import { create } from 'zustand';
import { MediaStream } from 'react-native-webrtc';
import {
  wsService,
  WSCallIncomingMessage,
  WSCallSDPMessage,
  WSCallICEMessage,
  WSErrorMessage,
} from '../services/wsService';
import { webrtcManager, ICEServer } from '../services/webrtc';
import { useAuthStore } from './authStore';
import { useUserStore } from './userStore';
import { userManager } from './userManager';

export type CallStatus = 'idle' | 'ringing' | 'connecting' | 'connected' | 'ending';

export interface CallSession {
  id: string;
  conversationId: string;
  peerId: string;
  peerName?: string;
  peerAvatar?: string | null;
  status: CallStatus;
  startedAt?: number;
  duration: number;
  isMuted: boolean;
  isSpeakerOn: boolean;
  isInitiator: boolean;
}

export interface IncomingCallInfo {
  callId: string;
  conversationId: string;
  callerId: string;
  callerName?: string;
  callerAvatar?: string | null;
  callType: string;
  iceServers: ICEServer[];
  receivedAt: number;
  lifetime?: number;
}

interface CallState {
  currentCall: CallSession | null;
  incomingCall: IncomingCallInfo | null;
  callDuration: number;
  peerStream: MediaStream | null;
  isMinimized: boolean;

  initCall: () => () => void;
  startCall: (
    conversationId: string,
    calleeId: string,
    calleeInfo?: { nickname?: string; username?: string; avatar?: string | null }
  ) => Promise<void>;
  acceptCall: () => Promise<void>;
  rejectCall: () => void;
  endCall: (reason?: string) => Promise<void>;
  toggleMute: () => void;
  toggleSpeaker: () => void;
  toggleMinimize: () => void;
}

let durationTimer: ReturnType<typeof setInterval> | null = null;
let callTimeoutTimer: ReturnType<typeof setTimeout> | null = null;
let initCallUnsub: (() => void) | null = null;
let unsubInvited: (() => void) | null = null;
let pendingOffer: { callId: string; sdp: string } | null = null;

// === Element + Telegram 结合: 常量 ===
const CALL_LIFETIME_MS = 55000;        // 55秒 (略小于后端60秒)
const CALL_TIMEOUT_MS = 115000;        // 115秒 (拨打方等待超时，略小于后端120秒)
const IGNORE_CALL_ID_TTL = 30000;       // 已处理callId保留30秒

// === Element: 已处理的 callId 集合 (防重复) ===
const processedCallIds = new Map<string, number>(); // callId -> timestamp

// 清理过期的 callId
function cleanupProcessedCallIds() {
  const now = Date.now();
  for (const [callId, timestamp] of processedCallIds) {
    if (now - timestamp > IGNORE_CALL_ID_TTL) {
      processedCallIds.delete(callId);
    }
  }
}

export const callStore = create<CallState>((set, get) => ({
  currentCall: null,
  incomingCall: null,
  callDuration: 0,
  peerStream: null,
  isMinimized: false,

  initCall: () => {
    // Prevent duplicate handler registration
    if (initCallUnsub) {
      initCallUnsub();
      initCallUnsub = null;
    }

    const unsubs: Array<() => void> = [];

    unsubs.push(
      wsService.on('call_incoming', async (msg) => {
        // === Element: 清理过期的 callId ===
        cleanupProcessedCallIds();

        // === Element: 检查是否已处理过该 callId ===
        if (processedCallIds.has(msg.call_id)) {
          console.log('[CallStore] Ignoring already processed call:', msg.call_id);
          return;
        }

        const { currentCall, incomingCall } = get();
        if (incomingCall) {
          wsService.sendCallBusy(msg.call_id);
          processedCallIds.set(msg.call_id, Date.now());
          return;
        }
        if (currentCall && currentCall.status !== 'idle') {
          wsService.sendCallBusy(msg.call_id);
          processedCallIds.set(msg.call_id, Date.now());
          return;
        }

