import * as plugins from './npmextra.plugins.js';
import * as paths from './npmextra.paths.js';

import { Task } from '@push.rocks/taskbuffer';

export type TKeyValueStore = 'custom' | 'userHomeDir';

export interface IKvStoreConstructorOptions {
  typeArg: TKeyValueStore;
  identityArg: string;
  customPath?: string;
  mandatoryKeys?: string[];
}

/**
 * kvStore is a simple key value store to store data about projects between runs
 */
export class KeyValueStore<T = any> {
  private dataObject: Partial<T> = {};
  private deletedObject: any = {};
  private mandatoryKeys: Set<string> = new Set();
  public changeSubject = new plugins.smartrx.rxjs.Subject();
  
  private storedStateString: string = '';
  public syncTask = new Task({
    name: 'syncTask',
    buffered: true,
    bufferMax: 1,
    execDelay: 0,
    taskFunction: async () => {
      
      this.dataObject = {
        ...plugins.smartfile.fs.toObjectSync(this.filePath),
        ...this.dataObject,
      };
      for (const key of Object.keys(this.deletedObject)) {
        delete this.dataObject[key];
      }
      this.deletedObject = {};
      await plugins.smartfile.memory.toFs(
        plugins.smartjson.stringifyPretty(this.dataObject),
        this.filePath
      );
      const newStateString = plugins.smartjson.stringify(this.dataObject);

      // change detection
      if (newStateString !== this.storedStateString) {
        this.storedStateString = newStateString;
        this.changeSubject.next(this.dataObject);
      }
    },
  });

  /**
   * computes the identity and filePath
   */
  private initFilePath = () => {
    if (this.customPath) {
      // Use custom path if provided
      const absolutePath = plugins.smartpath.transform.makeAbsolute(this.customPath, paths.cwd);
      this.filePath = absolutePath;
      if (plugins.smartfile.fs.isDirectorySync(this.filePath)) {
        this.filePath = plugins.path.join(this.filePath, this.identity + '.json');
      }
      plugins.smartfile.fs.ensureFileSync(this.filePath, '{}');
      return;
    }

    let baseDir: string;
    if (this.type === 'userHomeDir') {
      baseDir = paths.kvUserHomeDirBase;
    } else {
      throw new Error('kv type not supported');
    }
    this.filePath = plugins.path.join(baseDir, this.identity + '.json');
    plugins.smartfile.fs.ensureDirSync(baseDir);
    plugins.smartfile.fs.ensureFileSync(this.filePath, '{}');
  };

  // if no custom path is provided, try to store at home directory
  public type: TKeyValueStore;
  public identity: string;
  public filePath: string;
  private customPath?: string; // Optionally allow custom path

  /**
   * the constructor of keyvalue store
   * @param typeArg
   * @param identityArg
   * @param customPath Optional custom path for the keyValue store
   */
  constructor(optionsArg: IKvStoreConstructorOptions) {
    if (optionsArg.customPath && optionsArg.typeArg !== 'custom') {
      throw new Error('customPath can only be provided if typeArg is custom');
    }
    if (optionsArg.typeArg === 'custom' && !optionsArg.customPath) {
      throw new Error('customPath must be provided if typeArg is custom');
    }
    this.type = optionsArg.typeArg;
    this.identity = optionsArg.identityArg;
    this.customPath = optionsArg.customPath; // Store custom path if provided
    this.initFilePath();
    if (optionsArg.mandatoryKeys) {
      this.setMandatoryKeys(optionsArg.mandatoryKeys);
    }
  }

  /**
   * reads all keyValue pairs at once and returns them
   */
  public async readAll() {
    await this.syncTask.trigger();
    return this.dataObject;
  }

  /**
   * reads a keyValueFile from disk
   */
  public async readKey(keyArg: string) {
    await this.syncTask.trigger();
    return this.dataObject[keyArg];
  }

  /**
   * writes a specific key to the keyValueStore
   */
  public async writeKey(keyArg: string, valueArg: any) {
    await this.writeAll({
      [keyArg]: valueArg,
    });
  }

  public async deleteKey(keyArg: string) {
    this.deletedObject[keyArg] = this.dataObject[keyArg];
    await this.syncTask.trigger();
  }

  /**
   * writes all keyValue pairs in the object argument
   */
  public async writeAll(keyValueObject: { [key: string]: any }) {
    this.dataObject = { ...this.dataObject, ...keyValueObject };
    await this.syncTask.trigger();
  }

  /**
   * wipes a key value store from disk
   */
  public async wipe() {
    this.dataObject = {};
    await plugins.smartfile.fs.remove(this.filePath);
  }

  /**
   * resets the KeyValueStore to the initial state by syncing first, deleting all keys, and then triggering a sync again
   */
  public async reset() {
    await this.syncTask.trigger(); // Sync to get the latest state

    // Delete all keys from the dataObject and add them to deletedObject
    for (const key of Object.keys(this.dataObject)) {
      this.deletedObject[key] = this.dataObject[key];
      delete this.dataObject[key];
    }

    await this.syncTask.trigger(); // Sync again to reflect the deletion
  }

  private setMandatoryKeys(keys: string[]) {
    keys.forEach(key => this.mandatoryKeys.add(key));
  }

  public async getMissingMandatoryKeys(): Promise<string[]> {
    await this.readAll();
    return Array.from(this.mandatoryKeys).filter(key => !(key in this.dataObject));
  }

  public async waitForKeysPresent(keysArg: string[]): Promise<void> {
    const missingKeys = keysArg.filter(keyArg => !this.dataObject[keyArg]);
    if (missingKeys.length === 0) {
      return;
    }
    return new Promise((resolve, reject) => {
      const subscription = this.changeSubject.subscribe(() => {
        const missingKeys = keysArg.filter(keyArg => !this.dataObject[keyArg]);
        if (missingKeys.length === 0) {
          subscription.unsubscribe();
          resolve();
        }
      });
    });
  }
}