import { IsOptional, IsInt, Min, Max } from 'class-validator';
import { Type } from 'class-transformer';
import { ApiPropertyOptional } from '@nestjs/swagger';

export class PaginationDto {
  @ApiPropertyOptional({ default: 1 })
  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  page?: number = 1;

  @ApiPropertyOptional({ default: 20 })
  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  @Max(100)
  limit?: number = 20;
}

export interface PaginatedResult<T> {
  data: T[];
  meta: {
    total: number;
    page: number;
    limit: number;
    totalPages: number;
  };
}

export function paginate<T>(
  data: T[],
  total: number,
  page: number,
  limit: number,
): PaginatedResult<T> {
  return {
    data,
    meta: {
      total,
      page,
      limit,
      totalPages: Math.ceil(total / limit) || 1,
    },
  };
}