import { createServer } from 'http'
import { Server } from 'socket.io'

const SOCKET_PORT = parseInt(process.env.SOCKET_PORT || '3002')
const HTTP_PORT = parseInt(process.env.SOCKET_HTTP_PORT || '3003')
const INTERNAL_KEY = process.env.SOCKET_INTERNAL_KEY || ''

// ─── Socket.io Server ────────────────────────────────────────────────────────

const io = new Server(SOCKET_PORT, {
  cors: {
    origin: true, // Accepte dynamiquement toutes les origines (CORS fix)
    methods: ['GET', 'POST'],
    credentials: true,
  },
})

const rooms = new Map<string, Map<string, { userId: string; name: string; cursor: { x: number; y: number } | null; color: string }>>()

const COLORS = [
  '#e57373', '#81c784', '#64b5f6', '#ffb74d',
  '#ba68c8', '#4dd0e1', '#f06292', '#aed581',
  '#ff8a65', '#4fc3f7', '#dce775', '#f48fb1',
]

// ─── [UPDATE - TEMPS RÉEL] Node Locking in-memory ───────────────────────────
// Choix : Map in-memory + TTL automatique.
// Justification : locks volatiles par design, O(1), pas de deadlocks PostgreSQL.
// Migration Redis triviale si multi-instances (remplacer Map par SET NX EX).

const LOCK_TTL_MS = 15_000

interface IdeaLock {
  userId: string
  userName: string
  lockedAt: number
  timeoutHandle: ReturnType<typeof setTimeout>
}

// Map<sessionId, Map<ideaId, IdeaLock>>
const ideaLocks = new Map<string, Map<string, IdeaLock>>()

function acquireLock(
  sessionId: string,
  ideaId: string,
  userId: string,
  userName: string
): boolean {
  if (!ideaLocks.has(sessionId)) {
    ideaLocks.set(sessionId, new Map())
  }
  const sessionLocks = ideaLocks.get(sessionId)!
  const existing = sessionLocks.get(ideaId)

  if (existing && existing.userId !== userId) {
    const age = Date.now() - existing.lockedAt
    if (age < LOCK_TTL_MS) return false
    // Lock expiré → nettoyer
    clearTimeout(existing.timeoutHandle)
    sessionLocks.delete(ideaId)
  }

  const handle = setTimeout(() => {
    releaseLock(sessionId, ideaId, userId, true)
    io.to(sessionId).emit('idea:unlocked', { ideaId, reason: 'ttl_expired' })
  }, LOCK_TTL_MS)

  sessionLocks.set(ideaId, { userId, userName, lockedAt: Date.now(), timeoutHandle: handle })
  return true
}

function releaseLock(
  sessionId: string,
  ideaId: string,
  userId: string,
  expired = false
): boolean {
  const sessionLocks = ideaLocks.get(sessionId)
  if (!sessionLocks) return false
  const lock = sessionLocks.get(ideaId)
  if (!lock || lock.userId !== userId) return false
  if (!expired) clearTimeout(lock.timeoutHandle)
  sessionLocks.delete(ideaId)
  return true
}

function releaseAllLocksForUser(sessionId: string, userId: string): string[] {
  const sessionLocks = ideaLocks.get(sessionId)
  if (!sessionLocks) return []
  const released: string[] = []
  for (const [ideaId, lock] of sessionLocks.entries()) {
    if (lock.userId === userId) {
      clearTimeout(lock.timeoutHandle)
      sessionLocks.delete(ideaId)
      released.push(ideaId)
    }
  }
  return released
}

// ─── Socket.io Middleware ─────────────────────────────────────────────────────

io.use((socket, next) => {
  const userId = socket.handshake.auth.userId || `guest_${socket.id.slice(0, 8)}`
  const sessionId = socket.handshake.auth.sessionId
  const name = socket.handshake.auth.name || 'Guest'
  const isGuest = socket.handshake.auth.isGuest === true

  if (!sessionId) {
    return next(new Error('Missing sessionId'))
  }

  socket.data.userId = userId
  socket.data.sessionId = sessionId
  socket.data.name = name
  socket.data.isGuest = isGuest
  next()
})

// ─── Socket.io Connection Handler ────────────────────────────────────────────

io.on('connection', (socket) => {
  const sessionId = socket.data.sessionId
  const userId = socket.data.userId
  const name = socket.data.name

  socket.join(sessionId)

  if (!rooms.has(sessionId)) {
    rooms.set(sessionId, new Map())
  }

  const colorIdx = rooms.get(sessionId)!.size % COLORS.length
  const color = COLORS[colorIdx]

