v_x * this.v_x + this.v_y * this.v_y) > max_velocity) {
			/* Then don't go faster */
			if (Math.sign(this.v_x) == Math.sign(this.a_x)) {
				this.a_x = 0;
			}
			if (Math.sign(this.v_y) == Math.sign(this.a_y)) {
				this.a_y = 0;
			}
		}

		this.v_x += this.a_x;
		this.x += this.v_x;
		this.v_y += this.a_y;
		this.y += this.v_y;
		if (count % 20 === 0) {
			let num_bullets;
			if (this.health >= 0.8) {
				num_bullets = 5;
			} else if (this.health >= 0.7) {
				num_bullets = 6;
			} else if (this.health >= 0.5) {
				num_bullets = 7;
			} else if (this.health >= 0.4) {
				num_bullets = 8;
			} else if (this.health >= 0.3) {
				num_bullets = 9;
			} else if (this.health >= 0.2) {
				num_bullets = 10;
			} else {
				num_bullets = 11;
			}
			const result = [];
			for (let i = 0; i < num_bullets; i++) {
				result.push(random_bullet(this));
			}
			return result;
		} else {
			return [];
		}
	}

	injure(damage) {
		this.health -= damage;
	}

	center() {
		return [16, 23];
	}
}

export class GatesBullet {
	constructor(x, d_x, y, d_y) {
		this.x = x;
		this.y = y;
		this.d_x = d_x;
		this.d_y = d_y;
	}

	radius() {
		return 10;
	}

	center() {
		return [20, 20];
	}
}

function random_position() {
	return [
		Math.random() * (constants.x_dim - 200) + 100,
		Math.random() * 100,
	];
}

function random_bullet(enemy) {
	const multiplier = 2 + 3 * (1 - enemy.health);
	const theta = Math.random() * 2 * Math.PI / 3 + Math.PI / 6;
	const dx = Math.cos(theta) * multiplier;
	const dy = Math.sin(theta) * multiplier;
	return new GatesBullet(enemy.x, dx, enemy.y, dy);
}

function shorten(x, y, maxlen) {
	const len = Math.sqrt(x * x + y * y);
	if (len > maxlen) {
		return [x / len / 2, y / len / 2];
	} else {
		return [x, y];
	}
}