package app

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"net/http"
	"time"

	"github.com/owen/vibeproxy/internal/metrics"
)

type adminServer struct {
	srv *http.Server
}

func newAdminServer(addr string, handler http.Handler) *adminServer {
	return &adminServer{srv: &http.Server{
		Addr:         addr,
		Handler:      handler,
		ReadTimeout:  30 * time.Second,
		WriteTimeout: 60 * time.Second,
		IdleTimeout:  120 * time.Second,
	}}
}

func (a *adminServer) Start(ctx context.Context) error {
	errCh := make(chan error, 1)
	go func() {
		if err := a.srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			errCh <- fmt.Errorf("admin listener: %w", err)
		}
	}()
	select {
	case <-ctx.Done():
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
		defer cancel()
		return a.srv.Shutdown(shutdownCtx)
	case err := <-errCh:
		return err
	}
}

func healthzHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
}

func readyzHandler(db *sql.DB) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if err := db.PingContext(r.Context()); err != nil {
			w.WriteHeader(http.StatusServiceUnavailable)
			w.Write([]byte("database unavailable"))
			return
		}
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ready"))
	})
}

func metricsHandler() http.Handler {
	return metrics.Handler()
}