package config

import (
	"context"
	"errors"
	"flag"
	"os"
	"path/filepath"

	"github.com/peterbourgon/ff/v3"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"edge-infra.dev/pkg/lib/gcp/cloudsql"
)

// Config represents configuration for the lighthouse system.
type Config struct {
	WatchClient client.WithWatch
	DatabaseCfg *cloudsql.EdgePostgres
	ProjectID   string
	TopicID     string
}

// New returns a new system config instance.
func New() *Config {
	return &Config{}
}

// Init fetches the environment variables and sets the db config fields
func Init(ctx context.Context, cl client.WithWatch) (*Config, error) {
	s := New()
	fs := flag.NewFlagSet("lighthouse", flag.ContinueOnError)
	connectionName := ""
	user := ""
	name := ""
	fs.StringVar(&connectionName, "sql-connection-name", "", "SQL Connection Name")
	fs.StringVar(&user, "sql-user", "", "SQL Connection Username")
	fs.StringVar(&name, "sql-db-name", "", "SQL Connection Database Name")
	fs.StringVar(&s.ProjectID, "project-id", "", "GCP Project ID")
	fs.StringVar(&s.TopicID, "topic-id", "", "GCP Pubsub Topic")
	if err := ff.Parse(fs, os.Args[1:], ff.WithEnvVarNoPrefix()); err != nil {
		return nil, err
	}
	dbCfg, err := cloudsql.GCPPostgresConnection(connectionName).Username(user).DBName(name).AttachDialer(ctx)
	if err != nil {
		return nil, err
	}
	s.DatabaseCfg = dbCfg
	client := cl
	if cl == nil {
		client, err = InitWatchClient()
		if err != nil {
			return nil, err
		}
	}
	s.WatchClient = client
	return s, nil
}

// InitWatchClient creates a new kubernetes watch client.
func InitWatchClient() (client.WithWatch, error) {
	config, err := rest.InClusterConfig()
	if errors.Is(err, rest.ErrNotInCluster) {
		config, err = clientcmd.BuildConfigFromFlags("", filepath.Join(homedir.HomeDir(), ".kube", "config"))
		if err != nil {
			return nil, err
		}
	}
	ctrlClient, err := client.NewWithWatch(config, client.Options{})
	if err != nil {
		return nil, err
	}
	return ctrlClient, nil
}