import path from 'path';
import { fileURLToPath } from 'url';
import { createServer } from 'http';
import express from 'express';
import cors from 'cors';
import cookieParser from 'cookie-parser';
import dotenv from 'dotenv';
import { Server } from 'socket.io';
import natsAdapter from '@mickl/socket.io-nats-adapter';
const { createAdapter } = natsAdapter;
import { connectNats, getNatsConnection } from './lib/nats.js';
import pokerRoutes from './routes/poker.js';
import jiraRoutes from './routes/jira.js';
import roomRoutes from './routes/rooms.js';
import {
  canAccessSession,
  getSessionSnapshot,
  isSessionParticipant,
  joinSession,
  leaveSession,
  revealIfComplete,
  saveScopedEstimate,
  submitVote
} from './services/pokerService.js';
import { updateIssueEstimate } from './services/jiraService.js';
import { getSocketUser } from './middleware/auth.js';
import { safeError } from './lib/errors.js';

dotenv.config();

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const isProd = process.env.NODE_ENV === 'production';

const app = express();
const httpServer = createServer(app);

const port = Number(process.env.PORT || 4010);
if (isProd && !process.env.FRONTEND_URL) {
  throw new Error('FRONTEND_URL must be set in production.');
}
const frontendUrl = process.env.FRONTEND_URL || 'http://localhost:5174';
const corsOptions = { origin: frontendUrl, credentials: true };

function isAllowedOrigin(origin) {
  if (!origin) return !isProd;
  return origin === frontendUrl;
}

app.disable('x-powered-by');
app.use((_req, res, next) => {
  res.setHeader('X-Content-Type-Options', 'nosniff');
  res.setHeader('X-Frame-Options', 'DENY');
  res.setHeader('Referrer-Policy', 'no-referrer');
  res.setHeader('Permissions-Policy', 'geolocation=(), microphone=(), camera=()');
  if (isProd) {
    res.setHeader('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
  }
  next();
});

app.use(cors(corsOptions));
app.use(cookieParser());
app.use(express.json({ limit: '1mb' }));

app.get('/api/health', (_req, res) => {
  res.json({ status: 'ok' });
});

app.use('/api/poker', pokerRoutes);
app.use('/api/jira', jiraRoutes);
app.use('/api/poker/rooms', roomRoutes);

if (isProd) {
  const distPath = path.resolve(__dirname, '../../frontend/dist');
  app.use(express.static(distPath));
  app.get('*', (req, res) => {
    if (req.path.startsWith('/api/')) return res.status(404).json({ error: 'Not found' });
    res.sendFile(path.join(distPath, 'index.html'));
  });
}

const io = new Server(httpServer, {
  cors: corsOptions,
  allowRequest: (req, callback) => {
    if (isAllowedOrigin(req.headers.origin)) {
      callback(null, true);
      return;
    }
    callback('Origin not allowed', false);
  }
});

async function emitSessionState(sessionId) {
  const snapshot = await getSessionSnapshot(sessionId);
  if (!snapshot) return;

  io.to(`poker:${sessionId}`).emit('poker:participants', {
    sessionId,
    participants: snapshot.participants,
    votedUserKeys: snapshot.votedUserKeys,
    voteCount: snapshot.voteCount,
    participantCount: snapshot.participantCount
  });

  io.to(`poker:${sessionId}`).emit('poker:vote-update', {
    sessionId,
    voteCount: snapshot.voteCount,
    participantCount: snapshot.participantCount,
    votedUserKeys: snapshot.votedUserKeys,
    allVoted: snapshot.voteCount > 0 && snapshot.voteCount === snapshot.participantCount
  });

  if (snapshot.session.state === 'REVEALED' || snapshot.session.state === 'SAVED') {
    io.to(`poker:${sessionId}`).emit('poker:revealed', {
      sessionId,
      votes: snapshot.votesByUser,
      average: snapshot.session.averageEstimate,
      suggestedEstimate: snapshot.session.suggestedEstimate,
      savedEstimate: snapshot.session.savedEstimate
    });
  }
}

io.on('connection', (socket) => {
  const user = getSocketUser(socket);
  if (!user || !user.jiraCloudId) {
    socket.emit('poker:error', { error: 'Not authenticated' });
    socket.disconnect(true);
    return;
  }
  socket.user = user;

  socket.on('poker:join', async ({ sessionId }) => {
    try {
      if (!sessionId) {
        socket.emit('poker:error', { error: 'sessionId is required.' });
        return;
      }

      if (!await canAccessSession(sessionId, socket.user.jiraCloudId)) {
        socket.emit('poker:error', { error: 'Session not found.' });
        return;
      }

