package notices

import (
	"encoding/json"
	"net/http"
	"time"

	"github.com/wangjia/pangolin/server/internal/apierr"
	"github.com/wangjia/pangolin/server/internal/auth"
)

// listLimit 是 GET /v1/notices 单次返回的最大条数(合并广播+定向后按 published_at 倒序截断)。
const listLimit = 50

// Handler 承载 /v1/notices、/v1/notices/read 两个受保护端点。
type Handler struct {
	st *Store
}

func NewHandler(st *Store) *Handler {
	return &Handler{st: st}
}

// List handles GET /v1/notices: 返回该用户可见的通知(广播 ∪ 定向)与未读数。
func (h *Handler) List(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	uid, ok := auth.UserIDFromContext(ctx)
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}
	items, unreadCount, err := h.st.ListForUser(ctx, uid, time.Now().UTC(), listLimit)
	if err != nil {
		apierr.WriteJSON(w, http.StatusInternalServerError, apierr.ErrInternal)
		return
	}
	if items == nil {
		items = []Notice{}
	}
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	_ = json.NewEncoder(w).Encode(map[string]any{
		"notices":      items,
		"unread_count": unreadCount,
	})
}

// MarkRead handles POST /v1/notices/read: 把用户已读水位推进到当前时间。
func (h *Handler) MarkRead(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	uid, ok := auth.UserIDFromContext(ctx)
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}
	if err := h.st.MarkRead(ctx, uid, time.Now().UTC()); err != nil {
		apierr.WriteJSON(w, http.StatusInternalServerError, apierr.ErrInternal)
		return
	}
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	_ = json.NewEncoder(w).Encode(map[string]any{"ok": true})
}