// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for details.

import { ISpawnResult } from "./node/childProcess";
import { ErrorHelper } from "./error/errorHelper";
import { InternalErrorCode } from "./error/internalErrorCode";
import { InternalError } from "./error/internalError";

export interface PatternToFailure {
    pattern: string | RegExp;
    errorCode: number;
}

/* This class transforms a spawn process to only succeed if all defined success patterns
   are found on stdout, and none of the failure patterns were found on stderr */
export class OutputVerifier {
    private generatePatternsForSuccess: () => Promise<string[]>;
    private generatePatternToFailure: () => Promise<PatternToFailure[]>;
    private platformName: string;

    private output = "";
    private errors = "";

    constructor(
        generatePatternsForSuccess: () => Promise<string[]>,
        generatePatternToFailure: () => Promise<PatternToFailure[]>,
        platformName: string,
    ) {
        this.generatePatternsForSuccess = generatePatternsForSuccess;
        this.generatePatternToFailure = generatePatternToFailure;
        this.platformName = platformName;
    }

    public async process(spawnResult: ISpawnResult): Promise<void> {
        // Store all output
        this.store(spawnResult.stdout, newContent => (this.output += newContent));
        this.store(spawnResult.stderr, newContent => (this.errors += newContent));

        let processError: InternalError | undefined;

        try {
            await spawnResult.outcome;
        } catch (error) {
            processError = error;
        }

        const failurePatterns = await this.generatePatternToFailure();
        const patternsError = this.findAnyFailurePattern(failurePatterns);
        if (patternsError) {
            if (processError) {
                processError.message += "\n" + patternsError.message;
                throw processError;
            }
            throw patternsError;
        } else if (processError) {
            throw processError;
        } else {
            const successPatterns = await this.generatePatternsForSuccess(); // If not, we generate the success patterns
            if (!this.areAllSuccessPatternsPresent(successPatterns)) {
                // If we don't find all the success patterns, we also fail
                throw ErrorHelper.getInternalError(
                    InternalErrorCode.NotAllSuccessPatternsMatched,
                    this.platformName,
                    this.platformName,
                );
            } // else we found all the success patterns, so we succeed
        }
    }

    private store(stream: NodeJS.ReadableStream, append: (newContent: string) => void) {
        stream.on("data", (data: Buffer) => {
            append(data.toString());
        });
    }

    // We check the failure patterns one by one, to see if any of those appeared on the errors. If they did, we return the associated error
    private findAnyFailurePattern(patterns: PatternToFailure[]): InternalError | null {
        const errorsAndOutput = this.errors + this.output;
        let matches: RegExpMatchArray | null | undefined;
        const patternThatAppeared = patterns.find(pattern => {
            if (pattern.pattern instanceof RegExp) {
                matches = errorsAndOutput.match(pattern.pattern);
                return matches && matches.length;
            } else {
                return errorsAndOutput.indexOf(pattern.pattern as string) !== -1;
            }
        });

        const errorCode = patternThatAppeared ? patternThatAppeared.errorCode : null;

        if (errorCode) {
            if (matches && matches.length) {
                matches = matches.map(value => value.trim());
                return ErrorHelper.getInternalError(errorCode, matches.join("\n"));
            } else {
                return ErrorHelper.getInternalError(errorCode);
            }
        }
        return null;
    }

    // We check that all the patterns appeared on the output
    private areAllSuccessPatternsPresent(successPatterns: string[]): boolean {
        return successPatterns.every(pattern => {
            let patternRe = new RegExp(pattern, "i");
            return patternRe.test(this.output);
        });
    }
}
