import { spawn, type IPty } from '@skitee3000/bun-pty'
import { PORT_TERMINAL, WORKING_DIR, SHELL, SHELL_ARGS, DEFAULT_SESSION_ID, MAX_BUFFER_LINES } from '../config'
import { sessionState, type SessionStatePatch } from './session-state'

interface TerminalSession {
  id: string
  pty: IPty
  outputBuffer: string[]
  maxBufferSize: number
  clients: Set<any>
  createdAt: Date
}

// Agent terminal state tracking
interface AgentTerminalState {
  agentId: string
  sessionId: string
  command: string
  startedAt: Date | null
  isAgentRunning: boolean
}

export const agentSessions = new Map<string, AgentTerminalState>()

const AGENT_COMMANDS: Record<string, string> = {
  'main': 'claude',
  'ejecutor': 'ejecutor',
  'nucleo000': 'nucleo000'
}

// Store active terminal sessions by ID (persistent across reconnections)
const sessions = new Map<string, TerminalSession>()

// Map WebSocket to sessionId
const wsToSession = new Map<any, string>()

// ── Global terminal registry ──
// Tracks metadata about transcript-debug terminals so all clients can see/connect to them

interface TerminalRegistryEntry {
  ephemeralSessionId: string   // PTY session ID on this server
  transcriptSessionId: string  // Claude transcript session being resumed (or '__new__')
  agent: string                // ejecutor | nucleo000 | claude
  label: string                // First user message or short description
  command: string              // Full command that was run
  createdAt: string            // ISO timestamp
}

const terminalRegistry = new Map<string, TerminalRegistryEntry>() // keyed by ephemeralSessionId

function getRegistrySnapshot() {
  return Array.from(terminalRegistry.values()).map(entry => {
    const ptySession = sessions.get(entry.ephemeralSessionId)
    return {
      ...entry,
      alive: !!ptySession,
      clients: ptySession?.clients.size ?? 0,
      bufferSize: ptySession?.outputBuffer.length ?? 0
    }
  })
}

// Broadcast session state patch to ALL clients across ALL sessions
function broadcastSessionStatePatch(patch: SessionStatePatch) {
  const message = JSON.stringify(patch)
  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try { ws.send(message); clientCount++ } catch { /* skip */ }
    }
  }
  console.log(`[Terminal] State patch: ${patch.event} (${patch.agent}) → ${clientCount} clients`)
}

function broadcastRegistryChange() {
  const message = JSON.stringify({
    type: 'terminal-registry-change',
    registry: getRegistrySnapshot(),
    timestamp: Date.now()
  })
  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try { ws.send(message); clientCount++ } catch { /* skip */ }
    }
  }
  console.log(`[Terminal] Registry broadcast → ${clientCount} clients (${terminalRegistry.size} entries)`)
}

function getOrCreateSession(sessionId: string = DEFAULT_SESSION_ID): TerminalSession {
  let session = sessions.get(sessionId)

  if (!session) {
    console.log(`[Terminal] Creating new session: ${sessionId}`)
    const pty = spawn(SHELL, SHELL_ARGS, {
      name: 'xterm-256color',
      cols: 80,
      rows: 24,
      cwd: WORKING_DIR
    })

    session = {
      id: sessionId,
      pty,
      outputBuffer: [],
      maxBufferSize: MAX_BUFFER_LINES,
      clients: new Set(),
      createdAt: new Date()
    }

    // Capture output to buffer and send to clients
    pty.onData((data: string) => {
      session!.outputBuffer.push(data)
      if (session!.outputBuffer.length > session!.maxBufferSize) {
        session!.outputBuffer.shift()
      }

      for (const ws of session!.clients) {
        try {
          ws.send(JSON.stringify({ type: 'output', data }))
        } catch {
          // Client disconnected
        }
      }
    })

    // Handle PTY exit
    pty.onExit(({ exitCode }) => {
      console.log(`[Terminal] Session ${sessionId} exited with code ${exitCode}`)
      for (const ws of session!.clients) {
        try {
          ws.send(JSON.stringify({
            type: 'exit',
            data: `\r\n\x1b[33mSession ended (code ${exitCode})\x1b[0m\r\n`
          }))
        } catch { /* ignore */ }
      }
      sessions.delete(sessionId)

      // Auto-remove from terminal registry
      if (terminalRegistry.has(sessionId)) {
        terminalRegistry.delete(sessionId)
        broadcastRegistryChange()
      }

