/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import {readFileSync} from 'fs';
import {IMinimatch, Minimatch} from 'minimatch';
import * as path from 'path';
import {cd, exec, set} from 'shelljs';
import {parse as parseYaml} from 'yaml';

interface GlobMatcher {
  group: string;
  glob: string;
  matcher: IMinimatch;
  matchCount: number;
}

export function verify() {
  // Exit early on shelljs errors
  set('-e');

  // Regex Matcher for contains_any_globs conditions
  const CONTAINS_ANY_GLOBS_REGEX = /^'([^']+)',?$/;
  // Full path of the angular project directory
  const ANGULAR_PROJECT_DIR = process.cwd();
  // Change to the Angular project directory
  cd(ANGULAR_PROJECT_DIR);

  // Whether to log verbosely
  const VERBOSE_MODE = process.argv.includes('-v');
  // Full path to PullApprove config file
  const PULL_APPROVE_YAML_PATH = path.resolve(ANGULAR_PROJECT_DIR, '.pullapprove.yml');
  // All relative path file names in the git repo, this is retrieved using git rather
  // that a glob so that we only get files that are checked in, ignoring things like
  // node_modules, .bazelrc.user, etc
  const ALL_FILES = exec('git ls-tree --full-tree -r --name-only HEAD', {silent: true})
                        .trim()
                        .split('\n')
                        .filter((_: string) => !!_);
  if (!ALL_FILES.length) {
    console.error(
        `No files were found to be in the git tree, did you run this command from \n` +
        `inside the angular repository?`);
    process.exit(1);
  }

  /** Gets the glob matching information from each group's condition. */
  function getGlobMatchersFromCondition(
      groupName: string, condition: string): [GlobMatcher[], string[]] {
    const trimmedCondition = condition.trim();
    const globMatchers: GlobMatcher[] = [];
    const badConditionLines: string[] = [];

    // If the condition starts with contains_any_globs, evaluate all of the globs
    if (trimmedCondition.startsWith('contains_any_globs')) {
      trimmedCondition.split('\n')
          .slice(1, -1)
          .map(glob => {
            const trimmedGlob = glob.trim();
            const match = trimmedGlob.match(CONTAINS_ANY_GLOBS_REGEX);
            if (!match) {
              badConditionLines.push(trimmedGlob);
              return '';
            }
            return match[1];
          })
          .filter(globString => !!globString)
          .forEach(globString => globMatchers.push({
            group: groupName,
            glob: globString,
            matcher: new Minimatch(globString, {dot: true}),
            matchCount: 0,
          }));
    }
    return [globMatchers, badConditionLines];
  }

  /** Create logs for each review group. */
  function logGroups(groups: Map<string, Map<string, GlobMatcher>>) {
    Array.from(groups.entries()).sort().forEach(([groupName, globs]) => {
      console.groupCollapsed(groupName);
      Array.from(globs.values())
          .sort((a, b) => b.matchCount - a.matchCount)
          .forEach(glob => console.info(`${glob.glob} - ${glob.matchCount}`));
      console.groupEnd();
    });
  }

  /** Logs a header within a text drawn box. */
  function logHeader(...params: string[]) {
    const totalWidth = 80;
    const fillWidth = totalWidth - 2;
    const headerText = params.join(' ').substr(0, fillWidth);
    const leftSpace = Math.ceil((fillWidth - headerText.length) / 2);
    const rightSpace = fillWidth - leftSpace - headerText.length;
    const fill = (count: number, content: string) => content.repeat(count);

    console.info(`┌${fill(fillWidth, '─')}┐`);
    console.info(`│${fill(leftSpace, ' ')}${headerText}${fill(rightSpace, ' ')}│`);
    console.info(`└${fill(fillWidth, '─')}┘`);
  }

