import { VstoreConfig, VstoreSetConfig } from '../types/types';
import {
  filterEmptyValueAndFuncValue,
  getDefaultAdapter,
} from '../utils/utils';
import dayjs from 'dayjs';

class Vstore<T extends object = any> {
  config: VstoreConfig<T>;

  constructor(config?: VstoreConfig<T>) {
    this.config = config || {};
    this.config.adapter = this.config.adapter || getDefaultAdapter();
  }

  /**
   * Sets the value of the pair identified by key to value
   * @param originalKey key
   * @param value data
   * @param config VstoreSetConfig
   * @returns vstore
   */
  set<K extends keyof T>(
    originalKey: K,
    value: T[K],
    config?: VstoreSetConfig
  ) {
    this.checkAdapter();
    const key = this.getKey(originalKey);
    const expireAt = this.getExpireAt(config);
    const originData = {
      data: value,
      expireAt,
      once: config?.once,
    };
    const data = filterEmptyValueAndFuncValue(originData);
    if (data) {
      try {
        this.config.adapter.set(key, data);
      } catch (err) {
        this.config.errorHandler?.(err);
      }
    }
    return this;
  }

  /**
   * Get the current value associated with the given key, or undefined if the given key does not exist.
   * @param originalKey key
   * @returns  data
   */
  get<K extends keyof T>(originalKey: K): T[K] | undefined {
    const storageVal = this.getStorageValue(originalKey);
    if (storageVal === undefined) {
      return this.getDefaultValue(originalKey);
    }
    return storageVal;
  }

  /**
   * Removes the key/value pair with the given key, if a key/value pair with the given key exists.
   * @param originalKey key
   * @returns void;
   */
  del(originalKey: keyof T): void {
    this.checkAdapter();
    const key = this.getKey(originalKey);
    try {
      return this.config.adapter.del(key);
    } catch (err) {
      this.config.errorHandler?.(err);
    }
  }
  /**
   * Removes all the key/value pair.
   * @returns void;
   */
  clear() {
    this.checkAdapter();
    try {
      return this.config.adapter.clear();
    } catch (err) {
      this.config.errorHandler?.(err);
    }
  }
  private getKey(key) {
    if (this.config.formatKey) {
      return this.config.formatKey(key);
    }
    return key;
  }
  private getExpireAt(config?: VstoreSetConfig): undefined | number {
    if (config?.expireAt || (!config?.expire && this.config.expireAt)) {
      const expireAt = config?.expireAt || this.config.expireAt;
      // like '2022-01-01 12:00:00'
      const obj = dayjs(expireAt);
      if (obj.isValid()) {
        return obj.valueOf();
      }
      return void 0;
    }

    if (config?.expire || this.config.expire) {
      const expire = config?.expire || this.config.expire;
      let obj;
      if (typeof expire === 'number') {
        obj = dayjs().add(expire, 's');
      } else {
        obj = dayjs().add(expire?.[0], expire?.[1]);
      }
      if (obj.isValid()) {
        return obj.valueOf();
      }
    }
  }

  private getStorageValue<K extends keyof T>(originalKey: K): T[K] | undefined {
    this.checkAdapter();
    const key = this.getKey(originalKey);
    try {
      const result = this.config.adapter.get(key);
      if (!result) {
        return void 0;
      }
      if (result.expireAt) {
        const isexpired = dayjs().isAfter(dayjs(result.expireAt));
        if (isexpired) {
          this.del(key);
          return void 0;
        } else {
          return result.data;
        }
      } else {
        if (result?.once) {
          this.del(key);
        }
        return result.data;
      }
    } catch (err) {
      this.config.errorHandler?.(err);
    }
  }

  private getDefaultValue(key) {
    if (this.config.defaultValues) {
      return this.config.defaultValues[key];
    }
    return void 0;
  }

  private checkAdapter() {
    if (!this.config.adapter) {
      throw new Error('you need to define an adapter');
    }
  }

  /**
   * Create new vstores instance
   * @param config VstoreConfig
   * @returns vstore
   */
  create<D extends object>(config?: VstoreConfig<D>) {
    return new Vstore<D>(config);
  }
}

export default Vstore;