/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0.
 */

/**
 * Module for the configuration of MQTT5 clients to connect to AWS IoT
 *
 * @packageDocumentation
 */

import * as mqtt5 from "./mqtt5";
import * as io from "./io";
import * as auth from "./auth";
import {CrtError} from "./error";
import * as iot_shared from "../common/aws_iot_shared";
import * as http from "./http";
import * as mqtt_shared from "../common/mqtt_shared";

export { MqttConnectCustomAuthConfig } from '../common/aws_iot_shared';

/**
 * Websocket-specific MQTT5 client AWS IoT configuration options
 *
 * @category IoT
 */
export interface WebsocketSigv4Config {

    /**
     * Sources the AWS Credentials used to sign the websocket connection handshake.  If not provided, the
     * default credentials provider chain is used.
     */
    credentialsProvider?: auth.AwsCredentialsProvider;

    /**
     * AWS region the websocket connection is being established in.  Must match the region embedded in the
     * endpoint.  If not provided, pattern-matching logic is used to extract the region from the endpoint.
     * Use this option if the pattern-matching logic has not yet been updated to handle new endpoint formats.
     */
    region?: string;
}

/**
 * Builder pattern class to create an {@link mqtt5.Mqtt5ClientConfig} which can then be used to create
 * an {@link mqtt5.Mqtt5Client}, configured for use with AWS IoT.
 *
 * [MQTT5 Client User Guide](https://www.github.com/awslabs/aws-crt-nodejs/blob/main/MQTT5-UserGuide.md)
 *
 * @category IoT
 */
export class AwsIotMqtt5ClientConfigBuilder {

    private static DEFAULT_WEBSOCKET_MQTT_PORT : number = 443;
    private static DEFAULT_DIRECT_MQTT_PORT : number = 8883;

    private config: mqtt5.Mqtt5ClientConfig;

    private customAuthConfig?: iot_shared.MqttConnectCustomAuthConfig;

    private constructor(hostName : string, port: number, private tlsContextOptions: io.TlsContextOptions) {
        this.config = {
            hostName: hostName,
            port: port,
            connectProperties: {
                keepAliveIntervalSeconds: mqtt_shared.DEFAULT_KEEP_ALIVE
            },
            extendedValidationAndFlowControlOptions: mqtt5.ClientExtendedValidationAndFlowControl.AwsIotCoreDefaults
        };
    }

    /* Builders for different connection methods to AWS IoT Core */

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via mutual TLS
     * using X509 certificate and key at the supplied file paths.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param certPath - Path to certificate, in PEM format
     * @param keyPath - Path to private key, in PEM format
     */
    static newDirectMqttBuilderWithMtlsFromPath(hostName : string, certPath: string, keyPath: string) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_DIRECT_MQTT_PORT,
            io.TlsContextOptions.create_client_with_mtls_from_path(certPath, keyPath));

        if (io.is_alpn_available()) {
            builder.tlsContextOptions.alpn_list.unshift('x-amzn-mqtt-ca');
        }

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via mutual TLS
     * using in-memory X509 certificate and key.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param cert - Certificate, in PEM format
     * @param privateKey - Private key, in PEM format
     */
    static newDirectMqttBuilderWithMtlsFromMemory(hostName : string, cert: string, privateKey: string) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_DIRECT_MQTT_PORT,
            io.TlsContextOptions.create_client_with_mtls(cert, privateKey));

        if (io.is_alpn_available()) {
            builder.tlsContextOptions.alpn_list.unshift('x-amzn-mqtt-ca');
        }

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via mutual TLS
     * using a PKCS11 library for certificate and private key operations.
     *
     * NOTE: This configuration only works on Unix devices.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param pkcs11Options - PKCS#11 options.
     */
    static newDirectMqttBuilderWithMtlsFromPkcs11(hostName : string, pkcs11Options: io.TlsContextOptions.Pkcs11Options) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_DIRECT_MQTT_PORT,
            io.TlsContextOptions.create_client_with_mtls_pkcs11(pkcs11Options));

        if (io.is_alpn_available()) {
            builder.tlsContextOptions.alpn_list.unshift('x-amzn-mqtt-ca');
        }

