import { Worker } from 'worker_threads';
import { fileURLToPath } from 'url';
import path from 'path';
import jwt from 'jsonwebtoken';
import { defineTool, ToolError } from 'libllmorbiter';
import env from '../config/env.js';
import { prepareVfs, syncVfsToDb } from './vfs.js';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const ROOT_DIR = path.resolve(__dirname, '../..');
const WORKER_PATH = fileURLToPath(new URL('./javascript-worker.js', import.meta.url));

const DEFAULT_TIMEOUT_MS = 20_000;
const MAX_TIMEOUT_MS = 60_000;
const DEFAULT_MAX_OUTPUT = 20_000;
const DEFAULT_BUFFER_LIMIT = 32 * 1024 * 1024;

// Keys already logged as benign non-sandbox worker chatter. Under `node --watch` the loader
// emits `watch:import` / `watch:require` notices on the worker's parentPort for EVERY import,
// so warning per message floods the log. We warn once per distinct key instead.
const WATCH_NOISE_WARNED = new Set();

function runInWorker({ code, timeoutMs, vfsRoot, googleAuthId }) {
    return new Promise((resolve) => {
        let settled = false;
        const token = jwt.sign({ id: googleAuthId }, env.jwtSecret, { expiresIn: '5m' });

        const worker = new Worker(WORKER_PATH, {
            workerData: {
                code,
                root: ROOT_DIR,
                vmTimeout: timeoutMs,
                bufferLimit: DEFAULT_BUFFER_LIMIT,
                dashbackUrl: `http://127.0.0.1:${env.port}/api`,
                dashbackToken: token,
                vfsDir: vfsRoot,
                googleAuthId,
            },
        });

        const finish = (payload) => {
            if (settled) return;
            settled = true;
            clearTimeout(timer);
            try { worker.terminate(); } catch { /* already closed */ }
            resolve(payload);
        };

        const timer = setTimeout(() => {
            console.error(`[javascript_execute] sandbox worker timed out after ${timeoutMs} ms`);
            finish({ result: null, stdout: '', consoleLineCount: 0, timedOut: true, timeoutMs });
        }, timeoutMs);

        worker.on('message', (msg) => {
            // Ignore anything that is not a genuine sandbox report. Running the server under
            // `node --watch` (the `dev` script) installs a module-loader hook that posts
            // `watch:import` notices on this same channel; treating the first message as the
            // result made the sandbox appear to run for 0ms and return nothing.
            if (!msg || msg.__sandboxReport !== true) {
                // Those loader notices fire many times per run, so warn ONCE per key rather
    // than on every message — expected, benign noise while running under --watch.
          for (const key of Object.keys(msg || {})) {
            if (!WATCH_NOISE_WARNED.has(key)) {
  WATCH_NOISE_WARNED.add(key);
        console.warn(
       `[javascript_execute] ignoring non-sandbox worker message "${key}" ` +
      '(expected under `node --watch`; logged once per key).'
       );
        }
            }
                return;
            }
            finish(msg);
        });
        // A worker 'error' fires BEFORE any message when the thread fails to boot (e.g. an
        // import throws at startup). ALWAYS send a truthy `error` plus the full stack so the
        // parent can throw with something actionable; an empty `err.message` must never
        // degrade into a silent, result-less success payload.
        worker.on('error', (err) => finish({
            result: null,
            stdout: '',
            consoleLineCount: 0,
            error: (err && err.message)
                ? err.message
                : `Sandbox worker failed to start: ${err?.stack || err?.name || 'unknown error'}`,
            errorName: (err && err.name) || 'Error',
            stack: err && typeof err.stack === 'string' ? err.stack : undefined,
        }));
        worker.on('exit', (code) => {
            // `finish` is idempotent via `settled`, so a message that already resolved the
            // promise is never overwritten. Reaching here means the worker died WITHOUT
            // reporting — that is a hard failure, so log it and always carry a truthy error.
            if (!settled) {
                console.error(`[javascript_execute] sandbox worker exited without reporting (code ${code})`);
            }
            finish({
                result: null,
                stdout: '',
                consoleLineCount: 0,
                error: `Sandbox worker exited unexpectedly without reporting a result (code ${code}).`,
                errorName: 'WorkerExit',
            });
        });
    });
}

function formatSandboxError(code, report) {
    const errName = report.errorName || 'Error';
    const msg = report.error || 'Unknown error';
    const lines = [`${errName}: ${msg}`];
    if (report.stdout) {
        lines.push('Console output before crash:\n' + report.stdout);
    }
    return lines.join('\n');
}

