import { emptyDir, ensureDir } from "./utils/fs.ts";
import { posix } from "../deps/path.ts";
import {
  readFileSync,
  readTextFileSync,
  removeSync,
  writeFileSync,
  writeTextFileSync,
} from "../services/fs.ts";
import { md5 } from "./utils/digest.ts";

export interface Options {
  /** The folder to load the files from */
  folder: string;
}

/**
 * Class to manage cache in the _cache folder
 */
export default class Cache {
  #folder: string;

  constructor(options: Options) {
    this.#folder = options.folder;
  }

  /** Save some content in the cache folder */
  set(key: unknown[], value: string | Uint8Array): void {
    const path = this.getPath(key);

    ensureDir(posix.dirname(path));

    if (typeof value === "string") {
      writeTextFileSync(path, value);
    } else {
      writeFileSync(path, value);
    }
  }

  /** Remove content from the cache folder */
  remove(key: unknown[]): void {
    try {
      removeSync(this.getPath(key));
    } catch {
      // Ignore
    }
  }

  getPath(key: unknown[]): string {
    const paths = key.map((value) => {
      if (value instanceof Uint8Array || typeof value === "string") {
        return md5(value);
      }
      return md5(JSON.stringify(value));
    });
    return posix.join(this.#folder, ...paths);
  }

  /** Get the content from the cache folder as Uint8Array */
  getBytes(key: unknown[]): Uint8Array<ArrayBuffer> | undefined {
    try {
      return readFileSync(this.getPath(key));
    } catch {
      // Ignore
    }
  }

  /** Get the content from the cache folder as string */
  getText(key: unknown[]): string | undefined {
    try {
      return readTextFileSync(this.getPath(key));
    } catch {
      // Ignore
    }
  }

  /** Empty the cache folder */
  clear(): void {
    emptyDir(this.#folder);
  }
}