package thumbnail

import (
	"bytes"
	"image/jpeg"
	"testing"

	"github.com/stretchr/testify/require"

	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
)

func TestExpand(t *testing.T) {
	strippedImage := []byte{
		0x01, 0x0e, 0x28, 0xa3, 0x9e, 0x05, 0x26, 0x78, 0xa5, 0x03, 0x8e, 0xb4, 0xd2, 0x31, 0x40, 0x06,
		0x7d, 0x85, 0x19, 0xa4, 0xe2, 0x8e, 0x28, 0x00, 0xa2, 0x8a, 0x28, 0x03,
	}

	t.Run("Expand", func(t *testing.T) {
		a := require.New(t)

		to := make([]byte, 0, 1024)
		testutil.ZeroAlloc(t, func() {
			var err error
			to, err = ExpandTo(strippedImage, to[:0])
			a.NoError(err)
		})

		_, err := jpeg.Decode(bytes.NewReader(to))
		a.NoError(err)
	})
	t.Run("ExpandTwice", func(t *testing.T) {
		a := require.New(t)

		result, err := Expand(strippedImage)
		a.NoError(err)

		offset := len(result)
		result, err = ExpandTo(strippedImage, result)
		a.NoError(err)

		a.Equal(result[:offset], result[offset:])

		_, err = jpeg.Decode(bytes.NewReader(result[:offset]))
		a.NoError(err)

		_, err = jpeg.Decode(bytes.NewReader(result[offset:]))
		a.NoError(err)
	})
	t.Run("InvalidPrefix", func(t *testing.T) {
		a := require.New(t)
		_, err := ExpandTo([]byte{0x02, 0x0e, 0x28, 0xa3}, nil)
		a.Error(err)
	})
	t.Run("InvalidLength", func(t *testing.T) {
		a := require.New(t)
		_, err := ExpandTo([]byte{1, 2}, nil)
		a.Error(err)
	})
}