src/tools/sheets/duplicateSheet.ts

import type { FastMCP } from 'fastmcp';
import { UserError } from 'fastmcp';
import { z } from 'zod';
import { getSheetsClient } from '../../clients.js';

export function register(server: FastMCP) {
  server.addTool({
    name: 'duplicateSheet',
    description:
      'Duplicates a sheet (tab) within a spreadsheet, copying all values, formulas, formatting, validations, and conditional formatting. Use getSpreadsheetInfo to find the numeric sheet ID.',
    parameters: z.strictObject({
      spreadsheetId: z
        .string()
        .describe(
          'The spreadsheet ID — the long string between /d/ and /edit in a Google Sheets URL.'
        ),
      sheetId: z
        .number()
        .int()
        .describe('The numeric sheet ID to duplicate. Use getSpreadsheetInfo to find sheet IDs.'),
      newSheetName: z
        .string()
        .min(1)
        .optional()
        .describe(
          'Name for the duplicated sheet. If omitted, Google auto-names it "Copy of <original>".'
        ),
    }),
    execute: async (args, { log }) => {
      const sheets = await getSheetsClient();
      log.info(
        `Duplicating sheet ID ${args.sheetId} in spreadsheet ${args.spreadsheetId}${args.newSheetName ? ` as "${args.newSheetName}"` : ''}`
      );

      try {
        const response = await sheets.spreadsheets.batchUpdate({
          spreadsheetId: args.spreadsheetId,
          requestBody: {
            requests: [
              {
                duplicateSheet: {
                  sourceSheetId: args.sheetId,
                  newSheetName: args.newSheetName,
                },
              },
            ],
          },
        });

        const duplicatedSheet = response.data.replies?.[0]?.duplicateSheet?.properties;

        if (!duplicatedSheet) {
          throw new UserError('Failed to duplicate sheet - no sheet properties returned.');
        }

        return `Successfully duplicated sheet as "${duplicatedSheet.title}" (Sheet ID: ${duplicatedSheet.sheetId}).`;
      } catch (error: any) {
        log.error(
          `Error duplicating sheet in spreadsheet ${args.spreadsheetId}: ${error.message || error}`
        );
        if (error instanceof UserError) throw error;
        throw new UserError(`Failed to duplicate sheet: ${error.message || 'Unknown error'}`);
      }
    },
  });
}