// ==UserScript==
// @name 4chan Filter, Opera edition
// @author Anonymous
// @version 1.3a
// @description  The 4chan filter extension, rewritten to work with Opera. Inspired by the various filter extensions on userscripts.org for Firefox.
// @ujs:documentation http://sector-5.net/archives/4chan-filter-userscript-for-opera/
// @ujs:download http://files.sector-5.net/4chan-filter.js
// ==/UserScript==

if (/^http:\/\/boards\.4chan\.org\/\w{1,3}\//.test(window.location.href)) {

	// Pack everything into an anonymous function block to avoid functions and
	// variables from leaking out.
	(function() {

	/// Saves the currently selected values.
	/// @return Associative array with all settings
	function saveSettings() {
		// Checkboxes
		setValue('4chan-filter-hidetext', document.getElementById('4chan-filter-hidetext').checked, 0);
		setValue('4chan-filter-forcedanonymous', document.getElementById('4chan-filter-forcedanonymous').checked, 0);
		setValue('4chan-filter-stickywindow', document.getElementById('4chan-filter-stickywindow').checked, 0);
		// Input boxes
		setValue('4chan-filter-name', document.getElementById('4chan-filter-name').value, 0);
		setValue('4chan-filter-tripcode', document.getElementById('4chan-filter-tripcode').value, 0);
		setValue('4chan-filter-email', document.getElementById('4chan-filter-email').value, 0);
		setValue('4chan-filter-subject', document.getElementById('4chan-filter-subject').value, 0);
		setValue('4chan-filter-comment', document.getElementById('4chan-filter-comment').value, 0);
		setValue('4chan-filter-image', document.getElementById('4chan-filter-image').value, 0);
		// Update global settings
		settings = restoreSettings();
		return settings;
	}

	/// Loads the settings from previous sessions
	/// @return Associative array with all settings
	function restoreSettings() {
		/// Split the string by semicolon and precompile strings to
		/// regular expressions.
		var createRegExpArray = function(str) {
			if (str.length == 0) return [];
			else {
				var stringArray = str.split(';').filter(function (obj) {
					if (obj.length > 0) return true;
					else return false;
				});
				var regexpArray = stringArray.map(function (obj) {
					return new RegExp(obj);
				});
				return regexpArray;
			}
		}

		var array = new Object();

		// Checkboxes
		array['hidetext'] = getValue('4chan-filter-hidetext', false);
		array['forcedanonymous'] = getValue('4chan-filter-forcedanonymous', false);
		array['stickywindow'] = getValue('4chan-filter-stickywindow', true);
		// Input boxes
		array['name'] = createRegExpArray(getValue('4chan-filter-name', ''));
		array['tripcode'] = createRegExpArray(getValue('4chan-filter-tripcode', ''));
		array['email'] = createRegExpArray(getValue('4chan-filter-email', ''));
		array['subject'] = createRegExpArray(getValue('4chan-filter-subject', ''));
		array['comment'] = createRegExpArray(getValue('4chan-filter-comment', ''));
		array['image'] = createRegExpArray(getValue('4chan-filter-image', ''));

		return array;
	}

	/// Apply settings, filtering the page
	function applySettings(settings, root) {
		if (!root) root = document.body;

		filter_filterPosts(root, settings);

		if (settings['hidetext'])
			filter_hideText(root);
		if (settings['forcedanonymous'])
			filter_forcedAnonymous(root);
	}

	/// Restores the original page by replacing document.body with its cloned copy.
	function resetModifications(settings) {
		resetPending = true;
		document.body = documentClone.cloneNode(true);
		document.body.appendChild(createUserInterface(settings));
		applyStyles(settings);
		resetPending = false;
	}

	/// Apply style modifications to the control window
	function applyStyles(settings) {
		if (settings['stickywindow'])
			document.getElementById('4chan-filter').style.position = 'fixed';
		else
			document.getElementById('4chan-filter').style.position = 'absolute';
	}

	/// Stores a setting in a local cookie.
	/// Originally from `Emulate Greasemonkey functions' by TarquinWJ,
	/// http://userjs.org/scripts/browser/enhancements/aa-gm-functions
	function setValue(cookieName, cookieValue, lifeTime) {
		if( !cookieName ) { return; }
		if( lifeTime == "delete" ) { lifeTime = -10; } else { lifeTime = 31536000; }
		document.cookie = escape( cookieName ) + "=" + escape( cookieValue ) +
			";expires=" + ( new Date( ( new Date() ).getTime() + ( 1000 * lifeTime ) ) ).toGMTString() + ";path=/";
	}

