import path from "path";
import { deleteSync } from "del";

class CleanPlugin {
  constructor(pluginOptions, buildOptions) {
    this.pluginOptions = pluginOptions;
    this.buildOptions = buildOptions;
    this.previousAssets = [];
    this.pluginOptions = {
      dry: false,
      initialCleanPatterns: ["**/*"],
      verbose: false,
      ...pluginOptions,
    };
  }
  handleBuild(result) {
    const { outputs } = result.metafile ?? {};
    if (!outputs) {
      return;
    }
    const outputFiles = Object.keys(outputs);
    const removePatterns = this.previousAssets
      .filter((asset) => {
        return !outputFiles.includes(asset);
      })
      .map((asset) => {
        return path.basename(asset);
      });
    this.previousAssets = outputFiles;
    try {
      this.removeFiles(removePatterns);
    } catch (e) {
      console.error(`esbuild-clean-plugin: ${e}`);
    }
  }
  initialClean() {
    const { initialCleanPatterns } = this.pluginOptions;
    if (!initialCleanPatterns) {
      return;
    }
    this.removeFiles(initialCleanPatterns);
  }
  removeFiles(patterns) {
    const { outdir } = this.buildOptions;
    if (!outdir) {
      return;
    }
    const deletedFiles = deleteSync(patterns, {
      cwd: path.resolve(process.cwd(), outdir),
      dryRun: this.pluginOptions.dry,
    });
    this.printStats(deletedFiles);
  }
  printStats(fileNames) {
    const { dry, verbose } = this.pluginOptions;
    const { outdir } = this.buildOptions;
    if (!verbose || !outdir) {
      return;
    }
    const message = dry ? "dry" : "removed";
    fileNames.forEach((fileName) => {
      fileName = path.resolve(outdir, fileName);
      console.log(`esbuild-clean-plugin: ${message} ${fileName}`);
    });
  }
  validateOptions() {
    const { metafile, outdir } = this.buildOptions;
    if (!metafile) {
      console.warn(
        'esbuild-clean-plugin: The esbuild "metafile" option was not set, please set it to true. Stopping.'
      );
      return false;
    }
    if (!outdir) {
      console.warn(
        'esbuild-clean-plugin: The esbuild "outdir" option was not set, please supply it. Stopping.'
      );
      return false;
    }
    return true;
  }
}

export default function cleanPlugin(pluginOptions = {}) {
  return {
    name: "clean",
    setup(build) {
      const plugin = new CleanPlugin(pluginOptions, build.initialOptions);
      if (plugin.validateOptions()) {
        plugin.initialClean();
        build.onEnd((result) => {
          plugin.handleBuild(result);
        });
      }
    },
  };
}