package config

import (
	"crypto/rand"
	"fmt"
	"math/big"
	"time"

	"github.com/spf13/viper"
)

type Config struct {
	Server   ServerConfig
	Database DatabaseConfig
	Stripe   StripeConfig
	OVH      OVHConfig
	Mailer   MailerConfig
	Logging  LoggingConfig
	JWT      JWT
}

type ServerConfig struct {
	Address      string
	Port         int
	ReadTimeout  time.Duration
	WriteTimeout time.Duration
	IdleTimeout  time.Duration
	Tls          TlsConfig
}

type DatabaseConfig struct {
	DSN string
}

type StripeConfig struct {
	APIKey         string `mapstructure:"api_key" env:"STRIPE_API_KEY"`
	EndpointSecret string `mapstructure:"endpoint_secret" env:"STRIPE_WEBHOOK_SECRET"`
}

type OVHConfig struct {
	Endpoint    string
	AppKey      string
	AppSecret   string
	ConsumerKey string
}

type MailerConfig struct {
	Identity string
	Username string
	Password string
	Host     string
	Port     string
	From     string
}

type TlsConfig struct {
	CertFile string
	KeyFile  string
}
type LoggingConfig struct {
	Level  string
	Format string
}

type JWT struct {
	Secret string
}

func Load() (*Config, error) {
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath(".")
	viper.AddConfigPath("/etc/byom/")

	// Set defaults
	viper.SetDefault("server.port", 8080)
	viper.SetDefault("server.readTimeout", "15s")
	viper.SetDefault("server.writeTimeout", "15s")
	viper.SetDefault("server.idleTimeout", "60s")

	viper.SetDefault("database.dsn", ".trash/trash.db")
	//generate random secret for jwt
	secret, err := GenerateRandomString(256)
	if err != nil {
		return nil, fmt.Errorf("error generating random string: %w", err)
	}

	viper.SetDefault("jwt.secret", secret)

	// Environment variables
	viper.AutomaticEnv()
	viper.SetEnvPrefix("BYOM")

	// Bind environment variables
	viper.BindEnv("stripe.api_key", "STRIPE_API_KEY")
	viper.BindEnv("stripe.endpoint_secret", "STRIPE_WEBHOOK_SECRET")

	// Set defaults if needed
	viper.SetDefault("stripe.api_key", "")
	viper.SetDefault("stripe.endpoint_secret", "")

	if err := viper.ReadInConfig(); err != nil {
		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
			return nil, fmt.Errorf("error reading config: %w", err)
		}
	}

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

	return &config, nil
}

func GenerateRandomString(n int) (string, error) {
	const letters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
	ret := make([]byte, n)
	for i := 0; i < n; i++ {
		num, err := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
		if err != nil {
			return "", err
		}
		ret[i] = letters[num.Int64()]
	}

	return string(ret), nil
}