'use client';

/**
 * Client-side utilities for formatting email content
 * This file contains functions for formatting email content in the browser
 * without any server dependencies.
 */

interface EmailAddress {
  name?: string;
  address: string;
}

interface FormattedEmail {
  to: string;
  cc?: string;
  subject: string;
  body: string;
}

/**
 * Format an email for replying or forwarding
 * Client-side friendly version that doesn't depend on server modules
 */
export function formatEmailForReply(
  email: any, 
  type: 'reply' | 'reply-all' = 'reply'
): FormattedEmail {
  // Format the subject with Re: prefix
  const subject = formatSubject(email.subject || '(No subject)', type);
  
  // Format recipients
  let to = '';
  let cc = '';
  
  // Process 'to' field for reply
  if (typeof email.from === 'string') {
    to = email.from;
  } else if (Array.isArray(email.from)) {
    to = email.from.map((addr: EmailAddress) => 
      addr.name && addr.name !== addr.address 
        ? `${addr.name} <${addr.address}>`
        : addr.address
    ).join(', ');
  } else if (email.fromName || email.from) {
    // Handle cases where from is an object with name and address
    if (email.fromName && email.from && email.fromName !== email.from) {
      to = `${email.fromName} <${email.from}>`;
    } else {
      to = email.from;
    }
  }
  
  // For reply-all, include other recipients in cc
  if (type === 'reply-all' && email.to) {
    if (typeof email.to === 'string') {
      cc = email.to;
    } else if (Array.isArray(email.to)) {
      cc = email.to.map((addr: EmailAddress) => 
        addr.name && addr.name !== addr.address 
          ? `${addr.name} <${addr.address}>`
          : addr.address
      ).join(', ');
    }
    
    // Include cc recipients from original email too if available
    if (email.cc) {
      const ccList = typeof email.cc === 'string' 
        ? email.cc 
        : Array.isArray(email.cc) 
          ? email.cc.map((addr: EmailAddress) => addr.address).join(', ')
          : '';
          
      if (ccList) {
        cc = cc ? `${cc}, ${ccList}` : ccList;
      }
    }
  }
  
  // Create quote header
  const quoteHeader = createQuoteHeader(email);
  
  // Format body with quote
  let body = `<br/><br/>${quoteHeader}<blockquote style="margin: 0 0 0 0.8ex; border-left: 1px solid #ccc; padding-left: 1ex;">`;
  
  // Add quoted content
  if (email.content) {
    body += email.content;
  } else if (email.html) {
    body += email.html;
  } else if (email.text) {
    body += `<pre>${email.text}</pre>`;
  } else if (email.body) {
    body += email.body;
  } else {
    body += '<div style="color: #666; font-style: italic;">No content available</div>';
  }
  
  body += '</blockquote>';
  
  return {
    to,
    cc,
    subject,
    body
  };
}

function formatSubject(subject: string, type: 'reply' | 'reply-all' | 'forward'): string {
  // Clean up existing prefixes first
  let cleanSubject = subject.replace(/^(Re|Fwd|FW|Forward):\s*/gi, '');
  cleanSubject = cleanSubject.trim() || '(No subject)';
  
  // Add appropriate prefix
  if (type === 'forward') {
    return `Fwd: ${cleanSubject}`;
  } else {
    // For reply and reply-all
    return `Re: ${cleanSubject}`;
  }
}

function createQuoteHeader(email: any): string {
  let from = 'Unknown Sender';
  let date = email.date ? new Date(email.date).toLocaleString() : 'Unknown Date';
  let subject = email.subject || '(No subject)';
  let to = '';
  
  // Extract from
  if (typeof email.from === 'string') {
    from = email.from;
  } else if (Array.isArray(email.from)) {
    from = email.from.map((addr: EmailAddress) => 
      addr.name ? `${addr.name} <${addr.address}>` : addr.address
    ).join(', ');
  } else if (email.fromName || email.from) {
    from = email.fromName && email.fromName !== email.from
      ? `${email.fromName} <${email.from}>`
      : email.from;
  }
  
  // Extract to
  if (typeof email.to === 'string') {
    to = email.to;
  } else if (Array.isArray(email.to)) {
    to = email.to.map((addr: EmailAddress) => 
      addr.name ? `${addr.name} <${addr.address}>` : addr.address
    ).join(', ');
  }
  
  return `
    <div style="color: #666; margin-bottom: 10px; font-family: Arial, sans-serif;">
      <div>On ${date}, ${from} wrote:</div>
    </div>
  `;
}

/**
 * Format an email for forwarding
 */
export function formatEmailForForward(email: any): {
  subject: string;
  headerHtml: string;
} {
  // Format subject with Fwd: prefix
  const subject = formatSubject(email.subject || '(No subject)', 'forward');
  
  // Get sender information
  let fromString = 'Unknown Sender';
  if (typeof email.from === 'string') {
    fromString = email.from;
  } else if (Array.isArray(email.from)) {
    fromString = email.from.map((addr: EmailAddress) => 
      addr.name ? `${addr.name} <${addr.address}>` : addr.address
    ).join(', ');
  } else if (email.fromName && email.from) {
    fromString = email.fromName !== email.from 
      ? `${email.fromName} <${email.from}>` 
      : email.from;
  }
  
  // Get recipient information
  let toString = '';
  if (typeof email.to === 'string') {
    toString = email.to;
  } else if (Array.isArray(email.to)) {
    toString = email.to.map((addr: EmailAddress) => 
      addr.name ? `${addr.name} <${addr.address}>` : addr.address
    ).join(', ');
  }
  
  // Create header for forwarded email
  const headerHtml = `
    <div style="border-top: 1px solid #e1e1e1; margin-top: 20px; padding-top: 15px; font-family: Arial, sans-serif;">
      <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> ${email.date ? new Date(email.date).toLocaleString() : 'Unknown Date'}</div>
        <div><b>Subject:</b> ${email.subject || '(No subject)'}</div>
        <div><b>To:</b> ${toString || 'Unknown Recipient'}</div>
      </div>
    </div>
  `;
  
  return {
    subject,
    headerHtml
  };
}