const multimatch = require("multimatch");
const isGlob = require("is-glob");
const { TemplatePath } = require("@11ty/eleventy-utils");

const EleventyExtensionMap = require("./EleventyExtensionMap");
const EleventyBaseError = require("./EleventyBaseError");
const TemplatePassthrough = require("./TemplatePassthrough");
const checkPassthroughCopyBehavior = require("./Util/PassthroughCopyBehaviorCheck");

const debug = require("debug")("Eleventy:TemplatePassthroughManager");
const debugDev = require("debug")("Dev:Eleventy:TemplatePassthroughManager");

class TemplatePassthroughManagerConfigError extends EleventyBaseError {}
class TemplatePassthroughManagerCopyError extends EleventyBaseError {}

class TemplatePassthroughManager {
  constructor(eleventyConfig) {
    if (!eleventyConfig) {
      throw new TemplatePassthroughManagerConfigError("Missing `config` argument.");
    }
    this.eleventyConfig = eleventyConfig;
    this.config = eleventyConfig.getConfig();
    this.reset();
  }

  reset() {
    this.count = 0;
    this.conflictMap = {};
    this.incrementalFile = null;
    debug("Resetting counts to 0");
  }

  set extensionMap(extensionMap) {
    this._extensionMap = extensionMap;
  }

  get extensionMap() {
    if (!this._extensionMap) {
      this._extensionMap = new EleventyExtensionMap([], this.eleventyConfig);
    }
    return this._extensionMap;
  }

  setOutputDir(outputDir) {
    this.outputDir = outputDir;
  }

  setInputDir(inputDir) {
    this.inputDir = inputDir;
  }

  setDryRun(isDryRun) {
    this.isDryRun = !!isDryRun;
  }

  setRunMode(runMode) {
    this.runMode = runMode;
  }

  setIncrementalFile(path) {
    if (path) {
      this.incrementalFile = path;
    }
  }

  _normalizePaths(path, outputPath, copyOptions = {}) {
    return {
      inputPath: TemplatePath.addLeadingDotSlash(path),
      outputPath: outputPath ? TemplatePath.stripLeadingDotSlash(outputPath) : true,
      copyOptions,
    };
  }

  getConfigPaths() {
    let paths = [];
    let pathsRaw = this.config.passthroughCopies || {};
    debug("`addPassthroughCopy` config API paths: %o", pathsRaw);
    for (let [inputPath, { outputPath, copyOptions }] of Object.entries(pathsRaw)) {
      paths.push(this._normalizePaths(inputPath, outputPath, copyOptions));
    }
    debug("`addPassthroughCopy` config API normalized paths: %o", paths);
    return paths;
  }

  getConfigPathGlobs() {
    return this.getConfigPaths().map((path) => {
      return TemplatePath.convertToRecursiveGlobSync(path.inputPath);
    });
  }

  getNonTemplatePaths(paths) {
    let matches = [];
    for (let path of paths) {
      if (!this.extensionMap.hasEngine(path)) {
        matches.push(path);
      }
    }

    return matches;
  }

  getCopyCount() {
    return this.count;
  }

  setFileSystemSearch(fileSystemSearch) {
    this.fileSystemSearch = fileSystemSearch;
  }

  getTemplatePassthroughForPath(path, isIncremental = false) {
    let inst = new TemplatePassthrough(path, this.outputDir, this.inputDir, this.config);

    inst.setFileSystemSearch(this.fileSystemSearch);
    inst.setIsIncremental(isIncremental);
    inst.setDryRun(this.isDryRun);
    inst.setRunMode(this.runMode);

    return inst;
  }

  async copyPassthrough(pass) {
    if (!(pass instanceof TemplatePassthrough)) {
      throw new TemplatePassthroughManagerCopyError(
        "copyPassthrough expects an instance of TemplatePassthrough"
      );
    }

    let { inputPath } = pass.getPath();

    // TODO https://github.com/11ty/eleventy/issues/2452
    // De-dupe both the input and output paired together to avoid the case
    // where an input/output pair has been added via multiple passthrough methods (glob, file suffix, etc)
    // Probably start with the `filter` callback in recursive-copy but it only passes relative paths
    // See the note in TemplatePassthrough.js->write()

    // Also note that `recursive-copy` handles repeated overwrite copy to the same destination just fine.
    // e.g. `for(let j=0, k=1000; j<k; j++) { copy("coolkid.jpg", "_site/coolkid.jpg"); }`

