import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
import { InjectRepository } from '@mikro-orm/nestjs';
import { EntityRepository, FilterQuery } from '@mikro-orm/core';
import { Role } from '../entities/role.entity';
import { Permission } from '../entities/permission.entity';
import { Restaurant } from '../../restaurants/entities/restaurant.entity';
import { EntityManager } from '@mikro-orm/postgresql';
import { CreateRoleDto } from '../dto/create-role.dto';
import { UpdateRoleDto } from '../dto/update-role.dto';
import { RolePermission } from '../entities/rolePermission.entity';

@Injectable()
export class RolesService {
  constructor(
    @InjectRepository(Role)
    private readonly roleRepository: EntityRepository<Role>,
    @InjectRepository(Permission)
    private readonly permissionRepository: EntityRepository<Permission>,
    private readonly em: EntityManager,
  ) { }

  async createRestaurantRole(dto: CreateRoleDto, restId: string) {
    const { name, permissionIds } = dto;

    // Check if role already exists
    const existing = await this.roleRepository.findOne({ name, restaurant: restId ? { id: restId } : null });
    if (existing) {
      throw new BadRequestException('Role with this name already exists for the restaurant');
    }

    let restaurant: Restaurant | null = null;
    if (restId) {
      restaurant = await this.em.findOne(Restaurant, { id: restId });
      if (!restaurant) {
        throw new NotFoundException('Restaurant not found');
      }
    }

    const role = this.roleRepository.create({
      name,
      restaurant,
      isSystem: false,
    });

    // Add permissions if provided
    if (permissionIds && permissionIds.length > 0) {
      const permissions = await this.permissionRepository.find({ id: { $in: permissionIds } });
      if (permissions.length !== permissionIds.length) {
        throw new BadRequestException('One or more permissions not found');
      }
      permissions.forEach(p => role.permissions.add(p));
    }

    await this.em.persistAndFlush(role);
    return role;
  }

  async findAllGeneralAndRestaurantRoles(restId: string) {
    const where: FilterQuery<Role> = { $or: [{ restaurant: restId }, { restaurant: null }], isSystem: false };

    const roles = await this.roleRepository.find(where, {
      orderBy: { createdAt: 'desc' },
      populate: ['permissions', 'restaurant'],
    });

    return roles;
  }

  async findOne(restId: string, id: string) {
    const role = await this.roleRepository.findOne(
      { id, restaurant: { id: restId } },
      { populate: ['permissions', 'restaurant'] },
    );
    if (!role) {
      throw new NotFoundException('Role not found');
    }
    return role;
  }

  async update(restId: string, id: string, dto: UpdateRoleDto) {
    const role = await this.roleRepository.findOne(
      { id, restaurant: { id: restId } },
      { populate: ['permissions', 'restaurant'] },
    );
    if (!role) {
      throw new NotFoundException('Role not found');
    }

    if (dto.name) {
      role.name = dto.name;
    }

    if (dto.permissionIds && dto.permissionIds.length >= 0) {
      // Clear existing permissions and add new ones
      role.permissions.removeAll();
      const permissions = await this.permissionRepository.find({ id: { $in: dto.permissionIds } });
      if (permissions.length !== dto.permissionIds.length) {
        throw new BadRequestException('One or more permissions not found');
      }
      permissions.forEach(p => role.permissions.add(p));
    }

    await this.em.persistAndFlush(role);
    return role;
  }

  async findAllSystemRoles() {
    const roles = await this.roleRepository.find(
      { isSystem: true },
      {
        orderBy: { createdAt: 'desc' },
        populate: ['permissions', 'restaurant'],
      },
    );

    return roles;
  }

  async remove(restId: string, id: string) {
    const role = await this.roleRepository.findOne(
      { id, restaurant: { id: restId } },
      { populate: ['permissions', 'restaurant'] },
    );
    if (!role) {
      throw new NotFoundException('Role not found');
    }
    if (!role.admins.isEmpty()) {
      throw new BadRequestException('Role has admins');
    }

    // Hard delete pivot table entries (role_permissions) before soft deleting the role
    await this.em.nativeDelete(RolePermission, { role: { id: role.id } });

    // Soft delete the role
    role.deletedAt = new Date();
    return this.em.persistAndFlush(role);
  }
}