package walk

import (
	"fmt"
	"testing"

	"github.com/rclone/rclone/fs"
	"github.com/rclone/rclone/fstest/mockobject"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// Mock callback to collect the entries
func mockCallback(entries fs.DirEntries) error {
	// Do nothing or log for testing purposes
	return nil
}

func TestNewListRHelper(t *testing.T) {
	callback := mockCallback
	helper := NewListRHelper(callback)

	assert.NotNil(t, helper)
	assert.Equal(t, fmt.Sprintf("%p", callback), fmt.Sprintf("%p", helper.callback))
	assert.Empty(t, helper.entries)
}

func TestListRHelperAdd(t *testing.T) {
	callbackInvoked := false
	callback := func(entries fs.DirEntries) error {
		callbackInvoked = true
		return nil
	}

	helper := NewListRHelper(callback)
	entry := mockobject.Object("A")
	require.NoError(t, helper.Add(entry))

	assert.Len(t, helper.entries, 1)
	assert.False(t, callbackInvoked, "Callback should not be invoked before reaching 100 entries")

	// Check adding a nil entry doesn't change anything
	require.NoError(t, helper.Add(nil))
	assert.Len(t, helper.entries, 1)
	assert.False(t, callbackInvoked, "Callback should not be invoked before reaching 100 entries")
}

func TestListRHelperSend(t *testing.T) {
	entry := mockobject.Object("A")
	callbackInvoked := false
	callback := func(entries fs.DirEntries) error {
		callbackInvoked = true
		assert.Equal(t, 100, len(entries))
		for _, obj := range entries {
			assert.Equal(t, entry, obj)
		}
		return nil
	}

	helper := NewListRHelper(callback)

	// Add 100 entries to force the callback to be invoked
	for i := 0; i < 100; i++ {
		require.NoError(t, helper.Add(entry))
	}

	assert.Len(t, helper.entries, 0)
	assert.True(t, callbackInvoked, "Callback should be invoked after 100 entries")
}

func TestListRHelperFlush(t *testing.T) {
	entry := mockobject.Object("A")
	callbackInvoked := false
	callback := func(entries fs.DirEntries) error {
		callbackInvoked = true
		assert.Equal(t, 1, len(entries))
		for _, obj := range entries {
			assert.Equal(t, entry, obj)
		}
		return nil
	}

	helper := NewListRHelper(callback)
	require.NoError(t, helper.Add(entry))
	assert.False(t, callbackInvoked, "Callback should not have been invoked yet")
	require.NoError(t, helper.Flush())

	assert.True(t, callbackInvoked, "Callback should be invoked on flush")
	assert.Len(t, helper.entries, 0, "Entries should be cleared after flush")
}