package database

import (
	"context"
	"database/sql"
	"database/sql/driver"
	"errors"
	"sync/atomic"
	"testing"
)

var failedPingClosed atomic.Int32
var errPingUnavailable = errors.New("database unavailable")

type failedPingDriver struct{}
type failedPingConnection struct{}

func (failedPingDriver) Open(string) (driver.Conn, error) { return failedPingConnection{}, nil }
func (failedPingConnection) Prepare(string) (driver.Stmt, error) {
	return nil, errors.New("not implemented")
}
func (failedPingConnection) Begin() (driver.Tx, error)  { return nil, errors.New("not implemented") }
func (failedPingConnection) Close() error               { failedPingClosed.Add(1); return nil }
func (failedPingConnection) Ping(context.Context) error { return errPingUnavailable }

func init() { sql.Register("goOmniFailPing", failedPingDriver{}) }

func TestOpenClosesPoolWhenStartupPingFails(t *testing.T) {
	failedPingClosed.Store(0)
	cfg := DefaultConfig()
	cfg.Driver, cfg.DSN = "goOmniFailPing", "test"
	pool, err := Open(context.Background(), cfg)
	if pool != nil || !errors.Is(err, errPingUnavailable) {
		t.Fatalf("unexpected startup result: db=%v err=%v", pool, err)
	}
	if closed := failedPingClosed.Load(); closed != 1 {
		t.Fatalf("startup failure closed %d connections, want 1", closed)
	}
}