import { create } from 'zustand';
import {
  wsService,
  WSCallIncomingMessage,
  WSErrorMessage,
  api,
} from '@/services/core';
import { liveKitService } from '@/services/livekit';
import { getCurrentUserId } from '../auth/sessionStore';
import { useUserStore } from '../userStore';
import { userManager } from '../user/UserManager';

export type CallStatus =
  | 'idle'
  | 'calling'
  | 'ringing'
  | 'connecting'
  | 'connected'
  | 'reconnecting'
  | 'ended'
  | 'failed';

export type CallType = 'voice' | 'video';

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

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

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

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

// Module-level variables for timers
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 liveKitUnsubs: (() => void)[] = [];

// Constants
const CALL_LIFETIME_MS = 55000;
const CALL_TIMEOUT_MS = 115000;
const IGNORE_CALL_ID_TTL = 30000;

const processedCallIds = new Map<string, number>();

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

/**
 * Fetch LiveKit token from the backend and connect to the room.
 */
async function joinLiveKitRoom(callId: string, videoEnabled: boolean): Promise<void> {
  const res = await api.get<{ token: string; url: string }>('/calls/token', {
    room: callId,
  });

  const { token, url } = res.data;
  if (!token || !url) {
    throw new Error('Invalid LiveKit token response');
  }

  setupLiveKitEvents(callId);

  await liveKitService.connect(url, token);

  // Enable/disable video based on call type
  await liveKitService.setVideoEnabled(videoEnabled);
}

/**
 * Set up LiveKit room event handlers.
 */
function setupLiveKitEvents(callId: string): void {
  // Clean up any existing subscriptions
  liveKitUnsubs.forEach((unsub) => unsub());
  liveKitUnsubs = [];

  liveKitUnsubs.push(
    liveKitService.on('connected', () => {
      console.log('[CallStore] LiveKit connected');
      const now = Date.now();
      callStore.setState((s) => ({
        currentCall: s.currentCall
          ? { ...s.currentCall, status: 'connected', startedAt: now }
          : null,
      }));

      wsService.sendCallReady(callId);

      if (durationTimer) clearInterval(durationTimer);
      durationTimer = setInterval(() => {
        callStore.setState((s) => ({ callDuration: s.callDuration + 1 }));
      }, 1000);
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('disconnected', () => {
      console.log('[CallStore] LiveKit disconnected');
      const { currentCall } = callStore.getState();
      if (currentCall && currentCall.status !== 'ended' && currentCall.status !== 'failed') {
        callStore.setState((s) => ({
          currentCall: s.currentCall
            ? { ...s.currentCall, status: 'reconnecting' }
            : null,
        }));
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('reconnecting', () => {
      console.log('[CallStore] LiveKit reconnecting');
      callStore.setState((s) => ({
        currentCall: s.currentCall
          ? { ...s.currentCall, status: 'reconnecting' }
          : null,
      }));
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('reconnected', () => {
      console.log('[CallStore] LiveKit reconnected');
      callStore.setState((s) => ({
        currentCall: s.currentCall
          ? { ...s.currentCall, status: 'connected' }
          : null,
      }));
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('connectionStatusChanged', (status) => {
      console.log('[CallStore] LiveKit connection status:', status);
      const { currentCall } = callStore.getState();
      if (!currentCall) return;

      if (status === 'failed') {
        callStore.getState().endCall('connection_failed');
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('trackSubscribed', ({ track }) => {
      console.log('[CallStore] Remote track subscribed:', track.kind);
      if (track.kind === 'video') {
        callStore.setState((s) => ({
          currentCall: s.currentCall
            ? { ...s.currentCall, isPeerVideoEnabled: true }
            : null,
        }));
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('trackUnsubscribed', ({ track }) => {
      console.log('[CallStore] Remote track unsubscribed:', track.kind);
      if (track.kind === 'video') {
        callStore.setState((s) => ({
          currentCall: s.currentCall
            ? { ...s.currentCall, isPeerVideoEnabled: false }
            : null,
        }));
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('trackMuted', ({ publication }) => {
      if (publication.source === 'camera') {
        callStore.setState((s) => ({
          currentCall: s.currentCall
            ? { ...s.currentCall, isPeerVideoEnabled: false }
            : null,
        }));
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('trackUnmuted', ({ publication }) => {
      if (publication.source === 'camera') {
        callStore.setState((s) => ({
          currentCall: s.currentCall
            ? { ...s.currentCall, isPeerVideoEnabled: true }
            : null,
        }));
      }
    })
  );

  liveKitUnsubs.push(
    liveKitService.on('error', (err) => {
      console.error('[CallStore] LiveKit error:', err);
    })
  );
}

/**
 * Clean up all resources.
 */
function cleanupResources(): void {
  if (callTimeoutTimer) {
    clearTimeout(callTimeoutTimer);
    callTimeoutTimer = null;
  }
  if (durationTimer) {
    clearInterval(durationTimer);
    durationTimer = null;
  }
  liveKitUnsubs.forEach((unsub) => unsub());
  liveKitUnsubs = [];
}

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

  initCall: () => {
    if (initCallUnsub) {
      initCallUnsub();
      initCallUnsub = null;
    }

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

    unsubs.push(
      wsService.on('call_incoming', async (msg) => {
        cleanupProcessedCallIds();

