package main

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

	"ballet-island/backend/internal/database"
	"ballet-island/backend/internal/httpapi"
	"ballet-island/backend/internal/identity"
	"github.com/jackc/pgx/v5/pgxpool"
)

func main() {
	slog.SetDefault(slog.New(slog.NewJSONHandler(os.Stdout, nil)))
	if err := run(); err != nil {
		slog.Error("server stopped", "error", err)
		os.Exit(1)
	}
}

func run() error {
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	databaseURL := os.Getenv("DATABASE_URL")
	if databaseURL == "" {
		for _, key := range []string{"PGHOST", "PGDATABASE", "PGUSER", "PGPASSWORD"} {
			if os.Getenv(key) == "" {
				return fmt.Errorf("%s is required when DATABASE_URL is unset", key)
			}
		}
	}

	// Production uses a URL; local development retains libpq environment variables.
	pool, err := pgxpool.New(ctx, databaseURL)
	if err != nil {
		if databaseURL != "" {
			// Parser errors can include the URL, so do not log the credential-bearing input.
			return errors.New("configure database: invalid DATABASE_URL")
		}
		return fmt.Errorf("configure database: %w", err)
	}
	defer pool.Close()

	startupCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
	err = pool.Ping(startupCtx)
	if err == nil {
		err = database.Migrate(startupCtx, pool)
	}
	cancel()
	if err != nil {
		return fmt.Errorf("connect database: %w", err)
	}

	addr := os.Getenv("HTTP_ADDR")
	if addr == "" {
		addr = "127.0.0.1:8080"
	}
	server := &http.Server{
		Addr:              addr,
		Handler:           httpapi.NewAppHandler(pool, &identity.WeChat{AppID: os.Getenv("WECHAT_APP_ID"), AppSecret: os.Getenv("WECHAT_APP_SECRET")}, nil),
		ReadHeaderTimeout: 5 * time.Second,
		ReadTimeout:       10 * time.Second,
		WriteTimeout:      10 * time.Second,
		IdleTimeout:       60 * time.Second,
	}

	serverErr := make(chan error, 1)
	go func() {
		slog.Info("server starting", "address", addr)
		serverErr <- server.ListenAndServe()
	}()

	select {
	case err := <-serverErr:
		if !errors.Is(err, http.ErrServerClosed) {
			return err
		}
	case <-ctx.Done():
		slog.Info("server shutting down")
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		if err := server.Shutdown(shutdownCtx); err != nil {
			_ = server.Close()
			return fmt.Errorf("shutdown server: %w", err)
		}
	}
	return nil
}