// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.

import { murmur2 } from './hash';

import { IDebugger } from './tokens';

/**
 * A class that holds debugger configuration for all kernels.
 */
export class DebuggerConfig implements IDebugger.IConfig {
  /**
   * Returns an id based on the given code.
   *
   * @param code The source code.
   * @param kernel The kernel name from current session.
   */
  getCodeId(code: string, kernel: string): string {
    const fileParams = this._fileParams.get(kernel);

    if (!fileParams) {
      throw new Error(`Kernel (${kernel}) has no tmp file params.`);
    }

    const hash = this._hashMethods.get(kernel);

    if (!hash) {
      throw new Error(`Kernel (${kernel}) has no hashing params.`);
    }

    const { prefix, suffix } = fileParams;
    return `${prefix}${hash(code)}${suffix}`;
  }

  /**
   * Sets the hash parameters for a kernel.
   *
   * @param params - Hashing parameters for a kernel.
   */
  setHashParams(params: IDebugger.IConfig.HashParams): void {
    const { kernel, method, seed } = params;
    if (!kernel) {
      throw new TypeError(`Kernel name is not defined.`);
    }
    switch (method) {
      case 'Murmur2':
        this._hashMethods.set(kernel, code => murmur2(code, seed).toString());
        break;
      default:
        throw new Error(`Hash method (${method}) is not supported.`);
    }
  }

  /**
   * Sets the parameters used by the kernel to create temp files (e.g. cells).
   *
   * @param params - Temporary file prefix and suffix for a kernel.
   */
  setTmpFileParams(params: IDebugger.IConfig.FileParams): void {
    const { kernel, prefix, suffix } = params;
    if (!kernel) {
      throw new TypeError(`Kernel name is not defined.`);
    }
    this._fileParams.set(kernel, { kernel, prefix, suffix });
  }

  /**
   * Gets the parameters used for the temp files (e.e. cells) for a kernel.
   *
   * @param kernel - The kernel name from current session.
   */
  getTmpFileParams(kernel: string): IDebugger.IConfig.FileParams {
    return this._fileParams.get(kernel)!;
  }

  private _fileParams = new Map<string, IDebugger.IConfig.FileParams>();
  private _hashMethods = new Map<string, (code: string) => string>();
}