      // Mark agent as not running if this is an agent session
      if (sessionId.startsWith('agent-')) {
        const agentId = sessionId.replace('agent-', '')
        const state = agentSessions.get(agentId)
        if (state) {
          state.isAgentRunning = false
          console.log(`[Terminal] Agent ${agentId} marked as stopped (exit code ${exitCode})`)
        }
      }
    })

    sessions.set(sessionId, session)
    console.log(`[Terminal] Session ${sessionId} created, PID: ${pty.pid}`)
  }

  return session
}

// Kill an existing session's PTY process
export function killSession(sessionId: string): boolean {
  const session = sessions.get(sessionId)
  if (!session) return false

  console.log(`[Terminal] Killing session: ${sessionId} (PID: ${session.pty.pid})`)

  // Notify clients before killing
  for (const ws of session.clients) {
    try {
      ws.send(JSON.stringify({ type: 'session-restart', sessionId }))
    } catch { /* ignore */ }
  }

  try {
    session.pty.kill()
  } catch (e) {
    console.error(`[Terminal] Error killing PTY for ${sessionId}:`, e)
  }

  sessions.delete(sessionId)

  // Auto-remove from terminal registry
  if (terminalRegistry.has(sessionId)) {
    terminalRegistry.delete(sessionId)
    broadcastRegistryChange()
  }

  return true
}

// Start an agent command in its dedicated session
export async function startAgentInSession(agentId: string, force = false): Promise<AgentTerminalState> {
  const sessionId = `agent-${agentId}`
  const command = AGENT_COMMANDS[agentId] || agentId

  // If force restart, kill existing session first
  if (force && sessions.has(sessionId)) {
    killSession(sessionId)
    await new Promise(r => setTimeout(r, 300))
  }

  const session = getOrCreateSession(sessionId)

  // Write the agent command to the PTY
  session.pty.write(command + '\r')

  const state: AgentTerminalState = {
    agentId,
    sessionId,
    command,
    startedAt: new Date(),
    isAgentRunning: true
  }

  agentSessions.set(agentId, state)
  console.log(`[Terminal] Agent ${agentId} started in session ${sessionId} with command: ${command}`)

  return state
}

export function startTerminalServer() {
  const server = Bun.serve({
    port: PORT_TERMINAL,
    async fetch(req, server) {
      const url = new URL(req.url)

      const corsHeaders = {
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
        'Access-Control-Allow-Headers': 'Content-Type'
      }

      // CORS preflight
      if (req.method === 'OPTIONS') {
        return new Response(null, { headers: corsHeaders })
      }

      // Health check with session info
      if (url.pathname === '/health') {
        const sessionsInfo = Array.from(sessions.entries()).map(([id, s]) => ({
          id,
          clients: s.clients.size,
          pid: s.pty.pid,
          bufferSize: s.outputBuffer.length,
          createdAt: s.createdAt.toISOString()
        }))
        return Response.json({
          status: 'ok',
          sessions: sessionsInfo,
          cwd: WORKING_DIR
        }, { headers: corsHeaders })
      }

      // List active sessions
      if (url.pathname === '/sessions') {
        const list = Array.from(sessions.keys())
        return Response.json({ sessions: list })
      }

      // Claude status broadcast endpoint
      if (url.pathname === '/claude-status' && req.method === 'POST') {
        try {
          const body = await req.json() as { status: ClaudeStatus, tool?: string, agent?: string }
          broadcastClaudeStatus(body.status, body.tool, body.agent)
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      // Claude hook broadcast endpoint (rich data from stdin)
      if (url.pathname === '/claude-hook' && req.method === 'POST') {
        try {
          const body = await req.json()
          broadcastClaudeHook(body)
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      // Claude permission request broadcast endpoint
      if (url.pathname === '/claude-permission' && req.method === 'POST') {
        try {
          const body = await req.json()
          broadcastPermissionRequest(body)
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      // Agent sessions info
      if (url.pathname === '/agent-sessions' && req.method === 'GET') {
        const result: Record<string, any> = {}
        for (const [id, state] of agentSessions) {
          const session = sessions.get(state.sessionId)
          result[id] = {
            ...state,
            pid: session?.pty.pid ?? null,
            bufferSize: session?.outputBuffer.length ?? 0,
            clientCount: session?.clients.size ?? 0,
            sessionExists: !!session
          }
        }
        return Response.json(result, { headers: corsHeaders })
      }

      // Start agent in session
      if (url.pathname === '/start-agent' && req.method === 'POST') {
        try {
          const body = await req.json() as { agentId: string; force?: boolean }
          if (!body.agentId) {
            return Response.json({ error: 'agentId required' }, { status: 400, headers: corsHeaders })
          }
          const state = await startAgentInSession(body.agentId, body.force)
          return Response.json({ success: true, state }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
        }
      }

