/**
 * Read email functionality
 */
const config = require('../config');
const { callGraphAPI } = require('../utils/graph-api');
const { ensureAuthenticated } = require('../auth');
const { cleanBody } = require('../utils/bodyParser');
const { formatDateTime } = require('../utils/time-formatter');
const { normalizeMailbox, buildPath, withMailboxHeaders } = require('../utils/mailbox');

/**
 * Read email handler
 * @param {object} args - Tool arguments
 * @returns {object} - MCP response
 */
async function handleReadEmail(args) {
  const emailId = args.id;
  const mb = normalizeMailbox(args.mailbox);

  if (!emailId) {
    return {
      content: [{
        type: "text",
        text: "Email ID is required."
      }]
    };
  }

  try {
    const accessToken = await ensureAuthenticated();

    // Do not pre-encode the ID — callGraphAPI encodes each path segment once.
    const endpoint = buildPath(mb, `messages/${emailId}`);
    const queryParams = {
      $select: config.EMAIL_DETAIL_FIELDS
    };
    const opts = { headers: withMailboxHeaders(mb) };

    try {
      const email = await callGraphAPI(accessToken, 'GET', endpoint, null, queryParams, opts);

      if (!email) {
        return {
          content: [
            {
              type: "text",
              text: `Email with ID ${emailId} not found.`
            }
          ]
        };
      }

      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 = formatDateTime(email.receivedDateTime);

      let body = '';
      if (email.body) {
        body = cleanBody(email.body.content);
      } else {
        body = cleanBody(email.bodyPreview) || 'No content';
      }

      const mailboxLine = mb.kind === 'user' ? `Mailbox: ${mb.smtpOrUpn}\n` : '';

      const formattedEmail = `${mailboxLine}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}`;

      return {
        content: [
          {
            type: "text",
            text: formattedEmail
          }
        ]
      };
    } catch (error) {
      console.error(`Error reading email: ${error.message}`);

      if (error.message.includes("doesn't belong to the targeted mailbox")) {
        return {
          content: [
            {
              type: "text",
              text: `The email ID seems invalid or doesn't belong to the targeted mailbox${mb.kind === 'user' ? ` (${mb.smtpOrUpn})` : ''}. Pass the same mailbox used when listing/searching, or try a different email ID.`
            }
          ]
        };
      } else {
        return {
          content: [
            {
              type: "text",
              text: `Failed to read email: ${error.message}`
            }
          ]
        };
      }
    }
  } 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 email: ${error.message}`
      }]
    };
  }
}

module.exports = handleReadEmail;