/*
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */

import {
    AuthorizationCodeClient,
    ClientConfiguration,
    RefreshTokenClient,
    AuthenticationResult,
    Authority,
    AuthorityFactory,
    BaseAuthRequest,
    SilentFlowClient,
    Logger,
    ServerTelemetryManager,
    ServerTelemetryRequest,
    CommonSilentFlowRequest,
    CommonRefreshTokenRequest,
    CommonAuthorizationCodeRequest,
    CommonAuthorizationUrlRequest,
    CommonUsernamePasswordRequest,
    AuthenticationScheme,
    ResponseMode,
    AuthorityOptions,
    OIDC_DEFAULT_SCOPES,
    AzureRegionConfiguration,
    AuthError,
    AzureCloudOptions,
    AuthorizationCodePayload,
    Constants,
    StringUtils,
    createClientAuthError,
    ClientAuthErrorCodes,
    buildStaticAuthorityOptions,
    ClientAssertion as ClientAssertionType,
    getClientAssertion,
    ClientAssertionCallback,
    CacheOutcome,
    ClientAuthError,
} from "@azure/msal-common/node";
import {
    Configuration,
    buildAppConfiguration,
    NodeConfiguration,
} from "../config/Configuration.js";
import { CryptoProvider } from "../crypto/CryptoProvider.js";
import { NodeStorage } from "../cache/NodeStorage.js";
import { Constants as NodeConstants, ApiId } from "../utils/Constants.js";
import { TokenCache } from "../cache/TokenCache.js";
import { ClientAssertion } from "./ClientAssertion.js";
import { AuthorizationUrlRequest } from "../request/AuthorizationUrlRequest.js";
import { AuthorizationCodeRequest } from "../request/AuthorizationCodeRequest.js";
import { RefreshTokenRequest } from "../request/RefreshTokenRequest.js";
import { SilentFlowRequest } from "../request/SilentFlowRequest.js";
import { version, name } from "../packageMetadata.js";
import { UsernamePasswordRequest } from "../request/UsernamePasswordRequest.js";
import { NodeAuthError } from "../error/NodeAuthError.js";
import { UsernamePasswordClient } from "./UsernamePasswordClient.js";

/**
 * Base abstract class for all ClientApplications - public and confidential
 * @public
 */
export abstract class ClientApplication {
    protected readonly cryptoProvider: CryptoProvider;
    private tokenCache: TokenCache;

    /**
     * Platform storage object
     */
    protected storage: NodeStorage;
    /**
     * Logger object to log the application flow
     */
    protected logger: Logger;
    /**
     * Platform configuration initialized by the application
     */
    protected config: NodeConfiguration;
    /**
     * Client assertion passed by the user for confidential client flows
     */
    protected clientAssertion: ClientAssertion;
    protected developerProvidedClientAssertion:
        | string
        | ClientAssertionCallback;
    /**
     * Client secret passed by the user for confidential client flows
     */
    protected clientSecret: string;

    /**
     * Constructor for the ClientApplication
     */
    protected constructor(configuration: Configuration) {
        this.config = buildAppConfiguration(configuration);
        this.cryptoProvider = new CryptoProvider();
        this.logger = new Logger(
            this.config.system.loggerOptions,
            name,
            version
        );
        this.storage = new NodeStorage(
            this.logger,
            this.config.auth.clientId,
            this.cryptoProvider,
            buildStaticAuthorityOptions(this.config.auth)
        );
        this.tokenCache = new TokenCache(
            this.storage,
            this.logger,
            this.config.cache.cachePlugin
        );
    }

    /**
     * Creates the URL of the authorization request, letting the user input credentials and consent to the
     * application. The URL targets the /authorize endpoint of the authority configured in the
     * application object.
     *
     * Once the user inputs their credentials and consents, the authority will send a response to the redirect URI
     * sent in the request and should contain an authorization code, which can then be used to acquire tokens via
     * `acquireTokenByCode(AuthorizationCodeRequest)`.
     */
    async getAuthCodeUrl(request: AuthorizationUrlRequest): Promise<string> {
        this.logger.info("getAuthCodeUrl called", request.correlationId);
        const validRequest: CommonAuthorizationUrlRequest = {
            ...request,
            ...(await this.initializeBaseRequest(request)),
            responseMode: request.responseMode || ResponseMode.QUERY,
            authenticationScheme: AuthenticationScheme.BEARER,
        };

        const authClientConfig = await this.buildOauthClientConfiguration(
            validRequest.authority,
            validRequest.correlationId,
            validRequest.redirectUri,
            undefined,
            undefined,
            request.azureCloudOptions
        );
        const authorizationCodeClient = new AuthorizationCodeClient(
            authClientConfig
        );
        this.logger.verbose(
            "Auth code client created",
            validRequest.correlationId
        );
        return authorizationCodeClient.getAuthCodeUrl(validRequest);
    }

