#!/usr/bin/env node
'use strict';

/* eslint-disable no-console */

/**
 * watcher-manager.js — Top-level orchestrator for the Live Status v4 daemon.
 *
 * CLI: node watcher-manager.js start|stop|status
 *
 * Architecture:
 *   - SessionMonitor polls sessions.json every 2s for new/ended sessions
 *   - StatusWatcher watches transcript files via fs.watch (inotify)
 *   - StatusBox manages Mattermost posts (throttle, circuit breaker, retry)
 *   - HealthServer exposes /health endpoint
 *   - Offset persistence: save/restore last read positions on restart
 *   - Graceful shutdown: SIGTERM/SIGINT -> mark all boxes interrupted -> exit 0
 */

const fs = require('fs');

const { getConfig } = require('./config');
const { getLogger } = require('./logger');
const { SessionMonitor } = require('./session-monitor');
const { StatusWatcher } = require('./status-watcher');
const { StatusBox } = require('./status-box');
// status-formatter is used inline via require() in helpers
const { HealthServer } = require('./health');
const { loadLabels } = require('./tool-labels');

// ---- CLI Router ----
const cmd = process.argv[2];
if (cmd === 'start') {
  startDaemon().catch((err) => {
    console.error('Failed to start:', err.message);
    process.exit(1);
  });
} else if (cmd === 'stop') {
  stopDaemon();
} else if (cmd === 'status') {
  daemonStatus();
} else {
  console.log('Usage: node watcher-manager.js <start|stop|status>');
  process.exit(1);
}

// ---- PID File helpers ----
function writePidFile(pidFile) {
  // eslint-disable-next-line security/detect-non-literal-fs-filename
  fs.writeFileSync(pidFile, String(process.pid), 'utf8');
}

function readPidFile(pidFile) {
  try {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    return parseInt(fs.readFileSync(pidFile, 'utf8').trim(), 10);
  } catch (_e) {
    return null;
  }
}

function removePidFile(pidFile) {
  try {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    fs.unlinkSync(pidFile);
  } catch (_e) {
    /* ignore */
  }
}

function isProcessRunning(pid) {
  try {
    process.kill(pid, 0);
    return true;
  } catch (_e) {
    return false;
  }
}

// ---- Offset persistence ----
function loadOffsets(offsetFile) {
  try {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    return JSON.parse(fs.readFileSync(offsetFile, 'utf8'));
  } catch (_e) {
    return {};
  }
}

function saveOffsets(offsetFile, sessions) {
  const offsets = {};
  for (const [key, state] of sessions) {
    offsets[key] = {
      lastOffset: state.lastOffset || 0,
      transcriptFile: state.transcriptFile,
      startTime: state.startTime,
    };
  }
  try {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    fs.writeFileSync(offsetFile, JSON.stringify(offsets, null, 2), 'utf8');
  } catch (_e) {
    /* ignore write error */
  }
}

// ---- Status box marker for post recovery ----
function makeMarker(sessionKey) {
  return `<!-- sw:${sessionKey} -->`;
}

// ---- Main daemon ----
async function startDaemon() {
  const config = getConfig();
  const logger = getLogger();

  // Check if already running
  const existingPid = readPidFile(config.pidFile);
  if (existingPid && isProcessRunning(existingPid)) {
    console.error(`Daemon already running (PID ${existingPid})`);
    process.exit(1);
  }
  removePidFile(config.pidFile);

  // Write PID file
  writePidFile(config.pidFile);
  logger.info({ pid: process.pid, pidFile: config.pidFile }, 'Status watcher daemon starting');

  // Load tool labels
  loadLabels(config.toolLabelsFile);

  // Load persisted offsets for restart recovery
  const savedOffsets = loadOffsets(config.offsetFile);
  logger.info({ count: Object.keys(savedOffsets).length }, 'Loaded persisted session offsets');

  // Shared state
  // Map<sessionKey, { postId, agentId, channelId, rootPostId, children: Map }>
  const activeBoxes = new Map();

  // Pending sub-agents: spawnedBy key -> [info] (arrived before parent was added)
  const pendingSubAgents = new Map();
  let globalMetrics = {
    activeSessions: 0,
    updatesSent: 0,
    updatesFailed: 0,
    queueDepth: 0,
    lastError: null,
    circuit: { state: 'unknown' },
  };

