import { World } from './world';
import { addBridge } from 'scriptcraft-core';
import { PlayerEntity } from './entity';
import { ActionResult, Hand, Pos, Direction } from './core';

/**
 * Event
 */
class Event<T, K> {
    /**
     * @internal
     */
    #listeners: ((obj: T) => K)[] = [];
    /**
     * @internal
     */
    #defaultValue: K;

    /**
     * @internal
     */
    constructor(defaultValue: K) {
        this.#defaultValue = defaultValue;
    }

    /**
     * Add Event Listener
     * @param listener Event Listener
     */
    addListener(listener: (obj: T) => K): void {
        this.#listeners.push(listener);
    }

    /**
     * Remove Event Listener
     * @param listener Event Listener
     */
    removeListener(listener: (obj: T) => K): void {
        const index = this.#listeners.indexOf(listener, 0);
        if (index > -1) {
            this.#listeners.splice(index, 1);
        }
    }

    /**
     * @internal
     */
    run(obj: T): K {
        for (const listener of this.#listeners) {
            const value = listener(obj);
            if (this.#defaultValue !== null && value != this.#defaultValue) {
                return value;
            }
        }
        return this.#defaultValue;
    }
}

/**
 * Tick Event
 */
class WorldTickEvent {
    /**
     * @internal
     */
    readonly #world: World;

    /**
     * Get World
     * @returns World
     */
    getWorld(): World {
        return this.#world;
    }

    /**
     * @internal
     */
    constructor(world: World) {
        this.#world = world;
    }
}

/**
 * Block Event
 */
class BlockEvent {
    /**
     * @internal
     */
    readonly #world: World;
    /**
     * @internal
     */
    readonly #player: PlayerEntity;
    /**
     * @internal
     */
    readonly #hand: Hand;
    /**
     * @internal
     */
    readonly #pos: Pos;
    /**
     * @internal
     */
    readonly #side: Direction;

    /**
     * Get World
     * @returns World
     */
    getWorld(): World {
        return this.#world;
    }

    /**
     * Get Player
     * @returns Player
     */
    getPlayer(): PlayerEntity {
        return this.#player;
    }

    /**
     * Get Hand
     * @returns Hand
     */
    getHand(): Hand {
        return this.#hand;
    }

    /**
     * Get Block Position
     * @returns Block Position
     */
    getPos(): Pos {
        return this.#pos;
    }

    /**
     * Get Block Side
     * @returns Block Side
     */
    getSide(): Direction {
        return this.#side;
    }

    /**
     * @internal
     */
    constructor(player: PlayerEntity, world: World, hand: Hand, pos: Pos, side: Direction) {
        this.#player = player;
        this.#world = world;
        this.#hand = hand;
        this.#pos = pos;
        this.#side = side;
    }
}

/**
 * Item Event
 */
class ItemEvent {
    /**
     * @internal
     */
    readonly #world: World;
    /**
     * @internal
     */
    readonly #player: PlayerEntity;
    /**
     * @internal
     */
    readonly #hand: Hand;

    /**
     * Get World
     * @returns World
     */
    getWorld(): World {
        return this.#world;
    }

    /**
     * Get Player
     * @returns Player
     */
    getPlayer(): PlayerEntity {
        return this.#player;
    }

    /**
     * Get Hand
     * @returns Hand
     */
    getHand(): Hand {
        return this.#hand;
    }

    /**
     * @internal
     */
    constructor(player: PlayerEntity, world: World, hand: Hand) {
        this.#player = player;
        this.#world = world;
        this.#hand = hand;
    }
}

/**
 * All Events
 */
export class Events {
    /**
     * World Tick Event
     */
    static WORLD_TICK = new Event<WorldTickEvent, void>(null);
    /**
     * Attack Block Event
     */
    static ATTACK_BLOCK = new Event<BlockEvent, ActionResult>(ActionResult.PASS);
    /**
     * Use Block Event
     */
    static USE_BLOCK = new Event<BlockEvent, ActionResult>(ActionResult.PASS);
    /**
     * Use Item Event
     */
    static USE_ITEM = new Event<ItemEvent, ActionResult>(ActionResult.PASS);
}

addBridge('Event.worldTick', (world: JavaObject) => Events.WORLD_TICK.run(new WorldTickEvent(new World(world))));
addBridge('Event.attackBlock', (player: JavaObject, world: JavaObject, hand: keyof typeof Hand, x: number, y: number, z: number, side: keyof typeof Direction) => Events.ATTACK_BLOCK.run(new BlockEvent(new PlayerEntity(player), new World(world), Hand[hand], new Pos(x, y, z), Direction[side])));
addBridge('Event.useBlock', (player: JavaObject, world: JavaObject, hand: keyof typeof Hand, x: number, y: number, z: number, side: keyof typeof Direction) => Events.USE_BLOCK.run(new BlockEvent(new PlayerEntity(player), new World(world), Hand[hand], new Pos(x, y, z), Direction[side])));
addBridge('Event.useItem', (player: JavaObject, world: JavaObject, hand: keyof typeof Hand) => Events.USE_ITEM.run(new ItemEvent(new PlayerEntity(player), new World(world), Hand[hand])));