// Copyright 2015 Tim Heckman. All rights reserved.
// Copyright 2018-2025 The Gofrs. All rights reserved.
// Use of this source code is governed by the BSD 3-Clause
// license that can be found in the LICENSE file.

//go:build !js && !plan9 && !wasip1

package flock_test

import (
	"context"
	"os"
	"runtime"
	"testing"
	"time"

	"github.com/gofrs/flock"
	"github.com/stretchr/testify/suite"
)

type TestSuite struct {
	suite.Suite

	dir  bool
	opts []flock.Option

	path  string
	flock *flock.Flock
}

func Test(t *testing.T) {
	suite.Run(t, &TestSuite{})
}

func Test_dir(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("not supported on Windows")
	}

	suite.Run(t, &TestSuite{dir: true, opts: []flock.Option{flock.SetFlag(os.O_RDONLY)}})
}

func (s *TestSuite) SetupTest() {
	if s.dir {
		s.path = s.T().TempDir()

		s.flock = flock.New(s.path, s.opts...)

		return
	}

	tmpFile, err := os.CreateTemp(s.T().TempDir(), "go-flock-")
	s.Require().NoError(err)

	s.Require().NotNil(tmpFile)

	s.path = tmpFile.Name()

	err = tmpFile.Close()
	s.Require().NoError(err)

	err = os.Remove(s.path)
	s.Require().NoError(err)

	s.flock = flock.New(s.path, s.opts...)
}

func (s *TestSuite) TearDownTest() {
	_ = s.flock.Unlock()
	_ = os.Remove(s.path)
}

func (s *TestSuite) TestNew() {
	f := flock.New(s.path, s.opts...)
	s.Require().NotNil(f)

	s.Equal(f.Path(), s.path)
	s.False(f.Locked())
	s.False(f.RLocked())
}

func (s *TestSuite) TestFlock_Path() {
	s.Equal(s.path, s.flock.Path())
}

func (s *TestSuite) TestFlock_Locked() {
	s.False(s.flock.Locked())
}

func (s *TestSuite) TestFlock_RLocked() {
	s.False(s.flock.RLocked())
}

func (s *TestSuite) TestFlock_String() {
	s.Equal(s.path, s.flock.String())
}

func (s *TestSuite) TestFlock_TryLock() {
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())

	locked, err := s.flock.TryLock()
	s.Require().NoError(err)
	s.True(locked)
	s.True(s.flock.Locked())
	s.False(s.flock.RLocked())

	locked, err = s.flock.TryLock()
	s.Require().NoError(err)
	s.True(locked)

	// make sure we just return false with no error in cases
	// where we would have been blocked
	locked, err = flock.New(s.path, s.opts...).TryLock()
	s.Require().NoError(err)
	s.False(locked)
}

func (s *TestSuite) TestFlock_TryRLock() {
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())

	locked, err := s.flock.TryRLock()
	s.Require().NoError(err)
	s.True(locked)
	s.False(s.flock.Locked())
	s.True(s.flock.RLocked())

	locked, err = s.flock.TryRLock()
	s.Require().NoError(err)
	s.True(locked)

	// shared lock should not block.
	flock2 := flock.New(s.path, s.opts...)
	locked, err = flock2.TryRLock()
	s.Require().NoError(err)

	switch runtime.GOOS {
	case "aix", "solaris", "illumos":
		// When using POSIX locks, we can't safely read-lock the same
		// inode through two different descriptors at the same time:
		// when the first descriptor is closed, the second descriptor
		// would still be open but silently unlocked. So a second
		// TryRLock must return false.
		s.False(locked)
	default:
		s.True(locked)
	}

	// make sure we just return false with no error in cases
	// where we would have been blocked
	_ = s.flock.Unlock()
	_ = flock2.Unlock()
	_ = s.flock.Lock()
	locked, err = flock.New(s.path, s.opts...).TryRLock()
	s.Require().NoError(err)
	s.False(locked)
}

func (s *TestSuite) TestFlock_TryLockContext() {
	ctx, cancel := context.WithCancel(context.Background())

	// happy path
	locked, err := s.flock.TryLockContext(ctx, time.Second)
	s.Require().NoError(err)
	s.True(locked)

	// context already canceled
	cancel()

	locked, err = flock.New(s.path, s.opts...).TryLockContext(ctx, time.Second)
	s.Require().ErrorIs(err, context.Canceled)
	s.False(locked)

