/*
 * 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 { SourceLocation } from "@atomist/automation-client/lib/operations/common/SourceLocation";
import { ProjectReview, ReviewComment, Severity } from "@atomist/automation-client/lib/operations/review/ReviewResult";
import { isLocalProject } from "@atomist/automation-client/lib/project/local/LocalProject";
import { Project } from "@atomist/automation-client/lib/project/Project";
import { NoParameters } from "@atomist/automation-client/lib/SmartParameters";
import { logger } from "@atomist/automation-client/lib/util/logger";
import * as appRoot from "app-root-path";
import * as path from "path";
import { execPromise } from "../../../api-helper/misc/child_process";
import { AutoInspectRegistration } from "../../../api/registration/AutoInspectRegistration";
import { CodeInspection, CodeInspectionRegistration } from "../../../api/registration/CodeInspectionRegistration";
import { IsTypeScript } from "../pushtest/tsPushTests";

export interface TslintPosition {
    character: number;
    line: number;
    position: number;
}

export interface TslintFix {
    innerStart: number;
    innerLength: number;
    innerText: string;
}

/**
 * Manually created interface representing the JSON output of the
 * tslint command-line utility.
 */
export interface TslintResult {
    endPosition: TslintPosition;
    failure: string;
    fix: TslintFix | TslintFix[];
    name: string;
    ruleName: string;
    ruleSeverity: "ERROR" | "WARNING";
    startPosition: TslintPosition;
}

export type TslintResults = TslintResult[];

export const tsLintReviewCategory = "Tslint";

/**
 * Return a review comment for a TSLint violation.
 */
function tslintReviewComment(
    detail: string,
    rule: string,
    severity: Severity = "info",
    sourceLocation?: SourceLocation,
): ReviewComment {
    return {
        category: tsLintReviewCategory,
        detail,
        severity,
        sourceLocation,
        subcategory: rule,
    };
}

/**
 * Convert the JSON output of TSLint to proper ReviewComments.  If any
 * part of the process fails, an empty array is returned.
 *
 * @param tslintOutput string output from running `tslint` that will be parsed and converted.
 * @return TSLint errors and warnings as ReviewComments
 */
export function mapTslintResultsToReviewComments(tslintOutput: string, dir: string): ReviewComment[] {
    let results: TslintResults;
    try {
        results = JSON.parse(tslintOutput);
    } catch (e) {
        logger.error(`Failed to parse TSLint output '${tslintOutput}': ${e.message}`);
        return [];
    }

    const comments = results.map(r => {
        const location: SourceLocation = {
            path: r.name.replace(dir + path.sep, ""),
            offset: r.startPosition.position,
            columnFrom1: r.startPosition.character + 1,
            lineFrom1: r.startPosition.line + 1,
        };
        const severity = r.ruleSeverity === "ERROR" ? "error" : "warn";
        return tslintReviewComment(r.failure, r.ruleName, severity, location);
    });
    return comments;
}

/**
 * Run TSLint on a project with a tslint.json file, using the standard
 * version of TSLint and its configuration, i.e., the ones in this
 * project.  At most 20 TSLint violations are returned, since they are
 * used to create a GitHub issue and if the body of that POST is too
 * large, it is rejected.
 */
export const RunTslintOnProject: CodeInspection<ProjectReview, NoParameters> = async (p: Project) => {
    const review: ProjectReview = { repoId: p.id, comments: [] };
    const tslintJson = "tslint.json";
    const tslintConfigFile = await p.getFile(tslintJson);
    if (!tslintConfigFile) {
        return review;
    }
    const baseDir = appRoot.path;
    const tslintExe = path.join(baseDir, "node_modules", ".bin", "tslint");
    const tslintConfig = path.join(baseDir, tslintJson);

    if (!isLocalProject(p)) {
        logger.error(`Project ${p.name} is not a local project`);
        return review;
    }
    const cwd = p.baseDir;
    logger.debug(`Running ${tslintExe} using ${tslintConfig} on ${p.name} in ${cwd}`);
    const tslintArgs = ["--config", tslintConfig, "--format", "json", "--project", cwd, "--force"];
    try {
        const tslintResult = await execPromise(tslintExe, tslintArgs, { cwd });
        if (tslintResult.stderr) {
            logger.debug(`TSLint standard error from ${p.name}: ${tslintResult.stderr}`);
        }
        const comments = mapTslintResultsToReviewComments(tslintResult.stdout, p.baseDir);
        review.comments.push(...comments);
    } catch (e) {
        logger.error(`Failed to run TSLint: ${e.message}`);
    }

    return review;
};

/**
 * Provide a code inspection that runs TSLint and returns a
 * ProjectReview.
 */
export const TslintInspection: CodeInspectionRegistration<ProjectReview, NoParameters> = {
    name: "RunTSLint",
    description: "Run TSLint on project",
    inspection: RunTslintOnProject,
    intent: "ts lint",
};

/**
 * Provide an auto inspect registration that runs TSLint and returns a
 * ProjectReview.
 */
export const TslintAutoInspectRegistration: AutoInspectRegistration<ProjectReview, NoParameters> = {
    name: "TSLintAutoInspection",
    inspection: RunTslintOnProject,
    pushTest: IsTypeScript,
};