// Copyright 2020-2026 Buf Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package slicesx_test

import (
	"testing"

	"github.com/stretchr/testify/assert"

	"github.com/bufbuild/protocompile/internal/ext/slicesx"
)

func TestIndex(t *testing.T) {
	t.Parallel()
	assert := assert.New(t)

	x := []int{1, 2, 3, 4}
	assert.Equal(-1, slicesx.PointerIndex[[]int](nil, nil))
	assert.Equal(-1, slicesx.PointerIndex(x, nil))
	assert.Equal(-1, slicesx.PointerIndex(x, new(int)))
	assert.Equal(0, slicesx.PointerIndex(x, &x[0]))
	assert.Equal(1, slicesx.PointerIndex(x, &x[1]))
	assert.Equal(2, slicesx.PointerIndex(x, &x[2]))
	assert.Equal(3, slicesx.PointerIndex(x, &x[3]))
	assert.Equal(-1, slicesx.PointerIndex(x[1:], &x[0]))
	assert.Equal(-1, slicesx.PointerIndex(x[:2], &x[3]))
	assert.Equal(0, slicesx.PointerIndex(x[2:], &x[2]))
}