  // Shared StatusBox instance (single http.Agent pool)
  const sharedStatusBox = new StatusBox({
    baseUrl: config.mm.baseUrl,
    token: config.mm.token,
    logger: logger.child({ module: 'status-box' }),
    throttleMs: config.throttleMs,
    maxMessageChars: config.maxMessageChars,
    maxRetries: config.maxRetries,
    maxSockets: config.mm.maxSockets,
  });

  // StatusWatcher
  const watcher = new StatusWatcher({
    transcriptDir: config.transcriptDir,
    idleTimeoutS: config.idleTimeoutS,
    logger: logger.child({ module: 'status-watcher' }),
  });

  // SessionMonitor
  const monitor = new SessionMonitor({
    transcriptDir: config.transcriptDir,
    pollMs: config.sessionPollMs,
    defaultChannel: config.defaultChannel,
    logger: logger.child({ module: 'session-monitor' }),
  });

  // Health server
  const healthServer = new HealthServer({
    port: config.healthPort,
    logger: logger.child({ module: 'health' }),
    getMetrics: () => ({
      ...globalMetrics,
      ...sharedStatusBox.getMetrics(),
      activeSessions: activeBoxes.size,
    }),
  });

  // ---- Session Added ----
  monitor.on('session-added', async (info) => {
    const { sessionKey, transcriptFile, spawnedBy, channelId, rootPostId, agentId } = info;

    // Skip if no channel
    if (!channelId) {
      logger.debug({ sessionKey }, 'No channel for session — skipping');
      return;
    }

    // Enforce MAX_ACTIVE_SESSIONS
    if (activeBoxes.size >= config.maxActiveSessions) {
      logger.warn(
        { sessionKey, maxActiveSessions: config.maxActiveSessions },
        'Max active sessions reached — dropping session',
      );
      return;
    }

    // Sub-agent: skip creating own post (embedded in parent)
    if (spawnedBy) {
      if (activeBoxes.has(spawnedBy)) {
        linkSubAgent(
          activeBoxes,
          watcher,
          spawnedBy,
          { sessionKey, transcriptFile, channelId, agentId, spawnDepth: info.spawnDepth },
          logger,
        );
      } else {
        // Parent not yet tracked — queue for later
        logger.debug({ sessionKey, spawnedBy }, 'Sub-agent queued (parent not yet tracked)');
        if (!pendingSubAgents.has(spawnedBy)) pendingSubAgents.set(spawnedBy, []);
        pendingSubAgents
          .get(spawnedBy)
          .push({ sessionKey, transcriptFile, channelId, agentId, spawnDepth: info.spawnDepth });
      }
      return;
    }

    let postId;

    // Check for existing post (restart recovery)
    const saved = savedOffsets[sessionKey]; // eslint-disable-line security/detect-object-injection
    if (saved) {
      // Try to find existing post in channel history
      postId = await findExistingPost(sharedStatusBox, channelId, sessionKey, logger);
    }

    // Create new post if none found
    if (!postId) {
      try {
        const initialText = buildInitialText(agentId, sessionKey);
        postId = await sharedStatusBox.createPost(channelId, initialText, rootPostId);
        logger.info({ sessionKey, postId, channelId }, 'Created status box');
      } catch (err) {
        logger.error({ sessionKey, err }, 'Failed to create status post');
        globalMetrics.lastError = err.message;
        return;
      }
    }

    activeBoxes.set(sessionKey, {
      postId,
      channelId,
      agentId,
      rootPostId,
      children: new Map(),
    });
    globalMetrics.activeSessions = activeBoxes.size;

    // Register in watcher
    const initialState = saved
      ? { lastOffset: saved.lastOffset, startTime: saved.startTime, agentId }
      : { agentId };
    watcher.addSession(sessionKey, transcriptFile, initialState);

    // Process any pending sub-agents that were waiting for this parent
    if (pendingSubAgents.has(sessionKey)) {
      const pending = pendingSubAgents.get(sessionKey);
      pendingSubAgents.delete(sessionKey);
      for (const childInfo of pending) {
        logger.debug(
          { childKey: childInfo.sessionKey, parentKey: sessionKey },
          'Processing queued sub-agent',
        );
        linkSubAgent(activeBoxes, watcher, sessionKey, childInfo, logger);
      }
    }
  });

