'use client';

import { useState, useRef, useEffect } from 'react';
import { formatEmailForReplyOrForward, EmailMessage, EmailAddress } from '@/lib/services/email-service';
import { X, Paperclip, ChevronDown, ChevronUp, SendHorizontal, Loader2 } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Card, CardContent, CardHeader, CardTitle, CardFooter } from '@/components/ui/card';
import DOMPurify from 'isomorphic-dompurify';

interface ComposeEmailProps {
  initialEmail?: EmailMessage | null;
  type?: 'new' | 'reply' | 'reply-all' | 'forward';
  onClose: () => void;
  onSend: (emailData: {
    to: string;
    cc?: string;
    bcc?: string;
    subject: string;
    body: string;
    attachments?: Array<{
      name: string;
      content: string;
      type: string;
    }>;
  }) => Promise<void>;
}

export default function ComposeEmail({ 
  initialEmail, 
  type = 'new', 
  onClose, 
  onSend 
}: ComposeEmailProps) {
  // Email form state
  const [to, setTo] = useState<string>('');
  const [cc, setCc] = useState<string>('');
  const [bcc, setBcc] = useState<string>('');
  const [subject, setSubject] = useState<string>('');
  const [body, setBody] = useState<string>('');
  const [showCc, setShowCc] = useState<boolean>(false);
  const [showBcc, setShowBcc] = useState<boolean>(false);
  const [sending, setSending] = useState<boolean>(false);
  const [attachments, setAttachments] = useState<Array<{
    name: string;
    content: string;
    type: string;
  }>>([]);
  
  // Refs
  const editorRef = useRef<HTMLDivElement>(null);
  const attachmentInputRef = useRef<HTMLInputElement>(null);
  
  // Initialize the form when replying to or forwarding an email
  useEffect(() => {
    if (initialEmail && type !== 'new') {
      if (type === 'forward') {
        initializeForwardedEmail();
      } else {
        // For reply/reply-all, continue using formatEmailForReplyOrForward
        const formattedEmail = formatEmailForReplyOrForward(initialEmail, type as 'reply' | 'reply-all');
        
        setTo(formattedEmail.to);
        
        if (formattedEmail.cc) {
          setCc(formattedEmail.cc);
          setShowCc(true);
        }
        
        setSubject(formattedEmail.subject);
        setBody(formattedEmail.body);
      }
      
      // Focus editor after initializing
      setTimeout(() => {
        if (editorRef.current) {
          editorRef.current.focus();
          
          // Place cursor at the beginning of the content
          const selection = window.getSelection();
          const range = document.createRange();
          
          range.setStart(editorRef.current, 0);
          range.collapse(true);
          
          selection?.removeAllRanges();
          selection?.addRange(range);
        }
      }, 100);
    }
  }, [initialEmail, type]);

  // Format date for the forwarded message header
  const formatDate = (date: Date | null): string => {
    if (!date) return '';
    try {
      return date.toLocaleString('en-US', {
        weekday: 'short',
        year: 'numeric', 
        month: 'short', 
        day: 'numeric',
        hour: '2-digit',
        minute: '2-digit'
      });
    } catch (e) {
      return date.toString();
    }
  };
  
  // Format sender address in a readable format
  const formatSender = (from: Array<{name?: string, address: string}> | undefined): string => {
    if (!from || from.length === 0) return 'Unknown';
    return from.map(sender => 
      sender.name && sender.name !== sender.address 
        ? `${sender.name} <${sender.address}>`
        : sender.address
    ).join(', ');
  };
  
  // Format recipient addresses in a readable format
  const formatRecipients = (recipients: Array<{name?: string, address: string}> | undefined): string => {
    if (!recipients || recipients.length === 0) return '';
    return recipients.map(recipient => 
      recipient.name && recipient.name !== recipient.address 
        ? `${recipient.name} <${recipient.address}>`
        : recipient.address
    ).join(', ');
  };

  // Initialize forwarded email with clear structure and style preservation
  const initializeForwardedEmail = async () => {
    console.log('Starting initializeForwardedEmail');
    if (!initialEmail) {
      console.error('No email available for forwarding');
      setBody('<div style="color: #666; font-style: italic;">No email available for forwarding</div>');
      return;
    }