    /**
     * Acquires a token by exchanging the Authorization Code received from the first step of OAuth2.0
     * Authorization Code flow.
     *
     * `getAuthCodeUrl(AuthorizationCodeUrlRequest)` can be used to create the URL for the first step of OAuth2.0
     * Authorization Code flow. Ensure that values for redirectUri and scopes in AuthorizationCodeUrlRequest and
     * AuthorizationCodeRequest are the same.
     */
    async acquireTokenByCode(
        request: AuthorizationCodeRequest,
        authCodePayLoad?: AuthorizationCodePayload
    ): Promise<AuthenticationResult> {
        this.logger.info("acquireTokenByCode called");
        if (request.state && authCodePayLoad) {
            this.logger.info("acquireTokenByCode - validating state");
            this.validateState(request.state, authCodePayLoad.state || "");
            // eslint-disable-next-line no-param-reassign
            authCodePayLoad = { ...authCodePayLoad, state: "" };
        }
        const validRequest: CommonAuthorizationCodeRequest = {
            ...request,
            ...(await this.initializeBaseRequest(request)),
            authenticationScheme: AuthenticationScheme.BEARER,
        };

        const serverTelemetryManager = this.initializeServerTelemetryManager(
            ApiId.acquireTokenByCode,
            validRequest.correlationId
        );
        try {
            const authClientConfig = await this.buildOauthClientConfiguration(
                validRequest.authority,
                validRequest.correlationId,
                validRequest.redirectUri,
                serverTelemetryManager,
                undefined,
                request.azureCloudOptions
            );
            const authorizationCodeClient = new AuthorizationCodeClient(
                authClientConfig
            );
            this.logger.verbose(
                "Auth code client created",
                validRequest.correlationId
            );
            return await authorizationCodeClient.acquireToken(
                validRequest,
                authCodePayLoad
            );
        } catch (e) {
            if (e instanceof AuthError) {
                e.setCorrelationId(validRequest.correlationId);
            }
            serverTelemetryManager.cacheFailedRequest(e);
            throw e;
        }
    }

    /**
     * Acquires a token by exchanging the refresh token provided for a new set of tokens.
     *
     * This API is provided only for scenarios where you would like to migrate from ADAL to MSAL. Otherwise, it is
     * recommended that you use `acquireTokenSilent()` for silent scenarios. When using `acquireTokenSilent()`, MSAL will
     * handle the caching and refreshing of tokens automatically.
     */
    async acquireTokenByRefreshToken(
        request: RefreshTokenRequest
    ): Promise<AuthenticationResult | null> {
        this.logger.info(
            "acquireTokenByRefreshToken called",
            request.correlationId
        );
        const validRequest: CommonRefreshTokenRequest = {
            ...request,
            ...(await this.initializeBaseRequest(request)),
            authenticationScheme: AuthenticationScheme.BEARER,
        };

        const serverTelemetryManager = this.initializeServerTelemetryManager(
            ApiId.acquireTokenByRefreshToken,
            validRequest.correlationId
        );
        try {
            const refreshTokenClientConfig =
                await this.buildOauthClientConfiguration(
                    validRequest.authority,
                    validRequest.correlationId,
                    validRequest.redirectUri || "",
                    serverTelemetryManager,
                    undefined,
                    request.azureCloudOptions
                );
            const refreshTokenClient = new RefreshTokenClient(
                refreshTokenClientConfig
            );
            this.logger.verbose(
                "Refresh token client created",
                validRequest.correlationId
            );
            return await refreshTokenClient.acquireToken(validRequest);
        } catch (e) {
            if (e instanceof AuthError) {
                e.setCorrelationId(validRequest.correlationId);
            }
            serverTelemetryManager.cacheFailedRequest(e);
            throw e;
        }
    }