  // IMPORTANT: Utiliser socket.id au lieu de userId pour supporter le refresh et multi-onglets
  rooms.get(sessionId)!.set(socket.id, { name, cursor: null, color, userId }) // Note: On doit ajouter userId dans l'objet pour le retrouver

  io.to(sessionId).emit('presence:update', Array.from(rooms.get(sessionId)!.values()).map(data => ({
    userId: data.userId, // On renvoie bien le userId attendu par le client
    name: data.name,
    cursor: data.cursor,
    color: data.color,
  })))

  // ── Curseur ──────────────────────────────────────────────────────────────

  socket.on('cursor:move', (cursor: { x: number; y: number }) => {
    const room = rooms.get(sessionId)
    if (!room) return
    const user = room.get(socket.id)
    if (!user) return
    user.cursor = cursor
    socket.to(sessionId).emit('cursor:update', { userId, cursor })
  })

  // ── Idées (événements existants) ─────────────────────────────────────────

  socket.on('idea:added', (data: { ideaId: string; title: string; userId: string; userName: string }) => {
    socket.to(sessionId).emit('idea:added', data)
  })

  socket.on('idea:dismissed', (data: { ideaId: string; userId: string }) => {
    // Libérer le lock si l'idée était verrouillée par cet utilisateur
    releaseLock(sessionId, data.ideaId, userId)
    socket.to(sessionId).emit('idea:dismissed', data)
  })

  socket.on('idea:moved', (data: { ideaId: string; positionX: number; positionY: number; userId: string }) => {
    socket.to(sessionId).emit('idea:moved', data)
  })

  socket.on('activity:new', (data: { action: string; userId: string; userName: string; details: any }) => {
    io.to(sessionId).emit('activity:new', data)
  })

  // ── [UPDATE - TEMPS RÉEL] Node Locking ───────────────────────────────────

  socket.on('idea:lock_request', (data: { ideaId: string }) => {
    const acquired = acquireLock(sessionId, data.ideaId, userId, name)
    if (acquired) {
      // Notifier tout le room — le nœud est grisé pour tous les autres
      io.to(sessionId).emit('idea:locked', {
        ideaId: data.ideaId,
        lockedBy: userId,
        lockedByName: name,
        ttl: LOCK_TTL_MS,
      })
    } else {
      // Refus uniquement au demandeur
      const lock = ideaLocks.get(sessionId)?.get(data.ideaId)
      socket.emit('idea:lock_denied', {
        ideaId: data.ideaId,
        lockedBy: lock?.userId,
        lockedByName: lock?.userName,
      })
    }
  })

  socket.on('idea:unlock', (data: { ideaId: string }) => {
    const released = releaseLock(sessionId, data.ideaId, userId)
    if (released) {
      io.to(sessionId).emit('idea:unlocked', { ideaId: data.ideaId })
    }
  })

  // ── Déconnexion ───────────────────────────────────────────────────────────

  socket.on('disconnect', () => {
    // Libérer tous les locks de cet utilisateur
    const releasedIds = releaseAllLocksForUser(sessionId, userId)
    for (const ideaId of releasedIds) {
      io.to(sessionId).emit('idea:unlocked', { ideaId })
    }

    const room = rooms.get(sessionId)
    if (room) {
      room.delete(socket.id) // Utilise socket.id, pas userId
      if (room.size === 0) {
        rooms.delete(sessionId)
        ideaLocks.delete(sessionId)
      } else {
        io.to(sessionId).emit('presence:update', Array.from(room.values()).map(d => ({
          userId: d.userId, // Renvoie le userId correct
          name: d.name,
          cursor: d.cursor,
          color: d.color,
        })))
      }
    }
  })
})

// ─── [UPDATE - TEMPS RÉEL] Endpoint HTTP interne pour l'émission depuis les API routes ──
// Permet à next.js d'émettre des événements Socket sans couplage direct.
// Sécurisé par SOCKET_INTERNAL_KEY.

const httpServer = createServer((req, res) => {
  if (req.method === 'POST' && req.url === '/emit') {
    const key = req.headers['x-internal-key']
    if (INTERNAL_KEY && key !== INTERNAL_KEY) {
      res.writeHead(403).end('Forbidden')
      return
    }
    let body = ''
    req.on('data', chunk => (body += chunk))
    req.on('end', () => {
      try {
        const { sessionId, event, data } = JSON.parse(body)
        if (!sessionId || !event) {
          res.writeHead(400).end('Missing sessionId or event')
          return
        }
        io.to(sessionId).emit(event, data)
        res.writeHead(200).end('ok')
      } catch {
        res.writeHead(400).end('Invalid JSON')
      }
    })
  } else {
    res.writeHead(404).end()
  }
})

httpServer.listen(HTTP_PORT, () => {
  console.log(`Socket.io internal HTTP endpoint listening on port ${HTTP_PORT}`)
})

console.log(`Socket.io server running on port ${SOCKET_PORT}`)