import { Transport } from '../transport'
// const debug = require("debug")("engine:ws")

export class WebSocket extends Transport {
    public perMessageDeflate: any

    /**
     * WebSocket transport
     *
     * @param {http.IncomingMessage}
     * @api public
     */
    constructor(req) {
        super(req)
        this.socket = req.websocket
        this.socket.on("message", this.onData.bind(this))
        this.socket.once("close", this.onClose.bind(this))
        this.socket.on("error", this.onError.bind(this))
        this.writable = true
        this.perMessageDeflate = null
    }

    /**
     * Transport name
     *
     * @api public
     */
    get name() {
        return "websocket"
    }

    /**
     * Advertise upgrade support.
     *
     * @api public
     */
    get handlesUpgrades() {
        return true
    }

    /**
     * Advertise framing support.
     *
     * @api public
     */
    get supportsFraming() {
        return true
    }

    /**
     * Processes the incoming data.
     *
     * @param {String} encoded packet
     * @api private
     */
    onData(data) {
        // debug('received "%s"', data)
        super.onData(data)
    }

    /**
     * Writes a packet payload.
     *
     * @param {Array} packets
     * @api private
     */
    send(packets) {
        // console.log('WebSocket send packets', JSON.stringify(packets))
        const packet = packets.shift()
        if (typeof packet === "undefined") {
            this.writable = true
            this.emit("drain")
            return
        }

        // always creates a new object since ws modifies it
        const opts: any = {}
        if (packet.options) {
            opts.compress = packet.options.compress
        }

        const send = data => {
            if (this.perMessageDeflate) {
                const len =
                    "string" === typeof data ? Buffer.byteLength(data) : data.length
                if (len < this.perMessageDeflate.threshold) {
                    opts.compress = false
                }
            }
            console.trace('writing', data)
            this.writable = false

            this.socket.send(data, opts, err => {
                if (err) return this.onError("write error", err.stack)
                this.send(packets)
            })
        }

        if (packet.options && typeof packet.options.wsPreEncoded === "string") {
            send(packet.options.wsPreEncoded)
        } else {
            this.parser.encodePacket(packet, this.supportsBinary, send)
        }
    }

    /**
     * Closes the transport.
     *
     * @api private
     */
    doClose(fn) {
        // debug("closing")
        this.socket.close()
        fn && fn()
    }
}