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via mutual TLS
     * using a PKCS12 file.
     *
     * Note: This configuration only works on MacOS devices.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param pkcs12_options - The PKCS#12 options to use in the builder.
     */
    static newDirectMqttBuilderWithMtlsFromPkcs12(hostName : string, pkcs12_options: io.Pkcs12Options) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_DIRECT_MQTT_PORT,
            io.TlsContextOptions.create_client_with_mtls_pkcs12_from_path(pkcs12_options.pkcs12_file, pkcs12_options.pkcs12_password));

        if (io.is_alpn_available()) {
            builder.tlsContextOptions.alpn_list.unshift('x-amzn-mqtt-ca');
        }

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via mutual TLS
     * using a certificate entry in a Windows certificate store.
     *
     * NOTE: This configuration only works on Windows devices.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param certificatePath - Path to certificate in a Windows certificate store.
     *      The path must use backslashes and end with the certificate's thumbprint.
     *      Example: `CurrentUser\MY\A11F8A9B5DF5B98BA3508FBCA575D09570E0D2C6`
     */
    static newDirectMqttBuilderWithMtlsFromWindowsCertStorePath(hostName : string, certificatePath: string) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_DIRECT_MQTT_PORT,
            io.TlsContextOptions.create_client_with_mtls_windows_cert_store_path(certificatePath));

        if (io.is_alpn_available()) {
            builder.tlsContextOptions.alpn_list.unshift('x-amzn-mqtt-ca');
        }

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via TLS,
     * authenticating via a custom authenticator.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param customAuthConfig - AWS IoT custom auth configuration
     */
    static newDirectMqttBuilderWithCustomAuth(hostName : string, customAuthConfig: iot_shared.MqttConnectCustomAuthConfig) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_WEBSOCKET_MQTT_PORT,
            new io.TlsContextOptions());

        builder.customAuthConfig = iot_shared.canonicalizeCustomAuthConfig(customAuthConfig);
        builder.tlsContextOptions.alpn_list = ["mqtt"];

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via websockets,
     * using AWS Sigv4 signing to establish authenticate.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param options - additional sigv4-oriented options to use
     */
    static newWebsocketMqttBuilderWithSigv4Auth(hostName : string, options?: WebsocketSigv4Config) : AwsIotMqtt5ClientConfigBuilder {
        let tlsContextOptions = new io.TlsContextOptions();
        tlsContextOptions.alpn_list = [];

        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_WEBSOCKET_MQTT_PORT,
            tlsContextOptions);

        let credentialsProvider = options?.credentialsProvider;
        if (!credentialsProvider) {
            credentialsProvider = auth.AwsCredentialsProvider.newDefault();
        }

        builder.config.websocketHandshakeTransform = async (request, done) => {
            try {
                const signingConfig : auth.AwsSigningConfig = {
                    algorithm: auth.AwsSigningAlgorithm.SigV4,
                    signature_type: auth.AwsSignatureType.HttpRequestViaQueryParams,
                    provider: credentialsProvider as auth.AwsCredentialsProvider,
                    region: options?.region ?? iot_shared.extractRegionFromEndpoint(hostName),
                    service: "iotdevicegateway",
                    signed_body_value: auth.AwsSignedBodyValue.EmptySha256,
                    omit_session_token: true,
                };

                await auth.aws_sign_request(request, signingConfig);
                done();
            } catch (error) {
                if (error instanceof CrtError) {
                    done(error.error_code);
                } else {
                    done(3); /* TODO: AWS_ERROR_UNKNOWN */
                }
            }
        };

        return builder;
    }

    /**
     * Create a new MQTT5 client builder that will create MQTT5 clients that connect to AWS IoT Core via websockets,
     * authenticating via a custom authenticator.
     *
     * @param hostName - AWS IoT endpoint to connect to
     * @param customAuthConfig - AWS IoT custom auth configuration
     */
     static newWebsocketMqttBuilderWithCustomAuth(hostName : string, customAuthConfig: iot_shared.MqttConnectCustomAuthConfig) : AwsIotMqtt5ClientConfigBuilder {
        let builder = new AwsIotMqtt5ClientConfigBuilder(
            hostName,
            AwsIotMqtt5ClientConfigBuilder.DEFAULT_WEBSOCKET_MQTT_PORT,
            new io.TlsContextOptions());
        builder.customAuthConfig = customAuthConfig;

        builder.config.websocketHandshakeTransform = async (request, done) => {
            done(0);
        };

        return builder;
    }

    /* Instance Methods for various config overrides */

    /**
     * Overrides the default system trust store.
     *
     * @param caDirpath - Only used on Unix-style systems where all trust anchors are
     * stored in a directory (e.g. /etc/ssl/certs).
     * @param caFilepath - Single file containing all trust CAs, in PEM format
     */
    withCertificateAuthorityFromPath(caDirpath?: string, caFilepath?: string) : AwsIotMqtt5ClientConfigBuilder {
        this.tlsContextOptions.override_default_trust_store_from_path(caDirpath, caFilepath);
        return this;
    }

