// Package main is the entry point for the background-processor worker.
package main

import (
	"context"
	"embed"
	"os"
	"os/signal"
	"syscall"
	"time"

	"git.threesix.ai/jordan/slack-q-1770281596/pkg/config"
	"git.threesix.ai/jordan/slack-q-1770281596/pkg/database"
	"git.threesix.ai/jordan/slack-q-1770281596/pkg/logging"
	"git.threesix.ai/jordan/slack-q-1770281596/pkg/queue"
	"git.threesix.ai/jordan/slack-q-1770281596/workers/background-processor/internal/handlers"
	workerconfig "git.threesix.ai/jordan/slack-q-1770281596/workers/background-processor/internal/config"
)

//go:embed migrations/*.sql
var migrationsFS embed.FS

func main() {
	// Initialize logger first (with defaults) so we can log config errors
	logger := logging.New(logging.Config{
		Level:  logging.LevelInfo,
		Format: logging.FormatJSON,
	}).WithService("background-processor")

	// Initialize configuration
	cfg, err := workerconfig.Load()
	if err != nil {
		logger.Error("failed to load config", "error", err)
		os.Exit(1)
	}

	// Reconfigure logger with loaded config
	logger = logging.New(logging.Config{
		Level:       logging.ParseLevel(cfg.Logging.Level),
		Format:      logging.ParseFormat(cfg.Logging.Format),
		Environment: cfg.AppConfig.Environment,
		AddSource:   cfg.AppConfig.IsDevelopment(),
	}).WithService("background-processor")

	logger.Info("starting background-processor worker")

	// Setup graceful shutdown
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Connect to database
	pool, err := database.Connect(ctx, cfg.Database.URL, database.Options{
		MaxOpenConns:    cfg.Database.MaxOpenConns,
		MaxIdleConns:    cfg.Database.MaxIdleConns,
		ConnMaxLifetime: cfg.Database.ConnMaxLifetime,
	})
	if err != nil {
		logger.Error("failed to connect to database", "error", err)
		os.Exit(1)
	}
	defer pool.Close()
	logger.Info("connected to database", "url", pool.URL)

	// Run migrations
	database.MustRunMigrations(ctx, pool, migrationsFS, "migrations")
	logger.Info("migrations complete")

	// Initialize queue
	jobQueue := queue.NewPostgresQueue(pool.DB, logger)

	// Initialize and start handler
	handler := handlers.New(logger, jobQueue, handlers.Config{
		PollInterval:     cfg.Worker.PollInterval,
		StaleJobTimeout:  cfg.Worker.StaleJobTimeout,
		JobTimeout:       cfg.Worker.JobTimeout,
	})

	// Register job handlers
	// TODO: Register your job handlers here
	// handler.RegisterHandler("send_email", emailHandler)
	// handler.RegisterHandler("process_image", imageHandler)

	// Setup signal handling
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	// Start worker in goroutine
	go handler.Run(ctx)

	// Start stale job recovery in goroutine
	go runStaleJobRecovery(ctx, jobQueue, cfg.Worker.StaleJobTimeout, logger)

	// Wait for shutdown signal
	sig := <-sigCh
	logger.Info("received shutdown signal", "signal", sig.String())

	// Trigger graceful shutdown with grace period
	logger.Info("initiating graceful shutdown")
	cancel()

	// Give in-flight jobs time to complete (grace period)
	// This allows handlers to notice context cancellation and finish cleanly.
	const shutdownGracePeriod = 5 * time.Second
	time.Sleep(shutdownGracePeriod)

	logger.Info("background-processor worker stopped")
}

// runStaleJobRecovery periodically requeues jobs that have been running too long.
func runStaleJobRecovery(ctx context.Context, q *queue.PostgresQueue, timeout time.Duration, logger *logging.Logger) {
	const staleCheckInterval = time.Minute
	ticker := time.NewTicker(staleCheckInterval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			count, err := q.RequeueStale(ctx, timeout)
			if err != nil {
				logger.Error("failed to requeue stale jobs", "error", err)
			} else if count > 0 {
				logger.Info("requeued stale jobs", "count", count)
			}
		}
	}
}