package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/grafana/grafana-app-sdk/plugin/kubeconfig"
	"github.com/grafana/grafana-app-sdk/simple"
	"github.com/grafana/grafana/pkg/services/authz"
)

const (
	ConnTypeGRPC = "grpc"
	ConnTypeHTTP = "http"
)

type Config struct {
	OTelConfig       simple.OpenTelemetryConfig
	WebhookServer    WebhookServerConfig
	KubeConfig       *kubeconfig.NamespacedConfig
	ZanzanaClient    authz.ZanzanaClientConfig
	FolderReconciler FolderReconcilerConfig
}

type WebhookServerConfig struct {
	Port        int
	TLSCertPath string
	TLSKeyPath  string
}

type FolderReconcilerConfig struct {
	Namespace string
}

func LoadConfigFromEnv() (*Config, error) {
	cfg := Config{}
	cfg.OTelConfig.ServiceName = os.Getenv("OTEL_SERVICE_NAME")
	switch strings.ToLower(os.Getenv("OTEL_CONN_TYPE")) {
	case ConnTypeGRPC:
		cfg.OTelConfig.ConnType = ConnTypeGRPC
	case ConnTypeHTTP:
		cfg.OTelConfig.ConnType = ConnTypeHTTP
	case "":
		// Default
		cfg.OTelConfig.ConnType = ConnTypeHTTP
	default:
		return nil, fmt.Errorf("unknown OTEL_CONN_TYPE '%s'", os.Getenv("OTEL_CONN_TYPE"))
	}
	cfg.OTelConfig.Host = os.Getenv("OTEL_HOST")
	portStr := os.Getenv("OTEL_PORT")
	if portStr == "" {
		if cfg.OTelConfig.ConnType == ConnTypeGRPC {
			// Default OTel GRPC port
			cfg.OTelConfig.Port = 4317
		} else {
			// Default OTel HTTP port
			cfg.OTelConfig.Port = 4318
		}
	} else {
		var err error
		cfg.OTelConfig.Port, err = strconv.Atoi(portStr)
		if err != nil {
			return nil, fmt.Errorf("invalid OTEL_PORT '%s': %w", portStr, err)
		}
	}

	whPortStr := os.Getenv("WEBHOOK_PORT")
	if whPortStr == "" {
		cfg.WebhookServer.Port = 8443
	} else {
		var err error
		cfg.WebhookServer.Port, err = strconv.Atoi(whPortStr)
		if err != nil {
			return nil, fmt.Errorf("invalid WEBHOOK_PORT '%s': %w", whPortStr, err)
		}
	}

	cfg.WebhookServer.TLSCertPath = os.Getenv("WEBHOOK_CERT_PATH")
	cfg.WebhookServer.TLSKeyPath = os.Getenv("WEBHOOK_KEY_PATH")

	// Load the kube config
	kubeConfigFile := os.Getenv("KUBE_CONFIG_FILE")
	if kubeConfigFile != "" {
		kubeConfig, err := LoadKubeConfigFromFile(kubeConfigFile)
		if err != nil {
			return nil, fmt.Errorf("unable to load kubernetes configuration from file '%s': %w", kubeConfigFile, err)
		}
		cfg.KubeConfig = kubeConfig
	} else if folderAppURL := os.Getenv("FOLDER_APP_URL"); folderAppURL != "" {
		exchangeUrl := os.Getenv("TOKEN_EXCHANGE_URL")
		authToken := os.Getenv("AUTH_TOKEN")
		namespace := os.Getenv("FOLDER_APP_NAMESPACE")
		if exchangeUrl == "" || authToken == "" {
			return nil, fmt.Errorf("TOKEN_EXCHANGE_URL and AUTH_TOKEN must be set when FOLDER_APP_URL is set")
		}

		kubeConfig, err := LoadKubeConfigFromFolderAppURL(folderAppURL, exchangeUrl, authToken, namespace)
		if err != nil {
			return nil, fmt.Errorf("unable to load kubernetes configuration from folder app URL '%s': %w", folderAppURL, err)
		}
		cfg.KubeConfig = kubeConfig
	} else {
		kubeConfig, err := LoadInClusterConfig()
		if err != nil {
			return nil, fmt.Errorf("unable to load in-cluster kubernetes configuration: %w", err)
		}
		cfg.KubeConfig = kubeConfig
	}

	cfg.ZanzanaClient.Address = os.Getenv("ZANZANA_ADDR")
	cfg.ZanzanaClient.Token = os.Getenv("ZANZANA_TOKEN")
	cfg.ZanzanaClient.TokenExchangeURL = os.Getenv("TOKEN_EXCHANGE_URL")
	cfg.ZanzanaClient.ServerCertFile = os.Getenv("ZANZANA_SERVER_CERT_FILE")

	cfg.FolderReconciler.Namespace = os.Getenv("FOLDER_RECONCILER_NAMESPACE")

	return &cfg, nil
}