        // === Element: 检查 lifetime 过期 ===
        const callAge = Date.now() - msg.created_at;
        const lifetime = msg.lifetime || 60000; // 默认60秒
        if (callAge > lifetime - 5000) { // 留5秒余量
          console.log('[CallStore] Ignoring stale incoming call, age:', callAge, 'ms, lifetime:', lifetime);
          wsService.sendCallReject(msg.call_id);
          processedCallIds.set(msg.call_id, Date.now());
          return;
        }

        // Try to get caller info from cache first, then fetch from API
        let caller: { nickname?: string; username?: string; avatar?: string | null } | null =
          useUserStore.getState().userCache[msg.caller_id];
        if (!caller) {
          try {
            const fetchedCaller = await userManager.getUserById(msg.caller_id);
            if (fetchedCaller) {
              caller = {
                nickname: fetchedCaller.nickname,
                username: fetchedCaller.username,
                avatar: fetchedCaller.avatar,
              };
            }
          } catch (err) {
            console.log('[CallStore] Failed to fetch caller info:', err);
          }
        }
        const callerName = caller?.nickname || caller?.username || msg.caller_id;

        set({
          incomingCall: {
            callId: msg.call_id,
            conversationId: msg.conversation_id,
            callerId: msg.caller_id,
            callerName,
            callerAvatar: caller?.avatar,
            callType: msg.call_type,
            iceServers: msg.ice_servers || [],
            receivedAt: Date.now(),
            lifetime: msg.lifetime,
          },
        });

        // 标记为已处理
        processedCallIds.set(msg.call_id, Date.now());

        // 设置超时 (使用 lifetime)
        if (callTimeoutTimer) clearTimeout(callTimeoutTimer);
        const remainingTime = Math.max(lifetime - callAge - 1000, 5000); // 剩余时间，最少5秒
        callTimeoutTimer = setTimeout(() => {
          const { incomingCall: ic } = get();
          if (ic?.callId === msg.call_id) {
            console.log('[CallStore] Incoming call timeout');
            wsService.sendCallReject(msg.call_id);
            processedCallIds.set(msg.call_id, Date.now());
            set({ incomingCall: null });
          }
        }, remainingTime);
      })
    );

    unsubs.push(
      wsService.on('call_accepted', async (msg) => {
        const { currentCall } = get();
        if (!currentCall || currentCall.id !== msg.call_id) return;

        try {
          await webrtcManager.initialize(msg.ice_servers || []);
          await webrtcManager.createLocalStream(true);

          // Listen for WebRTC events
          const unsubRTC = webrtcManager.onEvent((event) => {
            if (event.type === 'icecandidate' && event.candidate) {
              wsService.sendCallICE(currentCall.id, JSON.stringify(event.candidate.toJSON()));
            }
            if (event.type === 'remotestream') {
              set({ peerStream: event.stream });
            }
            if (event.type === 'connectionstatechange') {
              if (event.state === 'connected') {
                const now = Date.now();
                set((s) => ({
                  currentCall: s.currentCall
                    ? { ...s.currentCall, status: 'connected', startedAt: now }
                    : null,
                }));
                if (durationTimer) clearInterval(durationTimer);
                durationTimer = setInterval(() => {
                  set((s) => ({ callDuration: s.callDuration + 1 }));
                }, 1000);
              }
              if (event.state === 'disconnected' || event.state === 'failed') {
                get().endCall('connection_lost');
              }
            }
          });
          void unsubRTC;

          // startCall creates PeerConnection, adds tracks, and creates offer for initiator
          const offer = await webrtcManager.startCall(true);
          if (offer) {
            wsService.sendCallSDP(currentCall.id, 'offer', offer.sdp || '');
          }
        } catch (err) {
          console.error('[CallStore] call_accepted error:', err);
          get().endCall('connection_failed');
        }
      })
    );

    unsubs.push(
      wsService.on('call_rejected', (msg) => {
        const { currentCall } = get();
        if (currentCall?.id !== msg.call_id) return;
        console.log('[CallStore] Call rejected');
        get().endCall('rejected');
      })
    );

    unsubs.push(
      wsService.on('call_busy', (msg) => {
        const { currentCall } = get();
        if (currentCall?.id !== msg.call_id) return;
        console.log('[CallStore] Call busy');
        get().endCall('busy');
      })
    );

    unsubs.push(
      wsService.on('call_ended', (msg) => {
        const { currentCall, incomingCall } = get();

