package main

import (
	"context"
	"fmt"
	"log/slog"
	"os"
	"os/signal"
	"runtime/debug"
	"syscall"

	"github.com/spf13/cobra"
	"golang.org/x/term"

	"git.warky.dev/wdevs/pgsql-broker/pkg/broker"
	"git.warky.dev/wdevs/pgsql-broker/pkg/broker/adapter"
	"git.warky.dev/wdevs/pgsql-broker/pkg/broker/config"
	"git.warky.dev/wdevs/pgsql-broker/pkg/broker/install"
)

var (
	// Version information (injected by build)
	Version   = "dev"
	BuildTime = "unknown"
	Commit    = "unknown"

	// Command line flags
	cfgFile    string
	logLevel   string
	verifyOnly bool

	withRoles             bool
	adminUser             string
	adminPassword         string
	brokerAdminPassword   string
	brokerRuntimePassword string
	brokerEnqueuePassword string
)

func main() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
}

var rootCmd = &cobra.Command{
	Use:   "pgsql-broker",
	Short: "PostgreSQL job broker for background job processing",
	Long: `PostgreSQL Broker is a job processing system that uses PostgreSQL
LISTEN/NOTIFY for event-driven job execution. It supports multiple queues,
priority-based scheduling, and horizontal scaling.`,
	Version: fmt.Sprintf("%s (built %s, commit %s)", Version, BuildTime, Commit),
}

var startCmd = &cobra.Command{
	Use:   "start",
	Short: "Start the broker instance",
	Long:  `Start the broker instance and begin processing jobs from the database queue.`,
	RunE: func(cmd *cobra.Command, args []string) error {
		return runBroker()
	},
}

var versionCmd = &cobra.Command{
	Use:   "version",
	Short: "Print version information",
	Run: func(cmd *cobra.Command, args []string) {
		fmt.Printf("pgsql-broker version %s\n", Version)
		fmt.Printf("Built: %s\n", BuildTime)
		fmt.Printf("Commit: %s\n", Commit)
	},
}

var installCmd = &cobra.Command{
	Use:   "install",
	Short: "Install database schema (tables and procedures)",
	Long: `Install the required database schema including tables and stored procedures.
This command will create all necessary tables and functions in the configured database.`,
	RunE: func(cmd *cobra.Command, args []string) error {
		return runInstall()
	},
}

func init() {
	rootCmd.AddCommand(startCmd)
	rootCmd.AddCommand(versionCmd)
	rootCmd.AddCommand(installCmd)

	// Persistent flags
	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is broker.yaml)")
	rootCmd.PersistentFlags().StringVar(&logLevel, "log-level", "info", "log level (debug, info, warn, error)")

	// Install command flags
	installCmd.Flags().BoolVar(&verifyOnly, "verify-only", false, "only verify installation without installing")
	installCmd.Flags().BoolVar(&withRoles, "with-roles", false, "also create/update the broker_admin, broker_runtime, and broker_enqueue roles")
	installCmd.Flags().StringVar(&adminUser, "admin-user", "", "superuser/CREATEROLE login used only for --with-roles (falls back to PGUSER/PG_USER env)")
	installCmd.Flags().StringVar(&adminPassword, "admin-password", "", "password for --admin-user (falls back to PGPASSWORD/PG_PASS env, then an interactive prompt)")
	installCmd.Flags().StringVar(&brokerAdminPassword, "broker-admin-password", "", "password to set for broker_admin (falls back to BROKER_ADMIN_PASSWORD env, then an interactive prompt)")
	installCmd.Flags().StringVar(&brokerRuntimePassword, "broker-runtime-password", "", "password to set for broker_runtime (falls back to BROKER_RUNTIME_PASSWORD env, then an interactive prompt)")
	installCmd.Flags().StringVar(&brokerEnqueuePassword, "broker-enqueue-password", "", "password to set for broker_enqueue (falls back to BROKER_ENQUEUE_PASSWORD env, then an interactive prompt)")
}

