// Package config provides environment-based configuration for handler services.
package config

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

// Settings holds base configuration for all handler services.
// Values are loaded from environment variables with sensible defaults.
type Settings struct {
	// Service identification
	ServiceName      string
	ServiceVersion   string
	ServiceNamespace string
	DeploymentEnv    string

	// NATS configuration
	NATSURL        string
	NATSUser       string
	NATSPassword   string
	NATSQueueGroup string

	// Redis/Valkey configuration
	RedisURL      string
	RedisPassword string

	// Milvus configuration
	MilvusHost       string
	MilvusPort       int
	MilvusCollection string

	// Service endpoints
	EmbeddingsURL string
	RerankerURL   string
	LLMURL        string
	TTSURL        string
	STTURL        string

	// OpenTelemetry configuration
	OTELEnabled  bool
	OTELEndpoint string
	OTELUseHTTP  bool

	// HyperDX configuration
	HyperDXEnabled  bool
	HyperDXAPIKey   string
	HyperDXEndpoint string

	// MLflow configuration
	MLflowTrackingURI    string
	MLflowExperimentName string
	MLflowEnabled        bool

	// Health check configuration
	HealthPort int
	HealthPath string
	ReadyPath  string

	// Timeouts
	HTTPTimeout time.Duration
	NATSTimeout time.Duration
}

// Load creates a Settings populated from environment variables with defaults.
func Load() *Settings {
	return &Settings{
		ServiceName:      getEnv("SERVICE_NAME", "handler"),
		ServiceVersion:   getEnv("SERVICE_VERSION", "1.0.0"),
		ServiceNamespace: getEnv("SERVICE_NAMESPACE", "ai-ml"),
		DeploymentEnv:    getEnv("DEPLOYMENT_ENV", "production"),

		NATSURL:        getEnv("NATS_URL", "nats://nats.ai-ml.svc.cluster.local:4222"),
		NATSUser:       getEnv("NATS_USER", ""),
		NATSPassword:   getEnv("NATS_PASSWORD", ""),
		NATSQueueGroup: getEnv("NATS_QUEUE_GROUP", ""),

		RedisURL:      getEnv("REDIS_URL", "redis://valkey.ai-ml.svc.cluster.local:6379"),
		RedisPassword: getEnv("REDIS_PASSWORD", ""),

		MilvusHost:       getEnv("MILVUS_HOST", "milvus.ai-ml.svc.cluster.local"),
		MilvusPort:       getEnvInt("MILVUS_PORT", 19530),
		MilvusCollection: getEnv("MILVUS_COLLECTION", "documents"),

		EmbeddingsURL: getEnv("EMBEDDINGS_URL", "http://embeddings-predictor.ai-ml.svc.cluster.local"),
		RerankerURL:   getEnv("RERANKER_URL", "http://reranker-predictor.ai-ml.svc.cluster.local"),
		LLMURL:        getEnv("LLM_URL", "http://vllm-predictor.ai-ml.svc.cluster.local"),
		TTSURL:        getEnv("TTS_URL", "http://tts-predictor.ai-ml.svc.cluster.local"),
		STTURL:        getEnv("STT_URL", "http://whisper-predictor.ai-ml.svc.cluster.local"),

		OTELEnabled:  getEnvBool("OTEL_ENABLED", true),
		OTELEndpoint: getEnv("OTEL_ENDPOINT", "http://opentelemetry-collector.observability.svc.cluster.local:4317"),
		OTELUseHTTP:  getEnvBool("OTEL_USE_HTTP", false),

		HyperDXEnabled:  getEnvBool("HYPERDX_ENABLED", false),
		HyperDXAPIKey:   getEnv("HYPERDX_API_KEY", ""),
		HyperDXEndpoint: getEnv("HYPERDX_ENDPOINT", "https://in-otel.hyperdx.io"),

		MLflowTrackingURI:    getEnv("MLFLOW_TRACKING_URI", "http://mlflow.mlflow.svc.cluster.local:80"),
		MLflowExperimentName: getEnv("MLFLOW_EXPERIMENT_NAME", ""),
		MLflowEnabled:        getEnvBool("MLFLOW_ENABLED", true),

		HealthPort: getEnvInt("HEALTH_PORT", 8080),
		HealthPath: getEnv("HEALTH_PATH", "/health"),
		ReadyPath:  getEnv("READY_PATH", "/ready"),

		HTTPTimeout: getEnvDuration("HTTP_TIMEOUT", 60*time.Second),
		NATSTimeout: getEnvDuration("NATS_TIMEOUT", 30*time.Second),
	}
}

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

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

func getEnvBool(key string, fallback bool) bool {
	if v := os.Getenv(key); v != "" {
		if b, err := strconv.ParseBool(v); err == nil {
			return b
		}
	}
	return fallback
}

func getEnvDuration(key string, fallback time.Duration) time.Duration {
	if v := os.Getenv(key); v != "" {
		if f, err := strconv.ParseFloat(v, 64); err == nil {
			return time.Duration(f * float64(time.Second))
		}
	}
	return fallback
}