'use client';

import { useState, useEffect, useMemo, useCallback } from 'react';
import EmailPreview from './EmailPreview';
import ComposeEmailAdapter from './ComposeEmailAdapter';
import { Loader2 } from 'lucide-react';
import { useEmailFetch } from '@/hooks/use-email-fetch';
import { debounce } from '@/lib/utils/debounce';
import { EmailMessage } from '@/types/email';
import { adaptLegacyEmail } from '@/lib/utils/email-adapters';

interface EmailPanelProps {
  selectedEmail: {
    emailId: string;
    accountId: string;
    folder: string;
  } | null;
  onSendEmail: (email: any) => Promise<void>;
  accounts?: Array<{
    id: string;
    email: string;
    display_name?: string;
  }>;
}

// Type for the legacy ComposeEmail component props
interface ComposeEmailProps {
  initialEmail?: any;
  type?: 'new' | 'reply' | 'reply-all' | 'forward';
  onClose: () => void;
  onSend: (emailData: {
    to: string;
    cc?: string;
    bcc?: string;
    subject: string;
    body: string;
    fromAccount?: string;
    attachments?: Array<{
      name: string;
      content: string;
      type: string;
    }>;
  }) => Promise<void>;
}

export default function EmailPanel({ 
  selectedEmail, 
  onSendEmail,
  accounts = []
}: EmailPanelProps) {
  // Use the new email fetch hook
  const { email, loading, error, fetchEmail } = useEmailFetch({
    onEmailLoaded: (email) => {
      // Handle any post-load actions
      console.log('Email loaded:', email.id);
    },
    onError: (error) => {
      console.error('Error loading email:', error);
    }
  });
  
  // Compose mode state
  const [isComposing, setIsComposing] = useState<boolean>(false);
  const [composeType, setComposeType] = useState<'new' | 'reply' | 'reply-all' | 'forward'>('new');

  // Convert the email to the standardized format
  const standardizedEmail = useMemo(() => {
    if (!email) {
      return null;
    }
    
    // The useEmailFetch hook now provides fully formatted email
    return email;
  }, [email]);

  // Debounced email fetch
  const debouncedFetchEmail = useCallback(
    debounce((emailId: string, accountId: string, folder: string) => {
      fetchEmail(emailId, accountId, folder);
    }, 300),
    [fetchEmail]
  );

  // Load email content when selectedEmail changes
  useEffect(() => {
    if (selectedEmail) {
      // CRITICAL FIX: Store the current account ID to check for changes
      // This helps prevent race conditions during account switching
      const currentAccountId = selectedEmail.accountId;
      console.log(`EmailPanel: Loading email ${selectedEmail.emailId} from account ${currentAccountId}`);
      
      debouncedFetchEmail(selectedEmail.emailId, selectedEmail.accountId, selectedEmail.folder);
      setIsComposing(false);
      
      // Return a cleanup function that can detect and handle account changes
      return () => {
        console.log(`EmailPanel: Cleaning up email fetch for account ${currentAccountId}`);
      };
    }
  }, [selectedEmail, debouncedFetchEmail]);
  
  // Handle reply/forward actions
  const handleReply = (type: 'reply' | 'reply-all' | 'forward') => {
    setComposeType(type);
    setIsComposing(true);
  };
  
  // Handle compose mode close
  const handleComposeClose = () => {
    setIsComposing(false);
    setComposeType('new');
  };

  // Wrap the onSendEmail function to ensure it returns a Promise
  const handleSendEmail = async (emailData: any) => {
    try {
      return await onSendEmail(emailData);
    } catch (error) {
      console.error('Error sending email:', error);
      throw error; // Re-throw to let ComposeEmail handle it
    }
  };

  // If no email is selected and not composing
  if (!selectedEmail && !isComposing) {
    return (
      <div className="h-full flex items-center justify-center">
        <div className="text-center text-muted-foreground">
          <p>Select an email to view or</p>
          <button 
            className="text-primary mt-2 hover:underline"
            onClick={() => {
              setComposeType('new');
              setIsComposing(true);
            }}
          >
            Compose a new message
          </button>
        </div>
      </div>
    );
  }
  
  // Show loading state
  if (loading) {
    return (
      <div className="h-full flex items-center justify-center">
        <div className="text-center">
          <Loader2 className="h-8 w-8 animate-spin mx-auto mb-4 text-primary" />
          <p>Loading email...</p>
        </div>
      </div>
    );
  }
  
  // Show error state
  if (error) {
    return (
      <div className="h-full flex items-center justify-center">
        <div className="text-center text-destructive">
          <p>{error}</p>
          <button 
            className="text-primary mt-2 hover:underline"
            onClick={() => selectedEmail && fetchEmail(selectedEmail.emailId, selectedEmail.accountId, selectedEmail.folder)}
          >
            Try again
          </button>
        </div>
      </div>
    );
  }
  
  // Show compose mode or email preview
  return (
    <div className="h-full">
      {isComposing ? (
        <ComposeEmailAdapter
          initialEmail={standardizedEmail}
          type={composeType}
          onClose={handleComposeClose}
          onSend={handleSendEmail}
          accounts={accounts}
        />
      ) : (
        <div className="max-w-4xl mx-auto h-full">
          <EmailPreview 
            email={standardizedEmail}
            onReply={handleReply}
          />
        </div>
      )}
    </div>
  );
}

// Helper function to normalize address to string format
function normalizeAddress(address: any): string {
  if (!address) return '';
  
  // If already a string, return as is
  if (typeof address === 'string') {
    return address;
  }
  
  // If array of EmailAddress objects
  if (Array.isArray(address)) {
    return address.map(addr => {
      if (typeof addr === 'object' && addr !== null) {
        // Handle EmailAddress object
        if ('name' in addr && 'address' in addr) {
          return addr.name && addr.name !== addr.address 
            ? `${addr.name} <${addr.address}>`
            : addr.address;
        }
      }
      return String(addr || '');
    }).join(', ');
  }
  
  // Handle single EmailAddress object
  if (typeof address === 'object' && address !== null) {
    if ('name' in address && 'address' in address) {
      return address.name && address.name !== address.address 
        ? `${address.name} <${address.address}>`
        : address.address;
    }
  }
  
  // Fallback
  return String(address);
}