'use client';

import React, { useEffect, useRef, useState, useCallback } from 'react';
import Script from 'next/script';
import { useRouter } from 'next/navigation';
import {
  DEFAULT_JITSI_CONFIG_OVERRIDES,
  DEFAULT_JITSI_INTERFACE_OVERRIDES,
} from '@/lib/jitsi';

declare global {
  interface Window {
    JitsiMeetExternalAPI: any;
  }
}

export interface JitsiClassroomProps {
  roomName: string;
  tenantSlug: string;
  jwtToken?: string;
  domain?: string;
  displayName?: string;
  email?: string;
  avatarUrl?: string;
  isHost?: boolean;
  onJoined?: (event: any) => void;
  onLeft?: () => void;
}

export default function JitsiClassroom({
  roomName,
  tenantSlug,
  jwtToken,
  domain = 'jitsi.my127001.ca',
  displayName = 'Participant',
  email,
  avatarUrl,
  isHost = false,
  onJoined,
  onLeft,
}: JitsiClassroomProps) {
  const router = useRouter();
  const containerRef = useRef<HTMLDivElement>(null);
  const jitsiApiRef = useRef<any>(null);
  const [scriptLoaded, setScriptLoaded] = useState(false);
  const [scriptError, setScriptError] = useState(false);
  const [isConnected, setIsConnected] = useState(false);
  const [participantsCount, setParticipantsCount] = useState(1);

  const handleExit = useCallback(() => {
    if (jitsiApiRef.current) {
      try {
        jitsiApiRef.current.dispose();
      } catch (e) {
        console.error('Error disposing Jitsi API:', e);
      }
      jitsiApiRef.current = null;
    }
    onLeft?.();
    router.push(`/${tenantSlug}/classes`);
  }, [router, tenantSlug, onLeft]);

  const initJitsi = useCallback(() => {
    if (!window.JitsiMeetExternalAPI || !containerRef.current || jitsiApiRef.current) {
      return;
    }

    try {
      // Clear container before mounting
      containerRef.current.innerHTML = '';

      const options = {
        roomName,
        parentNode: containerRef.current,
        width: '100%',
        height: '100%',
        jwt: jwtToken,
        userInfo: {
          displayName,
          email,
        },
        configOverwrite: {
          ...DEFAULT_JITSI_CONFIG_OVERRIDES,
          // Host vs Participant controls
          startWithAudioMuted: !isHost,
          startWithVideoMuted: false,
        },
        interfaceConfigOverwrite: {
          ...DEFAULT_JITSI_INTERFACE_OVERRIDES,
        },
      };

      const api = new window.JitsiMeetExternalAPI(domain, options);
      jitsiApiRef.current = api;

      // Event Listeners
      api.addEventListener('videoConferenceJoined', (event: any) => {
        setIsConnected(true);
        onJoined?.(event);
      });

      api.addEventListener('videoConferenceLeft', () => {
        setIsConnected(false);
        handleExit();
      });

      api.addEventListener('participantJoined', (event: any) => {
        setParticipantsCount((prev) => prev + 1);
      });

      api.addEventListener('participantLeft', () => {
        setParticipantsCount((prev) => Math.max(1, prev - 1));
      });

      api.addEventListener('readyToClose', () => {
        handleExit();
      });

      // Set avatar if provided
      if (avatarUrl) {
        api.executeCommand('avatarUrl', avatarUrl);
      }
    } catch (err) {
      console.error('Failed to initialize JitsiMeetExternalAPI:', err);
      setScriptError(true);
    }
  }, [
    roomName,
    jwtToken,
    domain,
    displayName,
    email,
    avatarUrl,
    isHost,
    onJoined,
    handleExit,
  ]);

  useEffect(() => {
    if (scriptLoaded) {
      initJitsi();
    }

    return () => {
      if (jitsiApiRef.current) {
        try {
          jitsiApiRef.current.dispose();
        } catch {
          // ignore cleanup errors
        }
        jitsiApiRef.current = null;
      }
    };
  }, [scriptLoaded, initJitsi]);

  return (
    <div className="relative w-full h-full min-h-0 min-w-0 flex-1 flex flex-col bg-[#121212] rounded-xl overflow-hidden border border-neutral-800 shadow-2xl">
      {/* External Jitsi Meet API Script */}
      <Script
        src={`https://${domain}/external_api.js`}
        strategy="afterInteractive"
        onReady={() => setScriptLoaded(true)}
        onError={() => {
          console.warn(`Could not load external_api.js from https://${domain}, activating iframe fallback mode`);
          setScriptError(true);
        }}
      />

      {/* Classroom Status Top Bar */}
      <div className="shrink-0 flex flex-wrap items-center justify-between gap-x-3 gap-y-2 px-3 sm:px-4 py-2.5 bg-neutral-900 border-b border-neutral-800 text-xs">
        <div className="flex min-w-0 flex-[1_1_16rem] items-center gap-2 sm:gap-3">
          <span className="shrink-0 flex items-center gap-1.5 font-medium text-neutral-200">
            <span
              className={`w-2.5 h-2.5 rounded-full ${
                isConnected ? 'bg-emerald-500 animate-pulse' : 'bg-amber-400'
              }`}
            />
            {isConnected ? 'LIVE CLASSROOM' : 'CONNECTING...'}
          </span>
          <span className="hidden sm:inline text-neutral-500">|</span>
          <span className="hidden sm:block min-w-0 truncate text-neutral-400 font-mono" title={roomName}>Room: {roomName}</span>
          {isHost && (
            <span className="shrink-0 px-2 py-0.5 rounded text-[10px] bg-emerald-500/10 text-emerald-400 border border-emerald-500/20 font-semibold">
              HOST / INSTRUCTOR
            </span>
          )}
        </div>

        <div className="shrink-0 flex items-center gap-3">
          <span className="hidden sm:inline text-neutral-400">
            {participantsCount} participant{participantsCount !== 1 ? 's' : ''}
          </span>
          <button
            onClick={handleExit}
            className="px-3 py-1 bg-red-600/80 hover:bg-red-600 text-white font-medium rounded transition"
          >
            Leave Class
          </button>
        </div>
      </div>

      {/* Primary Video Container */}
      <div className="relative flex-1 min-h-0 min-w-0 w-full overflow-hidden bg-[#121212]">
        {/* Loading overlay when waiting for API */}
        {!scriptLoaded && !scriptError && (
          <div className="absolute inset-0 flex flex-col items-center justify-center bg-[#121212] z-10 text-neutral-300">
            <div className="w-8 h-8 border-2 border-emerald-500 border-t-transparent rounded-full animate-spin mb-3"></div>
            <p className="text-sm font-medium">Initializing secure live classroom...</p>
            <p className="text-xs text-neutral-500 mt-1">Connecting to {domain}</p>
          </div>
        )}

        {/* Script Fallback Direct Iframe Mode */}
        {scriptError ? (
          <iframe
            src={`https://${domain}/${encodeURIComponent(roomName)}${jwtToken ? `?jwt=${encodeURIComponent(jwtToken)}` : ''}#config.prejoinPageEnabled=false&config.disableThirdPartyRequests=true`}
            allow="camera; microphone; display-capture; autoplay; clipboard-write"
            className="absolute inset-0 block w-full h-full border-0"
            title="Jitsi Classroom Live Session"
          />
        ) : (
          <div ref={containerRef} className="absolute inset-0 w-full h-full" />
        )}
      </div>
    </div>
  );
}