package main

import (
	"context"
	"database/sql"
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"

	_ "github.com/go-sql-driver/mysql"

	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/loadsim"
)

func main() {
	log.SetFlags(log.LstdFlags | log.Lmicroseconds)
	flagCfg := loadsim.RegisterFlags(flag.CommandLine)
	cleanupRegistration := flag.Bool("cleanup-registration", false, "delete this run's loopback JT808 registration rows after the simulation")
	cleanupOnly := flag.Bool("cleanup-only", false, "skip the simulation and only clean the configured JT808 phone range")
	mysqlDSN := flag.String("mysql-dsn", strings.TrimSpace(os.Getenv("MYSQL_DSN")), "MySQL DSN used only by JT808 registration cleanup")
	if err := flag.CommandLine.Parse(os.Args[1:]); err != nil {
		log.Fatal(err)
	}
	cfg, err := flagCfg.Build()
	if err != nil {
		log.Fatal(err)
	}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()
	if *cleanupOnly {
		deleted, err := cleanupJT808Registrations(ctx, cfg, *mysqlDSN)
		if err != nil {
			log.Fatal(err)
		}
		log.Printf("jt808 synthetic registration cleanup completed rows_deleted=%d", deleted)
		return
	}

	log.Printf("load simulation started protocol=%s addr=%s connections=%d connect_rate=%d send_interval=%s duration=%s template=%s",
		cfg.Protocol, cfg.Addr, cfg.Connections, cfg.ConnectRatePerSecond, cfg.SendInterval, cfg.Duration, cfg.Template)
	stats, err := (loadsim.Runner{}).Run(ctx, cfg)
	if err != nil {
		log.Fatal(err)
	}
	log.Print(formatStats(stats))
	if *cleanupRegistration {
		deleted, err := cleanupJT808Registrations(ctx, cfg, *mysqlDSN)
		if err != nil {
			log.Fatal(err)
		}
		log.Printf("jt808 synthetic registration cleanup completed rows_deleted=%d", deleted)
	}
}

func cleanupJT808Registrations(ctx context.Context, cfg loadsim.Config, dsn string) (int64, error) {
	if cfg.Protocol != loadsim.ProtocolJT808 {
		return 0, fmt.Errorf("registration cleanup only supports jt808")
	}
	if strings.TrimSpace(dsn) == "" {
		return 0, fmt.Errorf("mysql-dsn or MYSQL_DSN is required for registration cleanup")
	}
	db, err := sql.Open("mysql", dsn)
	if err != nil {
		return 0, fmt.Errorf("open mysql for registration cleanup: %w", err)
	}
	defer db.Close()
	return cleanupJT808RegistrationsWithDB(ctx, db, cfg)
}

type cleanupExecer interface {
	ExecContext(context.Context, string, ...any) (sql.Result, error)
}

func cleanupJT808RegistrationsWithDB(ctx context.Context, exec cleanupExecer, cfg loadsim.Config) (int64, error) {
	firstPhone := fmt.Sprintf("%012d", cfg.JT808PhoneBase)
	lastPhone := fmt.Sprintf("%012d", cfg.JT808PhoneBase+int64(cfg.Connections)-1)
	result, err := exec.ExecContext(ctx, `DELETE FROM jt808_registration
WHERE phone BETWEEN ? AND ?
  AND source_ip IN ('127.0.0.1', '::1')`, firstPhone, lastPhone)
	if err != nil {
		return 0, fmt.Errorf("delete loopback jt808 registrations: %w", err)
	}
	deleted, err := result.RowsAffected()
	if err != nil {
		return 0, fmt.Errorf("read registration cleanup result: %w", err)
	}
	return deleted, nil
}

func formatStats(stats loadsim.Stats) string {
	return fmt.Sprintf("connections_opened=%d connections_failed=%d frames_written=%d write_errors=%d response_bytes=%d read_errors=%d",
		stats.ConnectionsOpened,
		stats.ConnectionsFailed,
		stats.FramesWritten,
		stats.WriteErrors,
		stats.ResponseBytes,
		stats.ReadErrors,
	)
}