package config

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

// Config holds the application configuration
type Config struct {
	Port string
	
	// Database configuration
	DatabaseURL      string
	DatabaseMaxConns int32
	DatabaseTimeout  time.Duration
	
	// SQS configuration
	SQSQueueURL       string
	SQSRegion         string
	SQSMaxMessages    int32
	SQSWaitTimeSeconds int32
	SQSVisibilityTimeout int32
	
	// Processing configuration
	ProcessingWorkers    int
	ProcessingBatchSize  int
	IdempotencyEnabled   bool
	
	// Validation configuration
	ValidationProvider string
}

// Load loads configuration from environment variables with defaults
func Load() *Config {
	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}

	databaseURL := os.Getenv("DATABASE_URL")
	if databaseURL == "" {
		databaseURL = "postgres://postgres:password@localhost:5432/meteor_development?sslmode=disable"
	}

	databaseMaxConns := parseInt32(os.Getenv("DATABASE_MAX_CONNS"), 10)
	databaseTimeout := parseDuration(os.Getenv("DATABASE_TIMEOUT"), 30*time.Second)

	sqsQueueURL := os.Getenv("SQS_QUEUE_URL")
	if sqsQueueURL == "" {
		sqsQueueURL = "https://sqs.us-east-1.amazonaws.com/123456789012/meteor-raw-events-queue"
	}

	sqsRegion := os.Getenv("SQS_REGION")
	if sqsRegion == "" {
		sqsRegion = "us-east-1"
	}

	sqsMaxMessages := parseInt32(os.Getenv("SQS_MAX_MESSAGES"), 10)
	sqsWaitTimeSeconds := parseInt32(os.Getenv("SQS_WAIT_TIME_SECONDS"), 20)
	sqsVisibilityTimeout := parseInt32(os.Getenv("SQS_VISIBILITY_TIMEOUT"), 300)

	processingWorkers := parseInt(os.Getenv("PROCESSING_WORKERS"), 5)
	processingBatchSize := parseInt(os.Getenv("PROCESSING_BATCH_SIZE"), 10)
	idempotencyEnabled := parseBool(os.Getenv("IDEMPOTENCY_ENABLED"), true)

	validationProvider := os.Getenv("VALIDATION_PROVIDER")
	if validationProvider == "" {
		validationProvider = "mvp" // Default to MVP provider for backward compatibility
	}

	return &Config{
		Port:                 port,
		DatabaseURL:          databaseURL,
		DatabaseMaxConns:     databaseMaxConns,
		DatabaseTimeout:      databaseTimeout,
		SQSQueueURL:          sqsQueueURL,
		SQSRegion:            sqsRegion,
		SQSMaxMessages:       sqsMaxMessages,
		SQSWaitTimeSeconds:   sqsWaitTimeSeconds,
		SQSVisibilityTimeout: sqsVisibilityTimeout,
		ProcessingWorkers:    processingWorkers,
		ProcessingBatchSize:  processingBatchSize,
		IdempotencyEnabled:   idempotencyEnabled,
		ValidationProvider:   validationProvider,
	}
}

// Helper functions for parsing environment variables
func parseInt(s string, defaultValue int) int {
	if s == "" {
		return defaultValue
	}
	if val, err := strconv.Atoi(s); err == nil {
		return val
	}
	return defaultValue
}

func parseInt32(s string, defaultValue int32) int32 {
	if s == "" {
		return defaultValue
	}
	if val, err := strconv.ParseInt(s, 10, 32); err == nil {
		return int32(val)
	}
	return defaultValue
}

func parseBool(s string, defaultValue bool) bool {
	if s == "" {
		return defaultValue
	}
	if val, err := strconv.ParseBool(s); err == nil {
		return val
	}
	return defaultValue
}

func parseDuration(s string, defaultValue time.Duration) time.Duration {
	if s == "" {
		return defaultValue
	}
	if val, err := time.ParseDuration(s); err == nil {
		return val
	}
	return defaultValue
}