package site

import (
	"RenewCMS/api/pkg/apperr"
	validator "RenewCMS/api/pkg/validator"
	"RenewCMS/internal/infrastructure/useCases"
	"encoding/json"
	"log"
	"net/http"
	"net/url"
	"strconv"
	"time"

	"github.com/go-chi/chi/v5"
)

const (
	defaultSitemapPage = 1
	defaultSitemapSize = 100
	totalCountHeader   = "X-Total-Count"
)

type SitemapHandler struct {
	ListUseCase *useCases.ListSitemapUseCase
}

func NewSitemapHandler(list *useCases.ListSitemapUseCase) *SitemapHandler {
	return &SitemapHandler{ListUseCase: list}
}

type sitemapQuery struct {
	Page int `validate:"gte=1"`
	Size int `validate:"oneof=25 50 100 500"`
}

type sitemapItem struct {
	URL        string `json:"url"`
	ModifiedAt string `json:"modified_at"`
	Noindex    bool   `json:"noindex"`
}

func sitemapIntParam(values url.Values, name string, fallback int) (int, error) {
	if !values.Has(name) {
		return fallback, nil
	}
	return strconv.Atoi(values.Get(name))
}

func readSitemapQuery(values url.Values) (sitemapQuery, error) {
	page, err := sitemapIntParam(values, "page", defaultSitemapPage)
	if err != nil {
		return sitemapQuery{}, err
	}
	size, err := sitemapIntParam(values, "size", defaultSitemapSize)
	if err != nil {
		return sitemapQuery{}, err
	}
	return sitemapQuery{Page: page, Size: size}, nil
}

func (h *SitemapHandler) Sitemap(w http.ResponseWriter, r *http.Request) {
	query, err := readSitemapQuery(r.URL.Query())
	if err != nil || validator.Validate.Struct(query) != nil {
		http.Error(w, apperr.BodyErrorMessage, http.StatusBadRequest)
		return
	}

	page, err := h.ListUseCase.List(chi.URLParam(r, "key"), query.Page, query.Size)
	if err != nil {
		writeSiteError(w, err)
		return
	}

	items := make([]sitemapItem, 0, len(page.Entries))
	for _, entry := range page.Entries {
		items = append(items, sitemapItem{URL: entry.URL, ModifiedAt: entry.ModifiedAt.UTC().Format(time.RFC3339), Noindex: entry.Noindex})
	}
	body, err := json.Marshal(items)
	if err != nil {
		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
		return
	}
	w.Header().Set(totalCountHeader, strconv.Itoa(page.Total))
	if _, err := w.Write(body); err != nil {
		log.Printf("Failed to write response: %v", err)
	}
}