    // Debug the email object structure
    console.log('Forwarding email object:', {
      id: initialEmail.id,
      subject: initialEmail.subject,
      fromLength: initialEmail.from?.length,
      from: initialEmail.from,
      to: initialEmail.to,
      date: initialEmail.date,
      hasContent: Boolean(initialEmail.content),
      contentLength: initialEmail.content?.length,
      hasHtml: Boolean(initialEmail.html),
      htmlLength: initialEmail.html?.length
    });

    try {
      // Format subject with Fwd: prefix if needed
      const subjectBase = initialEmail.subject || '(No subject)';
      const subjectRegex = /^(Fwd|FW|Forward):\s*/i;
      const subject = subjectRegex.test(subjectBase) 
        ? subjectBase 
        : `Fwd: ${subjectBase}`;
      
      setSubject(subject);
      
      // Format the forwarded message with a well-structured header
      const fromString = Array.isArray(initialEmail.from) && initialEmail.from.length > 0
        ? initialEmail.from.map(addr => addr.name 
            ? `${addr.name} <${addr.address}>` 
            : addr.address).join(', ')
        : 'Unknown';
      
      const toString = Array.isArray(initialEmail.to) && initialEmail.to.length > 0
        ? initialEmail.to.map(addr => addr.name 
            ? `${addr.name} <${addr.address}>` 
            : addr.address).join(', ')
        : '';
      
      const dateString = initialEmail.date 
        ? typeof initialEmail.date === 'string'
          ? new Date(initialEmail.date).toLocaleString()
          : initialEmail.date.toLocaleString()
        : new Date().toLocaleString();
      
      // Create a clean wrapper that won't interfere with the original email's styling
      // Use inline styles for the header to avoid CSS conflicts
      const headerHtml = `
        <div style="border-top: 1px solid #e1e1e1; margin-top: 20px; padding-top: 15px; font-family: Arial, sans-serif; color: #333;">
          <div style="margin-bottom: 15px;">
            <div style="font-weight: normal; margin-bottom: 10px;">---------- Forwarded message ---------</div>
            <div><b>From:</b> ${fromString}</div>
            <div><b>Date:</b> ${dateString}</div>
            <div><b>Subject:</b> ${subjectBase}</div>
            <div><b>To:</b> ${toString}</div>
          </div>
        </div>
      `;
      
      // Process the original content
      let originalContent = '';
      
      // First try to use the API to parse and sanitize the email content
      try {
        // Use server-side parsing via fetch API to properly handle complex emails
        const response = await fetch('/api/parse-email', {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify({ 
            email: initialEmail.content || initialEmail.html || initialEmail.text || '' 
          }),
        });
        
        if (response.ok) {
          const parsedEmail = await response.json();
          
          if (parsedEmail.html && parsedEmail.html.trim()) {
            console.log('Using parsed HTML content for forward');
            
            // Create an iframe-like containment for the email content
            // This prevents CSS from the original email leaking into our compose view
            originalContent = `
              <div class="email-content-container">
                ${parsedEmail.html}
              </div>
            `;
          } else if (parsedEmail.text && parsedEmail.text.trim()) {
            console.log('Using parsed text content for forward');
            originalContent = `<div style="white-space: pre-wrap; font-family: monospace;">${parsedEmail.text}</div>`;
          } else {
            console.log('No content available from parser');
            originalContent = '<div style="color: #666; font-style: italic; padding: 10px; font-size: 14px; border: 1px dashed #ccc; margin: 10px 0; text-align: center; background-color: #f9f9f9;">No content available</div>';
          }
        } else {
          throw new Error('Failed to parse email content');
        }
      } catch (parseError) {
        console.error('Error parsing email content:', parseError);
        
        // Fall back to direct content handling if API parsing fails
        if (initialEmail.html && initialEmail.html.trim()) {
          console.log('Falling back to HTML content for forward');
          // Use DOMPurify to sanitize HTML and remove dangerous elements
          originalContent = DOMPurify.sanitize(initialEmail.html, {
            ADD_TAGS: ['style', 'div', 'span', 'p', 'br', 'hr', 'h1', 'h2', 'h3', 'img', 'table', 'tr', 'td', 'th'],
            ADD_ATTR: ['style', 'class', 'id', 'src', 'alt', 'href', 'target'],
            FORBID_TAGS: ['script', 'iframe', 'object', 'embed'],
            FORBID_ATTR: ['onerror', 'onload', 'onclick', 'onmouseover']
          });
        } else if (initialEmail.content && initialEmail.content.trim()) {
          console.log('Falling back to content field for forward');
          originalContent = DOMPurify.sanitize(initialEmail.content);
        } else if (initialEmail.text && initialEmail.text.trim()) {
          console.log('Falling back to text content for forward');
          originalContent = `<div style="white-space: pre-wrap; font-family: monospace;">${initialEmail.text}</div>`;
        } else {
          console.log('No content available for forward');
          originalContent = '<div style="color: #666; font-style: italic; padding: 10px; font-size: 14px; border: 1px dashed #ccc; margin: 10px 0; text-align: center; background-color: #f9f9f9;">No content available</div>';
        }
      }
      
