package profile

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"syscall"
	"testing"
	"time"
)

type ownerCall struct {
	path     string
	uid, gid int
}

type fakeFileOperations struct {
	calls        []ownerCall
	failContains string
	syncErr      error
}

func (f *fakeFileOperations) SetOwner(file *os.File, uid, gid int) error {
	f.calls = append(f.calls, ownerCall{path: file.Name(), uid: uid, gid: gid})
	if f.failContains != "" && strings.Contains(filepath.Base(file.Name()), f.failContains) {
		return errors.New("injected ownership failure")
	}
	return nil
}

func (f *fakeFileOperations) SyncDirectory(*os.File) error { return f.syncErr }

type fakeIdentityEnvironment struct {
	current UserIdentity
	users   map[string]UserIdentity
	env     map[string]string
}

func (f fakeIdentityEnvironment) CurrentUser() (UserIdentity, error) { return f.current, nil }
func (f fakeIdentityEnvironment) LookupUser(name string) (UserIdentity, error) {
	identity, ok := f.users[name]
	if !ok {
		return UserIdentity{}, errors.New("not found")
	}
	return identity, nil
}
func (f fakeIdentityEnvironment) LookupEnv(name string) (string, bool) {
	value, ok := f.env[name]
	return value, ok
}

func TestFileStoreLockSerializesAcrossProcesses(t *testing.T) {
	if path := os.Getenv("PROXYCTL_LOCK_HELPER_PATH"); path != "" {
		store := NewFileStore(path)
		_, err := store.Mutate(func(state State) (State, error) {
			state.Profiles = append(state.Profiles, Profile{Name: "child"})
			return state, nil
		})
		if err != nil {
			t.Fatal(err)
		}
		return
	}

	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	store := NewFileStore(path)
	if _, err := store.Mutate(func(state State) (State, error) { return state, nil }); err != nil {
		t.Fatal(err)
	}
	lock, err := os.OpenFile(path+".lock", os.O_RDWR, 0o600)
	if err != nil {
		t.Fatal(err)
	}
	defer lock.Close()
	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_EX); err != nil {
		t.Fatal(err)
	}

	command := exec.Command(os.Args[0], "-test.run=^TestFileStoreLockSerializesAcrossProcesses$")
	command.Env = append(os.Environ(), "PROXYCTL_LOCK_HELPER_PATH="+path)
	done := make(chan error, 1)
	go func() { done <- command.Run() }()
	select {
	case err := <-done:
		t.Fatalf("child mutation did not wait for lock: %v", err)
	case <-time.After(100 * time.Millisecond):
	}
	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_UN); err != nil {
		t.Fatal(err)
	}
	select {
	case err := <-done:
		if err != nil {
			t.Fatalf("child mutation after unlock: %v", err)
		}
	case <-time.After(5 * time.Second):
		_ = command.Process.Kill()
		t.Fatal("child mutation remained blocked after unlock")
	}
	state, err := store.Load()
	if err != nil {
		t.Fatal(err)
	}
	if len(state.Profiles) != 1 || state.Profiles[0].Name != "child" {
		t.Fatalf("state after serialized child mutation = %#v", state)
	}
}

func TestOwnedStoreAssignsInvokingUserToDirectoryLockAndReplacement(t *testing.T) {
	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	owner := UserIdentity{Username: "alice", UID: 1001, GID: 1002}
	operations := &fakeFileOperations{}
	store := newFileStore(path, &owner, operations)
	if _, err := store.Mutate(func(state State) (State, error) {
		state.Profiles = append(state.Profiles, Profile{Name: "office"})
		return state, nil
	}); err != nil {
		t.Fatal(err)
	}

	wantKinds := map[string]bool{"directory": false, "lock": false, "temporary replacement": false}
	for _, call := range operations.calls {
		if call.uid != owner.UID || call.gid != owner.GID {
			t.Fatalf("ownership call for %q used %d:%d, want %d:%d", call.path, call.uid, call.gid, owner.UID, owner.GID)
		}
		switch {
		case call.path == filepath.Dir(path):
			wantKinds["directory"] = true
		case call.path == path+".lock":
			wantKinds["lock"] = true
		case strings.HasPrefix(filepath.Base(call.path), ".profiles-"):
			wantKinds["temporary replacement"] = true
		}
	}
	for kind, seen := range wantKinds {
		if !seen {
			t.Errorf("no ownership assignment for %s; calls=%#v", kind, operations.calls)
		}
	}
}

func TestOwnedStoreReportsOwnershipFailuresBeforeCommit(t *testing.T) {
	for _, failure := range []string{"proxyctl", "profiles.json.lock", ".profiles-"} {
		t.Run(failure, func(t *testing.T) {
			path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
			owner := UserIdentity{Username: "alice", UID: 1001, GID: 1002}
			operations := &fakeFileOperations{failContains: failure}
			store := newFileStore(path, &owner, operations)
			_, err := store.Mutate(func(state State) (State, error) {
				state.Profiles = append(state.Profiles, Profile{Name: "must-not-commit"})
				return state, nil
			})
			if err == nil || !strings.Contains(err.Error(), "owner") {
				t.Fatalf("ownership failure = %v", err)
			}
			if _, statErr := os.Stat(path); !errors.Is(statErr, os.ErrNotExist) {
				t.Fatalf("configuration was committed after ownership failure: %v", statErr)
			}
		})
	}
}

func TestOwnedLoadRejectsConfigurationOwnershipFailure(t *testing.T) {
	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte(`{"profiles":[]}`), 0o600); err != nil {
		t.Fatal(err)
	}
	owner := UserIdentity{Username: "alice", UID: 1001, GID: 1002}
	operations := &fakeFileOperations{failContains: "profiles.json"}
	_, err := newFileStore(path, &owner, operations).Load()
	if err == nil || !strings.Contains(err.Error(), "set Profile configuration owner") {
		t.Fatalf("configuration ownership failure = %v", err)
	}
}

