import AssetsSource from "./AssetsSource";
import * as stringUtils from "../util/strings";
import { URI } from "../util/URI";
import { Config, AssetSourceOptions } from "../util/Options";
import { SassImplementation } from "../util/SassImplementation";

export default class AssetsCollection {
  options: Config;
  sass: SassImplementation;
  sources: Array<AssetsSource>;

  constructor(options: Config) {
    this.options = options;
    this.sass = options.eyeglass.engines.sass;
    this.sources = [];
  }

  /**
    * adds an AssetsSource to the collection
    * @param    {String} src - the source directory of the assets
    * @param    {Object} opts - the options to pass @see AssetsSource
    * @returns  {AssetsCollection} returns the instance of AssetsCollection for chaining
    */
  addSource(src: string, opts: Partial<AssetSourceOptions>): AssetsCollection {
    this.sources.push(new AssetsSource(src, opts));
    return this;
  }

  /**
    * returns the scss to register all the assets
    * @param    {String} name - the namespace to use
    * @returns  {String} the scss representation of the asset registration
    */
  asAssetImport(name: string | undefined): string {
    // builds the scss to register all the assets
    // this will look something like...
    //  @import "eyeglass/assets";
    //  @include asset-register-all("namespace",
    //    "path/to/foo.png": (
    //      filepath: "/absolute/namespace/path/to/foo.png",
    //      uri: "namespace/path/to/foo.png"
    //    ),
    //  );
    let contents = [
      '@import "eyeglass/assets";',
    ];
    for (let source of this.sources) {
      // get the assets for the entry
      let assets = source.getAssets(name);
      let namespace = (stringUtils.quoteJS(this.sass, assets.namespace) || "null");
      contents.push(`@include asset-register-all(${namespace}, (`)
      for (let asset of assets.files) {
        let url = URI.sass(this.sass, asset.name);
        let uri = URI.sass(this.sass, asset.uri);
        let filepath = URI.sass(this.sass, asset.sourcePath);
        contents.push(`  ${url}: (filepath: ${filepath}, uri: ${uri}),`)
      }
      contents.push("));")
    }
    return contents.join("\n");
  }

  /**
    * Build a string suitable for caching an instance of this
    * @returns {String} the cache key
    */
  cacheKey(name: string): string {
    return this.sources.map(function (source) {
      return source.cacheKey(name);
    }).sort().join("\x00");
  }
}