// Command admin-dashboard is a stateless, server-rendered web UI over
// control-api's /api/v1/admin/* HTTP API — see docs/DASHBOARD.md. It never
// connects to the database and holds no state of its own.
package main

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

	"cloudipvalidator/internal/config"
	"cloudipvalidator/internal/dashboard"
)

func main() {
	configPath := flag.String("config", "configs/admin-dashboard.yaml", "path to admin-dashboard config file")
	flag.Parse()

	log := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo}))

	if err := run(*configPath, log); err != nil {
		log.Error("fatal", "err", err)
		os.Exit(1)
	}
}

func run(configPath string, log *slog.Logger) error {
	cfg, err := config.LoadAdminDashboard(configPath)
	if err != nil {
		return fmt.Errorf("load config: %w", err)
	}

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

	controlAPIToken := os.Getenv(cfg.ControlAPI.TokenEnv)
	if controlAPIToken == "" {
		log.Warn("control-api admin token is not set: calls to control-api are sent without credentials", "env", cfg.ControlAPI.TokenEnv)
	}

	srv, err := dashboard.New(dashboard.Config{
		ControlAPIBaseURL:     cfg.ControlAPI.BaseURL,
		ControlAPITimeout:     time.Duration(cfg.ControlAPI.TimeoutSeconds) * time.Second,
		LastCompletedCount:    cfg.Overview.LastCompletedCount,
		OverviewPollIntervalS: cfg.Overview.PollIntervalSeconds,
		ControlAPIToken:       controlAPIToken,
		Username:              os.Getenv(cfg.Auth.UsernameEnv),
		Password:              os.Getenv(cfg.Auth.PasswordEnv),
		SessionSecret:         os.Getenv(cfg.Auth.SessionSecretEnv),
		SessionTTL:            time.Duration(cfg.Auth.SessionTTLMinutes) * time.Minute,
	}, log)
	if err != nil {
		return fmt.Errorf("init dashboard: %w", err)
	}

	httpServer := &http.Server{Addr: cfg.Server.ListenAddr, Handler: srv.Handler()}

	errCh := make(chan error, 1)
	go func() {
		log.Info("listening", "addr", cfg.Server.ListenAddr, "control_api", cfg.ControlAPI.BaseURL)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			errCh <- err
		}
	}()

	select {
	case <-ctx.Done():
		log.Info("shutting down")
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		return httpServer.Shutdown(shutdownCtx)
	case err := <-errCh:
		return err
	}
}