      // Preserve all original structure by wrapping, not modifying the original content
      // Important: We add a style scope to prevent CSS leakage
      const forwardedContent = `
        ${headerHtml}
        <!-- Start original email content - DO NOT MODIFY THIS CONTENT -->
        <div class="original-email-content" style="margin-top: 10px; border-left: 2px solid #e1e1e1; padding-left: 15px;">
          <!-- Email content styling isolation container -->
          <div style="position: relative; overflow: auto;">
            ${originalContent}
          </div>
        </div>
        <!-- End original email content -->
      `;
      
      console.log('Setting body with forwarded content');
      setBody(forwardedContent);
      
    } catch (error) {
      console.error('Error initializing forwarded email:', error);
      
      // Even in error case, provide a usable template with empty values
      setBody(`
        <div style="border-top: 1px solid #e1e1e1; margin-top: 20px; padding-top: 15px; font-family: Arial, sans-serif; color: #333;">
          <div style="margin-bottom: 15px;">
            <div style="font-weight: normal; margin-bottom: 10px;">---------- Forwarded message ---------</div>
            <div><b>From:</b> ${initialEmail.from ? formatSender(initialEmail.from) : 'Unknown'}</div>
            <div><b>Date:</b> ${new Date().toLocaleString()}</div>
            <div><b>Subject:</b> ${initialEmail.subject || '(No subject)'}</div>
            <div><b>To:</b> ${initialEmail.to ? formatRecipients(initialEmail.to) : ''}</div>
          </div>
        </div>
        <div style="margin-top: 10px; padding: 10px; color: #d32f2f; font-style: italic; border: 1px dashed #d32f2f; margin: 10px 0; text-align: center; background-color: #fff8f8;">
          Error loading original message content. The original message may still be viewable in your inbox.
        </div>
      `);
    }
  };

  // Handle attachment selection
  const handleAttachmentClick = () => {
    attachmentInputRef.current?.click();
  };

  // Process selected files
  const handleFileSelection = async (e: React.ChangeEvent<HTMLInputElement>) => {
    const files = e.target.files;
    if (!files || files.length === 0) return;

    // Convert selected files to attachments
    const newAttachments = Array.from(files).map(file => ({
      file,
      uploading: true
    }));

    // Read files as data URLs
    for (const file of files) {
      const reader = new FileReader();
      
      reader.onload = (event) => {
        const content = event.target?.result as string;
        
        setAttachments(current => [
          ...current,
          {
            name: file.name,
            content: content.split(',')[1], // Remove data:mime/type;base64, prefix
            type: file.type
          }
        ]);
      };
      
      reader.readAsDataURL(file);
    }
    
    // Reset file input
    if (e.target) {
      e.target.value = '';
    }
  };

  // Remove attachment
  const removeAttachment = (index: number) => {
    setAttachments(current => current.filter((_, i) => i !== index));
  };

  // Send the email
  const handleSend = async () => {
    if (!to) {
      alert('Please specify at least one recipient');
      return;
    }

    try {
      setSending(true);
      
      await onSend({
        to,
        cc: cc || undefined,
        bcc: bcc || undefined,
        subject,
        body: editorRef.current?.innerHTML || body,
        attachments
      });
      
      onClose();
    } catch (error) {
      console.error('Error sending email:', error);
      alert('Failed to send email. Please try again.');
    } finally {
      setSending(false);
    }
  };

  // Handle editor input
  const handleEditorInput = (e: React.FormEvent<HTMLDivElement>) => {
    // Store the HTML content for use in the send function
    setBody(e.currentTarget.innerHTML);
  };

  return (
    <Card className="w-full h-full flex flex-col overflow-hidden shadow-lg">
      <CardHeader className="border-b py-2 px-4">
        <div className="flex justify-between items-center">
          <CardTitle className="text-lg">
            {type === 'new' ? 'New Message' : 
              type === 'reply' ? 'Reply' : 
              type === 'reply-all' ? 'Reply All' : 
              'Forward'}
          </CardTitle>
          <Button variant="ghost" size="icon" onClick={onClose}>
            <X className="h-4 w-4" />
          </Button>
        </div>
      </CardHeader>
      
