/**
 * Read multiple emails functionality
 */
const config = require('../config');
const { callGraphAPI } = require('../utils/graph-api');
const { ensureAuthenticated } = require('../auth');
const { cleanBody } = require('../utils/bodyParser');

/**
 * Format a single email for display
 * @param {object} email - Email object from Graph API
 * @param {string} emailId - Email ID for error context
 * @returns {string} - Formatted email text
 */
function formatEmail(email, emailId) {
  if (!email) {
    return `Email ID ${emailId}: Not found or inaccessible`;
  }

  try {
    // Format sender, recipients, etc.
    const sender = email.from ? `${email.from.emailAddress.name} (${email.from.emailAddress.address})` : 'Unknown';
    const to = email.toRecipients ? email.toRecipients.map(r => `${r.emailAddress.name} (${r.emailAddress.address})`).join(", ") : 'None';
    const cc = email.ccRecipients && email.ccRecipients.length > 0 ? email.ccRecipients.map(r => `${r.emailAddress.name} (${r.emailAddress.address})`).join(", ") : 'None';
    const bcc = email.bccRecipients && email.bccRecipients.length > 0 ? email.bccRecipients.map(r => `${r.emailAddress.name} (${r.emailAddress.address})`).join(", ") : 'None';
    const date = new Date(email.receivedDateTime).toLocaleString();
    
    // Extract and clean body content (cleanBody handles both HTML and plain text)
    let body = '';
    if (email.body) {
      body = cleanBody(email.body.content);
    } else {
      body = cleanBody(email.bodyPreview) || 'No content';
    }
    
    // Format the email
    return `From: ${sender}
To: ${to}
${cc !== 'None' ? `CC: ${cc}\n` : ''}${bcc !== 'None' ? `BCC: ${bcc}\n` : ''}Subject: ${email.subject}
Date: ${date}
Importance: ${email.importance || 'normal'}
Has Attachments: ${email.hasAttachments ? 'Yes' : 'No'}

${body}`;
  } catch (error) {
    return `Email ID ${emailId}: Error formatting email - ${error.message}`;
  }
}

/**
 * Read multiple emails handler
 * @param {object} args - Tool arguments
 * @returns {object} - MCP response
 */
async function handleReadMultipleEmails(args) {
  const emailIds = args.ids;
  
  if (!emailIds || !Array.isArray(emailIds) || emailIds.length === 0) {
    return {
      content: [{ 
        type: "text", 
        text: "Email IDs array is required and must contain at least one ID."
      }]
    };
  }

  // Limit the number of emails to prevent overwhelming responses
  const maxEmails = 10;
  if (emailIds.length > maxEmails) {
    return {
      content: [{ 
        type: "text", 
        text: `Too many email IDs provided. Maximum allowed is ${maxEmails}, but ${emailIds.length} were provided.`
      }]
    };
  }
  
  try {
    // Get access token
    const accessToken = await ensureAuthenticated();
    
    // Create concurrent API calls for all email IDs
    const emailPromises = emailIds.map(async (emailId) => {
      try {
        const endpoint = `me/messages/${encodeURIComponent(emailId)}`;
        const queryParams = {
          $select: config.EMAIL_DETAIL_FIELDS
        };
        
        const email = await callGraphAPI(accessToken, 'GET', endpoint, null, queryParams);
        return { emailId, email, error: null };
      } catch (error) {
        console.error(`Error reading email ${emailId}: ${error.message}`);
        return { emailId, email: null, error: error.message };
      }
    });
    
    // Wait for all API calls to complete
    const results = await Promise.all(emailPromises);
    
    // Format all emails
    const formattedEmails = results.map((result, index) => {
      const emailNumber = index + 1;
      const separator = "=".repeat(80);
      
      if (result.error) {
        return `${separator}
EMAIL ${emailNumber} (ID: ${result.emailId})
${separator}
Error: ${result.error}`;
      } else {
        const formattedEmail = formatEmail(result.email, result.emailId);
        return `${separator}
EMAIL ${emailNumber} (ID: ${result.emailId})
${separator}
${formattedEmail}`;
      }
    });
    
    // Count successful vs failed reads
    const successCount = results.filter(r => !r.error && r.email).length;
    const errorCount = results.filter(r => r.error || !r.email).length;
    
    const summary = `Retrieved ${successCount} email(s) successfully${errorCount > 0 ? `, ${errorCount} failed` : ''}.

`;
    
    return {
      content: [
        {
          type: "text",
          text: summary + formattedEmails.join('\n\n')
        }
      ]
    };
  } catch (error) {
    if (error.message === 'Authentication required') {
      return {
        content: [{ 
          type: "text", 
          text: "Authentication required. Please use the 'authenticate' tool first."
        }]
      };
    }
    
    return {
      content: [{ 
        type: "text", 
        text: `Error accessing emails: ${error.message}`
      }]
    };
  }
}

module.exports = handleReadMultipleEmails;