/*
 * Copyright © 2020 Atomist, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
    Configuration,
    ConfigurationPostProcessor,
} from "@atomist/automation-client/lib/configuration";
import { guid } from "@atomist/automation-client/lib/internal/util/string";
import { logger } from "@atomist/automation-client/lib/util/logger";
import * as _ from "lodash";
import {
    ConfigurationValues,
    validateConfigurationValues,
} from "../../api/machine/ConfigurationValues";
import { SoftwareDeliveryMachine } from "../../api/machine/SoftwareDeliveryMachine";
import { SoftwareDeliveryMachineConfiguration } from "../../api/machine/SoftwareDeliveryMachineOptions";
import { FulfillGoalOnRequested } from "../handlers/events/delivery/goals/FulfillGoalOnRequested";
import {
    GoalExecutionAutomationEventListener,
    GoalExecutionRequestProcessor,
} from "../handlers/events/delivery/goals/goalExecution";
import { CacheCleanupAutomationEventListener } from "../handlers/events/delivery/goals/k8s/CacheCleanupAutomationEventListener";
import {
    EventSigningAutomationEventListener,
    wrapEventHandlersToVerifySignature,
} from "../signing/eventSigning";
import { GoalSigningAutomationEventListener } from "../signing/goalSigning";
import { toArray } from "../util/misc/array";
import { SdmGoalMetricReportingAutomationEventListener } from "../util/SdmGoalMetricReportingAutomationEventListener";
import {
    sdmExtensionPackStartupMessage,
    sdmStartupMessage,
} from "../util/startupMessage";
import { defaultSoftwareDeliveryMachineConfiguration } from "./defaultSoftwareDeliveryMachineConfiguration";
import { InvokeSdmStartupListenersAutomationEventListener } from "./InvokeSdmStartupListenersAutomationEventListener";
import { LocalSoftwareDeliveryMachineConfiguration } from "./LocalSoftwareDeliveryMachineOptions";
import {
    isGitHubAction,
    isInLocalMode,
} from "./modes";

/**
 * Options passed to the set up of the SDM.
 */
// tslint:disable-next-line:no-empty-interface
export interface ConfigureOptions extends ConfigurationValues {
    // Empty for future extensibility
}

/**
 * Type that can create a fully configured SDM
 */
export type SoftwareDeliveryMachineMaker =
    (configuration: LocalSoftwareDeliveryMachineConfiguration) => SoftwareDeliveryMachine | Promise<SoftwareDeliveryMachine>;

/**
 * Configure and set up a Software Delivery Machine instance with the automation-client framework for standalone
 * or single goal based execution
 * @param {(configuration: (Configuration & SoftwareDeliveryMachineOptions)) => SoftwareDeliveryMachine} machineMaker
 * @param {ConfigureOptions} options
 * @returns {ConfigurationPostProcessor}
 */
export function configureSdm(machineMaker: SoftwareDeliveryMachineMaker,
                             options: ConfigureOptions = {}): ConfigurationPostProcessor<LocalSoftwareDeliveryMachineConfiguration> {

    return async (config: Configuration) => {
        let mergedConfig = config as LocalSoftwareDeliveryMachineConfiguration;

        // Configure the local SDM
        mergedConfig = await doWithSdmLocal<LocalSoftwareDeliveryMachineConfiguration>(local => {
            return local.configureLocal()(mergedConfig);
        }) || mergedConfig;

        const defaultSdmConfiguration = defaultSoftwareDeliveryMachineConfiguration(config);
        mergedConfig = _.merge(defaultSdmConfiguration, mergedConfig);

        validateConfigurationValues(mergedConfig, options);
        const sdm = await machineMaker(mergedConfig);

        await doWithSdmLocal<void>(local =>
            sdm.addExtensionPacks(local.LocalLifecycle, local.LocalSdmConfig),
        );

        // Configure the job forking ability
        await configureJobLaunching(mergedConfig, sdm);
        configureGoalSigning(mergedConfig);
        configureEventSigning(mergedConfig);
        
        await registerMetadata(mergedConfig, sdm);

        // Register startup message detail
        _.update(mergedConfig, "logging.banner.contributors",
            old => !!old ? old : []);
        mergedConfig.logging.banner.contributors.push(
            sdmStartupMessage(sdm),
            sdmExtensionPackStartupMessage(sdm));

        _.update(mergedConfig, "listeners",
            old => !!old ? old : []);
        mergedConfig.listeners.push(
            new InvokeSdmStartupListenersAutomationEventListener(sdm),
            new SdmGoalMetricReportingAutomationEventListener());

        return mergedConfig;
    };
}

/**
 * Configure how this SDM is going to handle goals
 * @param mergedConfig
 * @param machine
 */
async function configureJobLaunching(mergedConfig: SoftwareDeliveryMachineConfiguration,
                                     machine: SoftwareDeliveryMachine): Promise<void> {
    const forked = process.env.ATOMIST_ISOLATED_GOAL === "true";
    if (forked) {
        configureSdmToRunExactlyOneGoal(mergedConfig, machine);
    } else {
        // initialize the GoalSchedulers
        for (const goalScheduler of toArray(mergedConfig.sdm.goalScheduler || [])) {
            if (!!goalScheduler.initialize) {
                await goalScheduler.initialize(mergedConfig);
            }
        }