  // ---- Session Removed ----
  monitor.on('session-removed', (sessionKey) => {
    // Don't immediately remove — let idle detection handle final flush
    logger.debug({ sessionKey }, 'Session removed from sessions.json');
  });

  // ---- Session Update (from watcher) ----
  watcher.on('session-update', (sessionKey, state) => {
    const box = activeBoxes.get(sessionKey);
    if (!box) {
      // Sub-agent: update parent
      updateParentWithChild(activeBoxes, watcher, sharedStatusBox, sessionKey, state, logger);
      return;
    }

    // Build status text
    const text = buildStatusText(box, state, activeBoxes, watcher, sessionKey);
    sharedStatusBox.updatePost(box.postId, text).catch((err) => {
      logger.error({ sessionKey, err }, 'Failed to update status post');
      globalMetrics.lastError = err.message;
      globalMetrics.updatesFailed++;
    });

    // Persist offsets periodically
    saveOffsets(config.offsetFile, watcher.sessions);
  });

  // ---- Session Idle (from watcher) ----
  watcher.on('session-idle', async (sessionKey, state) => {
    const box = activeBoxes.get(sessionKey);
    if (!box) {
      // Sub-agent completed
      updateParentWithChild(activeBoxes, watcher, sharedStatusBox, sessionKey, state, logger);
      return;
    }

    // Check all children are complete before marking done
    const allChildrenDone = checkChildrenComplete(box, watcher);
    if (!allChildrenDone) {
      logger.debug({ sessionKey }, 'Parent waiting for child sessions to complete');
      return;
    }

    // Final update with done status
    const doneState = { ...state, status: 'done' };
    const text = buildStatusText(box, doneState, activeBoxes, watcher, sessionKey);

    try {
      await sharedStatusBox.forceFlush(box.postId);
      await sharedStatusBox.updatePost(box.postId, text);
      logger.info({ sessionKey, postId: box.postId }, 'Session complete — status box updated');
    } catch (err) {
      logger.error({ sessionKey, err }, 'Failed to update final status');
    }

    // Clean up
    activeBoxes.delete(sessionKey);
    watcher.removeSession(sessionKey);
    globalMetrics.activeSessions = activeBoxes.size;

    // Persist final offsets
    saveOffsets(config.offsetFile, watcher.sessions);
  });

  // ---- Start all subsystems ----
  await healthServer.start();

  try {
    watcher.start();
  } catch (err) {
    logger.warn({ err }, 'fs.watch failed — creating transcript dir');
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    fs.mkdirSync(config.transcriptDir, { recursive: true });
    watcher.start();
  }

  monitor.start();

  logger.info('Status watcher daemon ready');

  // ---- Graceful shutdown ----
  let shuttingDown = false;
  async function shutdown(signal) {
    if (shuttingDown) return;
    shuttingDown = true;

    logger.info({ signal }, 'Shutting down gracefully');

    // Stop accepting new sessions
    monitor.stop();
    watcher.stop();

    // Mark all active boxes as interrupted
    const updates = [];
    for (const [sessionKey, box] of activeBoxes) {
      const state = watcher.getSessionState(sessionKey) || {
        sessionKey,
        status: 'interrupted',
        startTime: Date.now(),
        lines: [],
        agentId: box.agentId,
        depth: 0,
        tokenCount: 0,
        children: [],
      };
      const intState = { ...state, status: 'interrupted' };
      const text = buildStatusText(box, intState, activeBoxes, watcher, sessionKey);
      updates.push(
        sharedStatusBox
          .updatePost(box.postId, text)
          .catch((e) => logger.error({ sessionKey, e }, 'Shutdown update failed')),
      );
    }
    await Promise.allSettled(updates);
    await sharedStatusBox.flushAll();

    // Cleanup
    await healthServer.stop();
    sharedStatusBox.destroy();
    removePidFile(config.pidFile);

    logger.info('Shutdown complete');
    process.exit(0);
  }

  process.on('SIGTERM', () => shutdown('SIGTERM'));
  process.on('SIGINT', () => shutdown('SIGINT'));

  // Offset persistence interval (every 30s)
  setInterval(() => {
    saveOffsets(config.offsetFile, watcher.sessions);
  }, 30000);
}

