import path from 'path';
import { isDeepStrictEqual } from 'util';

import { Minimatch } from 'minimatch';
import { StrykerOptions, FileDescriptions, FileDescription, Location, Position } from '@stryker-mutator/api/core';
import { Logger } from '@stryker-mutator/api/logging';
import { commonTokens, tokens } from '@stryker-mutator/api/plugin';
import { ERROR_CODES, I, isErrnoException } from '@stryker-mutator/util';
import type { MutationTestResult } from 'mutation-testing-report-schema/api';

import { OpenEndLocation } from 'mutation-testing-report-schema';

import { defaultOptions, FileMatcher } from '../config/index.js';
import { coreTokens } from '../di/index.js';

import { Project } from './project.js';
import { FileSystem } from './file-system.js';

const ALWAYS_IGNORE = Object.freeze(['node_modules', '.git', '*.tsbuildinfo', '/stryker.log']);

export const IGNORE_PATTERN_CHARACTER = '!';
/**
 * @see https://stryker-mutator.io/docs/stryker-js/configuration/#mutate-string
 * @example
 * * "src/app.js:1-11" will mutate lines 1 through 11 inside app.js.
 * * "src/app.js:5:4-6:4" will mutate from line 5, column 4 through line 6 column 4 inside app.js (columns 4 are included).
 * * "src/app.js:5-6:4" will mutate from line 5, column 0 through line 6 column 4 inside app.js (column 4 is included).
 */
export const MUTATION_RANGE_REGEX = /(.*?):((\d+)(?::(\d+))?-(\d+)(?::(\d+))?)$/;

export class ProjectReader {
  private readonly mutatePatterns: readonly string[];
  private readonly ignoreRules: readonly string[];
  private readonly incremental: boolean;
  private readonly force: boolean;
  private readonly incrementalFile: string;

  public static inject = tokens(coreTokens.fs, commonTokens.logger, commonTokens.options);
  constructor(
    private readonly fs: I<FileSystem>,
    private readonly log: Logger,
    { mutate, tempDirName, ignorePatterns, incremental, incrementalFile, force, htmlReporter, jsonReporter }: StrykerOptions,
  ) {
    this.mutatePatterns = mutate;
    this.ignoreRules = [...ALWAYS_IGNORE, tempDirName, incrementalFile, htmlReporter.fileName, jsonReporter.fileName, ...ignorePatterns];
    this.incremental = incremental;
    this.incrementalFile = incrementalFile;
    this.force = force;
  }

  public async read(): Promise<Project> {
    const inputFileNames = await this.resolveInputFileNames();
    const fileDescriptions = this.resolveFileDescriptions(inputFileNames);
    const project = new Project(this.fs, fileDescriptions, await this.readIncrementalReport());
    project.logFiles(this.log, this.ignoreRules, this.force, this.mutatePatterns);
    return project;
  }

  /**
   * Takes the list of file names and creates file description object from it, containing logic about wether or not it needs to be mutated.
   * If a mutate pattern starts with a `!`, it negates the pattern.
   * @param inputFileNames the file names to filter
   */
  private resolveFileDescriptions(inputFileNames: string[]): FileDescriptions {
    // Only log about useless patterns when the user actually configured it
    const logAboutUselessPatterns = !isDeepStrictEqual(this.mutatePatterns, defaultOptions.mutate);

    // Start out without files to mutate
    const mutateInputFileMap = new Map<string, FileDescription>();
    inputFileNames.forEach((fileName) => mutateInputFileMap.set(fileName, { mutate: false }));

    // Now lets see what we need to mutate
    for (const pattern of this.mutatePatterns) {
      if (pattern.startsWith(IGNORE_PATTERN_CHARACTER)) {
        const files = this.filterMutatePattern(mutateInputFileMap.keys(), pattern.substring(1));
        if (logAboutUselessPatterns && files.size === 0) {
          this.log.warn(`Glob pattern "${pattern}" did not exclude any files.`);
        }
        for (const fileName of files.keys()) {
          mutateInputFileMap.set(fileName, { mutate: false });
        }
      } else {
        const files = this.filterMutatePattern(inputFileNames, pattern);
        if (logAboutUselessPatterns && files.size === 0) {
          this.log.warn(`Glob pattern "${pattern}" did not result in any files.`);
        }
        for (const [fileName, file] of files) {
          mutateInputFileMap.set(fileName, this.mergeFileDescriptions(file, mutateInputFileMap.get(fileName)));
        }
      }
    }
    return Object.fromEntries(mutateInputFileMap);
  }

  private mergeFileDescriptions(first: FileDescription, second?: FileDescription): FileDescription {
    if (second) {
      if (Array.isArray(first.mutate) && Array.isArray(second.mutate)) {
        return { mutate: [...second.mutate, ...first.mutate] };
      } else if (first.mutate && !second.mutate) {
        return first;
      } else if (!first.mutate && second.mutate) {
        return second;
      } else {
        return { mutate: false };
      }
    }
    return first;
  }