        _.update(mergedConfig, "commands",
            old => !!old ? old : []);
        mergedConfig.commands.push(...machine.commandHandlers);

        _.update(mergedConfig, "events",
            old => !!old ? old : []);
        mergedConfig.events.push(...machine.eventHandlers);

        _.update(mergedConfig, "ingesters",
            old => !!old ? old : []);
        mergedConfig.ingesters.push(...machine.ingesters);
    }
}

/**
 * Configure SDM to run only one goal
 * @param mergedConfig
 * @param sdm
 */
function configureSdmToRunExactlyOneGoal(mergedConfig: SoftwareDeliveryMachineConfiguration,
                                         sdm: SoftwareDeliveryMachine): void {
    if (process.env.ATOMIST_JOB_NAME) {
        mergedConfig.name = process.env.ATOMIST_REGISTRATION_NAME;
    } else {
        mergedConfig.name = `${mergedConfig.name}-${process.env.ATOMIST_GOAL_ID || guid()}`;
    }

    // Force ephemeral policy and no handlers or ingesters
    mergedConfig.policy = "ephemeral";
    mergedConfig.commands = [];
    mergedConfig.events = [
        () => new FulfillGoalOnRequested(
            sdm.goalFulfillmentMapper,
            [...sdm.goalExecutionListeners])];
    mergedConfig.ingesters = [];
    mergedConfig.ws.enabled = false;
    mergedConfig.cluster.enabled = false;

    mergedConfig.listeners.push(
        new GoalExecutionAutomationEventListener(sdm),
        new CacheCleanupAutomationEventListener(sdm));
    mergedConfig.requestProcessorFactory =
        (automations, cfg, listeners) => new GoalExecutionRequestProcessor(automations, cfg, listeners);
}

/**
 * Configure SDM to sign and verify goals
 * @param mergedConfig
 */
function configureGoalSigning(mergedConfig: SoftwareDeliveryMachineConfiguration): void {
    if (!!mergedConfig.sdm.goalSigning && mergedConfig.sdm.goalSigning.enabled === true) {
        _.update(mergedConfig, "graphql.listeners",
            old => !!old ? old : []);
        mergedConfig.graphql.listeners.push(
            new GoalSigningAutomationEventListener(mergedConfig.sdm.goalSigning));
    }
}

/**
 * Configure SDM to sign and verify events
 * @param mergedConfig
 */
function configureEventSigning(mergedConfig: SoftwareDeliveryMachineConfiguration): void {
    if (mergedConfig.sdm?.eventSigning?.enabled === true) {
        _.update(mergedConfig, "graphql.listeners",
            old => !!old ? old : []);
        mergedConfig.graphql.listeners.push(
            new EventSigningAutomationEventListener(mergedConfig.sdm.eventSigning));
        mergedConfig.events = wrapEventHandlersToVerifySignature(
            mergedConfig.events || [], mergedConfig.sdm.eventSigning);
    }
}

async function registerMetadata(config: Configuration,
                                machine: SoftwareDeliveryMachine): Promise<void> {
    // tslint:disable-next-line:no-implicit-dependencies
    const sdmPj = require("@atomist/sdm/package.json");

    config.metadata = {
        ...config.metadata,
        "atomist.sdm": `${sdmPj.name}:${sdmPj.version}`,
        "atomist.sdm.name": machine.name,
        "atomist.sdm.extension-packs": machine.extensionPacks.map(ex => `${ex.name}:${ex.version}`).join(", "),
    };

    config.sdm.name = machine.name;

    await doWithSdmLocal(() => {
        // tslint:disable-next-line:no-implicit-dependencies
        const sdmLocalPj = require("@atomist/sdm-local/package.json");
        config.metadata["atomist.sdm-local"] = `${sdmLocalPj.name}:${sdmLocalPj.version}`;
    });
}

/**
 * Perform the given operation with the sdm-local module if it's available.
 * If it isn't, silently continue without error.
 * @param {(sdmLocal: any) => any} callback
 * @return {any}
 */
async function doWithSdmLocal<R>(callback: (sdmLocal: any) => any): Promise<R | undefined> {
    if (isInLocalMode() || isGitHubAction()) {
        // tslint:disable-next-line:no-implicit-dependencies
        const local = attemptToRequire("@atomist/sdm-local", !process.env.ATOMIST_NPM_LOCAL_LINK);
        if (local) {
            return callback(local) as R;
        } else {
            logger.warn("Skipping local mode configuration because 'ATOMIST_NPM_LOCAL_LINK' was defined, " +
                "but '@atomist/sdm-local' could not be loaded");
            return undefined;
        }
    }
    return undefined;
}

/**
 * Attempt to NPM require module
 * @param module
 * @param failOnError
 */
function attemptToRequire<T = any>(module: string, failOnError: boolean): T | null {
    try {
        return require(module) as T;
    } catch (err) {
        if (failOnError) {
            throw new Error(`Unable to load '${module}'. Please install with 'npm install ${module}'.`);
        } else {
            return undefined;
        }
    }

}