      // Stop agent session
      if (url.pathname === '/stop-agent' && req.method === 'POST') {
        try {
          const body = await req.json() as { agentId: string }
          if (!body.agentId) {
            return Response.json({ error: 'agentId required' }, { status: 400, headers: corsHeaders })
          }
          const sessionId = `agent-${body.agentId}`
          const killed = killSession(sessionId)
          if (killed) {
            const state = agentSessions.get(body.agentId)
            if (state) state.isAgentRunning = false
          }
          return Response.json({ success: true, killed }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
        }
      }

      // Kill a specific session by ID (used for ephemeral sessions)
      if (url.pathname === '/kill-session' && req.method === 'POST') {
        try {
          const body = await req.json() as { sessionId: string }
          if (!body.sessionId) {
            return Response.json({ error: 'sessionId required' }, { status: 400, headers: corsHeaders })
          }
          const killed = killSession(body.sessionId)
          return Response.json({ success: true, killed }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
        }
      }

      // Transcript update broadcast endpoint
      if (url.pathname === '/transcript-update' && req.method === 'POST') {
        try {
          const body = await req.json()
          broadcastTranscriptUpdate(body as Record<string, unknown>)
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      // ── Terminal Registry endpoints ──

      // List all registered terminals (global, for all clients)
      if (url.pathname === '/terminal-registry' && req.method === 'GET') {
        return Response.json({ registry: getRegistrySnapshot() }, { headers: corsHeaders })
      }

      // Register a new terminal
      if (url.pathname === '/register-terminal' && req.method === 'POST') {
        try {
          const body = await req.json() as TerminalRegistryEntry
          if (!body.ephemeralSessionId) {
            return Response.json({ error: 'ephemeralSessionId required' }, { status: 400, headers: corsHeaders })
          }
          terminalRegistry.set(body.ephemeralSessionId, {
            ephemeralSessionId: body.ephemeralSessionId,
            transcriptSessionId: body.transcriptSessionId || '',
            agent: body.agent || '',
            label: body.label || '',
            command: body.command || '',
            createdAt: body.createdAt || new Date().toISOString()
          })
          console.log(`[Terminal] Registered terminal: ${body.ephemeralSessionId} → ${body.transcriptSessionId} (${body.agent})`)
          broadcastRegistryChange()
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 400, headers: corsHeaders })
        }
      }

      // Update a registered terminal (e.g. re-key transcriptSessionId, update label)
      if (url.pathname === '/update-terminal' && req.method === 'POST') {
        try {
          const body = await req.json() as Partial<TerminalRegistryEntry> & { ephemeralSessionId: string }
          const entry = terminalRegistry.get(body.ephemeralSessionId)
          if (!entry) {
            return Response.json({ error: 'Not found' }, { status: 404, headers: corsHeaders })
          }
          if (body.transcriptSessionId !== undefined) entry.transcriptSessionId = body.transcriptSessionId
          if (body.label !== undefined) entry.label = body.label
          if (body.agent !== undefined) entry.agent = body.agent
          if (body.command !== undefined) entry.command = body.command
          broadcastRegistryChange()
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 400, headers: corsHeaders })
        }
      }

      // Unregister a terminal (does NOT kill the PTY — use /kill-session for that)
      if (url.pathname === '/unregister-terminal' && req.method === 'POST') {
        try {
          const body = await req.json() as { ephemeralSessionId: string }
          const deleted = terminalRegistry.delete(body.ephemeralSessionId)
          if (deleted) broadcastRegistryChange()
          return Response.json({ success: true, deleted }, { headers: corsHeaders })
        } catch (e: any) {
          return Response.json({ error: e.message }, { status: 400, headers: corsHeaders })
        }
      }

      // ── Session State endpoints (centralized state) ──

      if (url.pathname === '/session-state' && req.method === 'GET') {
        return Response.json({ agents: sessionState.getSnapshot() }, { headers: corsHeaders })
      }

      if (url.pathname.startsWith('/session-state/') && req.method === 'GET') {
        const agent = url.pathname.replace('/session-state/', '')
        const state = sessionState.getAgentState(agent)
        if (!state) return Response.json({ error: 'Agent not found' }, { status: 404, headers: corsHeaders })
        return Response.json(state, { headers: corsHeaders })
      }

