package db

import (
	"context"
	"os"
	"sync"
	"testing"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

// TestMigrateConcurrent runs Migrate from two goroutines against a real
// Postgres and asserts neither errors (the advisory lock serializes them;
// the loser sees every version recorded and no-ops). Requires a live DB:
// set PANEL_TEST_DSN to run, e.g.
//
//	PANEL_TEST_DSN=postgres://user:pw@localhost:5432/panel_test go test ./controller/internal/db/
//
// Skipped otherwise — no Postgres is assumed on dev machines or CI.
func TestMigrateConcurrent(t *testing.T) {
	dsn := os.Getenv("PANEL_TEST_DSN")
	if dsn == "" {
		t.Skip("PANEL_TEST_DSN not set; migration lock test needs a live Postgres")
	}
	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()
	pool, err := pgxpool.New(ctx, dsn)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	defer pool.Close()

	var wg sync.WaitGroup
	errs := make([]error, 2)
	for i := 0; i < 2; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			errs[i] = Migrate(ctx, pool)
		}(i)
	}
	wg.Wait()
	for i, e := range errs {
		if e != nil {
			t.Errorf("concurrent Migrate %d: %v", i, e)
		}
	}
}