// <nowiki>



/*

A user script that alerts you with a yellow banner at the top of a User Talk page if more than 3% of recent user talk diffs are self-deletions, with exceptions for some edit summary keywords such as "archiving".



Useful for detecting if a WP:PERM applicant is whitewashing their User Talk page by removing warnings without archiving them.

*/



class ErasedSectionsDetector {

	constructor( mw, $ ) {

		this.mw = mw;

		this.$ = $;

	}



	async execute() {

		if ( !this.shouldRunOnThisPage() ) {

			return;

		}

		const title = this.mw.config.get( 'wgPageName' ).replace( /_/g, ' ' );

		this.revisions = await this.getRevisions( title );

		const totalRevisionCount = this.revisions.length;

		this.addDiffsToRevisions();

		this.filterForRevisionsByThisEditorOnly();

		this.filterForContentRemoval();

		this.filterOutReasonableEditSummaries();

		this.expandBlankEditSummaries();

		const negativeDiffCount = this.revisions.length;

		const deletionPercent = negativeDiffCount / totalRevisionCount;

		if ( deletionPercent > 0.03 ) {

			this.addHtml( negativeDiffCount, totalRevisionCount );

			this.listenForShowDiffsClick();

		}

	}



	/**

	 * Add a message to blank edit summaries. This is so the hyperlink can be clicked.

	 */

	expandBlankEditSummaries() {

		this.revisions = this.revisions.map( function ( revision ) {

			if ( revision.comment === '' ) {

				revision.comment = '[no edit summary]';

			}

			return revision;

		} );

	}



	listenForShowDiffsClick() {

		this.$( '#ErasedSectionsDetector-SeeDiffs' ).on( 'click', function () {

			this.$( '#ErasedSectionsDetector-Diffs' ).toggle();

		}.bind( this ) );

	}



	addHtml( negativeDiffCount, totalRevisionCount ) {

		let html = `

			<div class="ErasedSectionsDetector">

				<div style="background-color: yellow">

					<span style="font-weight:bold">Warning:</span> This user has removed content from this page (probably without archiving it) in ${ negativeDiffCount } of the last ${ totalRevisionCount } revisions. <a id="ErasedSectionsDetector-SeeDiffs">Click here</a> to see diffs.

				</div>

				

				<div id="ErasedSectionsDetector-Diffs" style="border: 1px solid black; font-size: 80%; display: none;">

					<ul>

		`;



		for ( const revision of this.revisions ) {

			html += `

						<li>

							<a href="w/index.php?title=${ encodeURIComponent( this.mw.config.get( 'wgPageName' ) ) }&diff=prev&oldid=${ revision.revid }">

								${ revision.comment }

							</a>

						</li>

			`;

		}



		html += `

					</ul>

				</div>

			</div>

		`;



		this.$( '#contentSub2' ).after( html );

	}



	filterForContentRemoval() {

		this.revisions = this.revisions.filter( ( revision ) => revision.diff < 0 );

	}



	filterForRevisionsByThisEditorOnly() {

		const thisEditor = this.mw.config.get( 'wgTitle' );

		this.revisions = this.revisions.filter( ( revision ) => revision.user === thisEditor );

	}



	filterOutReasonableEditSummaries() {

		const keywordsToIgnore = 

			'arc', // arc, arch, archive, archiving, OneClickArchiver

			'bot mes', // mesg, message

			'mass mes',

			'newsletter'

		];

		for ( let keyword of keywordsToIgnore ) {

			this.revisions = this.revisions.filter( function ( revision ) {

				keyword = keyword.toLowerCase();

				const editSummary = revision.comment.toLowerCase();

				return !editSummary.includes( keyword );

			} );

		}

	}



	/**

	 * Given the Action API output of query revisions as a JavaScript object, add to this object a field called "diff" that is the difference +/- in size of that diff compared to the next oldest diff.

	 */

	addDiffsToRevisions() {

		const len = this.revisions.length;

		let lastRevisionSize = this.revisions len - 1 ].size;

		// need to store the OLDER revision's size in a buffer to compute a diff, so iterate BACKWARDS

		for ( let i = ( len - 2 ); i >= 0; i-- ) {

			const thisRevisionSize = this.revisions i ].size;

			this.revisions i ].diff = thisRevisionSize - lastRevisionSize;

			lastRevisionSize = thisRevisionSize;

		}

	}



	async getRevisions( title ) {

		const api = new this.mw.Api();

		const response = await api.get( {

			action: 'query',

			format: 'json',

			prop: 'revisions',

			titles: title,

			formatversion: '2',

			rvprop: 'comment|size|user|ids',

			rvslots: '',

			rvlimit: '500', // get 500 revisions

			rvdir: 'older' // get newest revisions (enumerate towards older entries)

		} );

		return response.query.pages 0 ].revisions;

	}



	shouldRunOnThisPage() {

		const isViewing = this.mw.config.get( 'wgAction' ) === 'view';

		if ( !isViewing ) {

			return false;

		}



		const isDiff = this.mw.config.get( 'wgDiffNewId' );

		if ( isDiff ) {

			return false;

		}



		const isDeletedPage = !this.mw.config.get( 'wgCurRevisionId' );

		if ( isDeletedPage ) {

			return false;

		}



		const namespace = this.mw.config.get( 'wgNamespaceNumber' );

		const isUserTalkNamespace =  3 ].includes( namespace );

		if ( !isUserTalkNamespace ) {

			return false;

		}



		const isSubPage = this.mw.config.get( 'wgPageName' ).includes( '/' );

		if ( isSubPage ) {

			return;

		}



		return true;

	}

}



$( async function () {

	await mw.loader.using(  'mediawiki.api' ], async () => {

		await ( new ErasedSectionsDetector( mw, $ ) ).execute();

	} );

} );



// </nowiki>