package cabana

import (
	"context"
	"errors"
	"testing"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"git.golem15.com/golem15/summercms/modules/pact"

	"gorm.io/gorm"
)

// subjectListener records every *pact.MCPSubjectChanged the bus delivers,
// the type pier listens for.
func subjectListener(app *backpack.App) *[]pact.MCPSubjectChanged {
	got := &[]pact.MCPSubjectChanged{}
	app.Events.Listen("test", func(_ context.Context, ev *pact.MCPSubjectChanged) error {
		*got = append(*got, *ev)
		return nil
	})
	return got
}

func TestFireSubjectChangedReachesPointerListener(t *testing.T) {
	app := backpack.New(nil)
	got := subjectListener(app)

	fireSubjectChanged(context.Background(), app, pact.MCPSubjectPermissions, 7, 0, 9)

	if len(*got) != 2 {
		t.Fatalf("delivered %d events, want 2: %+v", len(*got), *got)
	}
	for i, id := range []uint{7, 9} {
		ev := (*got)[i]
		if ev.Guard != backendSubjectGuard || ev.UserID != id || ev.Kind != pact.MCPSubjectPermissions {
			t.Fatalf("event %d = %+v", i, ev)
		}
	}
}

func TestFireSubjectChangedWaitsForCommit(t *testing.T) {
	_, db := newListService(t)
	app := backpack.New(nil)
	got := subjectListener(app)

	err := lagoon.Transaction(context.Background(), db, func(ctx context.Context, tx *gorm.DB) error {
		fireSubjectChanged(withTx(ctx, tx), app, pact.MCPSubjectDeleted, 3)
		if len(*got) != 0 {
			t.Fatalf("fired inside the transaction: %+v", *got)
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if len(*got) != 1 || (*got)[0].UserID != 3 || (*got)[0].Kind != pact.MCPSubjectDeleted {
		t.Fatalf("after commit got %+v, want one deleted event for 3", *got)
	}

	*got = nil
	rollback := errors.New("rollback")
	err = lagoon.Transaction(context.Background(), db, func(ctx context.Context, tx *gorm.DB) error {
		fireSubjectChanged(withTx(ctx, tx), app, pact.MCPSubjectDeleted, 4)
		return rollback
	})
	if !errors.Is(err, rollback) {
		t.Fatalf("err = %v, want rollback", err)
	}
	if len(*got) != 0 {
		t.Fatalf("a rolled-back transaction fired %+v", *got)
	}
}