"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.GDBProtocolWriter = exports.GDBProtocolReader = exports.GDBProtocolClient = void 0;
const Debug = require("debug");
const protocol_1 = require("./protocol");
const debug = Debug('native-run:ios:lib:protocol:gdb');
const ACK_SUCCESS = '+'.charCodeAt(0);
class GDBProtocolClient extends protocol_1.ProtocolClient {
    constructor(socket) {
        super(socket, new protocol_1.ProtocolReaderFactory(GDBProtocolReader), new GDBProtocolWriter());
    }
}
exports.GDBProtocolClient = GDBProtocolClient;
class GDBProtocolReader extends protocol_1.ProtocolReader {
    constructor(callback) {
        super(1 /* "Header" is '+' or '-' */, callback);
    }
    onData(data) {
        // the GDB protocol does not support body length in its header so we cannot rely on
        // the parent implementation to determine when a payload is complete
        try {
            // if there's data, add it to the existing buffer
            this.buffer = data ? Buffer.concat([this.buffer, data]) : this.buffer;
            // do we have enough bytes to proceed
            if (this.buffer.length < this.headerSize) {
                return; // incomplete header, wait for more
            }
            // first, check the header
            if (this.parseHeader(this.buffer) === -1) {
                // we have a valid header so check the body. GDB packets will always be a leading '$', data bytes,
                // a trailing '#', and a two digit checksum. minimum valid body is the empty response '$#00'
                // https://developer.apple.com/library/archive/documentation/DeveloperTools/gdb/gdb/gdb_33.html
                const packetData = this.buffer.toString().match('\\$.*#[0-9a-f]{2}');
                if (packetData == null) {
                    return; // incomplete body, wait for more
                }
                // extract the body and update the buffer
                const body = Buffer.from(packetData[0]);
                this.buffer = this.buffer.slice(this.headerSize + body.length);
                // parse the payload and recurse if there is more data to process
                this.callback(this.parseBody(body));
                if (this.buffer.length) {
                    this.onData();
                }
            }
        }
        catch (err) {
            this.callback(null, err);
        }
    }
    parseHeader(data) {
        if (data[0] !== ACK_SUCCESS) {
            throw new Error('Unsuccessful debugserver response');
        } // TODO: retry?
        return -1;
    }
    parseBody(buffer) {
        debug(`Response body: ${buffer.toString()}`);
        // check for checksum
        const checksum = buffer.slice(-3).toString();
        if (checksum.match(/#[0-9a-f]{2}/)) {
            // remove '$' prefix and checksum
            const msg = buffer.slice(1, -3).toString();
            if (validateChecksum(checksum, msg)) {
                return msg;
            }
            else {
                throw new Error('Invalid checksum received from debugserver');
            }
        }
        else {
            throw new Error("Didn't receive checksum");
        }
    }
}
exports.GDBProtocolReader = GDBProtocolReader;
class GDBProtocolWriter {
    write(socket, msg) {
        const { cmd, args } = msg;
        debug(`Socket write: ${cmd}, args: ${args}`);
        // hex encode and concat all args
        const encodedArgs = args
            .map(arg => Buffer.from(arg).toString('hex'))
            .join()
            .toUpperCase();
        const checksumStr = calculateChecksum(cmd + encodedArgs);
        const formattedCmd = `$${cmd}${encodedArgs}#${checksumStr}`;
        socket.write(formattedCmd);
    }
}
exports.GDBProtocolWriter = GDBProtocolWriter;
// hex value of (sum of cmd chars mod 256)
function calculateChecksum(cmdStr) {
    let checksum = 0;
    for (let i = 0; i < cmdStr.length; i++) {
        checksum += cmdStr.charCodeAt(i);
    }
    let result = (checksum % 256).toString(16);
    // pad if necessary
    if (result.length === 1) {
        result = `0${result}`;
    }
    return result;
}
function validateChecksum(checksum, msg) {
    // remove '#' from checksum
    const checksumVal = checksum.slice(1);
    // remove '$' from msg and calculate its checksum
    const computedChecksum = calculateChecksum(msg);
    debug(`Checksum: ${checksumVal}, computed checksum: ${computedChecksum}`);
    return checksumVal === computedChecksum;
}