    /**
     * Overrides the default system trust store.
     *
     * @param ca - Buffer containing all trust CAs, in PEM format
     */
    withCertificateAuthority(ca: string) : AwsIotMqtt5ClientConfigBuilder {
        this.tlsContextOptions.override_default_trust_store(ca);
        return this;
    }

    /**
     * Configures which TLS cipher preference should be used when establishing connections
     *
     * @param tlsCipherPreference cipher preference to use
     */
    withTlsCipherPreference(tlsCipherPreference: io.TlsCipherPreference) : AwsIotMqtt5ClientConfigBuilder {
        this.tlsContextOptions.tls_cipher_preference = tlsCipherPreference;
        return this;
    }

    /**
     * Overrides the IoT endpoint port to connect to.
     *
     * @param port The IoT endpoint port to connect to. Usually 8883 for MQTT, or 443 for websockets
     */
    withPort(port: number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.port = port;
        return this;
    }

    /**
     * Overrides all configurable options with respect to the CONNECT packet sent by the client, including the will.
     * These connect properties will be used for every connection attempt made by the client.  Custom authentication
     * configuration will override the username and password values in this configuration.
     *
     * @param connectPacket all configurable options with respect to the CONNECT packet sent by the client
     */
    withConnectProperties(connectPacket: mqtt5.ConnectPacket) : AwsIotMqtt5ClientConfigBuilder {
        this.config.connectProperties = connectPacket;
        return this;
    }

    /**
     * Overrides how the MQTT5 client should behave with respect to MQTT sessions.
     *
     * @param sessionBehavior how the MQTT5 client should behave with respect to MQTT sessions.
     */
    withSessionBehavior(sessionBehavior: mqtt5.ClientSessionBehavior) : AwsIotMqtt5ClientConfigBuilder {
        this.config.sessionBehavior = sessionBehavior;
        return this;
    }

    /**
     * Overrides how the reconnect delay is modified in order to smooth out the distribution of reconnection attempt
     * timepoints for a large set of reconnecting clients.
     *
     * @param retryJitterMode controls how the reconnect delay is modified in order to smooth out the distribution of
     * econnection attempt timepoints for a large set of reconnecting clients.
     */
    withRetryJitterMode(retryJitterMode: mqtt5.RetryJitterType) : AwsIotMqtt5ClientConfigBuilder {
        this.config.retryJitterMode = retryJitterMode;
        return this;
    }

    /**
     * Overrides the minimum amount of time to wait to reconnect after a disconnect.  Exponential backoff is performed
     * with controllable jitter after each connection failure.
     *
     * @param minReconnectDelayMs minimum amount of time to wait to reconnect after a disconnect.
     */
    withMinReconnectDelayMs(minReconnectDelayMs? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.minReconnectDelayMs = minReconnectDelayMs;
        return this;
    }

    /**
     * Overrides the maximum amount of time to wait to reconnect after a disconnect.  Exponential backoff is performed
     * with controllable jitter after each connection failure.
     *
     * @param maxReconnectDelayMs maximum amount of time to wait to reconnect after a disconnect.
     */
    withMaxReconnectDelayMs(maxReconnectDelayMs? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.maxReconnectDelayMs = maxReconnectDelayMs;
        return this;
    }

    /**
     * Overrides the amount of time that must elapse with an established connection before the reconnect delay is
     * reset to the minimum.  This helps alleviate bandwidth-waste in fast reconnect cycles due to permission
     * failures on operations.
     *
     * @param minConnectedTimeToResetReconnectDelayMs the amount of time that must elapse with an established
     * connection before the reconnect delay is reset to the minimum
     */
    withMinConnectedTimeToResetReconnectDelayMs(minConnectedTimeToResetReconnectDelayMs? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.minConnectedTimeToResetReconnectDelayMs = minConnectedTimeToResetReconnectDelayMs;
        return this;
    }

    /**
     * Overrides the time interval to wait after sending a CONNECT request for a CONNACK to arrive.  If one does not
     * arrive, the connection will be shut down.
     *
     * @param connackTimeoutMs time interval to wait after sending a CONNECT request for a CONNACK to arrive
     */
    withConnackTimeoutMs(connackTimeoutMs? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.connackTimeoutMs = connackTimeoutMs;
        return this;
    }

