package config

import (
	"fmt"
	"strings"

	"github.com/spf13/viper"
)

type Config struct {
	Hostname     	string 	`mapstructure:"HOSTNAME"`
	Port         	string 	`mapstructure:"PORT"`
	DatabaseUrl  	string 	`mapstructure:"POSTGRES_URL"`
	RedisUrl     	string 	`mapstructure:"REDIS_URL"`
	MinioUrl     	string 	`mapstructure:"MINIO_URL"`
	JwtAlgorithm 	string 	`mapstructure:"JWT_ALGORITHM"`
	JwtSecret    	string 	`mapstructure:"JWT_SECRET"`
	JwtIssuer    	string 	`mapstructure:"JWT_ISSUER"`
	JwtAudience  	string 	`mapstructure:"JWT_AUDIENCE"`
	JwtExpAccess 	int 		`mapstructure:"JWT_EXP_ACCESS"`
	JwtExpRefresh int 		`mapstructure:"JWT_EXP_REFRESH"`
	Environment  	string 	`mapstructure:"ENVIRONMENT"`
}

func Load() (*Config, error) {

	viper.SetDefault("HOSTNAME", "localhost")
	viper.SetDefault("PORT", "8080")
	viper.SetDefault("JWT_ALGORITHM", "HS256")
	viper.SetDefault("JWT_SECRET", "default_jwt_secret_please_change")
	viper.SetDefault("JWT_EXP_ACCESS", 5)
	viper.SetDefault("JWT_EXP_REFRESH", 10080)
	viper.SetDefault("JWT_AUDIENCE", "easywish")
	viper.SetDefault("JWT_ISSUER", "easywish")
	viper.SetDefault("ENVIRONMENT", "production")

	viper.AutomaticEnv()

	// Viper's AutomaticEnv() expects lowercase keys for unmarshalling into structs by default, 
	// while the environment variables and struct tags are in uppercase. 
	// Here's the stupidity we have to do to fix it:
	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	viper.BindEnv("HOSTNAME")
	viper.BindEnv("PORT")
	viper.BindEnv("POSTGRES_URL")
	viper.BindEnv("REDIS_URL")
	viper.BindEnv("MINIO_URL")
	viper.BindEnv("JWT_ALGORITHM")
	viper.BindEnv("JWT_SECRET")
	viper.BindEnv("JWT_ISSUER")
	viper.BindEnv("JWT_AUDIENCE")
	viper.BindEnv("JWT_EXP_ACCESS")
	viper.BindEnv("JWT_EXP_REFRESH")
	viper.BindEnv("ENVIRONMENT")

	required := []string{
		"POSTGRES_URL",
		"REDIS_URL",
		"MINIO_URL",
	}
	var missing []string
	for _, key := range required {
		if !viper.IsSet(key) {
			missing = append(missing, key)
		}
	}
	if len(missing) > 0 {
		return nil, fmt.Errorf("missing required environment variables: %s", strings.Join(missing, ", "))
	}

	var cfg Config
	if err := viper.Unmarshal(&cfg); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	config = &cfg

	return &cfg, nil
}

func GetConfig() *Config {

	if config == nil {
		
		if _, err := Load(); err != nil {
			panic(err)
		}
	}

	return config
}

var config *Config