/**
 * gstack browse server — persistent Chromium daemon
 *
 * Architecture:
 *   Bun.serve HTTP on localhost → routes commands to Playwright
 *   Console/network/dialog buffers: CircularBuffer in-memory + async disk flush
 *   Chromium crash → server EXITS with clear error (CLI auto-restarts)
 *   Auto-shutdown after BROWSE_IDLE_TIMEOUT (default 30 min)
 *
 * State:
 *   State file: <project-root>/.gstack/browse.json (set via BROWSE_STATE_FILE env)
 *   Log files:  <project-root>/.gstack/browse-{console,network,dialog}.log
 *   Port:       random 10000-60000 (or BROWSE_PORT env for debug override)
 */

import { BrowserManager } from './browser-manager';
import { handleReadCommand } from './read-commands';
import { handleWriteCommand } from './write-commands';
import { handleMetaCommand } from './meta-commands';
import { handleCookiePickerRoute } from './cookie-picker-routes';
import { resolveConfig, ensureStateDir, readVersionHash } from './config';
import * as fs from 'fs';
import * as path from 'path';
import * as crypto from 'crypto';

// ─── Config ─────────────────────────────────────────────────────
const config = resolveConfig();
ensureStateDir(config);

// ─── Auth ───────────────────────────────────────────────────────
const AUTH_TOKEN = crypto.randomUUID();
const BROWSE_PORT = parseInt(process.env.BROWSE_PORT || '0', 10);
const IDLE_TIMEOUT_MS = parseInt(process.env.BROWSE_IDLE_TIMEOUT || '1800000', 10); // 30 min

function validateAuth(req: Request): boolean {
  const header = req.headers.get('authorization');
  return header === `Bearer ${AUTH_TOKEN}`;
}

// ─── Buffer (from buffers.ts) ────────────────────────────────────
import { consoleBuffer, networkBuffer, dialogBuffer, addConsoleEntry, addNetworkEntry, addDialogEntry, type LogEntry, type NetworkEntry, type DialogEntry } from './buffers';
export { consoleBuffer, networkBuffer, dialogBuffer, addConsoleEntry, addNetworkEntry, addDialogEntry, type LogEntry, type NetworkEntry, type DialogEntry };

const CONSOLE_LOG_PATH = config.consoleLog;
const NETWORK_LOG_PATH = config.networkLog;
const DIALOG_LOG_PATH = config.dialogLog;
let lastConsoleFlushed = 0;
let lastNetworkFlushed = 0;
let lastDialogFlushed = 0;
let flushInProgress = false;

async function flushBuffers() {
  if (flushInProgress) return; // Guard against concurrent flush
  flushInProgress = true;

  try {
    // Console buffer
    const newConsoleCount = consoleBuffer.totalAdded - lastConsoleFlushed;
    if (newConsoleCount > 0) {
      const entries = consoleBuffer.last(Math.min(newConsoleCount, consoleBuffer.length));
      const lines = entries.map(e =>
        `[${new Date(e.timestamp).toISOString()}] [${e.level}] ${e.text}`
      ).join('\n') + '\n';
      await Bun.write(CONSOLE_LOG_PATH, (await Bun.file(CONSOLE_LOG_PATH).text().catch(() => '')) + lines);
      lastConsoleFlushed = consoleBuffer.totalAdded;
    }

    // Network buffer
    const newNetworkCount = networkBuffer.totalAdded - lastNetworkFlushed;
    if (newNetworkCount > 0) {
      const entries = networkBuffer.last(Math.min(newNetworkCount, networkBuffer.length));
      const lines = entries.map(e =>
        `[${new Date(e.timestamp).toISOString()}] ${e.method} ${e.url} → ${e.status || 'pending'} (${e.duration || '?'}ms, ${e.size || '?'}B)`
      ).join('\n') + '\n';
      await Bun.write(NETWORK_LOG_PATH, (await Bun.file(NETWORK_LOG_PATH).text().catch(() => '')) + lines);
      lastNetworkFlushed = networkBuffer.totalAdded;
    }

    // Dialog buffer
    const newDialogCount = dialogBuffer.totalAdded - lastDialogFlushed;
    if (newDialogCount > 0) {
      const entries = dialogBuffer.last(Math.min(newDialogCount, dialogBuffer.length));
      const lines = entries.map(e =>
        `[${new Date(e.timestamp).toISOString()}] [${e.type}] "${e.message}" → ${e.action}${e.response ? ` "${e.response}"` : ''}`
      ).join('\n') + '\n';
      await Bun.write(DIALOG_LOG_PATH, (await Bun.file(DIALOG_LOG_PATH).text().catch(() => '')) + lines);
      lastDialogFlushed = dialogBuffer.totalAdded;
    }
  } catch {
    // Flush failures are non-fatal — buffers are in memory
  } finally {
    flushInProgress = false;
  }
}