	/// Loads a setting from local cookies.
	/// Originally from `Emulate Greasemonkey functions' by TarquinWJ,
	/// http://userjs.org/scripts/browser/enhancements/aa-gm-functions
	function getValue(cookieName, oDefault) {
		var cookieJar = document.cookie.split( "; " );
		for( var x = 0; x < cookieJar.length; x++ ) {
			var oneCookie = cookieJar[x].split( "=" );
			if( oneCookie[0] == escape( cookieName ) ) {
				var footm = unescape( oneCookie[1] );

				if (footm == 'true') return true;
				else if  (footm == 'false') return false;
				else return footm;
			}
		}
		return oDefault;
	}

	/// Deletes a local settings cookie.
	/// Originally from `Emulate Greasemonkey functions' by TarquinWJ,
	/// http://userjs.org/scripts/browser/enhancements/aa-gm-functions
	function deleteValue(oKey) {
	   setValue( oKey, '', 'delete' );
	}

	/// Filter functions

	/// Hides all text within posts.
	function filter_hideText(root) {
		var posts = root.getElementsByTagName("blockquote");

		for (var i = 0; i < posts.length; ++i) {
			var text = posts[i].innerHTML;
			// Delete all posts without interboard-link (/rs/) or URL
			if (!(text.indexOf("http://") != -1 || text.indexOf(">>>/") != -1)) {
				while (posts[i].hasChildNodes())
					posts[i].removeChild(posts[i].firstChild)
			}
		}
	}

	/// Changes every name to Anonymous, removes every email link
	/// except for sage and strips every tripcode.
	function filter_forcedAnonymous(root) {
		// Remove names
		var nameTags = document.evaluate(
				"descendant-or-self::span[@class='commentpostername'] |" +
				"descendant-or-self::span[@class='postername']", root, null,
				XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);

		for (var i = 0; i < nameTags.snapshotLength; ++i)
		{
			var nameTag = nameTags.snapshotItem(i);
			if (nameTag.childNodes.length > 0)
			{
				var textContent = nameTag.childNodes[0];
				while (textContent != null && textContent.nodeType != 3) // Text node
					textContent = textContent.childNodes[0];
				textContent.nodeValue = "Anonymous";
			}

		}

		// Remove tripcodes
		var tripTags = document.evaluate(
				"descendant-or-self::span[@class='postertrip']", root, null,
				XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, nameTags);

		for (var i = 0; i < tripTags.snapshotLength; ++i)
			tripTags.snapshotItem(i).textContent = "";

		// Remove emails
		var emailTags = document.evaluate(
			"descendant-or-self::a[@class='linkmail']", root, null,
			XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, nameTags);

		for (var i = 0; i < emailTags.snapshotLength; ++i) {
			var node = emailTags.snapshotItem(i);
			if (node.href != 'mailto:sage') {
				// Remove all child nodes and move them one level up in the DOM tree
				while (node.hasChildNodes()) {
					var child = node.firstChild;
					node.removeChild(child);
					node.parentNode.insertBefore(child, node);
				}
				// Remove the now empty <a> element
				node.parentNode.removeChild(node);
			}
		}
	}

	/// Filters posts according to the values set in the configuration window.
	function filter_filterPosts(root, settings) {
		var filterCount = 0;
		var posts = root.getElementsByClassName('reply');

		for (var i = posts.length - 1; i >= 0; --i) {

			var postFiltered = false;

			// Check for matching name
			if (postFiltered == false && settings['name'] != null && settings['name'].length > 0)
			{
				var nameTags = posts[i].getElementsByClassName('commentpostername');
				if (nameTags.length > 0) {
					for (var j = 0; j < settings['name'].length; ++j) {
						// Work down towards the actual text node
						//var textContent = nameTags[0].childNodes[0];
						//while (textContent != null && textContent.nodeType != 3) // Text node
						//	textContent = textContent.childNodes[0];

						if (settings['name'][j].test(nameTags[0].textContent)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}

			// Check for matching tripcode
			if (postFiltered == false && settings['tripcode'] != null && settings['tripcode'].length > 0)
			{
				var tripcodeTags = posts[i].getElementsByClassName('postertrip');
				if (tripcodeTags.length > 0) {
					for (var j = 0; j < settings['tripcode'].length; ++j) {
						if (settings['tripcode'][j].test(tripcodeTags[0].textContent)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}

