appcore/request/pager.go

// Copyright 2024 Patial Tech (Ankit Patial).
//
// This file is part of code.patial.tech/go/appcore, which is MIT licensed.
// See http://opensource.org/licenses/MIT

package request

import (
	"net/http"
	"strconv"
	"strings"

	"code.patial.tech/go/appcore/ptr"
)

type Pager struct {
	Search      string
	OrderBy     *string `json:"orderBy"`
	OrderAsc    *bool   `json:"orderAsc"`
	Page        int     `json:"page"`
	Size        int     `json:"size"`
	Total       int     `json:"total"`
	TotalNeeded bool    `json:"-"`
}

func (i *Pager) HasSearch() bool {
	if i == nil {
		return false
	}

	return strings.TrimSpace(i.Search) != ""
}

func (i *Pager) Offset() int {
	if i == nil {
		return 0
	}

	return (i.Page - 1) * i.Limit()
}

func (i *Pager) Limit() int {
	if i == nil || ptr.GetNumber(&i.Size) < 1 {
		return 20
	}

	return i.Size
}

// GetPager info from request's query parameters
func GetPager(r *http.Request) Pager {
	p := Pager{
		Page:     1,
		Size:     20,
		OrderAsc: ptr.Bool(true),
	}

	if v := r.URL.Query().Get("q"); v != "" {
		p.Search = strings.TrimSpace(v)
	}

	if v := r.URL.Query().Get("pg"); v != "" {
		if vv, err := strconv.Atoi(v); err == nil {
			p.Page = int(vv)
		}
	}

	if v := r.URL.Query().Get("pg_s"); v != "" {
		if vv, err := strconv.Atoi(v); err == nil {
			p.Size = int(vv)
		}
	}

	if v := r.URL.Query().Get("pg_ob"); v != "" {
		p.OrderBy = &v
	}

	if v := r.URL.Query().Get("pg_o"); v != "" {
		switch strings.ToLower(v) {
		case "asc":
			p.OrderAsc = ptr.Bool(true)
		case "desc":
			p.OrderAsc = ptr.Bool(false)
		}
	}

	if v := r.URL.Query().Get("pg_t"); v == "n" {
		p.TotalNeeded = true
	}

	return p
}