package k8s

import (
	"fmt"
	"log/slog"
	"os"
	"path/filepath"

	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
)

// Client wraps a Kubernetes clientset with config used for template generation.
type Client struct {
	Clientset kubernetes.Interface
	Dynamic   dynamic.Interface
	Config    Config
}

// Config holds cluster-specific settings for pod template generation.
type Config struct {
	Domain           string // e.g. "spinoff.dev"
	Registry         string // e.g. "10.22.0.56:30500"
	GoldenImage      string // e.g. "dev-golden:v2"
	VPNGatewayNS     string // e.g. "claw-system"
	VPNGatewaySecret string // e.g. "vpn-gateway-secrets"
	AnthropicKey     string // baseroute anthropic key
	OpenAIKey        string // baseroute openai key
	ForgejoURL       string // e.g. "http://forgejo.dev-infra.svc:3000"
	DevPodAPIURL     string // e.g. "http://dev-pod-api.dev-infra.svc:8080"
}

// ConfigFromEnv reads Config from environment variables with defaults.
func ConfigFromEnv() Config {
	return Config{
		Domain:           envOrDefault("DOMAIN", "spinoff.dev"),
		Registry:         envOrDefault("REGISTRY", "10.22.0.56:30500"),
		GoldenImage:      envOrDefault("GOLDEN_IMAGE", "dev-golden:v2"),
		VPNGatewayNS:     envOrDefault("VPN_GATEWAY_NS", "claw-system"),
		VPNGatewaySecret: envOrDefault("VPN_GATEWAY_SECRET", "vpn-gateway-secrets"),
		AnthropicKey:     os.Getenv("DEFAULT_ANTHROPIC_KEY"),
		OpenAIKey:        os.Getenv("DEFAULT_OPENAI_KEY"),
		ForgejoURL:       envOrDefault("FORGEJO_URL", "http://forgejo.dev-infra.svc:3000"),
		DevPodAPIURL:     envOrDefault("DEV_POD_API_URL", "http://dev-pod-api.dev-infra.svc:8080"),
	}
}

// NewClient creates a Kubernetes client using in-cluster config,
// falling back to kubeconfig for local development.
func NewClient(cfg Config) (*Client, error) {
	restCfg, err := rest.InClusterConfig()
	if err != nil {
		slog.Info("in-cluster config not available, falling back to kubeconfig")
		restCfg, err = kubeconfigFromDefault()
		if err != nil {
			return nil, fmt.Errorf("create k8s config: %w", err)
		}
	}

	clientset, err := kubernetes.NewForConfig(restCfg)
	if err != nil {
		return nil, fmt.Errorf("create k8s clientset: %w", err)
	}

	dyn, err := dynamic.NewForConfig(restCfg)
	if err != nil {
		return nil, fmt.Errorf("create dynamic client: %w", err)
	}

	return &Client{
		Clientset: clientset,
		Dynamic:   dyn,
		Config:    cfg,
	}, nil
}

// NewClientWithClientset creates a Client with pre-configured clients (for testing).
func NewClientWithClientset(clientset kubernetes.Interface, dyn dynamic.Interface, cfg Config) *Client {
	return &Client{
		Clientset: clientset,
		Dynamic:   dyn,
		Config:    cfg,
	}
}

func kubeconfigFromDefault() (*rest.Config, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return nil, fmt.Errorf("get home dir: %w", err)
	}
	kubeconfig := filepath.Join(home, ".kube", "config")
	return clientcmd.BuildConfigFromFlags("", kubeconfig)
}

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