			// Check for matching email
			if (postFiltered == false && settings['email'] != null && settings['email'].length > 0)
			{
				var emailTags = posts[i].getElementsByClassName('linkmail');
				if (emailTags.length > 0) {
					for (var j = 0; j < settings['email'].length; ++j) {
						// Skip 'mailto:' in emailTags[0].href (hence the 7)
						if (settings['email'][j].test(emailTags[0].href.substring(7))) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}

			// Check for matching subject
			if (postFiltered == false && settings['subject'] != null && settings['subject'].length > 0)
			{
				var subjectTags = posts[i].getElementsByClassName('replytitle');
				if (subjectTags.length > 0) {
					for (var j = 0; j < settings['subject'].length; ++j) {
						if (settings['subject'][j].test(subjectTags[0].textContent)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}

			// Check for matching comment
			if (postFiltered == false && settings['comment'] != null && settings['comment'].length > 0)
			{
				var commentTags = posts[i].getElementsByTagName('blockquote');
				if (commentTags.length > 0) {
					for (var j = 0; j < settings['comment'].length; ++j) {
						if (settings['comment'][j].test(commentTags[0].textContent)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}

			// Check for matching image name
			if (postFiltered == false && settings['image'] != null && settings['image'].length > 0)
			{
				/*
				var imageTags = document.evaluate("span[@class='filesize']/span[@title]", posts[i], null,
					XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
				if (imageTags.snapshotLength > 0) {
					for (var j = 0; j < settings['image'].length; ++j) {
						if (settings['image'][j].test(imageTags.snapshotItem(0).title)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}*/
				
				var imageTag = document.evaluate("span[@class='filesize']", posts[i], null,
					XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
				if (imageTag != null) {
					for (var j = 0; j < settings['image'].length; ++j) {
						if (settings['image'][j].test(imageTag.textContent)) {
							posts[i].parentNode.parentNode.removeChild(posts[i].parentNode);
							postFiltered = true;
							++filterCount;
							break;
						}
					}
				}
			}
		}

		// Update filter display
		if (filterCount > 0) {
			var title = document.getElementById('4chan-filter-titletag');
			if (title != null)
				title.textContent = 'Images: ' + imageCount +
					' Posts: ' + (postCount - filterCount) +
					' (' + postCount + ')';
		}
	}

	/// Create the user interface
	/// @return DocumentFragment object
	function createUserInterface(settings) {
		// Top level container
		var topContainer = document.createElement('div');
		topContainer.id = '4chan-filter';
		topContainer.style.right = '5px';
		topContainer.style.top = '20px';
		topContainer.style.width = '235px';
		//topContainer.style.backgroundColor = '#D6DAF0';
		topContainer.style.border = '1px solid black';

		/// Utility function to find out if a node is descendant node of another node
		function isChildOrSame(child, parent) {
			while (child) {
				if (child == parent)
					return true;
				else
					child = child.parentNode;
			}
			return false;
		}

		// Mouse-over shows the settings...
		topContainer.onmouseover = function(event) {
			if (!isChildOrSame(event.relatedTarget, event.currentTarget)) {
				var innerContainer = document.getElementById('4chan-filter-inner');
				innerContainer.style.display = 'block';
			}
		}
		// Mouse-out saves settings.
		topContainer.onmouseout = function(event) {
			if (!isChildOrSame(event.relatedTarget, event.currentTarget)) {
				var innerContainer = document.getElementById('4chan-filter-inner');
				innerContainer.style.display = 'none';
				var settings = saveSettings();
				applyStyles(settings);
			}
		};

		// Title tag
		var title = document.createElement('h4');
		title.id = '4chan-filter-titletag';
		title.style.textAlign = 'center';
		title.textContent = 'Images: ' + imageCount + ' Posts: ' + postCount;
		topContainer.appendChild(title);

		// Inner container - This container only expands when the mouse hovers over the control panel
		var innerContainer = document.createElement('div');
		topContainer.appendChild(innerContainer)
		innerContainer.id = '4chan-filter-inner';
		innerContainer.style.display = 'none';
		innerContainer.style.textAlign = 'right';
		innerContainer.style.padding = '5px';

