import { map, type MapStore } from 'nanostores';
import { computeFileModifications } from '~/utils/diff';
import { createScopedLogger } from '~/utils/logger';
import { unreachable } from '~/utils/unreachable';
import type { ProtocolFile } from '../replay/SimulationPrompt';

const logger = createScopedLogger('FilesStore');

export type FileMap = Record<string, ProtocolFile | undefined>;

export class FilesStore {
  /**
   * Tracks the number of files without folders.
   */
  #size = 0;

  /**
   * @note Keeps track all modified files with their original content since the last user message.
   * Needs to be reset when the user sends another message and all changes have to be submitted
   * for the model to be aware of the changes.
   */
  #modifiedFiles: Map<string, string> = import.meta.hot?.data.modifiedFiles ?? new Map();

  /**
   * Map of files that matches the state of WebContainer.
   */
  files: MapStore<FileMap> = import.meta.hot?.data.files ?? map({});

  get filesCount() {
    return this.#size;
  }

  constructor() {
    if (import.meta.hot) {
      import.meta.hot.data.files = this.files;
      import.meta.hot.data.modifiedFiles = this.#modifiedFiles;
    }
  }

  getFile(filePath: string) {
    const dirent = this.files.get()[filePath];
    return dirent;
  }

  getFileModifications() {
    return computeFileModifications(this.files.get(), this.#modifiedFiles);
  }

  resetFileModifications() {
    this.#modifiedFiles.clear();
  }

  async saveFile(filePath: string, content: string) {
    try {
      const oldContent = this.getFile(filePath)?.content;

      if (!oldContent) {
        console.log('CurrentFiles', JSON.stringify(Object.keys(this.files.get())));
        unreachable(`Cannot save unknown file ${filePath}`);
      }

      if (!this.#modifiedFiles.has(filePath)) {
        this.#modifiedFiles.set(filePath, oldContent);
      }

      // we immediately update the file and don't rely on the `change` event coming from the watcher
      this.files.setKey(filePath, { path: filePath, content });

      logger.info('File updated');
    } catch (error) {
      logger.error('Failed to update file content\n\n', error);

      throw error;
    }
  }
}