import { constants as fsConstants } from 'node:fs';
import fs from 'node:fs/promises';
import path from 'node:path';
import { Worker } from 'bullmq';
import { config } from './config.js';
import {
  createRedisConnection,
  getSearchRecord,
  markSearchCompleted,
  markSearchFailed,
  markSearchProcessing,
  releaseActiveSearchLock,
  storeResultRecord
} from '../../backend/src/redis-store.js';
import { parseMatcherCsv, resolvePklPath, runFaceMatcher } from './worker-utils.js';

const connection = createRedisConnection(config.redisUrl);

async function ensureMatcherBinaryAvailable() {
  try {
    await fs.access(config.matcherBinary, fsConstants.X_OK);
  } catch (error) {
    console.error(`FaceAI processor cannot start because the matcher binary is unavailable: ${config.matcherBinary}`);
    console.error('Ensure FACEAI_MATCHER_BINARY points to a real executable and that the processor image includes the Unix face_matcher binary.');
    if (error?.code === 'ENOENT') {
      console.error('The configured matcher path does not exist inside the processor runtime.');
    } else if (error?.code === 'EACCES') {
      console.error('The configured matcher path exists but is not executable by the processor runtime.');
    }

    throw error;
  }
}

console.log(`FaceAI processor configured matcher binary: ${config.matcherBinary}`);

function formatLogLine(message, details) {
  const timestamp = new Date().toISOString();
  if (details === undefined) {
    return `[${timestamp}] ${message}\n`;
  }

  return `[${timestamp}] ${message} ${JSON.stringify(details)}\n`;
}

async function appendSearchLog(logPath, message, details) {
  await fs.mkdir(path.dirname(logPath), { recursive: true });
  await fs.appendFile(logPath, formatLogLine(message, details), 'utf8');
}

async function resolveCompletionCode(logPath, matchCount) {
  if (matchCount > 0) {
    return null;
  }

  const matcherLog = await fs.readFile(logPath, 'utf8').catch(() => '');
  if (/nessun\s+volt|no\s+faces?|no\s+face|0\s+faces?/i.test(matcherLog)) {
    return 'NO_FACES_FOUND';
  }

  return 'NO_FACES_FOUND';
}

async function completeSearch(search, searchId, searchLogPath, matchCount, matches, completionCode) {
  const result = await storeResultRecord(connection, {
    raceId: search.raceId,
    raceName: search.raceName,
    userId: search.userId,
    returnUrl: search.returnUrl,
    lang: search.lang,
    matches
  }, config.resultTtlSeconds);

  await appendSearchLog(searchLogPath, 'Completed FaceAI search', {
    resultId: result.id,
    matchCount,
    completionCode
  });

  await markSearchCompleted(connection, searchId, result.id, matchCount, config.searchTtlSeconds, {
    completionCode
  });
  await releaseActiveSearchLock(connection, search.userId, searchId);
}

async function processJob(job) {
  const searchId = String(job.data.searchId || '');
  const search = await getSearchRecord(connection, searchId);
  if (!search) {
    throw new Error(`Search ${searchId} not found`);
  }

  await markSearchProcessing(connection, searchId, config.searchTtlSeconds);

  const searchDir = path.join(config.runtimeRoot, 'searches', searchId);
  const searchLogDir = path.join(config.logRoot, 'searches', searchId);
  const searchLogPath = path.join(searchLogDir, 'worker.log');
  await fs.mkdir(searchDir, { recursive: true });
  await fs.mkdir(searchLogDir, { recursive: true });

  await appendSearchLog(searchLogPath, 'Starting FaceAI search', {
    searchId,
    raceId: search.raceId,
    userId: search.userId,
    selfiePath: search.selfiePath,
    runtimeRoot: config.runtimeRoot,
    logRoot: config.logRoot,
    queueName: config.queueName
  });

  try {
    const pklPath = await resolvePklPath({
      raceId: search.raceId,
      raceStorage: search.raceStorage,
      pklRoot: config.pklRoot
    });

    await appendSearchLog(searchLogPath, 'Resolved PKL path', {
      pklPath,
      raceStorage: search.raceStorage
    });

    const csvPath = path.join(searchDir, 'result.csv');
    const logPath = path.join(searchLogDir, 'matcher.log');

    await appendSearchLog(searchLogPath, 'Running matcher', {
      matcherBinary: config.matcherBinary,
      csvPath,
      matcherLogPath: logPath,
      timeoutMs: config.workerTimeoutMs
    });

    try {
      await runFaceMatcher({
        matcherBinary: config.matcherBinary,
        selfiePath: search.selfiePath,
        pklPath,
        csvPath,
        logPath,
        timeoutMs: config.workerTimeoutMs
      });
    } catch (error) {
      if (error.message === 'face_matcher exited with code 1') {
        await appendSearchLog(searchLogPath, 'Matcher reported no detectable faces', {
          matcherLogPath: logPath,
          selfiePath: search.selfiePath
        });
        await completeSearch(search, searchId, searchLogPath, 0, [], 'NO_FACES_FOUND');
        return;
      }

      throw error;
    }

    const matches = await parseMatcherCsv(csvPath);
    const completionCode = await resolveCompletionCode(logPath, matches.length);
    await completeSearch(search, searchId, searchLogPath, matches.length, matches, completionCode);
  } catch (error) {
    await appendSearchLog(searchLogPath, 'FaceAI search failed', {
      message: error.message,
      stack: error.stack || null
    });
    await markSearchFailed(connection, searchId, 'PROCESSOR_ERROR', error.message, config.searchTtlSeconds);
    await releaseActiveSearchLock(connection, search.userId, searchId);
    throw error;
  }
}

await ensureMatcherBinaryAvailable();

const worker = new Worker(config.queueName, processJob, {
  connection,
  concurrency: config.workerConcurrency
});

worker.on('completed', (job) => {
  console.log(`Completed FaceAI search ${job.data.searchId}`);
});

worker.on('failed', (job, error) => {
  const searchId = job?.data?.searchId || 'unknown';
  console.error(`Failed FaceAI search ${searchId}:`, error);
});

console.log(`FaceAI processor listening on queue ${config.queueName} with concurrency ${config.workerConcurrency}`);