text: /*---------------------------------------------------------------------------------------------
   *  Copyright (c) Microsoft Corporation. All rights reserved.
   *  Licensed under the MIT License. See License.txt in the project root for license information.
   *--------------------------------------------------------------------------------------------*/
  
  'use strict';
  
  (function () {
  	// From https://remysharp.com/2010/07/21/throttling-function-calls
  	function throttle(fn, threshhold, scope) {
  		threshhold || (threshhold = 250);
  		var last, deferTimer;
  		return function () {
  			var context = scope || this;
  
  			var now = +new Date,
  				args = arguments;
  			if (last && now < last + threshhold) {
  				// hold on to it
  				clearTimeout(deferTimer);
  				deferTimer = setTimeout(function () {
  					last = now;
  					fn.apply(context, args);
  				}, threshhold + last - now);
  			} else {
  				last = now;
  				fn.apply(context, args);
  			}
  		};
  	}
  
  	/**
  	 * Find the html elements that map to a specific target line in the editor.
  	 *
  	 * If an exact match, returns a single element. If the line is between elements,
  	 * returns the element prior to and the element after the given line.
  	 */
  	function getElementsForSourceLine(targetLine) {
  		const lines = document.getElementsByClassName('code-line');
  		let previous = lines[0] && +lines[0].getAttribute('data-line') ? { line: +lines[0].getAttribute('data-line'), element: lines[0] } : null;
  		for (const element of lines) {
  			const lineNumber = +element.getAttribute('data-line');
  			if (isNaN(lineNumber)) {
  				continue;
  			}
  			const entry = { line: lineNumber, element: element };
  			if (lineNumber === targetLine) {
  				return { previous: entry, next: null };
  			} else if (lineNumber > targetLine) {
  				return { previous, next: entry };
  			}
  			previous = entry;
  		}
  		return { previous };
  	}
  
  	/**
  	 * Find the html elements that are at a specific pixel offset on the page.
  	 */
  	function getLineElementsAtPageOffset(offset) {
  		const lines = document.getElementsByClassName('code-line');
  		let previous = null;
  		for (const element of lines) {
  			const line = +element.getAttribute('data-line');
  			if (isNaN(line)) {
  				continue;
  			}
  			const bounds = element.getBoundingClientRect();
  			const entry = { element, line };
  			if (offset >= window.scrollY + bounds.top && offset <= window.scrollY + bounds.top + bounds.height) {
  				// add progress through element
  				entry.line += (offset - (window.scrollY + bounds.top)) / (bounds.height);
  				return { previous: entry };
  			} else if (offset < window.scrollY + bounds.top) {
  				return { previous, next: entry };
  			}
  			previous = entry;
  		}
  		return { previous };
  	}
  
  	function getSourceRevealAddedOffset() {
  		return -(window.innerHeight * 1 / 5);
  	}
  
  	/**
  	 * Attempt to reveal the element for a source line in the editor.
  	 */
  	function scrollToRevealSourceLine(line) {
  		const {previous, next} = getElementsForSourceLine(line);
  		marker.update(previous && previous.element);
  		if (previous && window.initialData.scrollPreviewWithEditorSelection) {
  			let scrollTo = 0;
  			if (next) {
  				// Between two elements. Go to percentage offset between them.
  				const betweenProgress = (line - previous.line) / (next.line - previous.line);
  				const elementOffset = next.element.getBoundingClientRect().top - previous.element.getBoundingClientRect().top;
  				scrollTo = previous.element.getBoundingClientRect().top + betweenProgress * elementOffset;
  			} else {
  				scrollTo = previous.element.getBoundingClientRect().top;
  			}
  			window.scroll(0, window.scrollY + scrollTo + getSourceRevealAddedOffset());
  		}
  	}
  
  	function getEditorLineNumberForPageOffset(offset) {
  		const {previous, next} = getLineElementsAtPageOffset(offset);
  		if (previous) {
  			if (next) {
  				const betweenProgress = (offset - window.scrollY - previous.element.getBoundingClientRect().top) / (next.element.getBoundingClientRect().top - previous.element.getBoundingClientRect().top);
  				return previous.line + betweenProgress * (next.line - previous.line);
  			} else {
  				return previous.line;
  			}
  		}
  		return null;
  	}
  
  
  	class ActiveLineMarker {
  		update(before) {
  			this._unmarkActiveElement(this._current);
  			this._markActiveElement(before);
  			this._current = before;
  		}
  
  		_unmarkActiveElement(element) {
  			if (!element) {
  				return;
  			}
  			element.className = element.className.replace(/\bcode-active-line\b/g);
  		}
  
  		_markActiveElement(element) {
  			if (!element) {
  				return;
  			}
  			element.className += ' code-active-line';
  		}
  	}
  
  	var scrollDisabled = true;
  	var marker = new ActiveLineMarker();
  
  	window.onload = () => {
  		if (window.initialData.scrollPreviewWithEditorSelection) {
  			const initialLine = +window.initialData.line;
  			if (!isNaN(initialLine)) {
  				setTimeout(() => {
  					scrollDisabled = true;
  					scrollToRevealSourceLine(initialLine);
  				}, 0);
  			}
  		}
  	};
  
  	window.addEventListener('resize', () => {
  		scrollDisabled = true;
  	}, true);
  
  	window.addEventListener('message', (() => {
  		const doScroll = throttle(line => {
  			scrollDisabled = true;
  			scrollToRevealSourceLine(line);
  		}, 50);
  		return event => {
  			const line = +event.data.line;
  			if (!isNaN(line)) {
  				doScroll(line);
  			}
  		};
  	})(), false);
  
  	document.addEventListener('dblclick', event => {
  		if (!window.initialData.doubleClickToSwitchToEditor) {
  			return;
  		}
  
  		// Ignore clicks on links
  		for (let node = event.target; node; node = node.parentNode) {
  			if (node.tagName === "A") {
  				return;
  			}
  		}
  
  		const offset = event.pageY;
  		const line = getEditorLineNumberForPageOffset(offset);
  		if (!isNaN(line)) {
  			const args = [window.initialData.source, line];
  			window.parent.postMessage({
  				command: "did-click-link",
  				data: `command:_markdown.didClick?${encodeURIComponent(JSON.stringify(args))}`
  			}, "file://");
  		}
  	});
  
  	if (window.initialData.scrollEditorWithPreview) {
  		window.addEventListener('scroll', throttle(() => {
  			if (scrollDisabled) {
  				scrollDisabled = false;
  			} else {
  				const line = getEditorLineNumberForPageOffset(window.scrollY);
  				if (!isNaN(line)) {
  					const args = [window.initialData.source, line];
  					window.parent.postMessage({
  						command: "did-click-link",
  						data: `command:_markdown.revealLine?${encodeURIComponent(JSON.stringify(args))}`
  					}, "file://");
  				}
  			}
  		}, 50));
  	}
  }());