package handler

import (
	"net/http"
	"time"

	"github.com/prabhupadasays/spsays-bff/pkg/response"
)

// ListShortURLs — GET /admin/short-urls?q=&limit=&offset= — paginated list of
// shortened URLs, newest first.
func (h *AdminHandler) ListShortURLs(w http.ResponseWriter, r *http.Request) {
	q, limit, offset := pageParams(r)
	items, total, err := h.svc.ListShortURLs(r.Context(), q, limit, offset)
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "could not list short urls")
		return
	}
	response.JSONWithMeta(w, http.StatusOK, items, meta(total, limit, offset))
}

// ShortURLStats — GET /admin/short-urls/stats?from=YYYY-MM-DD&to=YYYY-MM-DD —
// today/week/month/all-time counts, plus a custom range when from+to are given.
func (h *AdminHandler) ShortURLStats(w http.ResponseWriter, r *http.Request) {
	from, to := parseDateRange(r)
	stats, err := h.svc.ShortURLStats(r.Context(), from, to)
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "could not load short url stats")
		return
	}
	response.JSON(w, http.StatusOK, stats)
}

// parseDateRange reads ?from=YYYY-MM-DD&to=YYYY-MM-DD (UTC). `to` is treated as
// inclusive, so the returned upper bound is the exclusive start of the next
// day. Returns (nil, nil) unless both dates are present and valid.
func parseDateRange(r *http.Request) (*time.Time, *time.Time) {
	fs := r.URL.Query().Get("from")
	ts := r.URL.Query().Get("to")
	if fs == "" || ts == "" {
		return nil, nil
	}
	from, err1 := time.ParseInLocation("2006-01-02", fs, time.UTC)
	to, err2 := time.ParseInLocation("2006-01-02", ts, time.UTC)
	if err1 != nil || err2 != nil {
		return nil, nil
	}
	toExclusive := to.AddDate(0, 0, 1)
	return &from, &toExclusive
}