    /**
     * Overrides how disconnects affect the queued and in-progress operations tracked by the client.  Also controls
     * how new operations are handled while the client is not connected.  In particular, if the client is not connected,
     * then any operation that would be failed on disconnect (according to these rules) will also be rejected.
     *
     * @param offlineQueueBehavior how disconnects affect the queued and in-progress operations tracked by the client
     *
     * @group Node-only
     */
    withOfflineQueueBehavior(offlineQueueBehavior: mqtt5.ClientOperationQueueBehavior) : AwsIotMqtt5ClientConfigBuilder {
        this.config.offlineQueueBehavior = offlineQueueBehavior;
        return this;
    }

    /**
     * Overrides the time interval to wait after sending a PINGREQ for a PINGRESP to arrive.  If one does not arrive,
     * the client will close the current connection.
     *
     * @param pingTimeoutMs time interval to wait after sending a PINGREQ for a PINGRESP to arrive
     *
     * @group Node-only
     */
    withPingTimeoutMs(pingTimeoutMs? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.pingTimeoutMs = pingTimeoutMs;
        return this;
    }

    /**
     * Overrides the time interval to wait for an ack after sending a QoS 1+ PUBLISH, SUBSCRIBE, or UNSUBSCRIBE before
     * failing the operation.  Defaults to no timeout.
     *
     * @param ackTimeoutSeconds the time interval to wait for an ack after sending a QoS 1+ PUBLISH, SUBSCRIBE,
     * or UNSUBSCRIBE before failing the operation
     *
     * @group Node-only
     */
    withAckTimeoutSeconds(ackTimeoutSeconds? : number) : AwsIotMqtt5ClientConfigBuilder {
        this.config.ackTimeoutSeconds = ackTimeoutSeconds;
        return this;
    }

    /**
     * Overrides the socket properties of the underlying MQTT connections made by the client.  Leave undefined to use
     * defaults (no TCP keep alive, 10 second socket timeout).
     *
     * @param socketOptions socket properties of the underlying MQTT connections made by the client
     *
     * @group Node-only
     */
    withSocketOptions(socketOptions: io.SocketOptions) : AwsIotMqtt5ClientConfigBuilder {
        this.config.socketOptions = socketOptions;
        return this;
    }

    /**
     * Overrides (tunneling) HTTP proxy usage when establishing MQTT connections.
     *
     * @param httpProxyOptions HTTP proxy options to use when establishing MQTT connections
     *
     * @group Node-only
     */
    withHttpProxyOptions(httpProxyOptions: http.HttpProxyOptions) : AwsIotMqtt5ClientConfigBuilder {
        this.config.httpProxyOptions = httpProxyOptions;
        return this;
    }

    /**
     * Overrides additional controls for client behavior with respect to operation validation and flow control; these
     * checks go beyond the base MQTT5 spec to respect limits of specific MQTT brokers.
     *
     * @param extendedValidationAndFlowControlOptions additional controls for client behavior with respect to operation
     * validation and flow control
     *
     * @group Node-only
     */
    withExtendedValidationAndFlowControlOptions(extendedValidationAndFlowControlOptions: mqtt5.ClientExtendedValidationAndFlowControl) : AwsIotMqtt5ClientConfigBuilder {
        this.config.extendedValidationAndFlowControlOptions = extendedValidationAndFlowControlOptions;
        return this;
    }

    /**
     * Overrides how the MQTT5 client should behave with respect to topic aliasing
     *
     * @param topicAliasingOptions how the MQTT5 client should behave with respect to topic aliasing
     */
    withTopicAliasingOptions(topicAliasingOptions: mqtt5.TopicAliasingOptions) : AwsIotMqtt5ClientConfigBuilder {
        this.config.topicAliasingOptions = topicAliasingOptions;
        return this;
    }

    /**
     * Constructs an MQTT5 Client configuration object for creating mqtt5 clients.
     */
    build() : mqtt5.Mqtt5ClientConfig {
        if (this.config.tlsCtx === undefined) {
            this.config.tlsCtx = new io.ClientTlsContext(this.tlsContextOptions);
        }

        // this is always set by the constructor, but check it to make typescript happy
        if (this.config.connectProperties) {
            this.config.connectProperties.username = iot_shared.buildMqtt5FinalUsername(this.customAuthConfig);
            if (this.customAuthConfig?.password) {
                this.config.connectProperties.password = this.customAuthConfig?.password;
            }
        }

        return this.config;
    }
}