	// timeout
	ctx, cancel = context.WithTimeout(context.Background(), 10*time.Millisecond)
	defer cancel()

	locked, err = flock.New(s.path, s.opts...).TryLockContext(ctx, time.Second)
	s.Require().ErrorIs(err, context.DeadlineExceeded)
	s.False(locked)
}

func (s *TestSuite) TestFlock_TryRLockContext() {
	ctx, cancel := context.WithCancel(context.Background())

	// happy path
	locked, err := s.flock.TryRLockContext(ctx, time.Second)
	s.Require().NoError(err)
	s.True(locked)

	// context already canceled
	cancel()

	locked, err = flock.New(s.path, s.opts...).TryRLockContext(ctx, time.Second)
	s.Require().ErrorIs(err, context.Canceled)
	s.False(locked)

	// timeout
	_ = s.flock.Unlock()
	_ = s.flock.Lock()

	ctx, cancel = context.WithTimeout(context.Background(), 10*time.Millisecond)
	defer cancel()

	locked, err = flock.New(s.path, s.opts...).TryRLockContext(ctx, time.Second)
	s.Require().ErrorIs(err, context.DeadlineExceeded)
	s.False(locked)
}

func (s *TestSuite) TestFlock_Unlock() {
	err := s.flock.Unlock()
	s.Require().NoError(err)

	// get a lock for us to unlock
	locked, err := s.flock.TryLock()
	s.Require().NoError(err)
	s.True(locked)
	s.True(s.flock.Locked())
	s.False(s.flock.RLocked())

	_, err = os.Stat(s.path)
	s.False(os.IsNotExist(err))

	err = s.flock.Unlock()
	s.Require().NoError(err)
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())
}

func (s *TestSuite) TestFlock_Lock() {
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())

	err := s.flock.Lock()
	s.Require().NoError(err)
	s.True(s.flock.Locked())
	s.False(s.flock.RLocked())

	// test that the short-circuit works
	err = s.flock.Lock()
	s.Require().NoError(err)

	//
	// Test that Lock() is a blocking call
	//
	ch := make(chan error, 2)
	gf := flock.New(s.path, s.opts...)

	defer func() { _ = gf.Unlock() }()

	go func(ch chan<- error) {
		ch <- nil

		ch <- gf.Lock()

		close(ch)
	}(ch)

	errCh, ok := <-ch
	s.True(ok)
	s.Require().NoError(errCh)

	err = s.flock.Unlock()
	s.Require().NoError(err)

	errCh, ok = <-ch
	s.True(ok)
	s.Require().NoError(errCh)
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())
	s.True(gf.Locked())
	s.False(gf.RLocked())
}

func (s *TestSuite) TestFlock_RLock() {
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())

	err := s.flock.RLock()
	s.Require().NoError(err)
	s.False(s.flock.Locked())
	s.True(s.flock.RLocked())

	// test that the short-circuit works
	err = s.flock.RLock()
	s.Require().NoError(err)

	//
	// Test that RLock() is a blocking call
	//
	ch := make(chan error, 2)

	gf := flock.New(s.path, s.opts...)

	defer func() { _ = gf.Unlock() }()

	go func(ch chan<- error) {
		ch <- nil

		ch <- gf.RLock()

		close(ch)
	}(ch)

	errCh, ok := <-ch
	s.True(ok)
	s.Require().NoError(errCh)

	err = s.flock.Unlock()
	s.Require().NoError(err)

	errCh, ok = <-ch
	s.True(ok)
	s.Require().NoError(errCh)
	s.False(s.flock.Locked())
	s.False(s.flock.RLocked())
	s.False(gf.Locked())
	s.True(gf.RLocked())
}

func (s *TestSuite) TestFlock_Stat() {
	// Test Stat when file doesn't exist yet (for non-directory case)
	if !s.dir {
		_, err := s.flock.Stat()
		s.True(os.IsNotExist(err))
	}

	// Create the lock file
	locked, err := s.flock.TryLock()
	s.Require().NoError(err)
	s.True(locked)

	// Test Stat after lock is acquired
	info, err := s.flock.Stat()
	s.Require().NoError(err)
	s.NotNil(info)

	// Check modification time is recent
	modTime := info.ModTime()
	s.WithinDuration(time.Now(), modTime, 1*time.Second)

	// Unlock and verify Stat still works (file persists)
	err = s.flock.Unlock()
	s.Require().NoError(err)

	info, err = s.flock.Stat()
	s.Require().NoError(err)
	s.NotNil(info)

	// The modification time should be approximately the same as before
	s.WithinDuration(modTime, info.ModTime(), 100*time.Millisecond)
}