        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;
        }

        const callAge = Date.now() - msg.created_at;
        const lifetime = msg.lifetime || 60000;
        if (callAge > lifetime - 5000) {
          console.log('[CallStore] Ignoring stale incoming call, age:', callAge);
          wsService.sendCallReject(msg.call_id);
          processedCallIds.set(msg.call_id, Date.now());
          return;
        }

        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,
            receivedAt: Date.now(),
            lifetime: msg.lifetime,
          },
        });

        processedCallIds.set(msg.call_id, Date.now());

        if (callTimeoutTimer) clearTimeout(callTimeoutTimer);
        const remainingTime = Math.max(lifetime - callAge - 1000, 5000);
        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;

        if (!currentCall.isInitiator) {
          console.log('[CallStore] Ignoring call_accepted, we are not the initiator');
          return;
        }

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

        try {
          set((s) => ({
            currentCall: s.currentCall
              ? { ...s.currentCall, status: 'connecting' }
              : null,
          }));

          const isVideoCall = currentCall.callType === 'video';
          await joinLiveKitRoom(currentCall.id, isVideoCall);
        } catch (err) {
          console.error('[CallStore] call_accepted LiveKit join 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();

        processedCallIds.set(msg.call_id, Date.now());

        if (currentCall?.id === msg.call_id) {
          console.log('[CallStore] Call ended, duration:', msg.duration);
          get().endCall('ended');
          return;
        }

        if (incomingCall?.callId === msg.call_id) {
          console.log('[CallStore] Incoming call cancelled by caller');
          if (callTimeoutTimer) {
            clearTimeout(callTimeoutTimer);
            callTimeoutTimer = null;
          }
          set({ incomingCall: null });
        }
      })
    );

    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 });
        }
      })
    );

    unsubs.push(
      wsService.on('error', (msg: WSErrorMessage) => {
        const { currentCall, incomingCall } = get();
        console.log('[CallStore] Server error:', msg.code, msg.message);

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

        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_peer_muted', (msg) => {
        console.log('[CallStore] Peer muted:', msg.user_id, msg.muted);
      })
    );

    const cleanup = () => {
      cleanupResources();
      if (unsubInvited) {
        unsubInvited();
        unsubInvited = null;
      }
      unsubs.forEach((unsub) => unsub());
      initCallUnsub = null;
    };
    initCallUnsub = cleanup;
    return cleanup;
  },

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

    const myUserId = getCurrentUserId();
    if (!myUserId) {
      console.error('[CallStore] Not logged in');
      return;
    }

    const cachedCallee = useUserStore.getState().userCache[calleeId];
    const callee = calleeInfo || cachedCallee;
    const calleeName = callee?.nickname || callee?.username || calleeId;

    set({
      currentCall: {
        id: '',
        conversationId,
        peerId: calleeId,
        peerName: calleeName,
        peerAvatar: callee?.avatar,
        callType,
        status: 'calling',
        duration: 0,
        isMuted: false,
        isSpeakerOn: false,
        isVideoEnabled: callType === 'video',
        isPeerVideoEnabled: false,
        isInitiator: true,
        isPeerReady: false,
      },
    });

    wsService.sendCallInvite(conversationId, calleeId, callType);

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

    if (callTimeoutTimer) clearTimeout(callTimeoutTimer);
    callTimeoutTimer = setTimeout(() => {
      const { currentCall: cc } = get();
      if (cc && cc.status === 'calling') {
        console.warn('[CallStore] Call timeout');
        get().endCall('timeout');
      }
    }, CALL_TIMEOUT_MS);
  },

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

    console.log('[CallStore] acceptCall, incomingCall.callType:', incomingCall.callType);

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

    const isVideoCall = incomingCall.callType === 'video';
    console.log('[CallStore] acceptCall, isVideoCall:', isVideoCall);

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

    wsService.sendCallAnswer(incomingCall.callId);

    try {
      await joinLiveKitRoom(incomingCall.callId, isVideoCall);
    } 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;

    cleanupResources();

    if (unsubInvited) {
      unsubInvited();
      unsubInvited = null;
    }

    const callId = currentCall.id;

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

    try {
      await liveKitService.disconnect();
    } catch (err) {
      console.error('[CallStore] Error disconnecting LiveKit:', err);
    }

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

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

    const newMuted = !currentCall.isMuted;
    liveKitService.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 }));
  },

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

    const newVideoEnabled = !currentCall.isVideoEnabled;
    await get().setVideoEnabled(newVideoEnabled);
  },

  setVideoEnabled: async (enabled: boolean) => {
    const { currentCall } = get();
    if (!currentCall) return;

    try {
      await liveKitService.setVideoEnabled(enabled);

      set((s) => ({
        currentCall: s.currentCall
          ? { ...s.currentCall, isVideoEnabled: enabled, callType: enabled ? 'video' : 'voice' }
          : null,
      }));
    } catch (err) {
      console.error('[CallStore] Failed to toggle video:', err);
    }
  },

  reset: () => {
    cleanupResources();

    if (initCallUnsub) {
      initCallUnsub();
      initCallUnsub = null;
    }

    if (unsubInvited) {
      unsubInvited();
      unsubInvited = null;
    }

    liveKitService.dispose();

    processedCallIds.clear();

    set({
      currentCall: null,
      incomingCall: null,
      callDuration: 0,
      isMinimized: false,
    });
  },
}));