import { EOL } from 'os';

import { I, requireResolve } from '@stryker-mutator/util';
import { Logger } from '@stryker-mutator/api/logging';
import { commonTokens, tokens, Injector } from '@stryker-mutator/api/plugin';
import { StrykerOptions, Mutant } from '@stryker-mutator/api/core';
import { DryRunCompletedEvent, RunTiming } from '@stryker-mutator/api/report';
import {
  DryRunResult,
  TestRunner,
  DryRunStatus,
  CompleteDryRunResult,
  TestStatus,
  TestResult,
  FailedTestResult,
  ErrorDryRunResult,
} from '@stryker-mutator/api/test-runner';
import { lastValueFrom, of } from 'rxjs';

import { coreTokens } from '../di/index.js';
import { Sandbox } from '../sandbox/sandbox.js';
import { Timer } from '../utils/timer.js';
import { createTestRunnerFactory } from '../test-runner/index.js';
import { MutationTestReportHelper } from '../reporters/mutation-test-report-helper.js';
import { ConfigError } from '../errors.js';
import { ConcurrencyTokenProvider, Pool, createTestRunnerPool } from '../concurrent/index.js';
import { FileMatcher } from '../config/index.js';
import { IncrementalDiffer, MutantTestPlanner, TestCoverage } from '../mutants/index.js';
import { CheckerFacade } from '../checker/index.js';
import { StrictReporter } from '../reporters/index.js';
import { objectUtils } from '../utils/object-utils.js';

import { IdGenerator } from '../child-proxy/id-generator.js';

import { MutationTestContext } from './4-mutation-test-executor.js';
import { MutantInstrumenterContext } from './2-mutant-instrumenter-executor.js';

const INITIAL_TEST_RUN_MARKER = 'Initial test run';

export interface DryRunContext extends MutantInstrumenterContext {
  [coreTokens.sandbox]: I<Sandbox>;
  [coreTokens.mutants]: readonly Mutant[];
  [coreTokens.checkerPool]: I<Pool<I<CheckerFacade>>>;
  [coreTokens.concurrencyTokenProvider]: I<ConcurrencyTokenProvider>;
}

function isFailedTest(testResult: TestResult): testResult is FailedTestResult {
  return testResult.status === TestStatus.Failed;
}

export class DryRunExecutor {
  public static readonly inject = tokens(
    commonTokens.injector,
    commonTokens.logger,
    commonTokens.options,
    coreTokens.timer,
    coreTokens.concurrencyTokenProvider,
    coreTokens.sandbox,
    coreTokens.reporter
  );

  constructor(
    private readonly injector: Injector<DryRunContext>,
    private readonly log: Logger,
    private readonly options: StrykerOptions,
    private readonly timer: I<Timer>,
    private readonly concurrencyTokenProvider: I<ConcurrencyTokenProvider>,
    private readonly sandbox: I<Sandbox>,
    private readonly reporter: StrictReporter
  ) {}

  public async execute(): Promise<Injector<MutationTestContext>> {
    const testRunnerInjector = this.injector
      .provideClass(coreTokens.workerIdGenerator, IdGenerator)
      .provideFactory(coreTokens.testRunnerFactory, createTestRunnerFactory)
      .provideValue(coreTokens.testRunnerConcurrencyTokens, this.concurrencyTokenProvider.testRunnerToken$)
      .provideFactory(coreTokens.testRunnerPool, createTestRunnerPool);
    const testRunnerPool = testRunnerInjector.resolve(coreTokens.testRunnerPool);
    const { result, timing } = await lastValueFrom(testRunnerPool.schedule(of(0), (testRunner) => this.executeDryRun(testRunner)));

    this.logInitialTestRunSucceeded(result.tests, timing);
    if (!result.tests.length) {
      throw new ConfigError('No tests were executed. Stryker will exit prematurely. Please check your configuration.');
    }

    return testRunnerInjector
      .provideValue(coreTokens.timeOverheadMS, timing.overhead)
      .provideValue(coreTokens.dryRunResult, result)
      .provideValue(coreTokens.requireFromCwd, requireResolve)
      .provideFactory(coreTokens.testCoverage, TestCoverage.from)
      .provideClass(coreTokens.incrementalDiffer, IncrementalDiffer)
      .provideClass(coreTokens.mutantTestPlanner, MutantTestPlanner)
      .provideClass(coreTokens.mutationTestReportHelper, MutationTestReportHelper)
      .provideClass(coreTokens.workerIdGenerator, IdGenerator);
  }

