package proc

import (
	"encoding/json"
	"os"
	"os/exec"
	"path/filepath"
	"syscall"
	"testing"
	"time"
)

const watchLockHelperEnv = "BROWSEROS_DEV_WATCH_LOCK_HELPER"

func TestMain(m *testing.M) {
	if os.Getenv(watchLockHelperEnv) == "1" {
		runWatchLockHelper()
		return
	}
	os.Exit(m.Run())
}

func TestWatchRunPathsStableAndDistinct(t *testing.T) {
	baseDir := t.TempDir()
	identity := WatchRunIdentity{
		Mode:    "watch",
		Profile: "/tmp/browseros-dev",
		Ports:   Ports{CDP: 9005, Server: 9105, Extension: 9305},
	}

	first := watchRunPaths(baseDir, identity)
	second := watchRunPaths(baseDir, identity)
	if first != second {
		t.Fatalf("expected stable paths, got %#v and %#v", first, second)
	}

	withDifferentPort := identity
	withDifferentPort.Ports.Server = 9106
	third := watchRunPaths(baseDir, withDifferentPort)
	if third.Lock == first.Lock || third.State == first.State {
		t.Fatalf("expected distinct paths for different ports, got %#v and %#v", first, third)
	}
}

func TestBrowserProfilePIDsFromPSSelectsOnlyDevAndTestProfiles(t *testing.T) {
	output := `
  111  111 /Applications/BrowserOS.app/Contents/MacOS/BrowserOS --user-data-dir=/tmp/browseros-dev
  222  222 /Applications/BrowserOS.app/Contents/MacOS/BrowserOS --user-data-dir=/tmp/browseros-dev-abcd
  333  333 /Applications/BrowserOS.app/Contents/MacOS/BrowserOS --user-data-dir=/var/folders/x/browseros-test-abcd
  444  444 /Applications/BrowserOS.app/Contents/MacOS/BrowserOS --user-data-dir=/Users/me/Library/Application Support/BrowserOS
  555  555 rg browseros-test-
`

	pids := browserProfilePIDsFromPS(output)

	if len(pids) != 3 || pids[0] != 111 || pids[1] != 222 || pids[2] != 333 {
		t.Fatalf("expected dev/test browser pids, got %#v", pids)
	}
}

func TestAcquireWatchRunLockWritesStateAndReleases(t *testing.T) {
	baseDir := t.TempDir()
	identity := WatchRunIdentity{
		Mode:    "watch",
		Profile: "/tmp/browseros-dev",
		Ports:   Ports{CDP: 9005, Server: 9105, Extension: 9305},
	}

	lock, stopped, err := AcquireWatchRunLockInDir(baseDir, identity, time.Second)
	if err != nil {
		t.Fatalf("AcquireWatchRunLockInDir returned error: %v", err)
	}
	if stopped {
		t.Fatal("expected first acquisition not to stop another run")
	}

	paths := watchRunPaths(baseDir, identity)
	state, err := ReadWatchRunState(paths.State)
	if err != nil {
		t.Fatalf("ReadWatchRunState returned error: %v", err)
	}
	if state.PID != os.Getpid() {
		t.Fatalf("expected state PID %d, got %d", os.Getpid(), state.PID)
	}
	if state.PGID <= 0 {
		t.Fatalf("expected positive PGID, got %d", state.PGID)
	}
	if state.Identity != identity {
		t.Fatalf("expected identity %#v, got %#v", identity, state.Identity)
	}
	if err := lock.Close(); err != nil {
		t.Fatalf("closing lock: %v", err)
	}
	if _, err := os.Stat(paths.State); !os.IsNotExist(err) {
		t.Fatalf("expected state file to be removed on close, got %v", err)
	}
	if _, err := os.Stat(paths.Lock); err != nil {
		t.Fatalf("expected lock file path to remain reusable, got %v", err)
	}

	lock, stopped, err = AcquireWatchRunLockInDir(baseDir, identity, time.Second)
	if err != nil {
		t.Fatalf("reacquiring lock returned error: %v", err)
	}
	if stopped {
		t.Fatal("expected reacquisition after close not to stop another run")
	}
	if err := lock.Close(); err != nil {
		t.Fatalf("closing reacquired lock: %v", err)
	}
}

func TestAcquireWatchRunLockRejectsInvalidPorts(t *testing.T) {
	identity := WatchRunIdentity{
		Mode:    "watch",
		Profile: "/tmp/browseros-dev",
		Ports:   Ports{CDP: 9005, Server: 65536, Extension: 9305},
	}

	if _, _, err := AcquireWatchRunLockInDir(t.TempDir(), identity, time.Second); err == nil {
		t.Fatal("expected invalid port error")
	}
}

func TestAcquireWatchRunLockStopsExistingOwnerByStatePGID(t *testing.T) {
	baseDir := t.TempDir()
	readyPath := filepath.Join(baseDir, "ready")
	identity := WatchRunIdentity{
		Mode:    "watch",
		Profile: "/tmp/browseros-dev",
		Ports:   Ports{CDP: 9005, Server: 9105, Extension: 9305},
	}
	identityJSON, err := json.Marshal(identity)
	if err != nil {
		t.Fatal(err)
	}

	cmd := exec.Command(os.Args[0], "-test.run=TestMain")
	cmd.Env = append(os.Environ(),
		watchLockHelperEnv+"=1",
		"BROWSEROS_DEV_WATCH_LOCK_BASE="+baseDir,
		"BROWSEROS_DEV_WATCH_LOCK_READY="+readyPath,
		"BROWSEROS_DEV_WATCH_LOCK_IDENTITY="+string(identityJSON),
	)
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	if err := cmd.Start(); err != nil {
		t.Fatalf("starting helper: %v", err)
	}
	defer cmd.Process.Kill()

	waitForFile(t, readyPath, 3*time.Second)

	lock, stopped, err := AcquireWatchRunLockInDir(baseDir, identity, 3*time.Second)
	if err != nil {
		t.Fatalf("AcquireWatchRunLockInDir returned error: %v", err)
	}
	defer lock.Close()
	if !stopped {
		t.Fatal("expected takeover to stop existing owner")
	}

	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()
	select {
	case <-done:
	case <-time.After(3 * time.Second):
		t.Fatal("expected helper process to exit after takeover")
	}
}

func runWatchLockHelper() {
	baseDir := os.Getenv("BROWSEROS_DEV_WATCH_LOCK_BASE")
	readyPath := os.Getenv("BROWSEROS_DEV_WATCH_LOCK_READY")
	var identity WatchRunIdentity
	if err := json.Unmarshal([]byte(os.Getenv("BROWSEROS_DEV_WATCH_LOCK_IDENTITY")), &identity); err != nil {
		os.Exit(2)
	}

	lock, _, err := AcquireWatchRunLockInDir(baseDir, identity, time.Second)
	if err != nil {
		os.Exit(3)
	}
	defer lock.Close()
	if err := os.WriteFile(readyPath, []byte("ready\n"), 0o644); err != nil {
		os.Exit(4)
	}
	time.Sleep(30 * time.Second)
}

func waitForFile(t *testing.T, path string, timeout time.Duration) {
	t.Helper()
	deadline := time.Now().Add(timeout)
	for {
		if _, err := os.Stat(path); err == nil {
			return
		}
		if time.Now().After(deadline) {
			t.Fatalf("timed out waiting for %s", path)
		}
		time.Sleep(50 * time.Millisecond)
	}
}