package pidlock

import (
	"os"
	"path/filepath"
	"strconv"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestAcquireAndRelease(t *testing.T) {
	tmpDir := t.TempDir()

	// Acquire lock
	lock, err := Acquire(tmpDir)
	require.NoError(t, err)
	require.NotNil(t, lock)

	// Verify PID file exists with our PID
	data, err := os.ReadFile(filepath.Join(tmpDir, "vaultik.pid"))
	require.NoError(t, err)
	pid, err := strconv.Atoi(string(data))
	require.NoError(t, err)
	assert.Equal(t, os.Getpid(), pid)

	// Release lock
	err = lock.Release()
	require.NoError(t, err)

	// Verify PID file is gone
	_, err = os.Stat(filepath.Join(tmpDir, "vaultik.pid"))
	assert.True(t, os.IsNotExist(err))
}

func TestAcquireBlocksSecondInstance(t *testing.T) {
	tmpDir := t.TempDir()

	// Acquire first lock
	lock1, err := Acquire(tmpDir)
	require.NoError(t, err)
	require.NotNil(t, lock1)
	defer func() { _ = lock1.Release() }()

	// Try to acquire second lock - should fail
	lock2, err := Acquire(tmpDir)
	assert.ErrorIs(t, err, ErrAlreadyRunning)
	assert.Nil(t, lock2)
}

func TestAcquireWithStaleLock(t *testing.T) {
	tmpDir := t.TempDir()

	// Write a stale PID file (PID that doesn't exist)
	stalePID := 999999999 // Unlikely to be a real process
	pidPath := filepath.Join(tmpDir, "vaultik.pid")
	err := os.WriteFile(pidPath, []byte(strconv.Itoa(stalePID)), 0600)
	require.NoError(t, err)

	// Should be able to acquire lock (stale lock is cleaned up)
	lock, err := Acquire(tmpDir)
	require.NoError(t, err)
	require.NotNil(t, lock)
	defer func() { _ = lock.Release() }()

	// Verify our PID is now in the file
	data, err := os.ReadFile(pidPath)
	require.NoError(t, err)
	pid, err := strconv.Atoi(string(data))
	require.NoError(t, err)
	assert.Equal(t, os.Getpid(), pid)
}

func TestReleaseIsIdempotent(t *testing.T) {
	tmpDir := t.TempDir()

	lock, err := Acquire(tmpDir)
	require.NoError(t, err)

	// Release multiple times - should not error
	err = lock.Release()
	require.NoError(t, err)

	err = lock.Release()
	require.NoError(t, err)
}

func TestReleaseNilLock(t *testing.T) {
	var lock *Lock
	err := lock.Release()
	assert.NoError(t, err)
}

func TestAcquireCreatesDirectory(t *testing.T) {
	tmpDir := t.TempDir()
	nestedDir := filepath.Join(tmpDir, "nested", "dir")

	lock, err := Acquire(nestedDir)
	require.NoError(t, err)
	require.NotNil(t, lock)
	defer func() { _ = lock.Release() }()

	// Verify directory was created
	info, err := os.Stat(nestedDir)
	require.NoError(t, err)
	assert.True(t, info.IsDir())
}