pagination.dto.ts

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

/**
 * Query parameters for pagination
 */
export class PaginationQueryDto {
  @ApiPropertyOptional({
    description: 'Page number (1-indexed)',
    example: 1,
    default: 1,
  })
  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  page: number = 1;

  @ApiPropertyOptional({
    description: 'Number of items per page',
    example: 10,
    minimum: 1,
    maximum: 100,
    default: 10,
  })
  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  @Max(100)
  limit: number = 10;

  @ApiPropertyOptional({
    description: 'Field to sort by',
    example: 'createdAt',
    default: 'createdAt',
  })
  @IsOptional()
  @IsString()
  sortBy: string = 'createdAt';

  @ApiPropertyOptional({
    description: 'Sort order',
    example: 'desc',
    enum: ['asc', 'desc'],
    default: 'desc',
  })
  @IsOptional()
  @IsIn(['asc', 'desc'])
  sortOrder: 'asc' | 'desc' = 'desc';
}

/**
 * Pagination metadata included in list responses
 */
export class PaginationMetadataDto {
  @ApiProperty({ example: 100 })
  total: number;

  @ApiProperty({ example: 1 })
  page: number;

  @ApiProperty({ example: 10 })
  limit: number;

  @ApiProperty({ example: 10 })
  pages: number;

  @ApiProperty({ example: true })
  hasNext: boolean;

  @ApiProperty({ example: false })
  hasPrev: boolean;

  @ApiProperty({ example: 'createdAt' })
  sortBy: string;

  @ApiProperty({ example: 'desc' })
  sortOrder: 'asc' | 'desc';
}

/**
 * Generic paginated response wrapper
 */
export class PaginatedResponseDto<T> {
  @ApiProperty({ isArray: true })
  data: T[];

  @ApiProperty({ type: PaginationMetadataDto })
  meta: PaginationMetadataDto;
}