    /**
     * Acquires a token silently when a user specifies the account the token is requested for.
     *
     * This API expects the user to provide an account object and looks into the cache to retrieve the token if present.
     * There is also an optional "forceRefresh" boolean the user can send to bypass the cache for access_token and id_token.
     * In case the refresh_token is expired or not found, an error is thrown
     * and the guidance is for the user to call any interactive token acquisition API (eg: `acquireTokenByCode()`).
     */
    async acquireTokenSilent(
        request: SilentFlowRequest
    ): Promise<AuthenticationResult> {
        const validRequest: CommonSilentFlowRequest = {
            ...request,
            ...(await this.initializeBaseRequest(request)),
            forceRefresh: request.forceRefresh || false,
        };

        const serverTelemetryManager = this.initializeServerTelemetryManager(
            ApiId.acquireTokenSilent,
            validRequest.correlationId,
            validRequest.forceRefresh
        );

        try {
            const clientConfiguration =
                await this.buildOauthClientConfiguration(
                    validRequest.authority,
                    validRequest.correlationId,
                    validRequest.redirectUri || "",
                    serverTelemetryManager,
                    undefined,
                    validRequest.azureCloudOptions
                );
            const silentFlowClient = new SilentFlowClient(clientConfiguration);
            this.logger.verbose(
                "Silent flow client created",
                validRequest.correlationId
            );
            try {
                // always overwrite the in-memory cache with the persistence cache (if it exists) before a cache lookup
                await this.tokenCache.overwriteCache();
                return await this.acquireCachedTokenSilent(
                    validRequest,
                    silentFlowClient,
                    clientConfiguration
                );
            } catch (error) {
                if (
                    error instanceof ClientAuthError &&
                    error.errorCode ===
                        ClientAuthErrorCodes.tokenRefreshRequired
                ) {
                    const refreshTokenClient = new RefreshTokenClient(
                        clientConfiguration
                    );
                    return refreshTokenClient.acquireTokenByRefreshToken(
                        validRequest
                    );
                }
                throw error;
            }
        } catch (error) {
            if (error instanceof AuthError) {
                error.setCorrelationId(validRequest.correlationId);
            }
            serverTelemetryManager.cacheFailedRequest(error);
            throw error;
        }
    }

    private async acquireCachedTokenSilent(
        validRequest: CommonSilentFlowRequest,
        silentFlowClient: SilentFlowClient,
        clientConfiguration: ClientConfiguration
    ): Promise<AuthenticationResult> {
        const [authResponse, cacheOutcome] =
            await silentFlowClient.acquireCachedToken({
                ...validRequest,
                scopes: validRequest.scopes?.length
                    ? validRequest.scopes
                    : [...OIDC_DEFAULT_SCOPES],
            });

        if (cacheOutcome === CacheOutcome.PROACTIVELY_REFRESHED) {
            this.logger.info(
                "ClientApplication:acquireCachedTokenSilent - Cached access token's refreshOn property has been exceeded'. It's not expired, but must be refreshed."
            );
            // refresh the access token in the background
            const refreshTokenClient = new RefreshTokenClient(
                clientConfiguration
            );

            try {
                await refreshTokenClient.acquireTokenByRefreshToken(
                    validRequest
                );
            } catch {
                // do nothing, this is running in the background and no action is to be taken upon success or failure
            }
        }

        // return the cached token
        return authResponse;
    }

    /**
     * Acquires tokens with password grant by exchanging client applications username and password for credentials
     *
     * The latest OAuth 2.0 Security Best Current Practice disallows the password grant entirely.
     * More details on this recommendation at https://tools.ietf.org/html/draft-ietf-oauth-security-topics-13#section-3.4
     * Microsoft's documentation and recommendations are at:
     * https://docs.microsoft.com/en-us/azure/active-directory/develop/msal-authentication-flows#usernamepassword
     *
     * @param request - UsenamePasswordRequest
     * @deprecated - Use a more secure flow instead
     */
    async acquireTokenByUsernamePassword(
        request: UsernamePasswordRequest
    ): Promise<AuthenticationResult | null> {
        this.logger.info(
            "acquireTokenByUsernamePassword called",
            request.correlationId
        );
        const validRequest: CommonUsernamePasswordRequest = {
            ...request,
            ...(await this.initializeBaseRequest(request)),
        };
        const serverTelemetryManager = this.initializeServerTelemetryManager(
            ApiId.acquireTokenByUsernamePassword,
            validRequest.correlationId
        );
        try {
            const usernamePasswordClientConfig =
                await this.buildOauthClientConfiguration(
                    validRequest.authority,
                    validRequest.correlationId,
                    "",
                    serverTelemetryManager,
                    undefined,
                    request.azureCloudOptions
                );
            const usernamePasswordClient = new UsernamePasswordClient(
                usernamePasswordClientConfig
            );
            this.logger.verbose(
                "Username password client created",
                validRequest.correlationId
            );
            return await usernamePasswordClient.acquireToken(validRequest);
        } catch (e) {
            if (e instanceof AuthError) {
                e.setCorrelationId(validRequest.correlationId);
            }
            serverTelemetryManager.cacheFailedRequest(e);
            throw e;
        }
    }

