/*
 * 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 { configurationValue } from "@atomist/automation-client/lib/configuration";
import * as GraphQL from "@atomist/automation-client/lib/graph/graphQL";
import { EventFired } from "@atomist/automation-client/lib/HandleEvent";
import { HandlerContext } from "@atomist/automation-client/lib/HandlerContext";
import { HandlerResult, reduceResults } from "@atomist/automation-client/lib/HandlerResult";
import { OnEvent } from "@atomist/automation-client/lib/onEvent";
import { logger } from "@atomist/automation-client/lib/util/logger";
import * as stringify from "json-stringify-safe";
import { updateGoal, UpdateSdmGoalParams } from "../../../api-helper/goal/storeGoals";
import { LoggingProgressLog } from "../../../api-helper/log/LoggingProgressLog";
import { WriteToAllProgressLog } from "../../../api-helper/log/WriteToAllProgressLog";
import { ExecuteGoalResult } from "../../../api/goal/ExecuteGoalResult";
import { SdmGoalEvent } from "../../../api/goal/SdmGoalEvent";
import { EventHandlerRegistration } from "../../../api/registration/EventHandlerRegistration";
import { ProgressLog, ProgressLogFactory } from "../../../spi/log/ProgressLog";
import { KubernetesDeployRequestedSdmGoal, SdmGoalState } from "../../../typings/types";
import { executeKubernetesDeployFulfill } from "../deploy/fulfiller";

/**
 * Event handler for deploying an application to a Kubernetes cluster.
 * The definition of the application to be deployed is handled by the
 * [[KubernetesDeploy]] goal of this or another SDM.  This SDM will
 * execute deployments configured for it, see [[eligibleDeployGoal]]
 * and [[verifyKubernetesApplicationDeploy]] for details.
 */
export const HandleKubernetesDeploy: OnEvent<KubernetesDeployRequestedSdmGoal.Subscription> = async (
    ef: EventFired<KubernetesDeployRequestedSdmGoal.Subscription>,
    context: HandlerContext,
): Promise<HandlerResult> => {
    if (!ef || !ef.data || !ef.data.SdmGoal) {
        const message = "Received event had no SdmGoal";
        logger.warn(message);
        return { code: 0, message };
    }
    const logFactory = configurationValue<ProgressLogFactory>("sdm.logFactory");

    return Promise.all(
        ef.data.SdmGoal.map(async g => {
            const goalEvent = g as SdmGoalEvent;
            const progressLog = new WriteToAllProgressLog(
                goalEvent.name,
                new LoggingProgressLog(goalEvent.name, "debug"),
                await logFactory(context, goalEvent),
            );
            try {
                const result = await executeKubernetesDeployFulfill({ context, goalEvent, progressLog });

                const updateParams: UpdateSdmGoalParams = {
                    state: result.code ? SdmGoalState.failure : SdmGoalState.success,
                    description: result.description,
                    error: result.code ? new Error(result.message) : undefined,
                    externalUrls: result.externalUrls,
                };
                try {
                    await updateGoal(context, goalEvent, updateParams);
                } catch (e) {
                    const msg = `Failed to update SDM goal ${goalEventString(goalEvent)} with params '${stringify(
                        updateParams,
                    )}': ${e.message}`;
                    progressLog.write(msg);
                    result.message = `${e.message}; ${msg}`;
                }
                if (!result.code) {
                    result.code = 0;
                }
                return result as ExecuteGoalResult & HandlerResult;
            } catch (e) {
                return failGoal(context, goalEvent, e.message, progressLog);
            }
        }),
    ).then(reduceResults);
};

/**
 * Create an event handler registration for this SDM to deploy
 * requested Kubernetes applications.
 */
export function kubernetesDeployHandler(
    self: string,
): EventHandlerRegistration<KubernetesDeployRequestedSdmGoal.Subscription> {
    return {
        name: "KubernetesDeploy",
        description: "Deploy application resources to Kubernetes cluster",
        tags: ["deploy", "kubernetes"],
        subscription: GraphQL.subscription({
            name: "KubernetesDeployRequestedSdmGoal",
            variables: { fulfillmentName: self },
        }),
        listener: HandleKubernetesDeploy,
    };
}

/**
 * Fail the provided goal using the message to set the description and
 * error message.
 *
 * @param context handler context to use to send the update
 * @param goalEvent SDM goal to update
 * @param message informative error message
 * @return a failure handler result using the provided error message
 */
async function failGoal(
    context: HandlerContext,
    goalEvent: SdmGoalEvent,
    message: string,
    log: ProgressLog,
): Promise<HandlerResult> {
    log.write(message);
    const params: UpdateSdmGoalParams = {
        state: SdmGoalState.failure,
        description: message,
        error: new Error(message),
    };
    try {
        await updateGoal(context, goalEvent, params);
    } catch (e) {
        const msg = `Failed to update SDM goal '${goalEventString(goalEvent)}' with params '${stringify(params)}': ${
            e.message
        }`;
        log.write(msg);
        return { code: 2, message: `${message}; ${msg}` };
    }
    return { code: 1, message };
}

/** Unique string for goal event. */
function goalEventString(goalEvent: SdmGoalEvent): string {
    return `${goalEvent.goalSetId}/${goalEvent.uniqueName}`;
}