package face

import (
	"os"
	"strconv"
	"time"
)

// Config holds configuration for the face service
type Config struct {
	// AWS Configuration
	Region          string
	CollectionID    string

	// Face Detection Configuration
	MaxFaces        int
	Threshold       float64
	QualityFilter   string

	// Cache Configuration
	CacheTTL        time.Duration
	SearchCacheTTL  time.Duration
	PhotoCacheTTL   time.Duration

	// Rate Limiting
	GuestRateLimit     int
	GuestRateWindowMin int
	AuthRateLimit      int
	AuthRateWindowMin  int

	// Image Optimization
	MaxImageSize    int
	ResizeWidth     int
	ResizeHeight    int
	ImageQuality    int
}

// DefaultConfig returns default configuration
func DefaultConfig() *Config {
	return &Config{
		Region:          getEnv("AWS_REGION", "us-east-1"),
		CollectionID:    getEnv("REKOGNITION_COLLECTION", "hatch-faces"),
		MaxFaces:        getEnvInt("REKOGNITION_MAX_FACES", 10),
		Threshold:       getEnvFloat("REKOGNITION_THRESHOLD", 80.0),
		QualityFilter:   getEnv("REKOGNITION_QUALITY_FILTER", "AUTO"),
		CacheTTL:        5 * time.Minute,
		SearchCacheTTL:  5 * time.Minute,
		PhotoCacheTTL:   24 * time.Hour,
		GuestRateLimit:  getEnvInt("RATE_LIMIT_GUEST_SEARCHES", 20),
		GuestRateWindowMin: getEnvInt("RATE_LIMIT_GUEST_WINDOW_MINUTES", 15),
		AuthRateLimit:   getEnvInt("RATE_LIMIT_AUTH_SEARCHES", 100),
		AuthRateWindowMin:  getEnvInt("RATE_LIMIT_AUTH_WINDOW_MINUTES", 1),
		MaxImageSize:    10 * 1024 * 1024, // 10MB
		ResizeWidth:     1024,
		ResizeHeight:    1024,
		ImageQuality:    85,
	}
}

// Validate checks if the configuration is valid
func (c *Config) Validate() error {
	if c.Region == "" {
		return ErrMissingRegion
	}
	if c.CollectionID == "" {
		return ErrMissingCollectionID
	}
	if c.MaxFaces <= 0 {
		return ErrInvalidMaxFaces
	}
	if c.Threshold < 0 || c.Threshold > 100 {
		return ErrInvalidThreshold
	}
	return nil
}

// Helper functions for environment variables

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

func getEnvInt(key string, defaultValue int) int {
	if value := os.Getenv(key); value != "" {
		if intValue, err := strconv.Atoi(value); err == nil {
			return intValue
		}
	}
	return defaultValue
}

func getEnvFloat(key string, defaultValue float64) float64 {
	if value := os.Getenv(key); value != "" {
		if floatValue, err := strconv.ParseFloat(value, 64); err == nil {
			return floatValue
		}
	}
	return defaultValue
}