package host

import (
	"context"
	"errors"
	"github.com/carlosframework/platform/internal/hostguard"
	"github.com/carlosframework/platform/internal/stopevidence"
	"testing"
)

type fix1WritersScan struct {
	stopKernelFunc
	scan func()
}

func (k fix1WritersScan) VerifyWritersStopped(context.Context, hostguard.FenceTarget, StopInventory, StopPeer, []stopevidence.DescriptorHint) (WritersKernelEvidence, error) {
	if k.scan != nil {
		k.scan()
	}
	return WritersKernelEvidence{}, nil
}

func TestPlan11Fix1WritersMustRemainClosed(t *testing.T) {
	for _, shape := range []string{"open", "unit-appears", "closed"} {
		t.Run(shape, func(t *testing.T) {
			f := newLaunchFixture(t, servingOp())
			if shape != "open" {
				if err := f.journal.CloseWriters(t.Context(), f.target); err != nil {
					t.Fatal(err)
				}
			}
			scans := 0
			k := claimUnitStopKernel{Journal: f.journal, Units: f.units, Inner: fix1WritersScan{scan: func() {
				scans++
				if shape == "unit-appears" {
					f.units.goneErr = errors.New("unit started during scan")
				}
			}}}
			_, err := k.VerifyWritersStopped(t.Context(), f.target, StopInventory{}, f.peer, nil)
			if shape == "closed" {
				if err != nil || scans != 1 {
					t.Fatalf("closed: %v, scans=%d", err, scans)
				}
				return
			}
			if err == nil {
				t.Fatal("writers-stopped accepted an open writer boundary")
			}
			if shape == "open" && scans != 0 {
				t.Fatal("scanned before writers closed")
			}
		})
	}
}