        // 标记为已处理
        processedCallIds.set(msg.call_id, Date.now());

        // If this is an active call, end it
        if (currentCall?.id === msg.call_id) {
          console.log('[CallStore] Call ended, duration:', msg.duration);
          get().endCall('ended');
          return;
        }

        // If this is an incoming call that was cancelled by caller, clear it
        if (incomingCall?.callId === msg.call_id) {
          console.log('[CallStore] Incoming call cancelled by caller');
          if (callTimeoutTimer) {
            clearTimeout(callTimeoutTimer);
            callTimeoutTimer = null;
          }
          set({ incomingCall: null });
        }
      })
    );

    // === Telegram: 其他设备已接听 ===
    unsubs.push(
      wsService.on('call_answered_elsewhere', (msg) => {
        const { incomingCall } = get();
        if (incomingCall?.callId === msg.call_id) {
          console.log('[CallStore] Call answered on another device');
          processedCallIds.set(msg.call_id, Date.now());
          if (callTimeoutTimer) {
            clearTimeout(callTimeoutTimer);
            callTimeoutTimer = null;
          }
          set({ incomingCall: null });
        }
      })
    );

    // === Telegram: 处理服务端错误 ===
    unsubs.push(
      wsService.on('error', (msg: WSErrorMessage) => {
        const { currentCall, incomingCall } = get();
        console.log('[CallStore] Server error:', msg.code, msg.message);

        // 处理 callee_offline 错误
        if (msg.code === 'callee_offline') {
          if (currentCall && currentCall.status === 'ringing') {
            console.log('[CallStore] Callee is offline');
            get().endCall('callee_offline');
          }
        }

        // 处理 call_already_answered 错误
        if (msg.code === 'call_already_answered') {
          if (incomingCall) {
            console.log('[CallStore] Call already answered on another device');
            processedCallIds.set(incomingCall.callId, Date.now());
            if (callTimeoutTimer) {
              clearTimeout(callTimeoutTimer);
              callTimeoutTimer = null;
            }
            set({ incomingCall: null });
          }
        }
      })
    );

    unsubs.push(
      wsService.on('call_sdp', async (msg: WSCallSDPMessage) => {
        const { currentCall } = get();
        if (!currentCall || currentCall.id !== msg.call_id) return;

        // Check that we are not the sender of this SDP message
        const myUserId = useAuthStore.getState().currentUser?.id;
        if (myUserId && msg.from_id === myUserId) return;

        try {
          const pc = webrtcManager.getPeerConnection();

          if (msg.payload.sdp_type === 'offer') {
            if (!pc) {
              // Cache offer for later processing when PeerConnection is ready
              pendingOffer = { callId: msg.call_id, sdp: msg.payload.sdp };
              console.log('[CallStore] Caching pending offer, PeerConnection not ready yet');
              return;
            }

            // We are the callee - only process if in 'stable' state
            const signalingState = pc.signalingState;
            if (signalingState !== 'stable') {
              console.warn('[CallStore] Ignoring offer, signaling state is', signalingState);
              return;
            }
            pendingOffer = null;
            await webrtcManager.setRemoteDescription({
              type: msg.payload.sdp_type,
              sdp: msg.payload.sdp,
            });
            const answer = await webrtcManager.createAnswer();
            wsService.sendCallSDP(msg.call_id, 'answer', answer.sdp || '');
          } else if (msg.payload.sdp_type === 'answer') {
            if (!pc) return;

