package server

import (
	"database/sql"
	"flag"
	"fmt"
	"os"
	"time"

	"github.com/peterbourgon/ff/v3"
	"google.golang.org/grpc"

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

type Config struct {
	MetricsAddr string
	HealthzAddr string

	ForemanProjectID string
	TopicID          string
	SubscriptionID   string

	DBConnection string
	DBName       string
	DBUsername   string
	DBPassword   string // for testing locally, not used when in the cloud.

	PollBannersPeriod     time.Duration
	PollBannersMaxRetries int

	PollSubscriptionExistsPeriod time.Duration

	// DelayScrapeMessageProcessing prevents deleting outdated watched field objects from thrashing the database
	// with unnecessary writes & deletes due to pubsub's out-of-order message delivery.
	//
	// Tests use a smaller value to prevent unnecessary delays.
	DelayScrapeMessageProcessing time.Duration

	BannerCheckPeriod time.Duration

	GarbageCollectDeletedWatchedFieldObjects bool

	DB             *sql.DB          // for testing, the flags for DB will be ignored if set.
	TestPubSubConn *grpc.ClientConn // for testing, needed since using manager.
}

func (cfg *Config) Validate() error {
	if cfg.MetricsAddr == "" {
		return fmt.Errorf("missing MetricsAddr")
	}
	if cfg.HealthzAddr == "" {
		return fmt.Errorf("missing HealthzAddr")
	}

	if cfg.DB == nil {
		switch "" {
		case cfg.DBConnection:
			return fmt.Errorf("missing DBConnection")
		case cfg.DBName:
			return fmt.Errorf("missing DBName")
		case cfg.DBUsername:
			return fmt.Errorf("missing DBUsername")
		case cfg.ForemanProjectID:
			return fmt.Errorf("missing ForemanProjectID")
		case cfg.TopicID:
			return fmt.Errorf("missing TopicID")
		case cfg.SubscriptionID:
			return fmt.Errorf("missing SubscriptionID")
		}
	}

	return nil
}

func (cfg *Config) ConnectToDB() (*sql.DB, error) {
	if cfg.DB != nil {
		return cfg.DB, nil
	}
	return cloudsql.GCPPostgresConnection(cfg.DBConnection).
		DBName(cfg.DBName).
		Username(cfg.DBUsername).
		Password(cfg.DBPassword).
		NewConnection()
}

func NewConfig() (*Config, error) {
	var cfg Config
	fs := flag.NewFlagSet("kinform-server", flag.ContinueOnError)

	fs.StringVar(&cfg.MetricsAddr, "metrics-addr", ":8081", "Address to bind metrics endpoint (/metrics) to")
	fs.StringVar(&cfg.HealthzAddr, "healthz-addr", ":8082", "Address to bind heath-check endpoints (/livez, /readyz) to")

	fs.StringVar(&cfg.ForemanProjectID, "foreman-project-id", "", "Foreman Project ID is used to create the shared PubSub client")
	fs.StringVar(&cfg.TopicID, "topic", "", "PubSub Topic ID where kinform publishes messages")
	fs.StringVar(&cfg.SubscriptionID, "subscription", "", "PubSub Subscription ID where psqlinjector receives kinform messages")

	fs.DurationVar(&cfg.DelayScrapeMessageProcessing, "delay-scrape-message-processing", 10*time.Second, "How long to wait before deleting outdated watched_field_objects after a cluster scrapes")
	fs.DurationVar(&cfg.BannerCheckPeriod, "banner-check-period", 60*time.Second, "The frequency of psqlinjector to check if banners were created or deleted")
	fs.BoolVar(&cfg.GarbageCollectDeletedWatchedFieldObjects, "gc-deleted-watched-field-objects", true, "Garbage collect deleted watched field objects at startup")

	fs.StringVar(&cfg.DBConnection, "db-connection", "", "postgress connection name")
	fs.StringVar(&cfg.DBName, "db-name", "", "name of db to connect to")
	fs.StringVar(&cfg.DBUsername, "db-username", "", "username of the db connection")
	fs.StringVar(&cfg.DBPassword, "db-password", "", "password of the db connection for testing locally")

	fs.DurationVar(&cfg.PollBannersPeriod, "poll-banners-period", 60*time.Second, "Time Duration period to poll for banner changes")
	fs.IntVar(&cfg.PollBannersMaxRetries, "poll-banners-max-retries", 5, "maximum amount of consecutive poll errors before psqlinjector quits")
	fs.DurationVar(&cfg.PollSubscriptionExistsPeriod, "poll-subscription-exists-period", 97*time.Second, "Time Duration period to probe for subscription deletions")

	if err := ff.Parse(fs, os.Args[1:], ff.WithEnvVarNoPrefix()); err != nil {
		return nil, err
	}

	return &cfg, nil
}