package server

import (
	"bufio"
	"os"
	"strings"
)

// Config holds application configuration from environment and .env file
type Config struct {
	S3Endpoint   string
	S3AccessKey  string
	S3SecretKey  string
	S3BucketName string
	S3UseSSL     bool
	S3Enabled    bool // Enable/disable S3 backend
	BaseDataset  string
	ConfigFile   string
	MetadataFile string
	Port         string
}

// LoadConfig loads configuration from .env file and environment variables
func LoadConfig() *Config {
	// Load .env file if exists
	loadEnvFile(".env")

	s3Enabled := getEnv("S3_ENABLED", "true") == "true"
	s3AccessKey := os.Getenv("S3_ACCESS_KEY")
	s3SecretKey := os.Getenv("S3_SECRET_KEY")

	// Disable S3 if credentials are missing
	if s3AccessKey == "" || s3SecretKey == "" {
		s3Enabled = false
	}

	return &Config{
		S3Endpoint:   getEnv("S3_ENDPOINT", "s3.amazonaws.com"),
		S3AccessKey:  s3AccessKey,
		S3SecretKey:  s3SecretKey,
		S3BucketName: getEnv("S3_BUCKET", "zfs-snapshots"),
		S3UseSSL:     getEnv("S3_USE_SSL", "true") != "false",
		S3Enabled:    s3Enabled,
		BaseDataset:  getEnv("ZFS_BASE_DATASET", "backup"),
		ConfigFile:   getEnv("CONFIG_FILE", "clients.json"),
		MetadataFile: getEnv("METADATA_FILE", "metadata.json"),
		Port:         getEnv("PORT", "8080"),
	}
}

// loadEnvFile loads key=value pairs from a .env file
func loadEnvFile(filename string) {
	file, err := os.Open(filename)
	if err != nil {
		return // .env file is optional
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())

		// Skip empty lines and comments
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}

		// Parse key=value
		parts := strings.SplitN(line, "=", 2)
		if len(parts) != 2 {
			continue
		}

		key := strings.TrimSpace(parts[0])
		value := strings.TrimSpace(parts[1])

		// Remove quotes if present
		if len(value) >= 2 && (value[0] == '"' || value[0] == '\'') {
			value = value[1 : len(value)-1]
		}

		// Only set if not already defined in environment
		if os.Getenv(key) == "" {
			os.Setenv(key, value)
		}
	}
}

// getEnv gets an environment variable with a default value
func getEnv(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}