      // ── Approval tracking endpoints ──

      if (url.pathname === '/add-approval' && req.method === 'POST') {
        try {
          const body = await req.json() as { agent: string, approval: any }
          const patch = sessionState.addApproval(body.agent, body.approval)
          broadcastSessionStatePatch({
            type: 'session-state-patch',
            agent: body.agent,
            patch,
            event: 'approval-added',
            timestamp: Date.now(),
          })
          return Response.json({ success: true }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      if (url.pathname === '/resolve-approval' && req.method === 'POST') {
        try {
          const body = await req.json() as { requestId: string, decision: string }
          const result = sessionState.resolveApproval(body.requestId)
          if (result) {
            broadcastSessionStatePatch({
              type: 'session-state-patch',
              agent: result.agent,
              patch: result.patch,
              event: 'approval-resolved',
              timestamp: Date.now(),
            })
          }
          return Response.json({ success: true, resolved: !!result }, { headers: corsHeaders })
        } catch {
          return Response.json({ error: 'Invalid JSON' }, { status: 400, headers: corsHeaders })
        }
      }

      // Check if this is a WebSocket upgrade request
      const upgradeHeader = req.headers.get('upgrade')
      console.log(`[Terminal] Request: ${req.method} ${url.pathname}, Upgrade: ${upgradeHeader}`)

      if (upgradeHeader?.toLowerCase() === 'websocket') {
        const sessionId = url.searchParams.get('session') || DEFAULT_SESSION_ID
        const success = server.upgrade(req, { data: { sessionId } })
        console.log(`[Terminal] WebSocket upgrade for session "${sessionId}": ${success ? 'success' : 'failed'}`)
        if (success) {
          return undefined
        }
        return new Response('WebSocket upgrade failed', { status: 400 })
      }

      return new Response(
        'Terminal WebSocket Server - Persistent Sessions\n\nEndpoints:\n  /health - Server status\n  /sessions - List active sessions\n  ws://...?session=<id> - Connect to session',
        { status: 200 }
      )
    },
    websocket: {
      open(ws) {
        const sessionId = (ws.data as any)?.sessionId || DEFAULT_SESSION_ID
        console.log(`[Terminal] Client connecting to session: ${sessionId}`)

        try {
          const session = getOrCreateSession(sessionId)
          session.clients.add(ws)
          wsToSession.set(ws, sessionId)

          // Send connection info (include buffer size so client knows if replay is needed)
          ws.send(JSON.stringify({
            type: 'connected',
            sessionId: session.id,
            isNew: session.outputBuffer.length === 0,
            hasHistory: session.outputBuffer.length > 0,
            bufferSize: session.outputBuffer.length
          }))

          // DON'T auto-replay here!
          // Client will request replay when terminal is visible and ready.
          // This fixes xterm.js rendering issues with hidden containers.
          console.log(`[Terminal] Client connected, buffer has ${session.outputBuffer.length} chunks (client will request replay)`)

          // Send centralized session state snapshot
          const snapshot = sessionState.getSnapshot()
          if (Object.keys(snapshot).length > 0) {
            ws.send(JSON.stringify({
              type: 'session-state-snapshot',
              agents: snapshot,
            }))
          }

          console.log(`[Terminal] Client joined session ${sessionId} (${session.clients.size} clients)`)
        } catch (e: any) {
          console.error('[Terminal] Error:', e)
          ws.send(JSON.stringify({ type: 'error', message: e.message }))
        }
      },
      message(ws, message) {
        try {
          const msg = JSON.parse(message as string)
          const sessionId = wsToSession.get(ws)
          if (!sessionId) return

          const session = sessions.get(sessionId)
          if (!session) return

          if (msg.type === 'input') {
            session.pty.write(msg.data)
          } else if (msg.type === 'resize' && msg.cols && msg.rows) {
            session.pty.resize(msg.cols, msg.rows)
            console.log(`[Terminal] Session ${sessionId} resized to ${msg.cols}x${msg.rows}`)
          } else if (msg.type === 'clear-buffer') {
            session.outputBuffer = []
            console.log(`[Terminal] Buffer cleared for session ${sessionId}`)
            ws.send(JSON.stringify({ type: 'buffer-cleared' }))
          } else if (msg.type === 'request-replay') {
            // Client requests fresh replay (used when terminal becomes visible)
            console.log(`[Terminal] Replay requested, buffer has ${session.outputBuffer.length} chunks`)

            if (session.outputBuffer.length > 0) {
              // If tailOnly specified, only send last N chunks (enough for a few screens)
              const tailOnly = msg.tailOnly === true
              const tailChunks = msg.chunks || 500 // Default ~500 chunks for tail