// Flush every 1 second
const flushInterval = setInterval(flushBuffers, 1000);

// ─── Idle Timer ────────────────────────────────────────────────
let lastActivity = Date.now();

function resetIdleTimer() {
  lastActivity = Date.now();
}

const idleCheckInterval = setInterval(() => {
  if (Date.now() - lastActivity > IDLE_TIMEOUT_MS) {
    console.log(`[browse] Idle for ${IDLE_TIMEOUT_MS / 1000}s, shutting down`);
    shutdown();
  }
}, 60_000);

// ─── Command Sets (exported for chain command) ──────────────────
export const READ_COMMANDS = new Set([
  'text', 'html', 'links', 'forms', 'accessibility',
  'js', 'eval', 'css', 'attrs',
  'console', 'network', 'cookies', 'storage', 'perf',
  'dialog', 'is',
]);

export const WRITE_COMMANDS = new Set([
  'goto', 'back', 'forward', 'reload',
  'click', 'fill', 'select', 'hover', 'type', 'press', 'scroll', 'wait',
  'viewport', 'cookie', 'cookie-import', 'cookie-import-browser', 'header', 'useragent',
  'upload', 'dialog-accept', 'dialog-dismiss',
]);

export const META_COMMANDS = new Set([
  'tabs', 'tab', 'newtab', 'closetab',
  'status', 'stop', 'restart',
  'screenshot', 'pdf', 'responsive',
  'chain', 'diff',
  'url', 'snapshot',
]);

// ─── Server ────────────────────────────────────────────────────
const browserManager = new BrowserManager();
let isShuttingDown = false;

// Find port: explicit BROWSE_PORT, or random in 10000-60000
async function findPort(): Promise<number> {
  // Explicit port override (for debugging)
  if (BROWSE_PORT) {
    try {
      const testServer = Bun.serve({ port: BROWSE_PORT, fetch: () => new Response('ok') });
      testServer.stop();
      return BROWSE_PORT;
    } catch {
      throw new Error(`[browse] Port ${BROWSE_PORT} (from BROWSE_PORT env) is in use`);
    }
  }

  // Random port with retry
  const MIN_PORT = 10000;
  const MAX_PORT = 60000;
  const MAX_RETRIES = 5;
  for (let attempt = 0; attempt < MAX_RETRIES; attempt++) {
    const port = MIN_PORT + Math.floor(Math.random() * (MAX_PORT - MIN_PORT));
    try {
      const testServer = Bun.serve({ port, fetch: () => new Response('ok') });
      testServer.stop();
      return port;
    } catch {
      continue;
    }
  }
  throw new Error(`[browse] No available port after ${MAX_RETRIES} attempts in range ${MIN_PORT}-${MAX_PORT}`);
}

/**
 * Translate Playwright errors into actionable messages for AI agents.
 */
function wrapError(err: any): string {
  const msg = err.message || String(err);
  // Timeout errors
  if (err.name === 'TimeoutError' || msg.includes('Timeout') || msg.includes('timeout')) {
    if (msg.includes('locator.click') || msg.includes('locator.fill') || msg.includes('locator.hover')) {
      return `Element not found or not interactable within timeout. Check your selector or run 'snapshot' for fresh refs.`;
    }
    if (msg.includes('page.goto') || msg.includes('Navigation')) {
      return `Page navigation timed out. The URL may be unreachable or the page may be loading slowly.`;
    }
    return `Operation timed out: ${msg.split('\n')[0]}`;
  }
  // Multiple elements matched
  if (msg.includes('resolved to') && msg.includes('elements')) {
    return `Selector matched multiple elements. Be more specific or use @refs from 'snapshot'.`;
  }
  // Pass through other errors
  return msg;
}

async function handleCommand(body: any): Promise<Response> {
  const { command, args = [] } = body;

  if (!command) {
    return new Response(JSON.stringify({ error: 'Missing "command" field' }), {
      status: 400,
      headers: { 'Content-Type': 'application/json' },
    });
  }

  try {
    let result: string;

