// Package server 提供 HTTP 服务与优雅启停。
package server

import (
	"context"
	"errors"
	"log/slog"
	"net/http"
	"os/signal"
	"syscall"
	"time"
)

// Server 封装 http.Server 与优雅关闭。
type Server struct {
	http *http.Server
	log  *slog.Logger
}

// New 创建 Server。
func New(addr string, handler http.Handler, log *slog.Logger) *Server {
	return &Server{
		http: &http.Server{
			Addr:              addr,
			Handler:           handler,
			ReadHeaderTimeout: 10 * time.Second,
			ReadTimeout:       30 * time.Second,
			WriteTimeout:      30 * time.Second,
			IdleTimeout:       60 * time.Second,
		},
		log: log,
	}
}

// Run 启动并阻塞，直到收到 SIGINT/SIGTERM 完成优雅关闭。
func (s *Server) Run() error {
	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	errCh := make(chan error, 1)
	go func() {
		s.log.Info("server: listening", "addr", s.http.Addr)
		errCh <- s.http.ListenAndServe()
	}()

	select {
	case err := <-errCh:
		if errors.Is(err, http.ErrServerClosed) {
			return nil
		}
		return err
	case <-ctx.Done():
		s.log.Info("server: shutting down")
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		return s.http.Shutdown(shutdownCtx)
	}
}