package middleware

import (
	"context"
	"net/http"
	"strconv"
)

type Pagination struct {
	Page     int
	PageSize int
}

const PaginationContextKey = "pagination"

func PaginationMiddleware() func(next http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			page := 1
			pageSize := 20

			if p := r.URL.Query().Get("page"); p != "" {
				if parsed, err := strconv.Atoi(p); err == nil && parsed >= 1 {
					page = parsed
				}
			}

			if ps := r.URL.Query().Get("page_size"); ps != "" {
				if parsed, err := strconv.Atoi(ps); err == nil && parsed >= 1 {
					pageSize = parsed
				}
			}

			if pageSize > 100 {
				pageSize = 100
			}

			ctx := context.WithValue(r.Context(), PaginationContextKey, Pagination{
				Page:     page,
				PageSize: pageSize,
			})

			next.ServeHTTP(w, r.WithContext(ctx))
		}

		return http.HandlerFunc(fn)
	}
}