//go:build ignore

package main

import (
	"database/sql"
	"fmt"
	"os"
	"strings"

	mysqlDriver "github.com/go-sql-driver/mysql"
)

const sharedBusinessDatabase = "meeting_im"

// This startup helper intentionally performs validation only. Database schema
// changes are managed by the checked-in SQL migrations and must not be applied
// implicitly while an IM Server pod is starting.
func main() {
	rawDSN := strings.TrimSpace(os.Getenv("IM_MYSQL_DSN"))
	dsn := strings.TrimPrefix(rawDSN, "mysql://")
	if dsn == "" {
		fatal("IM_MYSQL_DSN is required")
	}

	config, err := mysqlDriver.ParseDSN(dsn)
	if err != nil {
		fatal(fmt.Errorf("parse IM_MYSQL_DSN: %w", err))
	}
	if !strings.EqualFold(strings.TrimSpace(config.DBName), sharedBusinessDatabase) {
		fatal(fmt.Errorf("IM_MYSQL_DSN must select %s; got %q", sharedBusinessDatabase, config.DBName))
	}

	db, err := sql.Open("mysql", config.FormatDSN())
	if err != nil {
		fatal(err)
	}
	defer db.Close()
	if err = db.Ping(); err != nil {
		fatal(err)
	}

	var database string
	if err = db.QueryRow("SELECT DATABASE()").Scan(&database); err != nil {
		fatal(err)
	}
	if !strings.EqualFold(database, sharedBusinessDatabase) {
		fatal(fmt.Errorf("connected database is %q, want %q", database, sharedBusinessDatabase))
	}

	fmt.Printf("IM shared database validated: %s\n", database)
}

func fatal(v any) {
	fmt.Fprintln(os.Stderr, v)
	os.Exit(1)
}