// resolveCredential returns the first non-empty value among the flag value,
// the given environment variables (checked in order), and -- if none are
// set -- an interactive masked prompt. It errors rather than prompting when
// stdin is not a terminal, since a hang in a non-interactive context (CI,
// systemd) is worse than a clear failure.
func resolveCredential(flagVal string, envNames []string, promptLabel string) (string, error) {
	if flagVal != "" {
		return flagVal, nil
	}
	for _, name := range envNames {
		if v := os.Getenv(name); v != "" {
			return v, nil
		}
	}

	fd := int(os.Stdin.Fd())
	if !term.IsTerminal(fd) {
		return "", fmt.Errorf(
			"%s not provided and stdin is not a terminal to prompt on; pass it via flag or one of %v",
			promptLabel, envNames,
		)
	}

	fmt.Fprintf(os.Stderr, "%s: ", promptLabel)
	b, err := term.ReadPassword(fd)
	fmt.Fprintln(os.Stderr)
	if err != nil {
		return "", fmt.Errorf("failed to read %s: %w", promptLabel, err)
	}
	if len(b) == 0 {
		return "", fmt.Errorf("%s must not be empty", promptLabel)
	}
	return string(b), nil
}

func runBroker() (err error) {
	// Top-level safety net: an unrecovered panic anywhere in startup or the
	// shutdown wait must not crash the process with a raw trace -- log it
	// and return a normal error instead.
	defer func() {
		if r := recover(); r != nil {
			err = fmt.Errorf("recovered from panic in runBroker: %v\n%s", r, debug.Stack())
		}
	}()

	// Load configuration
	cfg, err := config.LoadConfig(cfgFile)
	if err != nil {
		return fmt.Errorf("failed to load config: %w", err)
	}

	// Override log level if specified
	if logLevel != "" {
		cfg.Logging.Level = logLevel
	}

	// Setup logger
	logger := createLogger(cfg.Logging)
	logger.Info("starting pgsql-broker", "version", Version, "databases", len(cfg.Databases))

	// Create broker (manages all database instances)
	b, err := broker.New(cfg, logger, Version)
	if err != nil {
		return fmt.Errorf("failed to create broker: %w", err)
	}

	// Start the broker (starts all database instances)
	if err := b.Start(); err != nil {
		return fmt.Errorf("failed to start broker: %w", err)
	}

	// Wait for shutdown signal
	waitForShutdown(b, logger)

	return nil
}

func runInstall() error {
	// Load configuration
	cfg, err := config.LoadConfig(cfgFile)
	if err != nil {
		return fmt.Errorf("failed to load config: %w", err)
	}

	// Override log level if specified
	if logLevel != "" {
		cfg.Logging.Level = logLevel
	}

	// Setup logger
	logger := createLogger(cfg.Logging)
	logger.Info("pgsql-broker database installer", "version", Version, "databases", len(cfg.Databases))

	ctx := context.Background()

	var rolePasswords install.RolePasswords
	var adminUserVal, adminPasswordVal string
	if withRoles {
		if verifyOnly {
			return fmt.Errorf("--with-roles cannot be combined with --verify-only")
		}

		var err error
		adminUserVal, err = resolveCredential(adminUser, []string{"PGUSER", "PG_USER"}, "admin user (superuser/CREATEROLE login for --with-roles)")
		if err != nil {
			return err
		}
		adminPasswordVal, err = resolveCredential(adminPassword, []string{"PGPASSWORD", "PG_PASS"}, "admin password")
		if err != nil {
			return err
		}
		rolePasswords.AdminPassword, err = resolveCredential(brokerAdminPassword, []string{"BROKER_ADMIN_PASSWORD"}, "broker_admin password")
		if err != nil {
			return err
		}
		rolePasswords.RuntimePassword, err = resolveCredential(brokerRuntimePassword, []string{"BROKER_RUNTIME_PASSWORD"}, "broker_runtime password")
		if err != nil {
			return err
		}
		rolePasswords.EnqueuePassword, err = resolveCredential(brokerEnqueuePassword, []string{"BROKER_ENQUEUE_PASSWORD"}, "broker_enqueue password")
		if err != nil {
			return err
		}
	}