    // Eventually we’ll want to move all of this to use Node’s fs.cp, which is experimental and only on Node 16+

    return pass
      .write()
      .then(({ count, map }) => {
        for (let src in map) {
          let dest = map[src];
          if (this.conflictMap[dest]) {
            if (src !== this.conflictMap[dest]) {
              throw new TemplatePassthroughManagerCopyError(
                `Multiple passthrough copy files are trying to write to the same output file (${dest}). ${src} and ${this.conflictMap[dest]}`
              );
            } else {
              // Multiple entries from the same source
              debug(
                "A passthrough copy entry (%o) caused the same file (%o) to be copied more than once to the output (%o). This is atomically safe but a waste of build resources.",
                inputPath,
                src,
                dest
              );
            }
          }

          debugDev("Adding %o to passthrough copy conflict map, from %o", dest, src);

          this.conflictMap[dest] = src;
        }

        if (pass.isDryRun) {
          // We don’t count the skipped files as we need to iterate over them
          debug(
            "Skipped %o (either from --dryrun or --incremental or for-free passthrough copy)",
            inputPath
          );
        } else {
          if (count) {
            this.count += count;
            debug("Copied %o (%d files)", inputPath, count || 0);
          } else {
            debug("Skipped copying %o (emulated passthrough copy)", inputPath);
          }
        }

        return {
          count,
          map,
        };
      })
      .catch(function (e) {
        return Promise.reject(
          new TemplatePassthroughManagerCopyError(`Having trouble copying '${inputPath}'`, e)
        );
      });
  }

  isPassthroughCopyFile(paths, changedFile) {
    // passthrough copy by non-matching engine extension (via templateFormats)
    for (let path of paths) {
      if (path === changedFile && !this.extensionMap.hasEngine(path)) {
        return true;
      }
    }

    for (let path of this.getConfigPaths()) {
      if (TemplatePath.startsWithSubPath(changedFile, path.inputPath)) {
        return path;
      }
      if (
        changedFile &&
        isGlob(path.inputPath) &&
        multimatch([changedFile], [path.inputPath]).length
      ) {
        return path;
      }
    }

    return false;
  }

  getAllNormalizedPaths(paths) {
    if (this.incrementalFile) {
      let isPassthrough = this.isPassthroughCopyFile(paths, this.incrementalFile);

      if (isPassthrough) {
        if (isPassthrough.outputPath) {
          return [this._normalizePaths(this.incrementalFile, isPassthrough.outputPath)];
        }

        return [this._normalizePaths(this.incrementalFile)];
      }

      // Fixes https://github.com/11ty/eleventy/issues/2491
      if (!checkPassthroughCopyBehavior(this.config, this.runMode)) {
        return [];
      }
    }

    let normalizedPaths = this.getConfigPaths();
    if (debug.enabled) {
      for (let path of normalizedPaths) {
        debug("TemplatePassthrough copying from config: %o", path);
      }
    }

    if (paths && paths.length) {
      let passthroughPaths = this.getNonTemplatePaths(paths);
      for (let path of passthroughPaths) {
        let normalizedPath = this._normalizePaths(path);

        debug(
          `TemplatePassthrough copying from non-matching file extension: ${normalizedPath.inputPath}`
        );

        normalizedPaths.push(normalizedPath);
      }
    }

    return normalizedPaths;
  }

  // keys: output
  // values: input
  getAliasesFromPassthroughResults(result) {
    let entries = {};
    for (let entry of result) {
      for (let src in entry.map) {
        let dest = TemplatePath.stripLeadingSubPath(entry.map[src], this.outputDir);
        entries["/" + dest] = src;
      }
    }
    return entries;
  }

  // Performance note: these can actually take a fair bit of time, but aren’t a
  // bottleneck to eleventy. The copies are performed asynchronously and don’t affect eleventy
  // write times in a significant way.
  async copyAll(templateExtensionPaths) {
    debug("TemplatePassthrough copy started.");
    let normalizedPaths = this.getAllNormalizedPaths(templateExtensionPaths);

    let passthroughs = normalizedPaths.map((path) => {
      // if incrementalFile is set but it isn’t a passthrough copy, normalizedPaths will be an empty array
      let isIncremental = !!this.incrementalFile;

      return this.getTemplatePassthroughForPath(path, isIncremental);
    });

    let promises = passthroughs.map((pass) => this.copyPassthrough(pass));
    return Promise.all(promises).then(async (results) => {
      let aliases = this.getAliasesFromPassthroughResults(results);
      await this.config.events.emit("eleventy.passthrough", {
        map: aliases,
      });

      debug(`TemplatePassthrough copy finished. Current count: ${this.count}`);
      return results;
    });
  }
}

module.exports = TemplatePassthroughManager;