/**
 * Creates the javascript_execute tool bound to the authenticated user and their company.
 * @param {{ googleAuthId: number }} ctx
 */
export function createJavascriptExecuteTool({ googleAuthId }) {
    return defineTool({
        name: 'javascript_execute',
        description:
            'Execute JS in isolated Node worker sandbox. Assign `module.exports` to return value (sync value or Promise; no bare top-level await — wrap async in IIFE: `module.exports = (async () => { ... })()`). ' +
            'REST API: `await fetch("/path")` (authenticated). ' +
            'VFS: `fs.readFileSync`/`writeFileSync` for binary artifacts/buffers/images (`image/` is read-only). ' +
            'Embed generated images in markdown: `![alt](path)`. Use find_files/read_file/patch for text. ' +
            'Globals: `fs`/`vfs`, `sharp`, WebCrypto `crypto` (`subtle`, `randomUUID`), web standard globals. Node built-ins unavailable (`require` fails).',
        strict: false,
        parameters: {
            type: 'object',
            additionalProperties: false,
            required: ['code'],
            properties: {
                code: {
                    type: 'string',
                    description: 'CommonJS JS code. Assign result to `module.exports`. Async code must use IIFE.',
                },
                timeout: {
                    type: 'number',
                    description: `Execution timeout in ms. Default ${DEFAULT_TIMEOUT_MS}, max ${MAX_TIMEOUT_MS}.`,
                },
                max_output: {
                    type: 'number',
                    description: `Max stdout chars. Default ${DEFAULT_MAX_OUTPUT}.`,
                },
            },
        },
        invoke: async ({ code, timeout = DEFAULT_TIMEOUT_MS, max_output = DEFAULT_MAX_OUTPUT }) => {
            if (typeof code !== 'string' || !code.trim()) {
                throw new ToolError('"code" must be a non-empty string.');
            }
            const hardTimeout = Math.min(Math.max(1000, Number(timeout) || DEFAULT_TIMEOUT_MS), MAX_TIMEOUT_MS);
            const maxOutput = Math.max(1000, Number(max_output) || DEFAULT_MAX_OUTPUT);

            const vfsRoot = await prepareVfs({ googleAuthId });
            let report;
            try {
                report = await runInWorker({ code, timeoutMs: hardTimeout, vfsRoot, googleAuthId });
            } finally {
                await syncVfsToDb({ googleAuthId, vfsRoot });
            }

            if (report.timedOut) {
                throw new ToolError(
                    `Sandbox exceeded the ${report.timeoutMs} ms timeout and was terminated.`
                );
            }

            if (report.error) {
                throw new ToolError(formatSandboxError(code, report));
            }

            // The worker ALWAYS reports a `result` key (javascript-worker.js). Its absence
            // means the worker died before reporting — that is a hard failure, not a result.
            // Throwing (rather than returning a success-shaped object) is deliberate: a
            // fabricated `{ ok:false, result:null }` reads to the model as "ran, returned
            // nothing", which is indistinguishable from a snippet that genuinely returned
            // undefined. Throw so the failure is unambiguous and gets logged.
            if (report === null || typeof report !== 'object' || !('result' in report)) {
                const keys = report && typeof report === 'object' ? Object.keys(report) : [];
                console.error(
                    '[javascript_execute] sandbox worker produced no result payload',
                    { keys, report }
                );
                throw new ToolError(
                    'Sandbox worker did not report a result payload. ' +
                    `Report keys: [${keys.join(', ') || 'none'}]. This is a harness failure, ` +
                    'not an empty result — check the server logs for the worker error above.'
                );
            }

            let stdout = report.stdout ?? '';
            let truncated = false;
            if (stdout.length > maxOutput) {
                stdout = stdout.slice(0, maxOutput);
                truncated = true;
            }

            const result = {
                ok: true,
                result: report.result,
                // Always present, even when empty, so callers can rely on the shape.
                stdout,
            };
            if (truncated) {
                result.truncated = true;
                result.truncationNote = `Console output longer than ${maxOutput} chars was capped.`;
            }
            result.consoleLines = report.consoleLineCount ?? 0;
            result.durationMs = report.durationMs ?? 0;
            return result;
        },
    });
}