import { Component, director, macro } from "cc";
export default class CountDownSchedule extends Component {
    private _lastUpdate = null;
    private _observers = null;

    public constructor() {
        super();
        this._observers = [];
        this._lastUpdate = (new Date()).getTime();
    };

    /**
     * 启动一个计时器
     * @param callback 每次回调
     * @param interval 执行间隔
     * @param key 计时器标识，用于移除使用
     * @example
     * <pre>
     *        private const = 0
     *        Global.cdSchedule.schedule(() => {
     *            this.const++;
     *            console.log(this.const);
     *            if (this.const == 10) {
     *                Global.cdSchedule.unschedule("test");
     *             }
     *         }, 1, "test");
     * </pre>
     */
    public schedule(callback, interval, key) {
        if (this._observers.length <= 0) {

            this._lastUpdate = (new Date()).getTime();
            director.getScheduler().schedule(this.onUpdateTime.bind(this), this, 0.05, macro.REPEAT_FOREVER, 0, false);
        }

        let obj = new CountDownObserver(callback, interval, key);
        this._observers.push(obj);
    }

    public onUpdateTime(dt: number) {
        let now = (new Date()).getTime();
        let deltaTime = (now - this._lastUpdate) / 1000;
        this._lastUpdate = now;

        for (let i = 0; i < this._observers.length; i++) {

            if (this._observers[i] && this._observers[i].update) {
                this._observers[i].update(deltaTime);
            }
        }

        return false;
    }

    /**
     * 通过计时器标识查找计时器是否存在
     * @param key 计时器标识
     * @returns 
     */
    public isScheduled(key) {
        for (let i = 0; i < this._observers.length; i++) {
            if (this._observers[i]._key == key) {
                return true;
            }
        }

        return false;
    }

    /**
     * 移除计时器
     * @param key 计时器标识
     */
    public unschedule(key) {
        for (let i = 0; i < this._observers.length; i++) {
            if (this._observers[i]._key == key) {
                this._observers.splice(i, 1);
                break;
            }
        }
    }

    /**
     * 移除所以计时器
     */
    public unscheduleAll() {
        director.getScheduler().unscheduleAllForTarget(this);
        this._observers = [];
    }
    public changeScheduleKey(oldKey, newKey) {
        for (let i = 0; i < this._observers.length; i++) {
            if (this._observers[i]._key == oldKey) {
                this._observers[i]._key = newKey;
                break;
            }
        }
    }
};


class CountDownObserver {
    private _interval = 0;
    private _elapsed = 0;
    private _callback = null;
    private _key = null;

    public constructor(callback, interval, key) {
        this._callback = callback;
        this._interval = interval;
        this._key = key;
    }

    public update(dt) {
        this._elapsed += dt;
        if (this._elapsed > this._interval) {
            if (this._callback) {
                this._callback(this._elapsed);
            }

            this._elapsed = 0.0;
        }
    }
}