package config

import (
	"context"
	"flag"
	"log"
	"os"
	"strconv"

	"github.com/joho/godotenv"
)

const LOCAL_ENV = ".env.local"

type Nats struct {
	Url       string
	Name      string
	EnableTls bool
	Cert      Tls
	Ctx       context.Context
}

type RestApi struct {
	Port string
	Ctx  context.Context
}

type Config struct {
	RestApi RestApi
	Nats    Nats
}

type Tls struct {
	CertFile string
	KeyFile  string
	CaFile   string
}

func NewConfig() *Config {

	loadEnvVariables()
	log.SetFlags(log.LstdFlags | log.Lshortfile)

	natsUrl := flag.String("nats_url", lookupEnvOrString("NATS_URL", "nats://localhost:4222"), "url for nats server")
	natsName := flag.String("nats_name", lookupEnvOrString("NATS_NAME", "adapter"), "name for nats client")
	natsEnableTls := flag.Bool("nats_enable_tls", lookupEnvOrBool("NATS_ENABLE_TLS", false), "enbale TLS to nats server")
	clientCrt := flag.String("client_crt", lookupEnvOrString("CLIENT_CRT", "cert.pem"), "client certificate file to TLS connection")
	clientKey := flag.String("client_key", lookupEnvOrString("CLIENT_KEY", "key.pem"), "client key file to TLS connection")
	serverCA := flag.String("server_ca", lookupEnvOrString("SERVER_CA", "rootCA.pem"), "server CA file to TLS connection")
	flApiPort := flag.String("api_port", lookupEnvOrString("REST_API_PORT", "4000"), "Rest api port")
	flHelp := flag.Bool("help", false, "Help")

	/*
		App variables priority:
		1º - Flag through command line.
		2º - Env variables.
		3º - Default flag value.
	*/

	flag.Parse()

	if *flHelp {
		flag.Usage()
		os.Exit(0)
	}

	ctx := context.TODO()

	return &Config{
		RestApi: RestApi{
			Port: *flApiPort,
			Ctx:  ctx,
		},
		Nats: Nats{
			Url:       *natsUrl,
			Name:      *natsName,
			EnableTls: *natsEnableTls,
			Ctx:       ctx,
			Cert: Tls{
				CertFile: *clientCrt,
				KeyFile:  *clientKey,
				CaFile:   *serverCA,
			},
		},
	}
}

func loadEnvVariables() {
	err := godotenv.Load()

	if _, err := os.Stat(LOCAL_ENV); err == nil {
		_ = godotenv.Overload(LOCAL_ENV)
		log.Printf("Loaded variables from '%s'", LOCAL_ENV)
		return
	}

	if err != nil {
		log.Println("Error to load environment variables:", err)
	} else {
		log.Println("Loaded variables from '.env'")
	}
}

func lookupEnvOrString(key string, defaultVal string) string {
	if val, _ := os.LookupEnv(key); val != "" {
		return val
	}
	return defaultVal
}

func lookupEnvOrBool(key string, defaultVal bool) bool {
	if val, _ := os.LookupEnv(key); val != "" {
		v, err := strconv.ParseBool(val)
		if err != nil {
			log.Fatalf("LookupEnvOrBool[%s]: %v", key, err)
		}
		return v
	}
	return defaultVal
}