/*
 * 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 { SeedDrivenGeneratorParameters } from "@atomist/automation-client/lib/operations/generate/SeedDrivenGeneratorParameters";
import { Project } from "@atomist/automation-client/lib/project/Project";
import { NoParameters } from "@atomist/automation-client/lib/SmartParameters";
import * as _ from "lodash";
import { computeStartingPoint } from "../../api-helper/command/generator/generatorCommand";
import { projectLoaderRepoLoader } from "../../api-helper/machine/projectLoaderRepoLoader";
import { toMachineOptions } from "../../api-helper/machine/toMachineOptions";
import { CachingProjectLoader } from "../../api-helper/project/CachingProjectLoader";
import { CommandListenerInvocation } from "../../api/listener/CommandListener";
import { SoftwareDeliveryMachine } from "../../api/machine/SoftwareDeliveryMachine";
import {
    CodeTransform,
    TransformResult,
    TransformReturnable,
} from "../../api/registration/CodeTransform";
import { GeneratorRegistration } from "../../api/registration/GeneratorRegistration";
import { ParametersObject } from "../../api/registration/ParametersDefinition";
import { toArray } from "../../core/util/misc/array";
import { UniversalTransform } from "./generatorSupport";

/**
 * Wrap provided generator to execute additional transformsAndParameters
 */
export function universalGenerator<P extends SeedDrivenGeneratorParameters = any>(
    sdm: SoftwareDeliveryMachine,
    generator: GeneratorRegistration<any>,
    transforms: Array<UniversalTransform<any>>,
): GeneratorRegistration<P> {
    return {
        ...generator,
        startingPoint: async pi => {
            const repoLoader = (p: SeedDrivenGeneratorParameters) =>
                projectLoaderRepoLoader(
                    sdm.configuration.sdm.projectLoader || new CachingProjectLoader(),
                    p.target.credentials,
                    true,
                );

            const project = await computeStartingPoint(
                pi.parameters as any,
                pi.context,
                repoLoader(pi.parameters as any),
                { ...(generator as any), redirecter: () => undefined },
                generator.startingPoint,
                generator,
                toMachineOptions(sdm),
            );

            const transformsToApply = [];
            for (const transform of transforms) {
                if (!!transform.test) {
                    if (await transform.test(project)) {
                        transformsToApply.push(transform);
                    }
                } else {
                    transformsToApply.push(transform);
                }
            }

            await enhanceWithSpecificParameters(transformsToApply, pi as any);

            // Safe the transformsAndParameters to invoke on the invocation to re-use later
            (pi as any).parameters.__transforms = transformsToApply;
            return project;
        },
        transform: async (p, pi) => {
            const universalTransforms = (pi.parameters as any).__transforms as Array<UniversalTransform<any>>;
            const computedTransforms = _.flatten(universalTransforms.map(t => toArray(t.transforms)));

            const trans = chainTransforms(...toArray(generator.transform || []), ...computedTransforms);
            return trans(p, pi, pi.parameters);
        },
    };
}

/**
 * Enrich parameters with the extras if needed
 */
async function enhanceWithSpecificParameters<P>(
    universalTransforms: Array<UniversalTransform<any>>,
    ctx: CommandListenerInvocation<any>,
): Promise<void> {
    const unsatisfiedParameters: ParametersObject<any> = {};
    for (const universalTransform of universalTransforms) {
        let params: ParametersObject<any>;
        if (typeof universalTransform.parameters === "function") {
            const paramsValues: any = await ctx.promptFor<P>(unsatisfiedParameters);
            params = await universalTransform.parameters({ ...ctx.parameters, ...paramsValues });
        } else {
            params = universalTransform.parameters;
        }
        _.forEach(params, (v, k) => {
            if (ctx.parameters[k] === undefined) {
                unsatisfiedParameters[k] = v;
            }
        });
    }

    const newParams: any = await ctx.promptFor<P>(unsatisfiedParameters);

    for (const name of Object.getOwnPropertyNames(newParams)) {
        ctx.parameters[name] = newParams[name];
    }
}

function chainTransforms<P = NoParameters>(...transforms: Array<CodeTransform<any>>): CodeTransform<P> {
    return async (p, sdmc, params) => {
        let cumulativeResult: TransformResult = {
            target: p,
            success: true,
            edited: false,
        };
        try {
            for (const t of transforms) {
                const lastResult = await t(p, sdmc, params);
                cumulativeResult = combineResults(toTransformResult(p, lastResult), cumulativeResult);
            }
            return cumulativeResult;
        } catch (error) {
            return { target: p, edited: cumulativeResult.edited, success: false, error };
        }
    };
}

function toTransformResult(p: Project, tr: TransformReturnable): TransformResult {
    const maybe = tr as TransformResult;
    if (maybe && maybe.success !== undefined) {
        return maybe;
    } else {
        return { target: p, success: true, edited: undefined };
    }
}

function combineResults(r1: TransformResult, r2: TransformResult): TransformResult {
    return {
        ...r1,
        ...r2,
        edited: r1.edited || r2.edited ? true : r1.edited === false && r2.edited === false ? false : undefined,
        success: r1.success && r2.success,
    };
}