  /** Runs the pull approve verification check on provided files. */
  function runVerification(files: string[]) {
    // All of the globs created for each group's conditions.
    const allGlobs: GlobMatcher[] = [];
    // The pull approve config file.
    const pullApprove = readFileSync(PULL_APPROVE_YAML_PATH, {encoding: 'utf8'});
    // All of the PullApprove groups, parsed from the PullApprove yaml file.
    const parsedPullApproveGroups =
        parseYaml(pullApprove).groups as{[key: string]: {conditions: string}};
    // All files which were found to match a condition in PullApprove.
    const matchedFiles = new Set<string>();
    // All files which were not found to match a condition in PullApprove.
    const unmatchedFiles = new Set<string>();
    // All PullApprove groups which matched at least one file.
    const matchedGroups = new Map<string, Map<string, GlobMatcher>>();
    // All PullApprove groups which did not match at least one file.
    const unmatchedGroups = new Map<string, Map<string, GlobMatcher>>();
    // All condition lines which were not able to be correctly parsed, by group.
    const badConditionLinesByGroup = new Map<string, string[]>();
    // Total number of condition lines which were not able to be correctly parsed.
    let badConditionLineCount = 0;

    // Get all of the globs from the PullApprove group conditions.
    Object.entries(parsedPullApproveGroups).forEach(([groupName, group]) => {
      for (const condition of group.conditions) {
        const [matchers, badConditions] = getGlobMatchersFromCondition(groupName, condition);
        if (badConditions.length) {
          badConditionLinesByGroup.set(groupName, badConditions);
          badConditionLineCount += badConditions.length;
        }
        allGlobs.push(...matchers);
      }
    });

    if (badConditionLineCount) {
      console.info(`Discovered ${badConditionLineCount} parsing errors in PullApprove conditions`);
      console.info(`Attempted parsing using: ${CONTAINS_ANY_GLOBS_REGEX}`);
      console.info();
      console.info(`Unable to properly parse the following line(s) by group:`);
      badConditionLinesByGroup.forEach((badConditionLines, groupName) => {
        console.info(`- ${groupName}:`);
        badConditionLines.forEach(line => console.info(`    ${line}`));
      });
      console.info();
      console.info(
          `Please correct the invalid conditions, before PullApprove verification can be completed`);
      process.exit(1);
    }

    // Check each file for if it is matched by a PullApprove condition.
    for (let file of files) {
      const matched = allGlobs.filter(glob => glob.matcher.match(file));
      matched.length ? matchedFiles.add(file) : unmatchedFiles.add(file);
      matched.forEach(glob => glob.matchCount++);
    }

    // Add each glob for each group to a map either matched or unmatched.
    allGlobs.forEach(glob => {
      const groups = glob.matchCount ? matchedGroups : unmatchedGroups;
      const globs = groups.get(glob.group) || new Map<string, GlobMatcher>();
      // Set the globs map in the groups map
      groups.set(glob.group, globs);
      // Set the glob in the globs map
      globs.set(glob.glob, glob);
    });

    // PullApprove is considered verified if no files or groups are found to be unsed.
    const verificationSucceeded = !(unmatchedFiles.size || unmatchedGroups.size);

    /**
     * Overall result
     */
    logHeader('Result');
    if (verificationSucceeded) {
      console.info('PullApprove verification succeeded!');
    } else {
      console.info(`PullApprove verification failed.\n`);
      console.info(`Please update '.pullapprove.yml' to ensure that all necessary`);
      console.info(`files/directories have owners and all patterns that appear in`);
      console.info(`the file correspond to actual files/directories in the repo.`);
    }
    /**
     * File by file Summary
     */
    logHeader('PullApprove file match results');
    console.groupCollapsed(`Matched Files (${matchedFiles.size} files)`);
    VERBOSE_MODE && matchedFiles.forEach(file => console.info(file));
    console.groupEnd();
    console.groupCollapsed(`Unmatched Files (${unmatchedFiles.size} files)`);
    unmatchedFiles.forEach(file => console.info(file));
    console.groupEnd();

    /**
     * Group by group Summary
     */
    logHeader('PullApprove group matches');
    console.groupCollapsed(`Matched Groups (${matchedGroups.size} groups)`);
    VERBOSE_MODE && logGroups(matchedGroups);
    console.groupEnd();
    console.groupCollapsed(`Unmatched Groups (${unmatchedGroups.size} groups)`);
    logGroups(unmatchedGroups);
    console.groupEnd();

    // Provide correct exit code based on verification success.
    process.exit(verificationSucceeded ? 0 : 1);
  }


  runVerification(ALL_FILES);
}