User:Dixtosa/WhoDidThat.js

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//Description: A new button in the toolbar helps to trace the user who caused the revision including the selected text
//To-do: expand templates?
//To-do: use binary-search instead of linear probing
//To-do: problems with deleted revisions
//working urls:
//https://en.wiktionary.org/w/api.php?titles=???????&action=query&prop=revisions&rvlimit=max
//https://en.wiktionary.org/w/api.php?titles=???????&action=query&prop=revisions&rvlimit=max&rvprop=ids|content
//https://en.wiktionary.org/w/api.php?titles=???????&action=query&prop=revisions&rvlimit=max&format=json
// [[mw:API:Revisions]]

if (mw.config.values.wgAction == "view" && mw.config.get("wgCanonicalSpecialPageName") === false) {
	mw.loader.using(['mediawiki.util']).then(function() {
		mw.util.addPortletLink('p-tb', 'javascript:WhoDidThat();', 'Who did that? (blame)', 'WhoDidThatJsBtn', "Find out who introduced selected text?", "");
	});
}

function WhoDidThat() {
	let text = window.getSelection().toString();
	if (text === "") mw.notify("Nothing is selected on the page!");
	else goToRevision(text);

	//inner functions
	function search_algorithm(text, revisions) {
		if (revisions.length <= 1) return 0;

		for (var i = 1; i < revisions.length; i++) {
			if (revisions[i].texthidden !== undefined) continue;
			if (revisions[i]["*"].search(text) == -1) return revisions[i - 1].revid;
		}
		return -1;
	}

	function goToRevision(text, pContinueData) {

		mw.notify("The script may take some time...");

		var params = {
			'titles': mw.config.values.wgPageName,
			'action': 'query',
			'prop': 'revisions',
			'rvlimit': 'max',
			'rvprop': 'ids|content', //'ids|flags|timestamp|comment|user|content',
			'format': 'json'
		};
		if (pContinueData && pContinueData.rvcontinue)
			params.rvcontinue = pContinueData.rvcontinue;

		$.get(mw.util.wikiScript('api'), params, function(data) {
			var continueData = data.continue;
			var articleId = mw.config.values.wgArticleId;
			var revisions = data.query.pages[articleId].revisions;
			var ans = search_algorithm(text, revisions);
			if (ans === -1 && continueData) {
				return goToRevision(text, continueData);
			}
			switch (ans) {
				case 0:
					alert("revisions.length <= 1");
					break;
				case -1:
					alert("from the beginning");
					break;
				default:
					location.href = "/w/index.php?title=" + articleId + "&diff=" + ans;
					break;
			}
		}).fail(function(xhr) {
			alert('Error    Request failed.');
		});
	}
}