extends "res://addons/gut/test.gd"

const Pixelmatch := preload("res://addons/pixelmatch/pixelmatch.gd")

const UPDATE = false
const options = {threshold = 0.05}


func test_icon_identical():
	diff_test("icon", "icon", "icon_emptydiff", options, 0)


func test_icon_modified():
	diff_test("icon", "icon_alt", "icon_diff", options, 1187)


func test_1_diff():
	diff_test("1a", "1b", "1diff", options, 143)


func test_1_diffmask():
	diff_test(
		"1a", "1b", "1diffmask", {threshold = 0.05, include_aa = false, diff_mask = true}, 143
	)


func test_1_emptydiffmask():
	diff_test("1a", "1a", "1emptydiffmask", {threshold = 0, diff_mask = true}, 0)


func test_2():
	diff_test(
		"2a",
		"2b",
		"2diff",
		{
			threshold = 0.05,
			alpha = 0.5,
			aa_color = Color(0, 192, 0),
			diff_color = Color(255, 0, 255)
		},
		12437
	)


func test_3():
	diff_test("3a", "3b", "3diff", options, 212)


func test_4():
	diff_test("4a", "4b", "4diff", options, 36049)


func test_5():
	diff_test("5a", "5b", "5diff", options, 0)


func test_6_diff():
	diff_test("6a", "6b", "6diff", options, 51)


func test_6_empty():
	diff_test("6a", "6a", "6empty", {threshold = 0}, 0)


func test_7():
	diff_test("7a", "7b", "7diff", {diff_color_alt = Color(0, 255, 0)}, 2448)


func diff_test(img1_name, img2_name, diff_name, options: Dictionary, expected_mismatch):
	var img1 = load_image(img1_name)
	var img2 = load_image(img2_name)
	var width = img1.get_width()
	var height = img1.get_height()
	var diff = Image.create(width, height, false, Image.FORMAT_RGBA8)

	var pixelmatch = Pixelmatch.new()
	for key in options.keys():
		pixelmatch.set(key, options[key])

	var mismatch = pixelmatch.diff(img1, img2, diff, width, height)
	var mismatch2 = pixelmatch.diff(img1, img2, null, width, height)

	if UPDATE:
		diff.save_png("res://test/fixtures/%s.pmtest.png" % diff_name)
	else:
		var expected_diff = load_image(diff_name)
		var diffmatcher = Pixelmatch.new()
		var diff_diff = diffmatcher.diff(expected_diff, diff, null, width, height)
		assert_eq(diff_diff, 0, "stored diff image matches actual diff image")

	assert_eq(
		mismatch, expected_mismatch, "number of mismatched pixels %s %s" % [img1_name, img2_name]
	)
	assert_eq(
		mismatch,
		mismatch2,
		"number of mismatched pixels without diff %s %s" % [img1_name, img2_name]
	)


func load_image(img_name) -> Image:
	var img = load("res://test/fixtures/%s.pmtest.png" % img_name)
	assert(img is Image)
	return img