    if (READ_COMMANDS.has(command)) {
      result = await handleReadCommand(command, args, browserManager);
    } else if (WRITE_COMMANDS.has(command)) {
      result = await handleWriteCommand(command, args, browserManager);
    } else if (META_COMMANDS.has(command)) {
      result = await handleMetaCommand(command, args, browserManager, shutdown);
    } else if (command === 'help') {
      const helpText = [
        'gstack browse — headless browser for AI agents',
        '',
        'Commands:',
        '  Navigation:    goto <url>, back, forward, reload',
        '  Interaction:   click <sel>, fill <sel> <text>, select <sel> <val>, hover, type, press, scroll, wait',
        '  Read:          text [sel], html [sel], links, forms, accessibility, cookies, storage, console, network, perf',
        '  Evaluate:      js <expr>, eval <expr>, css <sel> <prop>, attrs <sel>, is <sel> <state>',
        '  Snapshot:      snapshot [-i] [-c] [-d N] [-s sel] [-D] [-a] [-o path] [-C]',
        '  Screenshot:    screenshot [path], pdf [path], responsive <widths>',
        '  Tabs:          tabs, tab <id>, newtab [url], closetab [id]',
        '  State:         cookie <set|get|clear>, cookie-import <json>, cookie-import-browser [browser]',
        '  Headers:       header <set|clear> [name] [value], useragent [string]',
        '  Upload:        upload <sel> <file1> [file2...]',
        '  Dialogs:       dialog, dialog-accept [text], dialog-dismiss',
        '  Meta:          status, stop, restart, diff, chain, help',
        '',
        'Snapshot flags:',
        '  -i  interactive only    -c  compact (remove empty nodes)',
        '  -d N  limit depth       -s sel  scope to CSS selector',
        '  -D  diff vs previous    -a  annotated screenshot with ref labels',
        '  -o path  output file    -C  cursor-interactive elements',
      ].join('\n');
      return new Response(helpText, {
        status: 200,
        headers: { 'Content-Type': 'text/plain' },
      });
    } else {
      return new Response(JSON.stringify({
        error: `Unknown command: ${command}`,
        hint: `Available commands: ${[...READ_COMMANDS, ...WRITE_COMMANDS, ...META_COMMANDS].sort().join(', ')}`,
      }), {
        status: 400,
        headers: { 'Content-Type': 'application/json' },
      });
    }

    return new Response(result, {
      status: 200,
      headers: { 'Content-Type': 'text/plain' },
    });
  } catch (err: any) {
    return new Response(JSON.stringify({ error: wrapError(err) }), {
      status: 500,
      headers: { 'Content-Type': 'application/json' },
    });
  }
}

async function shutdown() {
  if (isShuttingDown) return;
  isShuttingDown = true;

  console.log('[browse] Shutting down...');
  clearInterval(flushInterval);
  clearInterval(idleCheckInterval);
  await flushBuffers(); // Final flush (async now)

  await browserManager.close();

  // Clean up state file
  try { fs.unlinkSync(config.stateFile); } catch {}

  process.exit(0);
}

// Handle signals
process.on('SIGTERM', shutdown);
process.on('SIGINT', shutdown);

// ─── Start ─────────────────────────────────────────────────────
async function start() {
  // Clear old log files
  try { fs.unlinkSync(CONSOLE_LOG_PATH); } catch {}
  try { fs.unlinkSync(NETWORK_LOG_PATH); } catch {}
  try { fs.unlinkSync(DIALOG_LOG_PATH); } catch {}

  const port = await findPort();

  // Launch browser
  await browserManager.launch();

  const startTime = Date.now();
  const server = Bun.serve({
    port,
    hostname: '127.0.0.1',
    fetch: async (req) => {
      resetIdleTimer();

      const url = new URL(req.url);

      // Cookie picker routes — no auth required (localhost-only)
      if (url.pathname.startsWith('/cookie-picker')) {
        return handleCookiePickerRoute(url, req, browserManager);
      }

      // Health check — no auth required (now async)
      if (url.pathname === '/health') {
        const healthy = await browserManager.isHealthy();
        return new Response(JSON.stringify({
          status: healthy ? 'healthy' : 'unhealthy',
          uptime: Math.floor((Date.now() - startTime) / 1000),
          tabs: browserManager.getTabCount(),
          currentUrl: browserManager.getCurrentUrl(),
        }), {
          status: 200,
          headers: { 'Content-Type': 'application/json' },
        });
      }

      // All other endpoints require auth
      if (!validateAuth(req)) {
        return new Response(JSON.stringify({ error: 'Unauthorized' }), {
          status: 401,
          headers: { 'Content-Type': 'application/json' },
        });
      }

      if (url.pathname === '/command' && req.method === 'POST') {
        const body = await req.json();
        return handleCommand(body);
      }

      return new Response('Not found', { status: 404 });
    },
  });

  // Write state file (atomic: write .tmp then rename)
  const state = {
    pid: process.pid,
    port,
    token: AUTH_TOKEN,
    startedAt: new Date().toISOString(),
    serverPath: path.resolve(import.meta.dir, 'server.ts'),
    binaryVersion: readVersionHash() || undefined,
  };
  const tmpFile = config.stateFile + '.tmp';
  fs.writeFileSync(tmpFile, JSON.stringify(state, null, 2), { mode: 0o600 });
  fs.renameSync(tmpFile, config.stateFile);

  browserManager.serverPort = port;
  console.log(`[browse] Server running on http://127.0.0.1:${port} (PID: ${process.pid})`);
  console.log(`[browse] State file: ${config.stateFile}`);
  console.log(`[browse] Idle timeout: ${IDLE_TIMEOUT_MS / 1000}s`);
}

start().catch((err) => {
  console.error(`[browse] Failed to start: ${err.message}`);
  process.exit(1);
});