package config

import (
	"fmt"
	"os"
	"strconv"
	"time"

	"github.com/joho/godotenv"
)

type Config struct {
	Server   ServerConfig
	Database DatabaseConfig
	JWT      JWTConfig
	Redis    RedisConfig
	NATS     NATSConfig
	Storage  StorageConfig
}

// ServerConfig type holds the information about the http server settings
type ServerConfig struct {
	Port         string        // HTTP port to listen on
	Environment  string        // can be development, staging, production
	ReadTimeout  time.Duration // Max time to read request
	WriteTimeout time.Duration // Max time to write response
}

// DatabaseConfig contains postgresSQL connection settings
type DatabaseConfig struct {
	Host            string        // Database host
	Port            string        // Database port
	User            string        // Database user
	Password        string        // Database password
	DBName          string        // Database name
	SSLMode         string        // SSL mode : disable, require, verify-full ? not sure what this field is set for
	MaxOpenConns    int           // Maximum open connections
	MaxIdleConns    int           // Maximum idle connections
	ConnMaxLifetime time.Duration // Maximum connection lifetime
}

// JWT Config contains JWT token settings
type JWTConfig struct {
	AccessSecret  string        // Secret for access tokens
	RefreshSecret string        // Secret for refresh tokens
	AccessExpiry  time.Duration // Accees token expiry (15 minutes)
	RefreshExpiry time.Duration // Refresh token expiry (7 days)
	Issuer        string        // Token issuer claim
}

type RedisConfig struct {
	Host     string // Redis host
	Port     string // Redis port
	Password string // Redis password (set to empty if no auth is set)
	DB       int    // Redis database number
}

// NATSConfig contains NATS messaging settings
type NATSConfig struct {
	URL string // NATS server URL
}

// StorageCongfig contains MinIO (s3) settings
type StorageConfig struct {
	Endpoint        string // MinIO endpoint
	AccessKeyID     string // Access key
	SecretAccessKey string // Secret key
	BucketName      string // Bucket name
	UseSSL          bool   // User HTTPS
}

func Load() (*Config, error) {
	if os.Getenv("APP_ENV") != "production" {
		if err := godotenv.Load(); err != nil {
			fmt.Println("Warning: .env file not found, using environment variables")
		}
	}

	cfg := &Config{
		Server: ServerConfig{
			Port:         getEnv("SERVER_PORT", "8080"),
			Environment:  getEnv("APP_ENV", "development"),
			ReadTimeout:  parseDuration(getEnv("SERVER_READ_TIMEOUT", "10s")),
			WriteTimeout: parseDuration(getEnv("SERVER_WRITE_TIMEOUT", "10s")),
		},
		Database: DatabaseConfig{
			Host:            getEnv("DB_HOST", "localhost"),
			Port:            getEnv("DB_PORT", "5432"),
			User:            getEnv("DB_USER", "aurganize"),
			Password:        getEnv("DB_PASSWORD", ""),
			DBName:          getEnv("DB_NAME", "aruganize_db_1"),
			SSLMode:         getEnv("DB_SSLMODE", "disable"),
			MaxOpenConns:    parseInt(getEnv("DB_MAX_OPEN_CONNECTIONS", "25")),
			MaxIdleConns:    parseInt(getEnv("DB_MAX_IDLE_CONNECTIONS", "5")),
			ConnMaxLifetime: parseDuration(getEnv("DB_CONNECTION_MAX_LIFETIME", "5m")),
		},

		JWT: JWTConfig{
			AccessSecret:  getEnv("JWT_ACCESS_SECRET", ""),
			RefreshSecret: getEnv("JWT_REFRESH_SECRET", ""),
			AccessExpiry:  parseDuration(getEnv("JWT_ACCESS_EXPIRY", "15m")),
			RefreshExpiry: parseDuration(getEnv("JWT_REFRESH_EXPIRY", "168h")),
			Issuer:        getEnv("JWT_ISSUER", "aurganize-v62"),
		},
		Redis: RedisConfig{
			Host:     getEnv("REDIST_HOST", "localhost"),
			Port:     getEnv("REDIS_PORT", "6379"),
			Password: getEnv("REDIS_PASSWORD", ""),
			DB:       parseInt(getEnv("REDIS_DB", "0")),
		},
		NATS: NATSConfig{
			URL: getEnv("NATS_URL", "nats://localhost:4222"),
		},
		Storage: StorageConfig{
			Endpoint:        getEnv("MINIO_ENDPOINT", "localhost:9000"),
			AccessKeyID:     getEnv("MINIO_ACCESS_KEY", "minioadmin"),
			SecretAccessKey: getEnv("MINIO_SECRET_KEY", "miniosecretkey"),
			BucketName:      getEnv("MINIO_BUCKET", "aurganize_bucket_1"),
			UseSSL:          parseBool(getEnv("MINIO_USE_SSL", "false")),
		},
	}
	if err := cfg.Validate(); err != nil {
		return nil, fmt.Errorf("configuration validation failure [%w]", err)
	}

	return cfg, nil
}

// Validate checks if all required configuration is present and valid
func (c *Config) Validate() error {
	// Database password required in production
	if c.Database.Password == "" && c.Server.Environment == "production" {
		return fmt.Errorf("DB_PASSWORD is required in production")
	}
	// JWT secrets are required always
	if c.JWT.AccessSecret == "" {
		return fmt.Errorf("JWT_ACCESS_SECRET is required")
	}

	if c.JWT.RefreshSecret == "" {
		return fmt.Errorf("JWT_REFRESH_SECRET is required")
	}
	// JWT secrets should be different
	if c.JWT.AccessSecret == c.JWT.RefreshSecret {
		return fmt.Errorf("JWT_ACCESS_SECRET and JWT_REFRESH_SECRET must be different")
	}

	validEnvs := map[string]bool{
		"development": true,
		"test":        true,
		"staging":     true,
		"UAT":         true,
		"production":  true,
	}
	if !validEnvs[c.Server.Environment] {
		return fmt.Errorf("invalid environment configured in enviroment")
	}
	return nil
}

// Helper Functions
func getEnv(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}

func parseDuration(s string) time.Duration {
	d, err := time.ParseDuration(s)
	if err != nil {
		return 0
	}
	return d
}

func parseInt(s string) int {
	i, err := strconv.Atoi(s)
	if err != nil {
		return 0
	}
	return i
}

func parseBool(s string) bool {
	b, err := strconv.ParseBool(s)
	if err != nil {
		return false
	}
	return b
}

// DatabaseDSN returns the PostgreSQL connection string
func (c *Config) DatabaseDSN() string {
	return fmt.Sprintf(
		"host=%s post %s user=%s password=%s dbname=%s sslmode=%s",
		c.Database.Host,
		c.Database.Port,
		c.Database.User,
		c.Database.Password,
		c.Database.DBName,
		c.Database.SSLMode,
	)
}

// RedisDSN returns the Redis connection string
func (c *Config) RedisDSN() string {
	return fmt.Sprintf("%s:%s", c.Redis.Host, c.Redis.Port)
}