  /**
   * Filters a given list of file names given a mutate pattern.
   * @param fileNames the file names to match to the pattern
   * @param mutatePattern the pattern to match with
   */
  private filterMutatePattern(fileNames: Iterable<string>, mutatePattern: string): Map<string, FileDescription> {
    const mutationRangeMatch = MUTATION_RANGE_REGEX.exec(mutatePattern);
    let mutate: FileDescription['mutate'] = true;
    if (mutationRangeMatch) {
      const [_, newPattern, _mutationRange, startLine, startColumn = '0', endLine, endColumn = Number.MAX_SAFE_INTEGER.toString()] =
        mutationRangeMatch;
      mutatePattern = newPattern;
      mutate = [
        {
          start: { line: parseInt(startLine) - 1, column: parseInt(startColumn) },
          end: { line: parseInt(endLine) - 1, column: parseInt(endColumn) },
        },
      ];
    }
    const matcher = new FileMatcher(mutatePattern);
    const inputFiles = new Map<string, FileDescription>();
    for (const fileName of fileNames) {
      if (matcher.matches(fileName)) {
        inputFiles.set(fileName, { mutate });
      }
    }
    return inputFiles;
  }

  private async resolveInputFileNames(): Promise<string[]> {
    const ignoreRules = this.ignoreRules.map((pattern) => new Minimatch(pattern, { dot: true, flipNegate: true, nocase: true }));

    /**
     * Rewrite of: https://github.com/npm/ignore-walk/blob/0e4f87adccb3e16f526d2e960ed04bdc77fd6cca/index.js#L213-L215
     */
    const matchesDirectoryPartially = (entryPath: string, rule: Minimatch) => {
      return rule.match(`/${entryPath}`, true) || rule.match(entryPath, true);
    };

    // Inspired by https://github.com/npm/ignore-walk/blob/0e4f87adccb3e16f526d2e960ed04bdc77fd6cca/index.js#L124
    const matchesDirectory = (entryName: string, entryPath: string, rule: Minimatch) => {
      return (
        matchesFile(entryName, entryPath, rule) ||
        rule.match(`/${entryPath}/`) ||
        rule.match(`${entryPath}/`) ||
        (rule.negate && matchesDirectoryPartially(entryPath, rule))
      );
    };

    // Inspired by https://github.com/npm/ignore-walk/blob/0e4f87adccb3e16f526d2e960ed04bdc77fd6cca/index.js#L123
    const matchesFile = (entryName: string, entryPath: string, rule: Minimatch) => {
      return rule.match(entryName) || rule.match(entryPath) || rule.match(`/${entryPath}`);
    };

    const crawlDir = async (dir: string, rootDir = dir): Promise<string[]> => {
      const dirEntries = await this.fs.readdir(dir, { withFileTypes: true });
      const relativeName = path.relative(rootDir, dir);
      const files = await Promise.all(
        dirEntries
          .filter((dirEntry) => {
            let included = true;
            const entryPath = `${relativeName.length ? `${relativeName}/` : ''}${dirEntry.name}`;
            ignoreRules.forEach((rule) => {
              if (rule.negate !== included) {
                const match = dirEntry.isDirectory() ? matchesDirectory(dirEntry.name, entryPath, rule) : matchesFile(dirEntry.name, entryPath, rule);
                if (match) {
                  included = rule.negate;
                }
              }
            });
            return included;
          })
          .map(async (dirent) => {
            if (dirent.isDirectory()) {
              return crawlDir(path.resolve(rootDir, relativeName, dirent.name), rootDir);
            } else {
              return path.resolve(rootDir, relativeName, dirent.name);
            }
          }),
      );
      return files.flat();
    };
    const files = await crawlDir(process.cwd());
    return files;
  }

  private async readIncrementalReport(): Promise<MutationTestResult | undefined> {
    if (!this.incremental) {
      return;
    }
    try {
      // TODO: Validate against the schema or stryker version?
      const contents = await this.fs.readFile(this.incrementalFile, 'utf-8');
      const result: MutationTestResult = JSON.parse(contents);
      return {
        ...result,
        files: Object.fromEntries(
          Object.entries(result.files).map(([fileName, file]) => [
            fileName,
            { ...file, mutants: file.mutants.map((mutant) => ({ ...mutant, location: reportLocationToStrykerLocation(mutant.location) })) },
          ]),
        ),
        testFiles:
          result.testFiles &&
          Object.fromEntries(
            Object.entries(result.testFiles).map(([fileName, file]) => [
              fileName,
              {
                ...file,
                tests: file.tests.map((test) => ({ ...test, location: test.location && reportOpenEndLocationToStrykerLocation(test.location) })),
              },
            ]),
          ),
      };
    } catch (err: unknown) {
      if (isErrnoException(err) && err.code === ERROR_CODES.NoSuchFileOrDirectory) {
        this.log.info('No incremental result file found at %s, a full mutation testing run will be performed.', this.incrementalFile);
        return;
      }
      // Whoops, didn't mean to catch this one!
      throw err;
    }
  }
}

function reportOpenEndLocationToStrykerLocation({ start, end }: OpenEndLocation): OpenEndLocation {
  return {
    start: reportPositionToStrykerPosition(start),
    end: end && reportPositionToStrykerPosition(end),
  };
}

function reportLocationToStrykerLocation({ start, end }: Location): Location {
  return {
    start: reportPositionToStrykerPosition(start),
    end: reportPositionToStrykerPosition(end),
  };
}

function reportPositionToStrykerPosition({ line, column }: Position): Position {
  // stryker's positions are 0-based
  return {
    line: line - 1,
    column: column - 1,
  };
}