      <CardContent className="p-0 flex-1 flex flex-col overflow-hidden">
        {/* Email header fields */}
        <div className="p-3 border-b space-y-2">
          <div className="flex items-center">
            <span className="w-16 text-sm font-medium">To:</span>
            <Input 
              value={to} 
              onChange={(e) => setTo(e.target.value)} 
              className="flex-1 border-0 shadow-none h-8 focus-visible:ring-0"
              placeholder="recipient@example.com"
            />
          </div>
          
          {showCc && (
            <div className="flex items-center">
              <span className="w-16 text-sm font-medium">Cc:</span>
              <Input 
                value={cc} 
                onChange={(e) => setCc(e.target.value)} 
                className="flex-1 border-0 shadow-none h-8 focus-visible:ring-0"
                placeholder="cc@example.com"
              />
            </div>
          )}
          
          {showBcc && (
            <div className="flex items-center">
              <span className="w-16 text-sm font-medium">Bcc:</span>
              <Input 
                value={bcc} 
                onChange={(e) => setBcc(e.target.value)} 
                className="flex-1 border-0 shadow-none h-8 focus-visible:ring-0"
                placeholder="bcc@example.com"
              />
            </div>
          )}
          
          {/* CC/BCC controls */}
          <div className="flex items-center text-xs">
            <button 
              className="text-primary hover:underline mr-3 flex items-center"
              onClick={() => setShowCc(!showCc)}
            >
              {showCc ? (
                <>
                  <ChevronUp className="h-3 w-3 mr-0.5" />
                  Hide Cc
                </>
              ) : (
                <>
                  <ChevronDown className="h-3 w-3 mr-0.5" />
                  Show Cc
                </>
              )}
            </button>
            
            <button 
              className="text-primary hover:underline flex items-center"
              onClick={() => setShowBcc(!showBcc)}
            >
              {showBcc ? (
                <>
                  <ChevronUp className="h-3 w-3 mr-0.5" />
                  Hide Bcc
                </>
              ) : (
                <>
                  <ChevronDown className="h-3 w-3 mr-0.5" />
                  Show Bcc
                </>
              )}
            </button>
          </div>
          
          <div className="flex items-center">
            <span className="w-16 text-sm font-medium">Subject:</span>
            <Input 
              value={subject} 
              onChange={(e) => setSubject(e.target.value)} 
              className="flex-1 border-0 shadow-none h-8 focus-visible:ring-0"
              placeholder="Subject"
            />
          </div>
        </div>
        
        {/* Email body editor */}
        <div 
          ref={editorRef}
          className="flex-1 overflow-auto p-4 focus:outline-none email-content"
          contentEditable={true}
          onInput={handleEditorInput}
          dangerouslySetInnerHTML={{ __html: body }}
          style={{ minHeight: '200px' }}
        />
        
        {/* Attachments list */}
        {attachments.length > 0 && (
          <div className="border-t p-2">
            <div className="text-sm font-medium mb-1">Attachments:</div>
            <div className="flex flex-wrap gap-2">
              {attachments.map((attachment, index) => (
                <div key={index} className="flex items-center gap-1 text-sm bg-muted px-2 py-1 rounded">
                  <Paperclip className="h-3 w-3" />
                  <span>{attachment.name}</span>
                  <button 
                    onClick={() => removeAttachment(index)}
                    className="ml-1 text-muted-foreground hover:text-destructive"
                  >
                    <X className="h-3 w-3" />
                  </button>
                </div>
              ))}
            </div>
          </div>
        )}
      </CardContent>
      
      <CardFooter className="border-t p-3 flex justify-between">
        <div>
          <input
            type="file"
            ref={attachmentInputRef}
            className="hidden"
            onChange={handleFileSelection}
            multiple
          />
          <Button
            variant="outline"
            size="sm"
            onClick={handleAttachmentClick}
          >
            <Paperclip className="h-4 w-4 mr-1" />
            Attach
          </Button>
        </div>
        
        <Button 
          size="sm" 
          onClick={handleSend}
          disabled={sending}
        >
          {sending ? (
            <>
              <Loader2 className="h-4 w-4 mr-1 animate-spin" />
              Sending...
            </>
          ) : (
            <>
              <SendHorizontal className="h-4 w-4 mr-1" />
              Send
            </>
          )}
        </Button>
      </CardFooter>
    </Card>
  );
}