	// Install/verify on all configured databases
	for i := range cfg.Databases {
		dbCfg := &cfg.Databases[i]
		logger.Info("processing database", "index", i, "name", dbCfg.Name, "host", dbCfg.Host, "database", dbCfg.Database)

		// Create database adapter. With --with-roles, the config file's own
		// user (typically the least-privilege broker_runtime) may not exist
		// yet on a fresh cluster -- migrations and role creation both run as
		// the admin login instead, since broker_admin must own the schema.
		pgCfg := dbCfg.ToPostgresConfig()
		if withRoles {
			pgCfg.User = adminUserVal
			pgCfg.Password = adminPasswordVal
		}
		dbAdapter := adapter.NewPostgresAdapter(pgCfg, logger)

		// Connect to database
		if err := dbAdapter.Connect(ctx); err != nil {
			return fmt.Errorf("failed to connect to database %s: %w", dbCfg.Name, err)
		}

		// Create installer
		installer := install.New(dbAdapter, logger)

		if verifyOnly {
			// Only verify installation
			logger.Info("verifying database schema", "database", dbCfg.Name)
			if err := installer.VerifyInstallation(ctx); err != nil {
				dbAdapter.Close()
				logger.Error("verification failed", "database", dbCfg.Name, "error", err)
				return fmt.Errorf("verification failed for %s: %w", dbCfg.Name, err)
			}
			logger.Info("database schema verified successfully", "database", dbCfg.Name)
		} else {
			// Apply migrations
			logger.Info("applying database migrations", "database", dbCfg.Name)
			if err := installer.ApplyMigrations(ctx); err != nil {
				dbAdapter.Close()
				logger.Error("installation failed", "database", dbCfg.Name, "error", err)
				return fmt.Errorf("installation failed for %s: %w", dbCfg.Name, err)
			}

			// Verify installation
			logger.Info("verifying installation", "database", dbCfg.Name)
			if err := installer.VerifyInstallation(ctx); err != nil {
				dbAdapter.Close()
				logger.Error("verification failed", "database", dbCfg.Name, "error", err)
				return fmt.Errorf("verification failed for %s: %w", dbCfg.Name, err)
			}

			logger.Info("database schema installed and verified successfully", "database", dbCfg.Name)
		}

		if withRoles && !verifyOnly {
			logger.Info("applying roles", "database", dbCfg.Name)
			if err := installer.InstallRoles(ctx, rolePasswords); err != nil {
				dbAdapter.Close()
				return fmt.Errorf("failed to install roles for %s: %w", dbCfg.Name, err)
			}
			logger.Info("roles installed successfully", "database", dbCfg.Name)
		}

		dbAdapter.Close()
	}

	if verifyOnly {
		logger.Info("all databases verified successfully")
	} else {
		logger.Info("all databases installed and verified successfully")
	}
	return nil
}

func createLogger(cfg config.LoggingConfig) adapter.Logger {
	// Parse log level
	var level slog.Level
	switch cfg.Level {
	case "debug":
		level = slog.LevelDebug
	case "info":
		level = slog.LevelInfo
	case "warn":
		level = slog.LevelWarn
	case "error":
		level = slog.LevelError
	default:
		level = slog.LevelInfo
	}

	// Create handler based on format
	var handler slog.Handler
	opts := &slog.HandlerOptions{Level: level}

	if cfg.Format == "text" {
		handler = slog.NewTextHandler(os.Stdout, opts)
	} else {
		handler = slog.NewJSONHandler(os.Stdout, opts)
	}

	return adapter.NewSlogLoggerWithHandler(handler)
}

func waitForShutdown(b *broker.Broker, logger adapter.Logger) {
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM, syscall.SIGINT)

	sig := <-sigChan
	logger.Info("received shutdown signal", "signal", sig)

	if err := b.Stop(); err != nil {
		logger.Error("error during shutdown", "error", err)
	}
}