            // We are the initiator - only process if in 'have-local-offer' state
            const signalingState = pc.signalingState;
            if (signalingState !== 'have-local-offer') {
              console.warn('[CallStore] Ignoring answer, signaling state is', signalingState);
              return;
            }
            await webrtcManager.setRemoteDescription({
              type: msg.payload.sdp_type,
              sdp: msg.payload.sdp,
            });
          }
        } catch (err) {
          console.error('[CallStore] call_sdp error:', err);
        }
      })
    );

    unsubs.push(
      wsService.on('call_ice', (msg: WSCallICEMessage) => {
        const { currentCall } = get();
        if (!currentCall || currentCall.id !== msg.call_id) return;

        // Ignore ICE candidates from ourselves
        const myUserId = useAuthStore.getState().currentUser?.id;
        if (myUserId && msg.from_id === myUserId) return;

        try {
          const candidate = typeof msg.payload.candidate === 'string'
            ? JSON.parse(msg.payload.candidate)
            : msg.payload.candidate;
          webrtcManager.addIceCandidate(candidate);
        } catch (err) {
          console.error('[CallStore] call_ice error:', err);
        }
      })
    );

    unsubs.push(
      wsService.on('call_peer_muted', (msg) => {
        console.log('[CallStore] Peer muted:', msg.user_id, msg.muted);
      })
    );

    const cleanup = () => {
      if (callTimeoutTimer) clearTimeout(callTimeoutTimer);
      if (durationTimer) clearInterval(durationTimer);
      unsubs.forEach((unsub) => unsub());
      initCallUnsub = null;
    };
    initCallUnsub = cleanup;
    return cleanup;
  },

  startCall: async (
    conversationId: string,
    calleeId: string,
    calleeInfo?: { nickname?: string; username?: string; avatar?: string | null }
  ) => {
    const { currentCall } = get();
    if (currentCall && currentCall.status !== 'idle') {
      console.warn('[CallStore] Already in a call');
      return;
    }

    const myUserId = useAuthStore.getState().currentUser?.id;
    if (!myUserId) {
      console.error('[CallStore] Not logged in');
      return;
    }

    // Use provided callee info first, then fall back to userCache
    const cachedCallee = useUserStore.getState().userCache[calleeId];
    const callee = calleeInfo || cachedCallee;
    const calleeName = callee?.nickname || callee?.username || calleeId;

    set({
      currentCall: {
        id: '', // Will be filled when call_invited response comes
        conversationId,
        peerId: calleeId,
        peerName: calleeName,
        peerAvatar: callee?.avatar,
        status: 'ringing',
        duration: 0,
        isMuted: false,
        isSpeakerOn: false,
        isInitiator: true,
      },
    });

    wsService.sendCallInvite(conversationId, calleeId);

    // Listen for call_invited to get the call_id
    if (unsubInvited) {
      unsubInvited();
    }
    unsubInvited = wsService.on('call_invited', (msg) => {
      set((s) => ({
        currentCall: s.currentCall
          ? { ...s.currentCall, id: msg.call_id }
          : null,
      }));
    });

    // Timeout - 使用 CALL_TIMEOUT_MS (115秒，略小于后端 120秒)
    if (callTimeoutTimer) clearTimeout(callTimeoutTimer);
    callTimeoutTimer = setTimeout(() => {
      const { currentCall: cc } = get();
      if (cc && cc.status === 'ringing') {
        console.warn('[CallStore] Call timeout');
        get().endCall('timeout');
      }
    }, CALL_TIMEOUT_MS);
  },

  acceptCall: async () => {
    const { incomingCall } = get();
    if (!incomingCall) return;

    if (callTimeoutTimer) {
      clearTimeout(callTimeoutTimer);
      callTimeoutTimer = null;
    }

    set({
      currentCall: {
        id: incomingCall.callId,
        conversationId: incomingCall.conversationId,
        peerId: incomingCall.callerId,
        peerName: incomingCall.callerName,
        peerAvatar: incomingCall.callerAvatar,
        status: 'connecting',
        duration: 0,
        isMuted: false,
        isSpeakerOn: false,
        isInitiator: false,
      },
      incomingCall: null,
    });

    wsService.sendCallAnswer(incomingCall.callId);

    try {
      await webrtcManager.initialize(incomingCall.iceServers);
      await webrtcManager.createLocalStream(true);