  private validateResultCompleted(runResult: DryRunResult): asserts runResult is CompleteDryRunResult {
    switch (runResult.status) {
      case DryRunStatus.Complete:
        const failedTests = runResult.tests.filter(isFailedTest);
        if (failedTests.length) {
          this.logFailedTestsInInitialRun(failedTests);
          throw new ConfigError('There were failed tests in the initial test run.');
        }
        return;
      case DryRunStatus.Error:
        this.logErrorsInInitialRun(runResult);
        break;
      case DryRunStatus.Timeout:
        this.logTimeoutInitialRun();
        break;
    }
    throw new Error('Something went wrong in the initial test run');
  }

  private async executeDryRun(testRunner: TestRunner): Promise<DryRunCompletedEvent> {
    if (this.options.dryRunOnly) {
      this.log.info('Note: running the dry-run only. No mutations will be tested.');
    }

    const dryRunTimeout = this.options.dryRunTimeoutMinutes * 1000 * 60;
    const project = this.injector.resolve(coreTokens.project);
    const dryRunFiles = objectUtils.map(project.filesToMutate, (_, name) => this.sandbox.sandboxFileFor(name));
    this.timer.mark(INITIAL_TEST_RUN_MARKER);
    this.log.info(
      `Starting initial test run (${this.options.testRunner} test runner with "${this.options.coverageAnalysis}" coverage analysis). This may take a while.`
    );
    this.log.debug(`Using timeout of ${dryRunTimeout} ms.`);
    const result = await testRunner.dryRun({
      timeout: dryRunTimeout,
      coverageAnalysis: this.options.coverageAnalysis,
      disableBail: this.options.disableBail,
      files: dryRunFiles,
    });
    const grossTimeMS = this.timer.elapsedMs(INITIAL_TEST_RUN_MARKER);
    this.validateResultCompleted(result);

    this.remapSandboxFilesToOriginalFiles(result);
    const timing = this.calculateTiming(grossTimeMS, result.tests);
    const dryRunCompleted = { result, timing };
    this.reporter.onDryRunCompleted(dryRunCompleted);
    return dryRunCompleted;
  }

  /**
   * Remaps test files to their respective original names outside the sandbox.
   * @param dryRunResult the completed result
   */
  private remapSandboxFilesToOriginalFiles(dryRunResult: CompleteDryRunResult) {
    const disableTypeCheckingFileMatcher = new FileMatcher(this.options.disableTypeChecks);
    dryRunResult.tests.forEach((test) => {
      if (test.fileName) {
        test.fileName = this.sandbox.originalFileFor(test.fileName);

        // HACK line numbers of the tests can be offset by 1 because the disable type checks preprocessor could have added a `// @ts-nocheck` line.
        // We correct for that here if needed
        // If we do more complex stuff in sandbox preprocessing in the future, we might want to add a robust remapping logic
        if (test.startPosition && disableTypeCheckingFileMatcher.matches(test.fileName)) {
          test.startPosition.line--;
        }
      }
    });
  }

  private logInitialTestRunSucceeded(tests: TestResult[], timing: RunTiming) {
    this.log.info(
      'Initial test run succeeded. Ran %s tests in %s (net %s ms, overhead %s ms).',
      tests.length,
      this.timer.humanReadableElapsed(INITIAL_TEST_RUN_MARKER),
      timing.net,
      timing.overhead
    );
  }

  /**
   * Calculates the timing variables for the test run.
   * grossTime = NetTime + overheadTime
   *
   * The overhead time is used to calculate exact timeout values during mutation testing.
   * See timeoutMS setting in README for more information on this calculation
   */
  private calculateTiming(grossTimeMS: number, tests: readonly TestResult[]): RunTiming {
    const netTimeMS = tests.reduce((total, test) => total + test.timeSpentMs, 0);
    const overheadTimeMS = grossTimeMS - netTimeMS;
    return {
      net: netTimeMS,
      overhead: overheadTimeMS < 0 ? 0 : overheadTimeMS,
    };
  }

  private logFailedTestsInInitialRun(failedTests: FailedTestResult[]): void {
    let message = 'One or more tests failed in the initial test run:';
    failedTests.forEach((test) => {
      message += `${EOL}\t${test.name}`;
      message += `${EOL}\t\t${test.failureMessage}`;
    });
    this.log.error(message);
  }
  private logErrorsInInitialRun(runResult: ErrorDryRunResult) {
    const message = `One or more tests resulted in an error:${EOL}\t${runResult.errorMessage}`;
    this.log.error(message);
  }

  private logTimeoutInitialRun() {
    this.log.error('Initial test run timed out!');
  }
}