    /**
     * Gets the token cache for the application.
     */
    getTokenCache(): TokenCache {
        this.logger.info("getTokenCache called");
        return this.tokenCache;
    }

    /**
     * Validates OIDC state by comparing the user cached state with the state received from the server.
     *
     * This API is provided for scenarios where you would use OAuth2.0 state parameter to mitigate against
     * CSRF attacks.
     * For more information about state, visit https://datatracker.ietf.org/doc/html/rfc6819#section-3.6.
     * @param state - Unique GUID generated by the user that is cached by the user and sent to the server during the first leg of the flow
     * @param cachedState - This string is sent back by the server with the authorization code
     */
    protected validateState(state: string, cachedState: string): void {
        if (!state) {
            throw NodeAuthError.createStateNotFoundError();
        }

        if (state !== cachedState) {
            throw createClientAuthError(ClientAuthErrorCodes.stateMismatch);
        }
    }

    /**
     * Returns the logger instance
     */
    getLogger(): Logger {
        return this.logger;
    }

    /**
     * Replaces the default logger set in configurations with new Logger with new configurations
     * @param logger - Logger instance
     */
    setLogger(logger: Logger): void {
        this.logger = logger;
    }

    /**
     * Builds the common configuration to be passed to the common component based on the platform configurarion
     * @param authority - user passed authority in configuration
     * @param serverTelemetryManager - initializes servertelemetry if passed
     */
    protected async buildOauthClientConfiguration(
        authority: string,
        requestCorrelationId: string,
        redirectUri: string,
        serverTelemetryManager?: ServerTelemetryManager,
        azureRegionConfiguration?: AzureRegionConfiguration,
        azureCloudOptions?: AzureCloudOptions
    ): Promise<ClientConfiguration> {
        this.logger.verbose(
            "buildOauthClientConfiguration called",
            requestCorrelationId
        );

        // precedence - azureCloudInstance + tenant >> authority and request  >> config
        const userAzureCloudOptions = azureCloudOptions
            ? azureCloudOptions
            : this.config.auth.azureCloudOptions;

        // using null assertion operator as we ensure that all config values have default values in buildConfiguration()
        const discoveredAuthority = await this.createAuthority(
            authority,
            requestCorrelationId,
            azureRegionConfiguration,
            userAzureCloudOptions
        );

        this.logger.info(
            `Building oauth client configuration with the following authority: ${discoveredAuthority.tokenEndpoint}.`,
            requestCorrelationId
        );

        serverTelemetryManager?.updateRegionDiscoveryMetadata(
            discoveredAuthority.regionDiscoveryMetadata
        );

        const clientConfiguration: ClientConfiguration = {
            authOptions: {
                clientId: this.config.auth.clientId,
                authority: discoveredAuthority,
                clientCapabilities: this.config.auth.clientCapabilities,
                redirectUri,
            },
            loggerOptions: {
                logLevel: this.config.system.loggerOptions.logLevel,
                loggerCallback: this.config.system.loggerOptions.loggerCallback,
                piiLoggingEnabled:
                    this.config.system.loggerOptions.piiLoggingEnabled,
                correlationId: requestCorrelationId,
            },
            cacheOptions: {
                claimsBasedCachingEnabled:
                    this.config.cache.claimsBasedCachingEnabled,
            },
            cryptoInterface: this.cryptoProvider,
            networkInterface: this.config.system.networkClient,
            storageInterface: this.storage,
            serverTelemetryManager: serverTelemetryManager,
            clientCredentials: {
                clientSecret: this.clientSecret,
                clientAssertion: await this.getClientAssertion(
                    discoveredAuthority
                ),
            },
            libraryInfo: {
                sku: NodeConstants.MSAL_SKU,
                version: version,
                cpu: process.arch || Constants.EMPTY_STRING,
                os: process.platform || Constants.EMPTY_STRING,
            },
            telemetry: this.config.telemetry,
            persistencePlugin: this.config.cache.cachePlugin,
            serializableCache: this.tokenCache,
        };

