import { Observable } from 'rxjs';
import { RxAVClient, RxAVObject, RxAVQuery, RxAVUser, RxAVApp } from '../RxLeanCloud';

/**
 * 一条推送消息
 * 
 * @export
 * @class RxAVPush
 */
export class RxAVPush {

    query: RxAVQuery;
    channels: Array<string>;
    expiration: Date;
    pushTime: Date;
    expirationInterval: number;
    data: { [key: string]: any };
    alert: string;
    prod: string;

    constructor() {
        this.query = new RxAVQuery('_Installation');
    }

    /**
     * 发送推送给符合查询条件的 _Installation
     * 
     * @static
     * @param {Object} data:{(string | { [key: string]: any })} 
     * @param {Object} filter:{{
     *         channels?: Array<string>,
     *         query?: RxAVQuery,
     *         prod?: string
     *     }} 
     * @returns {Observable<boolean>} 返回是否成功刚发送
     * 
     * @memberOf RxAVPush
     */
    public static sendContent(data: string | { [key: string]: any }, filter: {
        channels?: Array<string>,
        query?: RxAVQuery,
        prod?: string
    }) {
        let push = new RxAVPush();
        if (typeof data === 'string') {
            push.alert = data;
        } else {
            push.data = data;
        }
        if (filter.channels)
            push.channels = filter.channels;
        if (filter.query)
            push.query = filter.query;
        if (filter.prod) {
            push.prod = filter.prod;
        }
        return push.send();
    }

    /**
     * 向 RxAVUser 发送推送消息
     * 
     * @static
     * @param {RxAVUser} user
     * @param {any} data:{(string | { [key: string]: any })}
     * @param {string} prod
     * @returns {Observable<boolean>} 返回是否成功刚发送
     * 
     * @memberOf RxAVPush
     */
    public static sendTo(user: RxAVUser, data: string | { [key: string]: any }, prod?: string) {
        let query = new RxAVQuery('_Installation');
        query.relatedTo(user, RxAVUser.installationKey);
        return RxAVPush.sendContent(data, {
            query: query,
            prod: prod
        })
    }


    /**
     * 发送
     * 
     * @returns {Observable<boolean>}
     * 
     * @memberOf RxAVPush
     */
    public send(): Observable<boolean> {
        let data = this.encode();
        return RxAVUser.currentSessionToken().flatMap(sessionToken => {
            return RxAVClient.runCommand('/push', 'POST', data, sessionToken, this.query.app).map(body => {
                return true;
            });
        });
    }

    protected encode() {
        if (!this.alert && !this.data) throw new Error('A push must have either an Alert or Data');
        if (!this.channels && !this.query) throw new Error('A push must have either Channels or a Query');
        let data = this.data ? this.data : { alert: this.alert };
        if (this.channels)
            this.query = this.query.containedIn("channels", this.channels);
        let payload: { [key: string]: any } = {
            data: data,
            where: this.query.buildParameters()['where']
        };
        if (this.prod) {
            payload['prod'] = this.prod;
        }
        if (this.expiration)
            payload["expiration_time"] = this.expiration;
        else if (!this.expirationInterval) {
            payload["expiration_interval"] = this.expirationInterval;
        }
        if (this.pushTime) {
            payload["push_time"] = this.pushTime;
        }
        return payload;
    }

}