package host

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

type plan11CompositeKernel struct{ writers, noProcess int }

func (*plan11CompositeKernel) VerifyStopped(context.Context, hostguard.FenceTarget, StopInventory, DrainAcknowledgement) (StopKernelEvidence, error) {
	return StopKernelEvidence{}, nil
}
func (k *plan11CompositeKernel) VerifyWritersStopped(context.Context, hostguard.FenceTarget, StopInventory, StopPeer, []stopevidence.DescriptorHint) (WritersKernelEvidence, error) {
	k.writers++
	return WritersKernelEvidence{}, nil
}
func (k *plan11CompositeKernel) VerifyNoProcess(context.Context, hostguard.FenceTarget, StopInventory) (StopKernelEvidence, error) {
	k.noProcess++
	return StopKernelEvidence{}, nil
}

func TestPlan11IsolatedWrapperPreservesRootObservations(t *testing.T) {
	f := newLaunchFixture(t, servingOp())
	if _, err := f.root.Serve(t.Context(), f.peer, f.req); err != nil {
		t.Fatal(err)
	}
	if err := f.journal.CloseWriters(t.Context(), f.target); err != nil {
		t.Fatal(err)
	}
	inner := &plan11CompositeKernel{}
	k := claimUnitStopKernel{Inner: inner, Journal: f.journal, Units: f.units}
	writers, ok := any(k).(stopWritersKernel)
	if !ok {
		t.Fatal("isolated wrapper hides writers-stopped observation")
	}
	zero, ok := any(k).(stopNoProcessKernel)
	if !ok {
		t.Fatal("isolated wrapper hides session-zero observation")
	}
	f.units.goneErr = errors.New("unit is active")
	if _, err := writers.VerifyWritersStopped(t.Context(), f.target, StopInventory{}, f.peer, nil); err == nil || inner.writers != 0 {
		t.Fatal("active isolated writer passed observation")
	}
	target := f.target
	target.Session = 0
	if _, err := zero.VerifyNoProcess(t.Context(), target, StopInventory{}); err == nil || inner.noProcess != 0 {
		t.Fatal("active isolated unit passed session-zero observation")
	}
	f.units.goneErr = nil
	if _, err := writers.VerifyWritersStopped(t.Context(), f.target, StopInventory{}, f.peer, nil); err != nil || inner.writers != 1 {
		t.Fatalf("writers forwarding: %v %d", err, inner.writers)
	}
	if _, err := zero.VerifyNoProcess(t.Context(), target, StopInventory{}); err != nil || inner.noProcess != 1 {
		t.Fatalf("session-zero forwarding: %v %d", err, inner.noProcess)
	}
}

func TestPlan11WritersWitnessDoesNotShareCachedSlices(t *testing.T) {
	f := newWritersFixture(t)
	first, err := f.attempt.StopWriters(t.Context())
	if err != nil {
		t.Fatal(err)
	}
	expected := first.DBPaths[0]
	first.DBPaths[0] = "forged.db"
	next, err := f.attempt.StopWriters(t.Context())
	if err != nil {
		t.Fatal(err)
	}
	if next.DBPaths[0] != expected {
		t.Fatal("caller changed the cached session witness")
	}
}