const { ThumbnailWidthCalculator } = require( 'mmv' );

QUnit.module( 'mmv.ThumbnailWidthCalculator', QUnit.newMwEnvironment() );

QUnit.test( 'ThumbnailWidthCalculator constructor sense check', ( assert ) => {
	const badWidthBuckets = [];
	const goodWidthBuckets = [ 1 ];

	let thumbnailWidthCalculator = new ThumbnailWidthCalculator();
	assert.true( thumbnailWidthCalculator instanceof ThumbnailWidthCalculator, 'constructor with no argument works' );

	thumbnailWidthCalculator = new ThumbnailWidthCalculator( {} );
	assert.true( thumbnailWidthCalculator instanceof ThumbnailWidthCalculator, 'constructor with empty option argument works' );

	thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
		widthBuckets: goodWidthBuckets
	} );
	assert.true( thumbnailWidthCalculator instanceof ThumbnailWidthCalculator, 'constructor with non-default buckets works' );

	assert.throws( () => {
		thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
			widthBuckets: badWidthBuckets
		} );
	}, 'constructor with empty bucket list throws exception' );
} );

QUnit.test( 'findNextBucket() test', ( assert ) => {
	const thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
		widthBuckets: [ 100, 200 ]
	} );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 50 ), 100,
		'return first bucket for value smaller than all buckets' );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 300 ), 200,
		'return last bucket for value larger than all buckets' );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 150 ), 200,
		'return next bucket for value between two buckets' );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 100 ), 100,
		'return bucket for value equal to that bucket' );
} );

// Old tests for the default bucket sizes. Preserved because why not.
QUnit.test( 'We get sensible image sizes when we ask for them', ( assert ) => {
	const twc = new ThumbnailWidthCalculator();

	assert.strictEqual( twc.findNextBucket( 200 ), 320, 'Low target size gives us lowest possible size bucket' );
	assert.strictEqual( twc.findNextBucket( 320 ), 320, 'Asking for a bucket size gives us exactly that bucket size' );
	assert.strictEqual( twc.findNextBucket( 320.00001 ), 800, 'Asking for greater than an image bucket definitely gives us the next size up' );
	assert.strictEqual( twc.findNextBucket( 2000 ), 2560, 'The image bucketing also works on big screens' );
	assert.strictEqual( twc.findNextBucket( 3000 ), 2880, 'The image bucketing also works on REALLY big screens' );
} );

QUnit.test( 'findNextBucket() test with unordered bucket list', ( assert ) => {
	const thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
		widthBuckets: [ 200, 100 ]
	} );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 50 ), 100,
		'return first bucket for value smaller than all buckets' );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 300 ), 200,
		'return last bucket for value larger than all buckets' );

	assert.strictEqual( thumbnailWidthCalculator.findNextBucket( 150 ), 200,
		'return next bucket for value between two buckets' );
} );

QUnit.test( 'calculateFittingWidth() test', ( assert ) => {
	const boundingWidth = 100;
	const boundingHeight = 200;
	const thumbnailWidthCalculator = new ThumbnailWidthCalculator( { widthBuckets: [ 1 ] } );

	// 50x10 image in 100x200 box - need to scale up 2x
	assert.strictEqual(
		thumbnailWidthCalculator.calculateFittingWidth( boundingWidth, boundingHeight, 50, 10 ),
		100, 'fit calculation correct when limited by width' );

	// 10x100 image in 100x200 box - need to scale up 2x
	assert.strictEqual(
		thumbnailWidthCalculator.calculateFittingWidth( boundingWidth, boundingHeight, 10, 100 ),
		20, 'fit calculation correct when limited by height' );

	// 10x20 image in 100x200 box - need to scale up 10x
	assert.strictEqual(
		thumbnailWidthCalculator.calculateFittingWidth( boundingWidth, boundingHeight, 10, 20 ),
		100, 'fit calculation correct when same aspect ratio' );
} );

QUnit.test( 'calculateWidths() test', ( assert ) => {
	const boundingWidth = 100;
	const boundingHeight = 200;
	const thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
		widthBuckets: [ 8, 16, 32, 64, 128, 256, 512 ],
		devicePixelRatio: 1
	} );

	// 50x10 image in 100x200 box - image size should be 100x20, thumbnail should be 128x25.6
	let widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 50, 10 );
	assert.strictEqual( widths.cssWidth, 100, 'css width is correct when limited by width' );
	assert.strictEqual( widths.cssHeight, 20, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 128, 'real width is correct when limited by width' );

	// 10x100 image in 100x200 box - image size should be 20x200, thumbnail should be 32x320
	widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 10, 100 );
	assert.strictEqual( widths.cssWidth, 20, 'css width is correct when limited by height' );
	assert.strictEqual( widths.cssHeight, 200, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 32, 'real width is correct when limited by height' );

	// 10x20 image in 100x200 box - image size should be 100x200, thumbnail should be 128x256
	widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 10, 20 );
	assert.strictEqual( widths.cssWidth, 100, 'css width is correct when same aspect ratio' );
	assert.strictEqual( widths.cssHeight, 200, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 128, 'real width is correct when same aspect ratio' );
} );

QUnit.test( 'calculateWidths() test with non-standard device pixel ratio', ( assert ) => {
	const boundingWidth = 100;
	const boundingHeight = 200;
	const thumbnailWidthCalculator = new ThumbnailWidthCalculator( {
		widthBuckets: [ 8, 16, 32, 64, 128, 256, 512 ],
		devicePixelRatio: 2
	} );

	// 50x10 image in 100x200 box - image size should be 100x20, thumbnail should be 256x51.2
	let widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 50, 10 );
	assert.strictEqual( widths.cssWidth, 100, 'css width is correct when limited by width' );
	assert.strictEqual( widths.cssHeight, 20, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 256, 'real width is correct when limited by width' );

	// 10x100 image in 100x200 box - image size should be 20x200, thumbnail should be 64x640
	widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 10, 100 );
	assert.strictEqual( widths.cssWidth, 20, 'css width is correct when limited by height' );
	assert.strictEqual( widths.cssHeight, 200, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 64, 'real width is correct when limited by height' );

	// 10x20 image in 100x200 box - image size should be 100x200, thumbnail should be 256x512
	widths = thumbnailWidthCalculator.calculateWidths( boundingWidth, boundingHeight, 10, 20 );
	assert.strictEqual( widths.cssWidth, 100, 'css width is correct when same aspect ratio' );
	assert.strictEqual( widths.cssHeight, 200, 'css height is correct when limited by width' );
	assert.strictEqual( widths.real, 256, 'real width is correct when same aspect ratio' );
} );
