knowfoolery/backend/shared/infra/utils/httputil/pagination.go

// Package httputil provides HTTP utility functions for the KnowFoolery application.
package httputil

import (
	"strconv"

	"github.com/gofiber/fiber/v3"

	"knowfoolery/backend/shared/domain/types"
)

// PaginationFromQuery extracts pagination parameters from query string.
func PaginationFromQuery(c fiber.Ctx) types.Pagination {
	page := c.Query("page", "1")
	pageSize := c.Query("page_size", strconv.Itoa(types.DefaultPageSize))

	pageNum, err := strconv.Atoi(page)
	if err != nil || pageNum < 1 {
		pageNum = 1
	}

	pageSizeNum, err := strconv.Atoi(pageSize)
	if err != nil || pageSizeNum < 1 {
		pageSizeNum = types.DefaultPageSize
	}
	if pageSizeNum > types.MaxPageSize {
		pageSizeNum = types.MaxPageSize
	}

	return types.Pagination{
		Page:     pageNum,
		PageSize: pageSizeNum,
	}
}

// SortingParams holds sorting parameters.
type SortingParams struct {
	Field     string
	Direction string // "asc" or "desc"
}

// DefaultSorting returns default sorting parameters.
func DefaultSorting(defaultField string) SortingParams {
	return SortingParams{
		Field:     defaultField,
		Direction: "asc",
	}
}

// SortingFromQuery extracts sorting parameters from query string.
func SortingFromQuery(c fiber.Ctx, defaultField string, allowedFields []string) SortingParams {
	sort := c.Query("sort", defaultField)
	direction := c.Query("direction", "asc")

	// Validate sort field
	isAllowed := false
	for _, field := range allowedFields {
		if field == sort {
			isAllowed = true
			break
		}
	}
	if !isAllowed {
		sort = defaultField
	}

	// Validate direction
	if direction != "asc" && direction != "desc" {
		direction = "asc"
	}

	return SortingParams{
		Field:     sort,
		Direction: direction,
	}
}

// FilterParams holds common filter parameters.
type FilterParams struct {
	Search   string
	Status   string
	DateFrom string
	DateTo   string
	Custom   map[string]string
}

// FiltersFromQuery extracts common filter parameters from query string.
func FiltersFromQuery(c fiber.Ctx) FilterParams {
	return FilterParams{
		Search:   c.Query("search"),
		Status:   c.Query("status"),
		DateFrom: c.Query("date_from"),
		DateTo:   c.Query("date_to"),
		Custom:   make(map[string]string),
	}
}

// WithCustomFilter adds a custom filter parameter.
func (f *FilterParams) WithCustomFilter(c fiber.Ctx, name string) *FilterParams {
	if value := c.Query(name); value != "" {
		f.Custom[name] = value
	}
	return f
}

// QueryParams holds all common query parameters.
type QueryParams struct {
	Pagination types.Pagination
	Sorting    SortingParams
	Filters    FilterParams
}

// QueryParamsFromContext extracts all common query parameters.
func QueryParamsFromContext(c fiber.Ctx, defaultSortField string, allowedSortFields []string) QueryParams {
	return QueryParams{
		Pagination: PaginationFromQuery(c),
		Sorting:    SortingFromQuery(c, defaultSortField, allowedSortFields),
		Filters:    FiltersFromQuery(c),
	}
}