func TestLoadRejectsProfileConfigurationSymlinkWithoutChangingTarget(t *testing.T) {
	directory := t.TempDir()
	target := filepath.Join(directory, "target.json")
	if err := os.WriteFile(target, []byte(`{"profiles":[]}`), 0o644); err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(directory, "profiles.json")
	if err := os.Symlink(target, path); err != nil {
		t.Fatal(err)
	}
	_, err := NewFileStore(path).Load()
	if err == nil || !strings.Contains(err.Error(), "without following links") {
		t.Fatalf("symlink load error = %v", err)
	}
	info, statErr := os.Stat(target)
	if statErr != nil {
		t.Fatal(statErr)
	}
	if info.Mode().Perm() != 0o644 {
		t.Fatalf("symlink target mode changed to %#o", info.Mode().Perm())
	}
}

func TestMutationRejectsLockSymlinkWithoutChangingTarget(t *testing.T) {
	directory := filepath.Join(t.TempDir(), "proxyctl")
	if err := os.MkdirAll(directory, 0o700); err != nil {
		t.Fatal(err)
	}
	target := filepath.Join(t.TempDir(), "lock-target")
	if err := os.WriteFile(target, []byte("unchanged"), 0o644); err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(directory, "profiles.json")
	if err := os.Symlink(target, path+".lock"); err != nil {
		t.Fatal(err)
	}
	_, err := NewFileStore(path).Mutate(func(state State) (State, error) { return state, nil })
	if err == nil || !strings.Contains(err.Error(), "without following links") {
		t.Fatalf("lock symlink error = %v", err)
	}
	contents, readErr := os.ReadFile(target)
	if readErr != nil {
		t.Fatal(readErr)
	}
	if string(contents) != "unchanged" {
		t.Fatalf("lock symlink target was modified: %q", contents)
	}
	info, statErr := os.Stat(target)
	if statErr != nil {
		t.Fatal(statErr)
	}
	if info.Mode().Perm() != 0o644 {
		t.Fatalf("lock symlink target mode changed to %#o", info.Mode().Perm())
	}
}

func TestDirectorySyncFailureReturnsCommittedStateAndRecognizableError(t *testing.T) {
	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
	operations := &fakeFileOperations{syncErr: errors.New("injected sync failure")}
	store := newFileStore(path, nil, operations)
	next, err := store.Mutate(func(state State) (State, error) {
		state.Profiles = append(state.Profiles, Profile{Name: "committed"})
		return state, nil
	})
	var committed *CommitError
	if !errors.As(err, &committed) {
		t.Fatalf("sync failure = %v, want CommitError", err)
	}
	if len(next.Profiles) != 1 || next.Profiles[0].Name != "committed" {
		t.Fatalf("returned committed state = %#v", next)
	}
	loaded, loadErr := NewFileStore(path).Load()
	if loadErr != nil {
		t.Fatal(loadErr)
	}
	if fmt.Sprint(loaded) != fmt.Sprint(next) {
		t.Fatalf("disk state = %#v, committed state = %#v", loaded, next)
	}
}

func TestConfigPathUsesInvokingUserIdentityUnderSudo(t *testing.T) {
	environment := fakeIdentityEnvironment{
		current: UserIdentity{Username: "root", HomeDir: "/root"},
		users:   map[string]UserIdentity{"alice": {Username: "alice", HomeDir: "/home/alice", UID: 1001, GID: 1002}},
		env: map[string]string{
			"SUDO_USER":       "alice",
			"XDG_CONFIG_HOME": "/home/alice/.xdg/config",
		},
	}
	configuration, err := ResolveConfiguration(environment)
	if err != nil {
		t.Fatal(err)
	}
	want := filepath.Join("/home/alice/.xdg/config", "proxyctl", "profiles.json")
	if configuration.Path != want {
		t.Fatalf("configuration path = %q, want invoking user's XDG path %q", configuration.Path, want)
	}
	if configuration.Owner.Username != "alice" || configuration.Owner.UID != 1001 || configuration.Owner.GID != 1002 {
		t.Fatalf("configuration owner = %#v, want verified invoking-user identity", configuration.Owner)
	}
}

func TestConfigPathDoesNotReuseRootXDGForInvokingUser(t *testing.T) {
	environment := fakeIdentityEnvironment{
		current: UserIdentity{Username: "root", HomeDir: "/root"},
		users:   map[string]UserIdentity{"alice": {Username: "alice", HomeDir: "/home/alice", UID: 1001, GID: 1002}},
		env: map[string]string{
			"SUDO_USER":       "alice",
			"XDG_CONFIG_HOME": "/root/.config",
		},
	}
	path, err := ConfigPathWith(environment)
	if err != nil {
		t.Fatal(err)
	}
	want := filepath.Join("/home/alice/.config", "proxyctl", "profiles.json")
	if path != want {
		t.Fatalf("configuration path = %q, want invoking user's fallback %q", path, want)
	}
}

func TestConfigPathUsesRootForDirectRootLogin(t *testing.T) {
	environment := fakeIdentityEnvironment{
		current: UserIdentity{Username: "root", HomeDir: "/root"},
		users:   map[string]UserIdentity{},
		env:     map[string]string{"XDG_CONFIG_HOME": "/root/custom-config"},
	}
	path, err := ConfigPathWith(environment)
	if err != nil {
		t.Fatal(err)
	}
	want := filepath.Join("/root/custom-config", "proxyctl", "profiles.json")
	if path != want {
		t.Fatalf("configuration path = %q, want direct root path %q", path, want)
	}
}