const {
    LoggingDebugSession,
    InitializedEvent,
    TerminatedEvent,
    OutputEvent,
    StoppedEvent,
    Thread
} = require('vscode-debugadapter');

const { spawn } = require('child_process');

class MyLuaDebugSession extends LoggingDebugSession {

    constructor() {
        super("myLuaDebug.txt");
        this.setDebuggerLinesStartAt1(true);
        this.setDebuggerColumnsStartAt1(true);
    }

    initializeRequest(response, args) {
        this.sendEvent(new InitializedEvent());

        response.body = {
            supportsConfigurationDoneRequest: true
        };

        this.sendResponse(response);
    }

    handleLine(line) {
        if (line.startsWith("@@DEBUG@@")) {
            const json = JSON.parse(line.substring(9));

            if (json.type === "luaError") {
                const e = new OutputEvent(json.message + "\n", "stderr");
                e.body.source = { path: json.file };
                e.body.line = json.line;
                this.sendEvent(e);
                return;
            }

            if (json.type === "break") {
                this.currentFile = json.file;
                this.currentLine = json.line;

                this.sendEvent(new StoppedEvent("breakpoint", 1));
                return;
            }

            return;
        }

        // salida normal
        this.sendEvent(new OutputEvent(line + "\n", "stdout"));
    }

    launchRequest(response, args) {
        const program = args.program;
        const cwd = args.cwd || process.cwd();

        this.process = spawn(program, [], {
            cwd: cwd,
            stdio: ['pipe', 'pipe', 'pipe']
        });

        this.stdoutBuffer = "";

        this.process.stdout.on('data', data => {
            this.stdoutBuffer += data.toString();

            let idx;
            while ((idx = this.stdoutBuffer.indexOf("\n")) >= 0) {
                const line = this.stdoutBuffer.slice(0, idx).trim();
                this.stdoutBuffer = this.stdoutBuffer.slice(idx + 1);

                this.handleLine(line);
            }
        });

        this.process.stderr.on('data', data => {
            this.sendEvent(new OutputEvent(data.toString(), "stderr"));
        });

        this.process.on('exit', () => {
            this.sendEvent(new TerminatedEvent());
        });

        this.sendResponse(response);
    }

    setBreakPointsRequest(response, args) {
        const path = args.source.path;          // archivo donde se han puesto breakpoints
        const clientBreakpoints = args.breakpoints || [];

        // Extraemos solo las líneas
        const lines = clientBreakpoints.map(bp => bp.line);

        // Guardamos internamente los breakpoints
        if (!this.breakpoints)
            this.breakpoints = {};

        this.breakpoints[path] = lines;

        // Enviamos los breakpoints a tu aplicación por stdin
        const msg = {
            cmd: "setBreakpoints",
            file: path,
            lines: lines
        };

        this.process.stdin.write(
            "@@DEBUGCMD@@" + JSON.stringify(msg) + "\n"
        );

        // VSCode necesita una respuesta con los breakpoints "verificados"
        response.body = {
            breakpoints: lines.map(line => ({
                verified: true,
                line: line
            }))
        };

        this.sendResponse(response);
    }

    continueRequest(response, args) {
        const msg = {
            cmd: "continue"
        };

        this.process.stdin.write(
            "@@DEBUGCMD@@" + JSON.stringify(msg) + "\n"
        );

        this.sendResponse(response);
    }

    disconnectRequest(response, args) {
        const msg = { cmd: "continue" }; // por si estaba pausado
        this.process.stdin.write("@@DEBUGCMD@@" + JSON.stringify(msg) + "\n");

        this.process.kill();
        this.sendResponse(response);
    }

    threadsRequest(response) {
        // VSCode exige al menos un thread
        response.body = {
            threads: [
                new Thread(1, "Main Thread")
            ]
        };
        this.sendResponse(response);
    }

    stackTraceRequest(response, args) {
        response.body = {
            stackFrames: [
                {
                    id: 1,
                    name: "Lua",
                    source: { path: this.currentFile },
                    line: this.currentLine,
                    column: 1
                }
            ],
            totalFrames: 1
        };
        this.sendResponse(response);
    }

    configurationDoneRequest(response, args) {
        this.sendResponse(response);
    }

}

new MyLuaDebugSession().start(process.stdin, process.stdout);