// tslint:disable no-flag-args max-func-args
import * as Lint from 'tslint';
import * as fs from 'fs';
import * as chai from 'chai';
import * as ts from 'typescript';
import { ErrorTolerantWalker } from '../utils/ErrorTolerantWalker';

/**
 * Test Utilities.
 */
export namespace TestHelper {
    let program: ts.Program;

    /* tslint:disable:prefer-const */
    /**
     * This setting must point to your rule .js files. 3rd party libraries may reuse this class and change value.
     */
    export let RULES_DIRECTORY: string = 'dist/src/';

    /**
     * This setting must point to your formatter .js files. 3rd party libraries may reuse this class and change value.
     */
    export let FORMATTER_DIRECTORY: string = 'customFormatters/';

    /**
     * You must specify an encoding for file read/writes. 3rd party libraries may reuse this class and change value.
     */
    export let FILE_ENCODING: string = 'utf8';
    /* tslint:enable:prefer-const */

    export interface FailurePosition {
        character: number;
        line: number;
        position?: number;
    }
    export interface ExpectedFailure {
        ruleName: string;
        name: string;
        failure?: string;
        ruleSeverity?: string;
        endPosition?: FailurePosition;
        startPosition: FailurePosition;
    }

    export function assertNoViolation(ruleName: string, inputFileOrScript: string, useTypeChecker: boolean = false) {
        runRuleAndEnforceAssertions(ruleName, null, inputFileOrScript, [], useTypeChecker);
    }
    export function assertNoViolationWithOptions(
        ruleName: string,
        options: any[],
        inputFileOrScript: string,
        useTypeChecker: boolean = false
    ) {
        runRuleAndEnforceAssertions(ruleName, options, inputFileOrScript, [], useTypeChecker);
    }
    export function assertViolationsWithOptions(
        ruleName: string,
        options: any[],
        inputFileOrScript: string,
        expectedFailures: ExpectedFailure[],
        useTypeChecker: boolean = false
    ) {
        runRuleAndEnforceAssertions(ruleName, options, inputFileOrScript, expectedFailures, useTypeChecker);
    }
    export function assertViolations(
        ruleName: string,
        inputFileOrScript: string,
        expectedFailures: ExpectedFailure[],
        useTypeChecker: boolean = false
    ) {
        runRuleAndEnforceAssertions(ruleName, null, inputFileOrScript, expectedFailures, useTypeChecker);
    }
    export function assertViolationsWithTypeChecker(ruleName: string, inputFileOrScript: string, expectedFailures: ExpectedFailure[]) {
        runRuleAndEnforceAssertions(ruleName, null, inputFileOrScript, expectedFailures, true);
    }

    export function runRule(
        ruleName: string,
        userOptions: string[],
        inputFileOrScript: string,
        useTypeChecker: boolean = false
    ): Lint.LintResult {
        const configuration: Lint.Configuration.IConfigurationFile = {
            extends: [],
            jsRules: new Map<string, Partial<Lint.IOptions>>(),
            linterOptions: {},
            rules: new Map<string, Partial<Lint.IOptions>>(),
            rulesDirectory: [],
        };

        if (userOptions != null && userOptions.length > 0) {
            //options like `[4, 'something', false]` were passed, so prepend `true` to make the array like `[true, 4, 'something', false]`
            configuration.rules.set(ruleName, {
                ruleName,
                ruleArguments: userOptions,
            });
        } else {
            configuration.rules.set(ruleName, {
                ruleName,
            });
        }

        const options: Lint.ILinterOptions = {
            formatter: 'json',
            fix: false,
            rulesDirectory: RULES_DIRECTORY,
            formattersDirectory: FORMATTER_DIRECTORY,
        };

        const debug: boolean = ErrorTolerantWalker.DEBUG;
        ErrorTolerantWalker.DEBUG = true; // never fail silently
        let result: Lint.LintResult;
        if (useTypeChecker) {
            //program = Lint.Linter.createProgram([ ], './dist/test-data');
            program = ts.createProgram([inputFileOrScript], {});
        }
        if (inputFileOrScript.match(/.*\.ts(x)?$/)) {
            const contents = fs.readFileSync(inputFileOrScript, FILE_ENCODING);
            const linter = new Lint.Linter(options, useTypeChecker ? program : undefined);
            linter.lint(inputFileOrScript, contents, configuration);
            result = linter.getResult();
        } else {
            let filename: string;
            if (inputFileOrScript.indexOf('import React') > -1) {
                filename = 'file.tsx';
            } else {
                filename = 'file.ts';
            }

            const linter = new Lint.Linter(options, useTypeChecker ? program : undefined);
            linter.lint(filename, inputFileOrScript, configuration);
            result = linter.getResult();
        }
        ErrorTolerantWalker.DEBUG = debug;
        return result;
    }

    function runRuleAndEnforceAssertions(
        ruleName: string,
        userOptions: string[],
        inputFileOrScript: string,
        expectedFailures: ExpectedFailure[],
        useTypeChecker: boolean = false
    ) {
        const lintResult: Lint.LintResult = runRule(ruleName, userOptions, inputFileOrScript, useTypeChecker);
        const actualFailures: ExpectedFailure[] = JSON.parse(lintResult.output);

        // All the information we need is line and character of start position. For JSON comparison
        // to work, we will delete the information that we are not interested in from both actual and
        // expected failures.
        actualFailures.forEach(
            (actual: ExpectedFailure): void => {
                delete actual.startPosition.position;
                delete actual.endPosition;
                // Editors start counting lines and characters from 1, but tslint does it from 0.
                // To make thing easier to debug, align to editor values.
                actual.startPosition.line = actual.startPosition.line + 1;
                actual.startPosition.character = actual.startPosition.character + 1;
            }
        );
        expectedFailures.forEach(
            (expected: ExpectedFailure): void => {
                delete expected.startPosition.position;
                delete expected.endPosition;
                if (!expected.ruleSeverity) {
                    expected.ruleSeverity = 'ERROR';
                }
            }
        );

        const errorMessage = `Wrong # of failures: \n${JSON.stringify(actualFailures, null, 2)}`;
        chai.assert.equal(actualFailures.length, expectedFailures.length, errorMessage);

        expectedFailures.forEach(
            (expected: ExpectedFailure, index: number): void => {
                const actual = actualFailures[index];
                chai.assert.deepEqual(actual, expected);
            }
        );
    }
}