              let data: string
              if (tailOnly && session.outputBuffer.length > tailChunks) {
                // Send only the tail - more efficient for large buffers
                data = session.outputBuffer.slice(-tailChunks).join('')
                console.log(`[Terminal] Replaying tail (${tailChunks}/${session.outputBuffer.length} chunks), ${data.length} bytes`)
              } else {
                data = session.outputBuffer.join('')
                console.log(`[Terminal] Replaying full buffer (${session.outputBuffer.length} chunks), ${data.length} bytes`)
              }

              ws.send(JSON.stringify({
                type: 'replay',
                data,
                isTail: tailOnly && session.outputBuffer.length > tailChunks
              }))
            } else {
              console.log('[Terminal] No buffer to replay')
            }
          }
        } catch (e: any) {
          console.error('[Terminal] Error:', e)
        }
      },
      close(ws) {
        const sessionId = wsToSession.get(ws)
        if (sessionId) {
          const session = sessions.get(sessionId)
          if (session) {
            session.clients.delete(ws)
            console.log(`[Terminal] Client left session ${sessionId} (${session.clients.size} clients remaining)`)
            // Don't kill PTY - session persists
          }
          wsToSession.delete(ws)
        }
      }
    }
  })

  console.log(`[Terminal] WebSocket running at ws://localhost:${PORT_TERMINAL}`)
  return server
}

// Claude status types
type ClaudeStatus = 'idle' | 'processing' | 'toolUse' | 'toolDone' | 'reading' | 'writing' | 'sessionStart' | 'subagentStart' | 'subagentStop' | 'notification' | 'permissionRequest' | 'thinking'

// Broadcast Claude status to ALL clients across ALL sessions
export function broadcastClaudeStatus(status: ClaudeStatus, tool?: string, agent?: string) {
  const agentName = agent || 'main'

  // Track agent running state from sessionStart
  if (status === 'sessionStart') {
    const state = agentSessions.get(agentName)
    if (state) {
      state.isAgentRunning = true
      console.log(`[Terminal] Agent ${agentName} marked as running (sessionStart)`)
    }
  }

  const message = JSON.stringify({
    type: 'claude-status',
    status,
    tool,
    agent: agentName,
    timestamp: Date.now()
  })

  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try {
        ws.send(message)
        clientCount++
      } catch {
        // Client disconnected, ignore
      }
    }
  }

  console.log(`[Terminal] Claude status broadcast: ${status}${tool ? ` (${tool})` : ''} → ${clientCount} clients`)

  // Note: session state is updated via broadcastClaudeHook which has full payload context.
  // Direct /claude-status POSTs (from ejecutor's settings.local.json) are lightweight
  // and don't carry enough context to update full session state.
}

// Broadcast full Claude hook data to ALL clients
export function broadcastClaudeHook(data: Record<string, unknown>) {
  // ── Update centralized session state and broadcast patch ──
  const statePatch = sessionState.processHookEvent(data as any)
  broadcastSessionStatePatch(statePatch)

  // ── Legacy raw broadcast (dual temporal — kept for backward compatibility) ──
  const message = JSON.stringify({
    type: 'claude-hook',
    ...data,
    timestamp: Date.now()
  })

  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try {
        ws.send(message)
        clientCount++
      } catch {
        // Client disconnected, ignore
      }
    }
  }

  console.log(`[Terminal] Claude hook broadcast: ${data.hook_event_name || 'unknown'}${data.tool_name ? ` (${data.tool_name})` : ''} → ${clientCount} clients`)
}

// Broadcast permission request to ALL clients
export function broadcastPermissionRequest(data: Record<string, unknown>) {
  const message = JSON.stringify({
    type: 'claude-permission',
    ...data,
    timestamp: Date.now()
  })

  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try {
        ws.send(message)
        clientCount++
      } catch {
        // Client disconnected, ignore
      }
    }
  }

  console.log(`[Terminal] Permission request broadcast: ${data.tool_name || 'unknown'} (${data.requestId}) → ${clientCount} clients`)
}

// Broadcast transcript updates to ALL clients
export function broadcastTranscriptUpdate(data: Record<string, unknown>) {
  const message = JSON.stringify({
    type: 'transcript-update',
    ...data,
    timestamp: Date.now()
  })

  let clientCount = 0
  for (const [, session] of sessions) {
    for (const ws of session.clients) {
      try {
        ws.send(message)
        clientCount++
      } catch { /* skip */ }
    }
  }

  console.log(`[Terminal] Transcript update: ${data.hookEvent || 'fetch'} (${(data.messages as any[])?.length || 0} msgs) → ${clientCount} clients`)
}