		/// Creates a new input field and appropriate label,
		/// and adds it to parentContainer
		var createInputField = function(id, parentContainer) {
			var label = id.charAt(0).toUpperCase().concat(id.substring(1))
			var labelTag = document.createElement('label');
			labelTag.setAttribute('for', '4chan-filter-' + id);
			labelTag.textContent = label + ':';
			labelTag.style.marginRight = '5px';
			labelTag.style.verticalAlign = 'middle';
			var field = document.createElement('input');
			field.id = '4chan-filter-' + id;
			field.type = 'text';
			field.style.margin = '1px';
			field.style.verticalAlign = 'middle';
			if (settings[id] != null)
			{
				stringArray = settings[id].map(function(obj) {
					regexpString = obj.toString();
					// Strip the leading and trailing / character
					return regexpString.substring(1, regexpString.length - 1);
				});
				field.value = stringArray.join(';');
			}
			parentContainer.appendChild(labelTag);
			parentContainer.appendChild(field);
			parentContainer.appendChild(document.createElement('br'));
		}

		/// Create a new checkbox and appropriate label and
		/// adds it to parentContainer.
		var createCheckbox = function(id, title, parentContainer) {
			var label = document.createElement('label');
			label.setAttribute('for', '4chan-filter-' + id);
			label.textContent = ' ' + title + ': ';
			var checkbox = document.createElement('input');
			checkbox.id = '4chan-filter-' + id;
			checkbox.type = 'checkbox';
			if (settings[id]) checkbox.checked = true;
			parentContainer.appendChild(label);
			parentContainer.appendChild(checkbox);
			parentContainer.appendChild(document.createElement('br'));
		}

		// Hide text
		createCheckbox('hidetext', 'Hide text', innerContainer);;

		// Forced Anonymous
		createCheckbox('forcedanonymous', 'Forced Anonymous', innerContainer);

		// Setting fields
		createInputField('name', innerContainer);
		createInputField('tripcode', innerContainer);
		createInputField('email', innerContainer);
		createInputField('subject', innerContainer);
		createInputField('comment', innerContainer);
		createInputField('image', innerContainer);

		// Sticky window
		createCheckbox('stickywindow', 'Sticky window', innerContainer);

		// Command box
		var cmdBox = document.createElement('p');
		innerContainer.appendChild(cmdBox);
		cmdBox.style.margin = '10px 5px 5px 5px';

		cmdApply = document.createElement('a');
		cmdApply.textContent = 'Apply changes';
		cmdApply.style.marginLeft = '5px';
		cmdApply.onclick = function(e) {
			var settings = saveSettings();
			applySettings(settings);
			applyStyles(settings);
		}
		cmdBox.appendChild(cmdApply);

		cmdReset = document.createElement('a');
		cmdReset.textContent = 'Reset page';
		cmdReset.style.marginLeft = '5px';
		cmdReset.onclick = function (e) {
			resetModifications(settings);
		};
		cmdBox.appendChild(cmdReset);

		var lowerBox = document.createElement('p');
		innerContainer.appendChild(lowerBox);
		lowerBox.style.margin = '10px 5px 5px 5px';
		lowerBox.style.textAlign = 'center';

		var explanation = document.createElement('small');
		lowerBox.appendChild(explanation);
		explanation.appendChild(document.createTextNode(
			'Note: Separate values with semicolon. ' +
			'All text is interpreted as '));
		var link = document.createElement('a');
		link.href = 'https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/RegExp';
		link.target = '_blank';
		link.textContent = 'regular expression';
		explanation.appendChild(link);
		explanation.appendChild(document.createTextNode('.'));

		var fragment = document.createDocumentFragment();
		fragment.appendChild(topContainer);
		return fragment;
	}

	var postCount, imageCount, documentClone;

	var documentClone = null;

	var resetPending = false;

	// Restore all previous settings
	var settings = restoreSettings();

	document.addEventListener('DOMContentLoaded', function(e) {
		// Restore all previous settings
		//const settings = restoreSettings();

		// Clone document in order to be able to restore filtered posts
		// without reloading the page.
		documentClone = document.body.cloneNode(true);

		postCount = document.getElementsByClassName('reply').length +
					document.getElementsByClassName('postername').length;
		imageCount = document.evaluate("//img[@align='left']",
			document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null).snapshotLength;

		// Create the user interface and add it to the document
		document.body.appendChild(createUserInterface(settings));

		// Apply settings (i.e. filter posts by criteria specified in settings)
		applySettings(settings);
		applyStyles(settings);
	}, false);

	document.addEventListener('DOMNodeInserted', function(e) {
		if (e.target.nodeType == 1 && resetPending == false) {
			applySettings(settings, e.target);
		}
	}, false);

	})();
}