import * as repository from "@apihub24/repository";
import { Inject, Injectable } from "@nestjs/common";
import { IAccount } from "../contracts/models/account";
import { IGroup } from "../contracts/models/group";

@Injectable()
export class AccountService {
  constructor(
    @Inject("@apihub24/account_repository")
    private readonly accountRepository: repository.IRepository<IAccount>,
    @Inject("@apihub24/group_repository")
    private readonly groupRepository: repository.IRepository<IGroup>
  ) {}

  /**
   * This asynchronous method retrieves accounts that match a given filter.
   * @param filter A function that takes an `IAccount` object and returns a boolean. It serves as the condition for selecting accounts.
   * @returns A Promise that resolves to an array of `IAccount` objects that satisfy the filter condition.
   */
  async getBy(filter: (account: IAccount) => boolean): Promise<IAccount[]> {
    return await this.accountRepository.getBy(filter);
  }

  /**
   * This asynchronous method saves a single `IAccount` object. It uses the `accountRepository` to persist the account. If the save operation fails, it logs a warning and returns null.
   * @param account The `IAccount` object to be saved.
   * @returns A Promise that resolves to the saved `IAccount` object, or `null` if the save operation fails.
   */
  async save(account: IAccount): Promise<IAccount | null> {
    try {
      const accounts = await this.accountRepository.save([account]);
      return accounts?.length ? accounts[0] : null;
    } catch (err) {
      console.warn(err);
      return null;
    }
  }

  /**
   * This asynchronous method deletes accounts based on a provided filter.
   * @param filter A function that takes an `IAccount` object and returns a boolean. It specifies which accounts to delete.
   * @returns A Promise that resolves to `true` if the deletion is successful, and `false` otherwise.
   */
  async delete(filter: (account: IAccount) => boolean): Promise<boolean> {
    return await this.accountRepository.deleteBy(filter);
  }

  /**
   * This asynchronous method adds a specific account to a group. It first finds both the account and the group using their IDs. If they are found, it adds the group to the account's groups array and saves the updated account.
   * @param accountId The unique identifier of the account.
   * @param groupId The unique identifier of the group to which the account should be added.
   * @returns A Promise that resolves to the updated `IAccount` object.
   * @throws An error if the account or the group cannot be found, or if the updated account cannot be saved.
   */
  async addAccountToGroup(
    accountId: string,
    groupId: string
  ): Promise<IAccount> {
    const [account, group] = await this.getAccountAndGroup(accountId, groupId);
    account.groups = account.groups.filter((x) => x.id !== groupId);
    account.groups.push(group);
    const accountsSaved = await this.accountRepository.save([account]);
    if (!accountsSaved.length) {
      throw new Error(`account ${account.accountName} can not be saved`);
    }
    return accountsSaved[0];
  }

  /**
   * This asynchronous method removes a specific account from a group. It first finds the account and group, then filters the group out of the account's groups array before saving the updated account.
   * @param accountId The unique identifier of the account.
   * @param groupId The unique identifier of the group to be removed.
   * @returns A Promise that resolves to the updated `IAccount` object.
   * @throws An error if the account or the group cannot be found, or if the updated account cannot be saved.
   */
  async removeAccountFromGroup(
    accountId: string,
    groupId: string
  ): Promise<IAccount> {
    const [account] = await this.getAccountAndGroup(accountId, groupId);
    account.groups = account.groups.filter((x) => x.id !== groupId);
    const accountsSaved = await this.accountRepository.save([account]);
    if (!accountsSaved.length) {
      throw new Error(`account ${account.accountName} can not be saved`);
    }
    return accountsSaved[0];
  }

  private async getAccountAndGroup(
    accountId: string,
    groupId: string
  ): Promise<[IAccount, IGroup]> {
    const accounts = await this.accountRepository.getBy(
      (x) => x.id === accountId
    );
    if (!accounts.length) {
      throw new Error(`account with id ${accountId} not found`);
    }
    const groups = await this.groupRepository.getBy((x) => x.id === groupId);
    if (!groups.length) {
      throw new Error(`group with id ${groupId} not found`);
    }
    return [accounts[0], groups[0]];
  }
}