@IsTest
public with sharing class MicrosoftAuthTest {
     /*
     * Mock response for token endpoint
     */
    private class TokenMock implements HttpCalloutMock {
        public HTTPResponse respond(HTTPRequest req) {

            System.debug('Mock Endpoint >>> ' + req.getEndpoint());
            System.debug('Mock Body >>> ' + req.getBody());

            HttpResponse res = new HttpResponse();
            res.setStatusCode(200);
            res.setHeader('Content-Type', 'application/json');

            // Fake OAuth response
            res.setBody('{' +
                '"access_token":"TEST_ACCESS_TOKEN",' +
                '"refresh_token":"TEST_REFRESH_TOKEN"' +
            '}');
                return res;
        }
    }

     @IsTest
    static void testGetAccessToken_Success() {

        System.debug('===== testGetAccessToken_Success START =====');

        // Set mock
        Test.setMock(HttpCalloutMock.class, new TokenMock());

        Test.startTest();

        // Call method
        MicrosoftAuth obj = new MicrosoftAuth();
        obj.getAccessToken(
            'dummyAuthCode',
            'OneDrive',
            true,
            UserInfo.getUserId()
        );

        Test.stopTest();

        System.debug('===== testGetAccessToken_Success END =====');

        // OPTIONAL: If OAuthTokenManager.storeToken inserts record,
        // you can verify that record here with SOQL.
    }


     /*
     * Mock for SUCCESS response (Status 200)
     */
    private class RefreshTokenSuccessMock implements HttpCalloutMock {
        public HTTPResponse respond(HTTPRequest req) {

            System.debug('Mock Endpoint >>> ' + req.getEndpoint());
            System.debug('Mock Body >>> ' + req.getBody());

            HttpResponse res = new HttpResponse();
            res.setStatusCode(200);
            res.setHeader('Content-Type', 'application/json');

            res.setBody('{' +
                '"access_token":"NEW_ACCESS_TOKEN_123"' +
            '}');

            return res;
      }
    }

      /*
     * Mock for FAILURE response (Status 400)
     */
    private class RefreshTokenFailMock implements HttpCalloutMock {
        public HTTPResponse respond(HTTPRequest req) {

            HttpResponse res = new HttpResponse();
            res.setStatusCode(400);
            res.setBody('Invalid refresh token');

            return res;
        }
    }


     @IsTest
    static void testRefreshAccessToken_Success() {

        System.debug('===== testRefreshAccessToken_Success START =====');

        Test.setMock(HttpCalloutMock.class, new RefreshTokenSuccessMock());

        Test.startTest();

        String token = new MicrosoftAuth ()
            .refreshAccessToken('DUMMY_REFRESH_TOKEN');

        Test.stopTest();

        System.debug('Returned Token >>> ' + token);
            System.assertEquals('NEW_ACCESS_TOKEN_123', token,
            'Token should match mock response');

        System.debug('===== testRefreshAccessToken_Success END =====');
    }


    @IsTest
    static void testRefreshAccessToken_Failure() {

        System.debug('===== testRefreshAccessToken_Failure START =====');

        Test.setMock(HttpCalloutMock.class, new RefreshTokenFailMock());

        Test.startTest();

             String token = new MicrosoftAuth ()
            .refreshAccessToken('BAD_REFRESH_TOKEN');

        Test.stopTest();

        System.debug('Returned Token >>> ' + token);

        System.assertEquals(null, token,
            'Token should be null when status code is not 200');

        System.debug('===== testRefreshAccessToken_Failure END =====');
    }

     @IsTest
    static void testRevokeAccessToken() {

        System.debug('===== testRevokeAccessToken START =====');

        Test.startTest();

        // Call method
        MicrosoftAuth.revokeAccessToken('DUMMY_ACCESS_TOKEN');

        Test.stopTest();

        // Since method returns void and has no logic,
        // we only verify that no exception was thrown
        System.assert(true, 'Method executed successfully');

        System.debug('===== testRevokeAccessToken END =====');
    }
}