        return clientConfiguration;
    }

    private async getClientAssertion(
        authority: Authority
    ): Promise<ClientAssertionType> {
        if (this.developerProvidedClientAssertion) {
            this.clientAssertion = ClientAssertion.fromAssertion(
                await getClientAssertion(
                    this.developerProvidedClientAssertion,
                    this.config.auth.clientId,
                    authority.tokenEndpoint
                )
            );
        }

        return (
            this.clientAssertion && {
                assertion: this.clientAssertion.getJwt(
                    this.cryptoProvider,
                    this.config.auth.clientId,
                    authority.tokenEndpoint
                ),
                assertionType: NodeConstants.JWT_BEARER_ASSERTION_TYPE,
            }
        );
    }

    /**
     * Generates a request with the default scopes & generates a correlationId.
     * @param authRequest - BaseAuthRequest for initialization
     */
    protected async initializeBaseRequest(
        authRequest: Partial<BaseAuthRequest>
    ): Promise<BaseAuthRequest> {
        this.logger.verbose(
            "initializeRequestScopes called",
            authRequest.correlationId
        );
        // Default authenticationScheme to Bearer, log that POP isn't supported yet
        if (
            authRequest.authenticationScheme &&
            authRequest.authenticationScheme === AuthenticationScheme.POP
        ) {
            this.logger.verbose(
                "Authentication Scheme 'pop' is not supported yet, setting Authentication Scheme to 'Bearer' for request",
                authRequest.correlationId
            );
        }

        authRequest.authenticationScheme = AuthenticationScheme.BEARER;

        // Set requested claims hash if claims-based caching is enabled and claims were requested
        if (
            this.config.cache.claimsBasedCachingEnabled &&
            authRequest.claims &&
            // Checks for empty stringified object "{}" which doesn't qualify as requested claims
            !StringUtils.isEmptyObj(authRequest.claims)
        ) {
            authRequest.requestedClaimsHash =
                await this.cryptoProvider.hashString(authRequest.claims);
        }

        return {
            ...authRequest,
            scopes: [
                ...((authRequest && authRequest.scopes) || []),
                ...OIDC_DEFAULT_SCOPES,
            ],
            correlationId:
                (authRequest && authRequest.correlationId) ||
                this.cryptoProvider.createNewGuid(),
            authority: authRequest.authority || this.config.auth.authority,
        };
    }

    /**
     * Initializes the server telemetry payload
     * @param apiId - Id for a specific request
     * @param correlationId - GUID
     * @param forceRefresh - boolean to indicate network call
     */
    protected initializeServerTelemetryManager(
        apiId: number,
        correlationId: string,
        forceRefresh?: boolean
    ): ServerTelemetryManager {
        const telemetryPayload: ServerTelemetryRequest = {
            clientId: this.config.auth.clientId,
            correlationId: correlationId,
            apiId: apiId,
            forceRefresh: forceRefresh || false,
        };

        return new ServerTelemetryManager(telemetryPayload, this.storage);
    }

    /**
     * Create authority instance. If authority not passed in request, default to authority set on the application
     * object. If no authority set in application object, then default to common authority.
     * @param authorityString - authority from user configuration
     */
    private async createAuthority(
        authorityString: string,
        requestCorrelationId: string,
        azureRegionConfiguration?: AzureRegionConfiguration,
        azureCloudOptions?: AzureCloudOptions
    ): Promise<Authority> {
        this.logger.verbose("createAuthority called", requestCorrelationId);

        // build authority string based on auth params - azureCloudInstance is prioritized if provided
        const authorityUrl = Authority.generateAuthority(
            authorityString,
            azureCloudOptions
        );

        const authorityOptions: AuthorityOptions = {
            protocolMode: this.config.auth.protocolMode,
            knownAuthorities: this.config.auth.knownAuthorities,
            cloudDiscoveryMetadata: this.config.auth.cloudDiscoveryMetadata,
            authorityMetadata: this.config.auth.authorityMetadata,
            azureRegionConfiguration,
            skipAuthorityMetadataCache:
                this.config.auth.skipAuthorityMetadataCache,
        };

        return AuthorityFactory.createDiscoveredInstance(
            authorityUrl,
            this.config.system.networkClient,
            this.storage,
            authorityOptions,
            this.logger,
            requestCorrelationId
        );
    }

    /**
     * Clear the cache
     */
    clearCache(): void {
        this.storage.clear();
    }
}