      // Listen for WebRTC events
      const unsubRTC = webrtcManager.onEvent((event) => {
        if (event.type === 'icecandidate' && event.candidate) {
          wsService.sendCallICE(incomingCall.callId, JSON.stringify(event.candidate.toJSON()));
        }
        if (event.type === 'remotestream') {
          set({ peerStream: event.stream });
        }
        if (event.type === 'connectionstatechange') {
          if (event.state === 'connected') {
            const now = Date.now();
            set((s) => ({
              currentCall: s.currentCall
                ? { ...s.currentCall, status: 'connected', startedAt: now }
                : null,
            }));
            if (durationTimer) clearInterval(durationTimer);
            durationTimer = setInterval(() => {
              set((s) => ({ callDuration: s.callDuration + 1 }));
            }, 1000);
          }
          if (event.state === 'disconnected' || event.state === 'failed') {
            get().endCall('connection_lost');
          }
        }
      });
      void unsubRTC;

      // startCall creates PeerConnection and adds tracks (non-initiator, no offer)
      await webrtcManager.startCall(false);

      // Process any pending offer that arrived before PeerConnection was ready
      if (pendingOffer && pendingOffer.callId === incomingCall.callId) {
        const offerMsg = pendingOffer;
        pendingOffer = null;
        console.log('[CallStore] Processing pending offer after PeerConnection ready');
        try {
          await webrtcManager.setRemoteDescription({
            type: 'offer',
            sdp: offerMsg.sdp,
          });
          const answer = await webrtcManager.createAnswer();
          wsService.sendCallSDP(offerMsg.callId, 'answer', answer.sdp || '');
        } catch (err) {
          console.error('[CallStore] Failed to process pending offer:', err);
        }
      }
    } catch (err) {
      console.error('[CallStore] Failed to accept call:', err);
      get().endCall('connection_failed');
    }
  },

  rejectCall: () => {
    const { incomingCall } = get();
    if (!incomingCall) return;

    if (callTimeoutTimer) {
      clearTimeout(callTimeoutTimer);
      callTimeoutTimer = null;
    }

    wsService.sendCallReject(incomingCall.callId);
    set({ incomingCall: null });
  },

  endCall: async (reason = 'ended') => {
    const { currentCall } = get();
    if (!currentCall) return;

    if (callTimeoutTimer) {
      clearTimeout(callTimeoutTimer);
      callTimeoutTimer = null;
    }
    if (durationTimer) {
      clearInterval(durationTimer);
      durationTimer = null;
    }
    if (unsubInvited) {
      unsubInvited();
      unsubInvited = null;
    }
    pendingOffer = null;

    const callId = currentCall.id;

    set({
      currentCall: null,
      callDuration: 0,
      peerStream: null,
    });

    webrtcManager.dispose();

    if (callId && reason !== 'ended') {
      wsService.sendCallEnd(callId, reason);
    }
  },

  toggleMute: () => {
    const { currentCall } = get();
    if (!currentCall) return;

    const newMuted = !currentCall.isMuted;
    webrtcManager.setMuted(newMuted);
    if (currentCall.id) {
      wsService.sendCallMute(currentCall.id, newMuted);
    }
    set((s) => ({
      currentCall: s.currentCall ? { ...s.currentCall, isMuted: newMuted } : null,
    }));
  },

  toggleSpeaker: () => {
    const { currentCall } = get();
    if (!currentCall) return;
    set((s) => ({
      currentCall: s.currentCall
        ? { ...s.currentCall, isSpeakerOn: !s.currentCall.isSpeakerOn }
        : null,
    }));
  },

  toggleMinimize: () => {
    set((s) => ({ isMinimized: !s.isMinimized }));
  },
}));