import { Application, ServerInfo, FrontendSession } from 'omelox';
import { createHash } from 'crypto';
import { Code, ConnectorHost, common } from '../common';


// 网关处理
export class GateHandler {
    constructor(private app: Application) {

    }


    hashDispatch(id: string, servers: ServerInfo[]) {
        if (servers.length === 0) {
            return;
        }

        if (id === null || id === undefined) {
            return servers[0];
        }

        if (typeof (id) !== 'string') {
            id = String(id);
        }
        let md5 = createHash('md5').update(id).digest('hex');
        let hash = parseInt(md5.substr(0, 8), 16);

        return servers[hash % servers.length];
    }

    // 查询该用哪个connector
    public async queryEntry(msg: { openid: string }, session: FrontendSession): Promise<ConnectorHost> {
        // console.log("queryEntry" + msg.openid);
        let openid = msg.openid;
        if (!openid) {
           return {code: Code.FAIL};
        }

        let connectors = this.app.getServersByType('connector');
        if (!connectors || connectors.length === 0) {
            return {code: Code.FA_NO_SERVER_AVAILABLE};
        }

        let res = this.hashDispatch(openid, connectors);
        let connectorHost = {code: Code.OK, host: res.clientHost, port: res.clientPort, openid: openid, hash: '' };
        // 计算出hash给connector验证
        connectorHost.hash = common.calcConnectorHostHash(connectorHost);
        return connectorHost;
    }
}

export default function(app: Application) {
    return new GateHandler(app);
}