// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package imaging

import (
	"bytes"
	"flag"
	"image"
	"os"
	"path/filepath"
	"testing"

	"github.com/mattermost/mattermost/server/v8/channels/utils/fileutils"

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

var updateImagingFixtures = flag.Bool("update-fixtures", false, "overwrite imaging fixture files with actual output")

func TestGenerateThumbnail(t *testing.T) {
	tcs := []struct {
		name           string
		inputImg       image.Image
		targetWidth    int
		targetHeight   int
		expectedWidth  int
		expectedHeight int
	}{
		{
			name:         "empty image",
			inputImg:     image.NewRGBA(image.Rect(0, 0, 0, 0)),
			targetWidth:  120,
			targetHeight: 100,
		},
		{
			name:           "both dimensions lower than targets",
			inputImg:       image.NewRGBA(image.Rect(0, 0, 100, 50)),
			targetWidth:    120,
			targetHeight:   100,
			expectedWidth:  120,
			expectedHeight: 60,
		},
		{
			name:           "both dimensions equal to targets",
			inputImg:       image.NewRGBA(image.Rect(0, 0, 120, 100)),
			targetWidth:    120,
			targetHeight:   100,
			expectedWidth:  120,
			expectedHeight: 100,
		},
		{
			name:           "both dimensions higher than targets",
			inputImg:       image.NewRGBA(image.Rect(0, 0, 1000, 500)),
			targetWidth:    120,
			targetHeight:   100,
			expectedWidth:  120,
			expectedHeight: 60,
		},
		{
			name:           "width higher than target",
			inputImg:       image.NewRGBA(image.Rect(0, 0, 200, 100)),
			targetWidth:    120,
			targetHeight:   100,
			expectedWidth:  120,
			expectedHeight: 60,
		},
		{
			name:           "height higher than target",
			inputImg:       image.NewRGBA(image.Rect(0, 0, 100, 200)),
			targetWidth:    120,
			targetHeight:   100,
			expectedWidth:  50,
			expectedHeight: 100,
		},
	}

	for _, tc := range tcs {
		t.Run(tc.name, func(t *testing.T) {
			thumb := GenerateThumbnail(tc.inputImg, tc.targetWidth, tc.targetHeight)
			require.Equal(t, tc.expectedWidth, thumb.Bounds().Dx(), "expectedWidth")
			require.Equal(t, tc.expectedHeight, thumb.Bounds().Dy(), "expectedHeight")
		})
	}
}

func TestGeneratePreview(t *testing.T) {
	imgDir, ok := fileutils.FindDir("tests")
	require.True(t, ok)

	d, err := NewDecoder(DecoderOptions{})
	require.NoError(t, err)
	require.NotNil(t, d)

	inputFile, err := os.Open(filepath.Join(imgDir, "qa-data-graph.png"))
	require.NoError(t, err)
	defer inputFile.Close()

	inputImg, format, err := d.Decode(inputFile)
	require.NoError(t, err)
	require.Equal(t, "png", format)

	expectedFile, err := os.Open(filepath.Join(imgDir, "preview_test_qa_data_graph_1024.png"))
	require.NoError(t, err)
	defer expectedFile.Close()

	expectedImg, format, err := d.Decode(expectedFile)
	require.NoError(t, err)
	require.Equal(t, "png", format)

	preview := GeneratePreview(inputImg, 1024)
	requireSameImage(t, expectedImg, preview)
}

func TestGenerateMiniPreviewImage(t *testing.T) {
	imgDir, ok := fileutils.FindDir("tests")
	require.True(t, ok)

	d, err := NewDecoder(DecoderOptions{})
	require.NoError(t, err)
	require.NotNil(t, d)

	inputFile, err := os.Open(filepath.Join(imgDir, "qa-data-graph.png"))
	require.NoError(t, err)
	defer inputFile.Close()

	inputImg, format, err := d.Decode(inputFile)
	require.NoError(t, err)
	require.Equal(t, "png", format)

	fixturePath := filepath.Join(imgDir, "mini_preview_test_qa_data_graph_16x16_q90.jpg")

	out, err := GenerateMiniPreviewImage(inputImg, 16, 16, 90)
	require.NoError(t, err)

	if *updateImagingFixtures {
		require.NoError(t, os.WriteFile(fixturePath, out, 0600))
		return
	}

	expectedFile, err := os.Open(fixturePath)
	require.NoError(t, err)
	defer expectedFile.Close()

	expectedImg, format, err := d.Decode(expectedFile)
	require.NoError(t, err)
	require.Equal(t, "jpeg", format)

	actualImg, format, err := d.Decode(bytes.NewReader(out))
	require.NoError(t, err)
	require.Equal(t, "jpeg", format)

	requireSameImage(t, expectedImg, actualImg)
}