//go:build linux

package instancectl

import (
	"context"
	"encoding/json"
	"net"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestRev3ReservedUnitChecksAtTrampolineBoundary(t *testing.T) {
	for _, name := range []string{"valid", "expired during setup", "wrong peer", "wrong reservation", "replacement invocation", "main PID handed over"} {
		t.Run(name, func(t *testing.T) {
			u, ctl, in, _ := claimUnitFixture(t)
			dir, err := os.MkdirTemp("", "rg")
			if err != nil {
				t.Fatal(err)
			}
			defer os.RemoveAll(dir)
			u.ExeRoot = filepath.Join(dir, "exe")
			u.UnitRoot = filepath.Join(dir, "unit")
			u.DataRoot = filepath.Join(dir, "data")
			p := ClaimExecPermit{Reservation: "a:main", Inputs: "hash", BootID: "boot", SafeUntil: 200, Containment: 1}
			setup := false
			checks := 0
			received := make(chan error, 1)
			original := u.Systemctl
			u.Systemctl = func(ctx context.Context, args ...string) (string, error) {
				out, err := original(ctx, args...)
				if name == "main PID handed over" && args[0] == "show" && strings.Contains(strings.Join(args, ","), "MainPID") {
					ctl.mu.Lock()
					ctl.pid = os.Getpid()
					ctl.mu.Unlock()
				}
				if args[0] != "start" || err != nil {
					return out, err
				}
				setup = true
				ctl.mu.Lock()
				ctl.pid = os.Getpid()
				if name == "wrong peer" || name == "main PID handed over" {
					ctl.pid++
				}
				ctl.mu.Unlock()
				source, dropin, _ := u.launchPaths(in.Host)
				body, e := os.ReadFile(filepath.Join(dropin, "60-claim-launch.conf"))
				if e != nil || !strings.Contains(string(body), "BindReadOnlyPaths=/proc/sys/kernel/random/boot_id:"+ClaimExecBootID) || !strings.Contains(string(body), "instance-exec -claim-reservation="+ClaimExecSnapshot+" run %I\n") {
					t.Errorf("missing trusted trampoline binds/argument: %s %v", body, e)
				}
				go func() {
					c, e := net.Dial("unix", filepath.Join(source, "exec.sock"))
					if e != nil {
						received <- e
						return
					}
					defer c.Close()
					q := p
					if name == "wrong reservation" {
						q.Reservation = "other"
					}
					if e = json.NewEncoder(c).Encode(q); e == nil {
						var got ClaimExecPermit
						e = json.NewDecoder(c).Decode(&got)
					}
					received <- e
				}()
				return out, nil
			}
			l := Launch{Schema: LaunchSchema, Host: in.Host, Argv: []string{LiveDir + "/" + in.Host}}
			started, err := u.StartReserved(t.Context(), in, l, p, func() error {
				checks++
				if setup && name == "expired during setup" {
					return ErrClaimUnit
				}
				if setup && name == "replacement invocation" {
					ctl.mu.Lock()
					ctl.invocation = "replacement"
					ctl.mu.Unlock()
				}
				return nil
			})
			clientErr := <-received
			if name == "valid" || name == "main PID handed over" {
				if err != nil || clientErr != nil || checks != 2 || started.MainPID != os.Getpid() {
					t.Fatalf("start=%v gate=%v checks=%d", err, clientErr, checks)
				}
				source, _, _ := u.launchPaths(in.Host)
				if _, err := os.Lstat(filepath.Join(source, "exec.sock")); err != nil {
					t.Fatalf("ExecStopPost bind source removed early: %v", err)
				}
				_ = u.Stop(t.Context(), in.Host)
				if _, err := os.Lstat(filepath.Join(source, "exec.sock")); !os.IsNotExist(err) {
					t.Fatalf("stopped gate source retained: %v", err)
				}
			} else if err == nil || clientErr == nil {
				t.Fatalf("unsafe start=%v gate=%v", err, clientErr)
			}
			if !strings.Contains(ctl.joined(), "start ") {
				t.Fatal("did not reach asynchronous setup")
			}
		})
	}
}