      socket.join(`poker:${sessionId}`);
      const snapshot = await joinSession({
        sessionId,
        tenantCloudId: socket.user.jiraCloudId,
        userKey: socket.user.jiraAccountId,
        userName: socket.user.displayName,
        avatarUrl: socket.user.avatarUrl || null
      });
      if (!snapshot) {
        socket.emit('poker:error', { error: 'Session not found.' });
        return;
      }
      await emitSessionState(sessionId);
    } catch (error) {
      console.error('[socket] poker:join failed:', error);
      socket.emit('poker:error', { error: safeError(error) });
    }
  });

  socket.on('poker:vote', async ({ sessionId, vote }) => {
    try {
      if (!sessionId) {
        socket.emit('poker:error', { error: 'sessionId is required.' });
        return;
      }

      if (!await canAccessSession(sessionId, socket.user.jiraCloudId)) {
        socket.emit('poker:error', { error: 'Session not found.' });
        return;
      }
      if (!await isSessionParticipant(sessionId, socket.user.jiraAccountId)) {
        socket.emit('poker:error', { error: 'Join the session before voting.' });
        return;
      }

      const voteResult = await submitVote({
        sessionId,
        tenantCloudId: socket.user.jiraCloudId,
        userKey: socket.user.jiraAccountId,
        vote
      });
      if (!voteResult) {
        socket.emit('poker:error', { error: 'Unable to submit vote for this session.' });
        return;
      }
      const reveal = await revealIfComplete(sessionId);

      await emitSessionState(sessionId);

      if (reveal?.allVoted) {
        io.to(`poker:${sessionId}`).emit('poker:revealed', {
          sessionId,
          votes: reveal.votesByUser,
          average: reveal.average,
          suggestedEstimate: reveal.suggestedEstimate
        });
      }
    } catch (error) {
      console.error('[socket] poker:vote failed:', error);
      socket.emit('poker:error', { error: safeError(error) });
    }
  });

  socket.on('poker:save', async ({ sessionId, estimate }) => {
    try {
      if (!sessionId) {
        socket.emit('poker:error', { error: 'sessionId is required.' });
        return;
      }

      if (!await canAccessSession(sessionId, socket.user.jiraCloudId)) {
        socket.emit('poker:error', { error: 'Session not found.' });
        return;
      }
      if (!await isSessionParticipant(sessionId, socket.user.jiraAccountId)) {
        socket.emit('poker:error', { error: 'Join the session before saving.' });
        return;
      }

      const numericEstimate = Number(estimate);
      if (!Number.isFinite(numericEstimate)) {
        socket.emit('poker:error', { error: 'estimate must be a number.' });
        return;
      }

      const saved = await saveScopedEstimate({
        sessionId,
        estimate: numericEstimate,
        tenantCloudId: socket.user.jiraCloudId,
        userKey: socket.user.jiraAccountId
      });
      if (!saved) {
        socket.emit('poker:error', { error: 'Unable to save estimate for this session.' });
        return;
      }

      const issueRef = saved.session.issueId || saved.session.issueKey;
      try {
        await updateIssueEstimate(socket.user.jiraAccountId, issueRef, numericEstimate, saved.session.boardId);
      } catch (_jiraError) {
        // Jira update is best-effort so poker flow continues even when Jira is unavailable.
      }

      io.to(`poker:${sessionId}`).emit('poker:saved', {
        sessionId,
        estimate: numericEstimate,
        issueKey: saved.session.issueKey
      });

      io.to(`poker:${sessionId}`).emit('poker:ended', { sessionId });
    } catch (error) {
      console.error('[socket] poker:save failed:', error);
      socket.emit('poker:error', { error: safeError(error) });
    }
  });

  socket.on('poker:leave', async ({ sessionId }) => {
    try {
      if (!sessionId) return;
      if (!await canAccessSession(sessionId, socket.user.jiraCloudId)) return;
      await leaveSession({
        sessionId,
        tenantCloudId: socket.user.jiraCloudId,
        userKey: socket.user.jiraAccountId
      });
      socket.leave(`poker:${sessionId}`);
      await emitSessionState(sessionId);
    } catch (error) {
      console.error('[socket] poker:leave failed:', error);
      socket.emit('poker:error', { error: safeError(error) });
    }
  });
});

async function start() {
  const nc = await connectNats();
  io.adapter(createAdapter(nc));

  httpServer.listen(port, () => {
    // eslint-disable-next-line no-console
    console.log(`Pokerface backend listening on :${port}`);
  });
}

start().catch((error) => {
  // eslint-disable-next-line no-console
  console.error('Failed to start server:', error);
  process.exit(1);
});