// ---- Helper functions ----

function linkSubAgent(activeBoxes, watcher, parentKey, childInfo, logger) {
  const parentBox = activeBoxes.get(parentKey);
  if (!parentBox) return;

  const { sessionKey, transcriptFile, agentId, spawnDepth } = childInfo;

  if (!parentBox.children) parentBox.children = new Map();
  parentBox.children.set(sessionKey, { sessionKey, transcriptFile, agentId });

  watcher.addSession(sessionKey, transcriptFile, {
    agentId,
    depth: spawnDepth || 1,
  });

  logger.info({ sessionKey, parent: parentKey }, 'Sub-agent linked to parent');
}

function buildInitialText(agentId, sessionKey) {
  const { format } = require('./status-formatter');
  return format({
    sessionKey,
    status: 'active',
    startTime: Date.now(),
    lines: [],
    agentId,
    depth: 0,
    tokenCount: 0,
    children: [],
  });
}

function buildStatusText(box, state, activeBoxes, watcher, _sessionKey) {
  const { format } = require('./status-formatter');

  // Build child states for nesting
  const childStates = [];
  if (box.children && box.children.size > 0) {
    for (const [childKey] of box.children) {
      const childWatcherState = watcher.getSessionState(childKey);
      if (childWatcherState) {
        childStates.push({ ...childWatcherState, depth: 1 });
      }
    }
  }

  return format({ ...state, children: childStates });
}

function updateParentWithChild(activeBoxes, watcher, statusBox, childKey, childState, logger) {
  // Find parent
  for (const [parentKey, box] of activeBoxes) {
    if (box.children && box.children.has(childKey)) {
      const parentState = watcher.getSessionState(parentKey);
      if (!parentState) return;

      const text = buildStatusText(box, parentState, activeBoxes, watcher, parentKey);
      statusBox
        .updatePost(box.postId, text)
        .catch((err) => logger.error({ parentKey, childKey, err }, 'Failed to update parent'));
      return;
    }
  }
}

function checkChildrenComplete(box, watcher) {
  if (!box.children || box.children.size === 0) return true;
  for (const [childKey] of box.children) {
    const childState = watcher.getSessionState(childKey);
    if (childState && childState.status === 'active') return false;
  }
  return true;
}

async function findExistingPost(statusBox, channelId, sessionKey, logger) {
  // Search channel history for a post with our marker
  // This uses the Mattermost search API
  const marker = makeMarker(sessionKey);
  try {
    // Use the internal _apiCall method to search posts
    const result = await statusBox._apiCallWithRetry('POST', '/api/v4/posts/search', {
      channel_id: channelId,
      terms: marker,
      is_or_search: false,
    });
    if (result && result.posts) {
      for (const post of Object.values(result.posts)) {
        if (post.message && post.message.includes(marker)) {
          logger.info(
            { sessionKey, postId: post.id },
            'Found existing status post (restart recovery)',
          );
          return post.id;
        }
      }
    }
  } catch (_e) {
    /* search failed — create new post */
  }
  return null;
}

// ---- Stop command ----
function stopDaemon() {
  // Need to read config for pidFile location
  process.env.MM_BOT_TOKEN = process.env.MM_BOT_TOKEN || 'placeholder';
  let config;
  try {
    config = getConfig();
  } catch (_e) {
    config = { pidFile: '/tmp/status-watcher.pid' };
  }

  const pid = readPidFile(config.pidFile);
  if (!pid) {
    console.log('Daemon not running (no PID file)');
    return;
  }
  if (!isProcessRunning(pid)) {
    console.log(`Daemon not running (PID ${pid} not found)`);
    removePidFile(config.pidFile);
    return;
  }
  console.log(`Stopping daemon (PID ${pid})...`);
  process.kill(pid, 'SIGTERM');
}

// ---- Status command ----
function daemonStatus() {
  process.env.MM_BOT_TOKEN = process.env.MM_BOT_TOKEN || 'placeholder';
  let config;
  try {
    config = getConfig();
  } catch (_e) {
    config = { pidFile: '/tmp/status-watcher.pid', healthPort: 9090 };
  }

  const pid = readPidFile(config.pidFile);
  if (!pid) {
    console.log('Status: stopped');
    return;
  }
  if (!isProcessRunning(pid)) {
    console.log(`Status: stopped (stale PID ${pid})`);
    return;
  }
  console.log(`Status: running (PID ${pid})`);
  console.log(`Health: http://localhost:${config.healthPort}/health`);
}