package instancectl

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestPlan14BoundUnitPlacement(t *testing.T) {
	for _, name := range []string{"console.service", "woodstar-atbridge.service", "carlos-app@shop.example.service"} {
		t.Run(name, func(t *testing.T) {
			u, ctl, in, _ := claimUnitFixture(t)
			u.BoundHost, u.BoundUnit = in.Host, name
			ctl.group = "/" + BoundClaimUnitControlGroup(in.Host, name)
			ctl.events = filepath.Join(u.CgroupRoot, strings.TrimPrefix(ctl.group, "/"))
			if err := os.MkdirAll(ctl.events, 0755); err != nil {
				t.Fatal(err)
			}
			ctl.setPopulated(false)
			// A bound unit must never be started by the unreserved entrypoint.
			if _, err := u.Start(t.Context(), in); err == nil {
				t.Fatal("unreserved named launch")
			}
			if strings.Contains(ctl.joined(), "start ") {
				t.Fatal(ctl.joined())
			}
			if err := u.Gone(t.Context(), in.Host, ""); err != nil {
				t.Fatal(err)
			}
			ctl.state, ctl.invocation = "active", "replacement"
			ctl.setPopulated(true)
			if err := u.Gone(t.Context(), in.Host, "old"); !errors.Is(err, ErrClaimUnitBusy) {
				t.Fatalf("replacement with populated tree accepted: %v", err)
			}
			ctl.state = "inactive"
			if err := u.Gone(t.Context(), in.Host, "old"); !errors.Is(err, ErrClaimUnitBusy) {
				t.Fatalf("descendants accepted: %v", err)
			}
			ctl.setPopulated(false)
			if err := u.Gone(t.Context(), in.Host, "old"); err != nil {
				t.Fatal(err)
			}
			before := ctl.joined()
			if err := u.Stop(context.Background(), "sibling.example"); err == nil {
				t.Fatal("binding crossed hosts")
			}
			if ctl.joined() != before {
				t.Fatal("foreign host reached systemd")
			}
		})
	}
}

func TestPlan14BoundUnitNames(t *testing.T) {
	for _, name := range []string{"../console.service", "console.service/child", "x\n.service", "x@.service", "x.socket", "--x.service", "carlos-instance-control.service"} {
		u, ctl, in, _ := claimUnitFixture(t)
		u.BoundHost, u.BoundUnit = in.Host, name
		if err := u.Gone(t.Context(), in.Host, ""); err == nil {
			t.Fatalf("accepted %q", name)
		}
		if ctl.joined() != "" {
			t.Fatal("invalid binding reached systemd")
		}
	}
}

func TestPlan14BoundUnitExactStop(t *testing.T) {
	u, ctl, in, _ := claimUnitFixture(t)
	u.BoundHost, u.BoundUnit = in.Host, "console.service"
	ctl.group = "/" + BoundClaimUnitControlGroup(in.Host, u.BoundUnit)
	ctl.invocation, ctl.state = "replacement", "active"
	if err := u.StopInvocation(t.Context(), in.Host, "old"); err == nil {
		t.Fatal("stopped replacement")
	}
	if strings.Contains(ctl.joined(), "stop ") {
		t.Fatal(ctl.joined())
	}
	if err := u.StopInvocation(t.Context(), in.Host, ""); err == nil {
		t.Fatal("stopped unknown invocation")
	}
	ctl.invocation = "old"
	if err := u.StopInvocation(t.Context(), in.Host, "old"); err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(ctl.joined(), "stop console.service") {
		t.Fatal(ctl.joined())
	}
}

func TestPlan14BoundStopReportsInvocationRace(t *testing.T) {
	for _, changed := range []string{"invocation", "group"} {
		t.Run(changed, func(t *testing.T) {
			u, ctl, in, _ := claimUnitFixture(t)
			u.BoundHost, u.BoundUnit = in.Host, "console.service"
			ctl.group = "/" + BoundClaimUnitControlGroup(in.Host, u.BoundUnit)
			ctl.invocation, ctl.state = "old", "active"
			u.Systemctl = func(ctx context.Context, args ...string) (string, error) {
				if args[0] == "stop" {
					if changed == "invocation" {
						ctl.invocation = "replacement"
					} else {
						ctl.group = "/sibling.slice/console.service"
					}
				}
				return ctl.run(ctx, args...)
			}
			if err := u.StopInvocation(t.Context(), in.Host, "old"); !errors.Is(err, ErrClaimUnitBusy) {
				t.Fatal("uncertain stop reported success", err)
			}
		})
	}
}