/**
 * Functions to aid debugging, such as for saving screenshots and logs.
 */
import * as path from 'path';
import {driver} from './index';
import {getEnabledLogTypes, saveLogs} from './logs';

function getTestSuiteHierarchy(test: Mocha.Runnable): Mocha.Suite[] {
  const suites: Mocha.Suite[] = [];
  let parent = test.parent;
  while (parent) {
    suites.push(parent);
    parent = parent.parent;
  }
  return suites;
}

function sanitizeStringForFilename(name: string): string {
  return name
    .replace(/\s/g, '-')
    .replace(/[^A-Za-z0-9]/g, '')
    ;
}

function getFilePrefixForTest(test: Mocha.Runnable): string {
  const fileName = sanitizeStringForFilename(
    test.file ? path.basename(test.file, path.extname(test.file)) : ""
  );
  const suiteNames = getTestSuiteHierarchy(test)
    .map((suite) => sanitizeStringForFilename(suite.title.trim()))
    .filter((suite) => suite);

  return `${fileName}-${suiteNames.join('-')}`;
}

function suiteHasTestFailures(suite: Mocha.Suite): boolean {
  const thisSuiteHasFailures = suite.tests.some((test) => test.isFailed());
  const nestedSuitesHaveFailures = suite.suites.some((childSuite) => suiteHasTestFailures(childSuite));

  return thisSuiteHasFailures || nestedSuitesHaveFailures;
}

/**
 * Adds an afterEach() hook to the current test suite to save logs and screenshots after failed
 * tests. These are saved only if `MOCHA_WEBDRIVER_LOGDIR` variable is set, and named:
 *  - MOCHA_WEBDRIVER_LOGDIR/{testBaseName}-{logtype}.log
 *  - MOCHA_WEBDRIVER_LOGDIR/{testBaseName}-screenshot-{N}.png
 *
 * This should be called at suite level, not at root level (as this hook is only suitable for some
 * kinds of mocha tests, namely those using webdriver).
 */
export function enableDebugCapture() {
  beforeEach(async function() {
    if (this.runnable().parent!.root) {
      throw new Error("enableDebugCapture() should be called at suite level, not at root level");
    }

    // Fetches logs without saving them, in effect discarding all messages so far, so that the
    // saveLogs() call in afterEach() gets only the messages created during this test case.
    if (process.env.MOCHA_WEBDRIVER_LOGDIR) {
      for (const logType of getEnabledLogTypes()) {
        await driver.fetchLogs(logType);
      }
    }
  });

  afterEach(async function() {
    // Take snapshots after each failed test case.
    const test = this.currentTest!;
    if (test.state !== 'passed' && !test.pending) {
      const filePrefix = getFilePrefixForTest(test);
      if (process.env.MOCHA_WEBDRIVER_LOGDIR) {
        await driver.saveScreenshot(`${filePrefix}-screenshot-{N}.png`);
        for (const logType of getEnabledLogTypes()) {
          const messages = await driver.fetchLogs(logType);
          await saveLogs(messages, `${filePrefix}-${logType}-{N}.log`);
        }
      }
    }
  });

  after(async function() {
    // Dump any remaining log files. Certain error cases leave lingering logs, such as errors in before()
    // Retrieve the test suite the current after() hook is installed in.
    const hook = this.test;
    const suite = hook?.parent;
    if (!suite) { return; }

    const shouldSaveLogs = suiteHasTestFailures(suite) && process.env.MOCHA_WEBDRIVER_LOGDIR;

    if (shouldSaveLogs) {
      const filePrefix = getFilePrefixForTest(hook);
      for (const logType of getEnabledLogTypes()) {
        const messages = await driver.fetchLogs(logType);
        // Only save if there's messages, as there's potential for a lot of empty files here.
        if (messages.length > 0) {
          await saveLogs(messages, `${filePrefix}-afterSuiteCompleted-${logType}-{N}.log`);
        }
      }
    }
  });
}