package agentworkspace

import (
	"context"
	"errors"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"

	"iop/packages/go/agenttask"
)

func TestConfinementPlatformFailsWithTypedUnavailableError(t *testing.T) {
	identity, err := platformConfinementRevision()
	if err != nil {
		if !errors.Is(err, ErrConfinementUnavailable) {
			t.Fatalf("platform error = %v, want ErrConfinementUnavailable", err)
		}
		return
	}
	if identity == "" {
		t.Fatal("available confinement returned an empty platform identity")
	}
}

func TestConfinementLinuxUsesMetadataCompleteMountNamespacePolicy(t *testing.T) {
	if runtime.GOOS != "linux" {
		t.Skip("Linux-only confinement policy")
	}
	identity, err := platformConfinementRevision()
	if err != nil {
		if errors.Is(err, ErrConfinementUnavailable) {
			return
		}
		t.Fatalf("platform confinement revision: %v", err)
	}
	if !strings.Contains(identity, "mount-namespace-metadata") || strings.Contains(identity, "landlock") {
		t.Fatalf("Linux confinement identity = %q, want metadata-complete mount namespace policy", identity)
	}
}

func TestConfinementDarwinUsesBoundWorkingDirectory(t *testing.T) {
	if runtime.GOOS != "darwin" {
		t.Skip("Darwin-only confinement command")
	}
	workingDirectory := t.TempDir()
	command, err := platformConfinementCommand(
		context.Background(),
		agenttask.ConfinementBinding{WorkingDir: workingDirectory},
		confinementPolicy{WritableRoots: []string{workingDirectory}},
		"/usr/bin/true",
		nil,
	)
	if err != nil {
		t.Fatalf("platformConfinementCommand: %v", err)
	}
	if command.Dir != workingDirectory {
		t.Fatalf("confined command directory = %q", command.Dir)
	}
}

func TestConfinementProofRejectsTamperedBinding(t *testing.T) {
	baseRoot, localRoot := newWorkspaceFixture(t)
	writeFile(t, filepath.Join(baseRoot, "input.txt"), "base\n", 0o600)
	backend := newTestBackend(t, localRoot, baseRoot)
	prepared, err := backend.Prepare(
		context.Background(),
		testIsolationRequest("task", "task#1"),
	)
	if err != nil {
		t.Fatalf("Prepare: %v", err)
	}
	proof, ok := prepared.Confinement.(*ConfinementProof)
	if !ok {
		t.Fatalf("confinement proof type = %T", prepared.Confinement)
	}
	expected := proof.Binding()
	expected.ProfileRevision = "profile-r2"
	if err := proof.Validate(expected); err == nil {
		t.Fatal("profile rebinding passed confinement validation")
	}

	tampered := *proof
	tampered.binding = proof.Binding()
	tampered.binding.BaseRoot = filepath.Dir(baseRoot)
	if _, err := tampered.Start(
		context.Background(),
		agenttask.ConfinementCommand{Name: "true"},
	); err == nil {
		t.Fatal("tampered proof produced a child command")
	}
}

func TestConfinementStartCreatesProofOwnedPipes(t *testing.T) {
	started, err := startConfinementCommand(exec.Command(
		"sh",
		"-c",
		`read line; printf 'stdout:%s\n' "$line"; printf 'stderr:%s\n' "$line" >&2`,
	))
	if err != nil {
		t.Fatalf("startConfinementCommand: %v", err)
	}
	if started.Child() == nil ||
		started.Stdin() == nil ||
		started.Stdout() == nil ||
		started.Stderr() == nil {
		t.Fatalf("started handle is incomplete: %#v", started)
	}
	type readResult struct {
		content string
		err     error
	}
	stdoutResult := make(chan readResult, 1)
	stderrResult := make(chan readResult, 1)
	go func() {
		content, err := io.ReadAll(started.Stdout())
		stdoutResult <- readResult{content: string(content), err: err}
	}()
	go func() {
		content, err := io.ReadAll(started.Stderr())
		stderrResult <- readResult{content: string(content), err: err}
	}()
	if _, err := io.WriteString(started.Stdin(), "owned\n"); err != nil {
		t.Fatalf("write proof-owned stdin: %v", err)
	}
	if err := started.Stdin().Close(); err != nil {
		t.Fatalf("close proof-owned stdin: %v", err)
	}
	if err := started.Child().Wait(); err != nil {
		t.Fatalf("wait confined child: %v", err)
	}
	stdout := <-stdoutResult
	stderr := <-stderrResult
	if stdout.err != nil || stdout.content != "stdout:owned\n" {
		t.Fatalf("stdout = %q, %v", stdout.content, stdout.err)
	}
	if stderr.err != nil || stderr.content != "stderr:owned\n" {
		t.Fatalf("stderr = %q, %v", stderr.content, stderr.err)
	}
	if err := started.Abort(); err != nil {
		t.Fatalf("cleanup completed handle: %v", err)
	}
}

func TestConfinementStartCleansPipeAndProcessFailures(t *testing.T) {
	t.Run("pipe setup", func(t *testing.T) {
		var opened []*os.File
		calls := 0
		factory := func() (*os.File, *os.File, error) {
			calls++
			if calls == 3 {
				return nil, nil, errors.New("injected pipe failure")
			}
			reader, writer, err := os.Pipe()
			if err == nil {
				opened = append(opened, reader, writer)
			}
			return reader, writer, err
		}
		if _, err := startConfinementCommandWithPipes(
			exec.Command("true"),
			factory,
		); err == nil || !strings.Contains(err.Error(), "stderr pipe") {
			t.Fatalf("pipe setup error = %v", err)
		}
		assertClosedFiles(t, opened)
	})

	t.Run("process start", func(t *testing.T) {
		var opened []*os.File
		factory := func() (*os.File, *os.File, error) {
			reader, writer, err := os.Pipe()
			if err == nil {
				opened = append(opened, reader, writer)
			}
			return reader, writer, err
		}
		missing := filepath.Join(t.TempDir(), "missing-command")
		if _, err := startConfinementCommandWithPipes(
			exec.Command(missing),
			factory,
		); err == nil || !strings.Contains(err.Error(), "start confined child") {
			t.Fatalf("process start error = %v", err)
		}
		assertClosedFiles(t, opened)
	})
}

func TestConfinementAbortClosesPipesAndReapsChild(t *testing.T) {
	started, err := startConfinementCommand(exec.Command("sleep", "5"))
	if err != nil {
		t.Fatalf("startConfinementCommand: %v", err)
	}
	stdin := started.Stdin()
	stdout := started.Stdout()
	stderr := started.Stderr()
	if err := started.Abort(); err != nil {
		t.Fatalf("Abort: %v", err)
	}
	if started.Child().ProcessState == nil {
		t.Fatal("Abort did not reap the child")
	}
	if _, err := stdin.Write([]byte("leak")); err == nil {
		t.Fatal("Abort left stdin open")
	}
	if _, err := stdout.Read(make([]byte, 1)); err == nil {
		t.Fatal("Abort left stdout open")
	}
	if _, err := stderr.Read(make([]byte, 1)); err == nil {
		t.Fatal("Abort left stderr open")
	}
	if err := started.Abort(); err != nil {
		t.Fatalf("second Abort: %v", err)
	}
}

func assertClosedFiles(t *testing.T, files []*os.File) {
	t.Helper()
	for _, file := range files {
		if _, err := file.Stat(); err == nil {
			t.Fatalf("pipe endpoint %d remained open", file.Fd())
		}
	}
}