gmail-to-exchange365/src/server/folderMapper.ts

Complete Gmail to Exchange 365 migration tool with UI - Migrate emails, attachments, and folders seamlessly

import { Client } from "@microsoft/microsoft-graph-client";
import { FolderMapping } from "./types";

export async function getOrCreateFolder(
  client: Client,
  folderName: string,
  parentFolderId: string = "Inbox"
): Promise<string> {
  try {
    // Try to find existing folder
    const folders = await client
      .api(`/me/mailFolders/${parentFolderId}/childFolders`)
      .filter(`displayName eq '${folderName}'`)
      .get();

    if (folders.value && folders.value.length > 0) {
      return folders.value[0].id;
    }

    // Create new folder
    const newFolder = await client
      .api(`/me/mailFolders/${parentFolderId}/childFolders`)
      .post({
        displayName: folderName
      });

    return newFolder.id;
  } catch (error: any) {
    console.error(`Error creating folder ${folderName}:`, error.message);
    // Fallback to Inbox if folder creation fails
    return parentFolderId;
  }
}

export async function mapGmailLabelsToFolders(
  client: Client,
  gmailLabels: string[]
): Promise<FolderMapping[]> {
  const mappings: FolderMapping[] = [];

  // Map common Gmail labels to Exchange folders
  const commonMappings: Record<string, string> = {
    "INBOX": "Inbox",
    "SENT": "Sent Items",
    "DRAFT": "Drafts",
    "TRASH": "Deleted Items",
    "SPAM": "Junk Email",
    "IMPORTANT": "Important"
  };

  for (const label of gmailLabels) {
    const folderName = commonMappings[label.toUpperCase()] || label;
    try {
      const folderId = await getOrCreateFolder(client, folderName);
      mappings.push({
        gmailLabel: label,
        exchangeFolderId: folderId,
        exchangeFolderName: folderName
      });
    } catch (error: any) {
      console.error(`Error mapping label ${label}:`, error.message);
    }
  }

  return mappings;
}

export function getFolderIdForLabel(
  mappings: FolderMapping[],
  labels: string[]
): string {
  // Find the first matching label mapping
  for (const label of labels) {
    const mapping = mappings.find(m => m.gmailLabel === label);
    if (mapping) {
      return mapping.exchangeFolderId;
    }
  }
  
  // Default to Inbox
  return "Inbox";
}