package main

import (
	"os"
	"os/signal"
	"syscall"

	"context"

	"git.intra.yksa.space/gsn/predictor/internal/jobs/grib/updater"
	"git.intra.yksa.space/gsn/predictor/internal/pkg/errcodes"
	"git.intra.yksa.space/gsn/predictor/internal/pkg/grib"
	"git.intra.yksa.space/gsn/predictor/internal/pkg/log"
	"git.intra.yksa.space/gsn/predictor/internal/service"
	"git.intra.yksa.space/gsn/predictor/internal/transport/rest"
	"git.intra.yksa.space/gsn/predictor/internal/transport/rest/handler"
	"git.intra.yksa.space/gsn/predictor/pkg/redis"
	"git.intra.yksa.space/gsn/predictor/pkg/scheduler"
	env "github.com/caarlos0/env/v11"
	"go.uber.org/zap"
)

const servicePrefix = "GSN_PREDICTOR"

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

	cfg, err := loadConfig()
	if err != nil {
		log.Ctx(ctx).Fatal("failed to load configuration", zap.Error(err))
	}

	schedulerConfig, err := scheduler.NewConfig()
	if err != nil {
		log.Ctx(ctx).Fatal("failed to load scheduler configuration", zap.Error(err))
	}

	gribUpdaterConfig, err := updater.NewConfig()
	if err != nil {
		log.Ctx(ctx).Fatal("failed to load GRIB updater configuration", zap.Error(err))
	}

	log.Ctx(ctx).Info("Connecting to Redis", zap.String("host", cfg.RedisHost), zap.Int("port", cfg.RedisPort))
	redisService, err := redis.New(redis.Config{
		Host:     cfg.RedisHost,
		Port:     cfg.RedisPort,
		Password: cfg.RedisPassword,
		DB:       cfg.RedisDB,
	})
	if err != nil {
		log.Ctx(ctx).Fatal("failed to initialize Redis service", zap.Error(err), zap.String("host", cfg.RedisHost), zap.Int("port", cfg.RedisPort))
	}
	defer redisService.Close()

	gribService, err := grib.New(grib.ServiceConfig{
		Dir:        cfg.GribDir,
		TTL:        cfg.GribTTL,
		CacheTTL:   cfg.GribCacheTTL,
		Redis:      redisService,
		Parallel:   cfg.GribParallel,
		Client:     cfg.CreateHTTPClient(),
		DatasetURL: cfg.GribDatasetURL,
	})
	if err != nil {
		log.Ctx(ctx).Fatal("failed to initialize GRIB service", zap.Error(err))
	}
	defer gribService.Close()

	// Force GRIB update on startup in a goroutine
	go func() {
		log.Ctx(ctx).Info("Performing initial GRIB update (async)...")
		if err := gribService.Update(ctx); err != nil {
			log.Ctx(ctx).Error("initial GRIB update failed", zap.Error(err))
		} else {
			log.Ctx(ctx).Info("initial GRIB update complete")
		}
	}()

	svc, err := service.New(cfg, gribService, redisService)
	if err != nil {
		log.Ctx(ctx).Fatal("failed to initialize service", zap.Error(err))
	}
	defer svc.Close()

	var sched *scheduler.Scheduler
	if schedulerConfig.Enabled {
		sched = scheduler.New()

		gribJob := updater.New(gribService, gribUpdaterConfig)
		if err := sched.AddJob(gribJob); err != nil {
			log.Ctx(ctx).Error("failed to add GRIB update job to scheduler", zap.Error(err))
		}

		log.Ctx(ctx).Info("scheduler initialized with jobs")
	}

	handler := handler.New(svc)

	restConfig, err := rest.NewConfig()
	if err != nil {
		lg.Fatal("failed to init transport config", zap.Error(err))
	}

	transport, err := rest.New(handler, restConfig)
	if err != nil {
		lg.Fatal("failed to init transport", zap.Error(err))
	}

	svc.Start()
	if sched != nil {
		sched.Start()
		lg.Info("scheduler started")
	}

	lg.Info("service started successfully",
		zap.String("grib_dir", cfg.GribDir),
		zap.Duration("grib_ttl", cfg.GribTTL),
		zap.Duration("grib_cache_ttl", cfg.GribCacheTTL),
		zap.Int("grib_parallel", cfg.GribParallel),
		zap.Bool("scheduler_enabled", schedulerConfig.Enabled),
		zap.Duration("grib_update_interval", gribUpdaterConfig.Interval))

	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		lg.Info("starting HTTP server on port", zap.Int("port", restConfig.Port))
		transport.Run()
	}()

	<-sigChan
	lg.Info("received shutdown signal, stopping service")

	if sched != nil {
		sched.Stop()
		lg.Info("scheduler stopped")
	}
}

func loadConfig() (*service.Config, error) {
	cfg := &service.Config{}

	if err := env.ParseWithOptions(cfg, env.Options{
		PrefixTagName: servicePrefix + "_",
	}); err != nil {
		return nil, errcodes.Wrap(err, "failed to parse configuration")
	}

	return cfg, nil
}