package main

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

	"predictor-refactored/internal/downloader"
	"predictor-refactored/internal/service"
	"predictor-refactored/internal/transport/rest"
	"predictor-refactored/internal/transport/rest/handler"

	"github.com/go-co-op/gocron"
	"go.uber.org/zap"
)

func main() {
	log, err := zap.NewProduction()
	if err != nil {
		panic(err)
	}
	defer log.Sync()

	cfg := downloader.LoadConfig()
	log.Info("configuration loaded",
		zap.String("data_dir", cfg.DataDir),
		zap.Int("parallel", cfg.Parallel),
		zap.Duration("update_interval", cfg.UpdateInterval),
		zap.Duration("dataset_ttl", cfg.DatasetTTL))

	if err := os.MkdirAll(cfg.DataDir, 0o755); err != nil {
		log.Fatal("failed to create data directory", zap.Error(err))
	}

	svc := service.New(cfg, log)
	defer svc.Close()

	// Load elevation dataset (optional — falls back to sea-level termination)
	elevPath := "/srv/ruaumoko-dataset"
	if v := os.Getenv("PREDICTOR_ELEVATION_DATASET"); v != "" {
		elevPath = v
	}
	svc.LoadElevation(elevPath)

	// Initial dataset load (async so the server starts immediately)
	go func() {
		log.Info("performing initial dataset update...")
		if err := svc.Update(context.Background()); err != nil {
			log.Error("initial dataset update failed", zap.Error(err))
		} else {
			log.Info("initial dataset update complete")
		}
	}()

	// Scheduler for periodic dataset updates
	scheduler := gocron.NewScheduler(time.UTC)
	scheduler.Every(cfg.UpdateInterval).Do(func() {
		ctx, cancel := context.WithTimeout(context.Background(), 60*time.Minute)
		defer cancel()
		log.Info("scheduled dataset update starting")
		if err := svc.Update(ctx); err != nil {
			log.Error("scheduled dataset update failed", zap.Error(err))
		} else {
			log.Info("scheduled dataset update complete")
		}
	})
	scheduler.StartAsync()
	defer scheduler.Stop()

	// HTTP transport (ogen)
	port := 8080
	if p := os.Getenv("PREDICTOR_PORT"); p != "" {
		fmt.Sscanf(p, "%d", &port)
	}

	h := handler.New(svc, log)
	transport, err := rest.New(h, port, log)
	if err != nil {
		log.Fatal("failed to create transport", zap.Error(err))
	}

	go func() {
		if err := transport.Run(); err != nil {
			log.Fatal("HTTP server error", zap.Error(err))
		}
	}()

	log.Info("service started")

	// Graceful shutdown
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
	sig := <-sigChan
	log.Info("received shutdown signal", zap.String("signal", sig.String()))
}