User:Enterprisey/link-deleted-revs.js

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$( function () {
    function getTimestamps( revids, getPrev ) {
        return new mw.Api().get( {
            action: "query",
            prop: "deletedrevisions",
            revids: revids,
            drvprop: "ids|timestamp",
            formatversion: "2",
        } ).then( function ( data ) {
            var timestamps = {};
            data.query.pages[0].deletedrevisions.forEach( function ( rev ) {
                timestamps[rev.revid] = rev.timestamp;
            } );
            if( getPrev ) {
                var parents = data.query.pages[0].deletedrevisions.map( function ( rev ) {
                    return rev.parentid;
                } ).join( "|" );
                return getTimestamps( parents, false ).then( function ( data ) {
                    for( var revid in data.timestamps ) {
                        timestamps[revid] = data.timestamps[revid];
                    }
                    return {
                        title: data.title,
                        timestamps: timestamps,
                    };
                } );
            } else {
                return $.when( {
                    title: data.query.pages[0].title,
                    timestamps: timestamps,
                } );
            }
        } ).catch( function ( e ) { console.error( e ); } );
    }

    if( window.location.search.indexOf( "diff=" ) >= 0 &&
            !document.querySelector( "table.diff" ) ) {
        var status = $( "<p>" )
            .text( "Loading diff link..." )
            .appendTo( "#mw-content-text" );
        mw.loader.using( [ "mediawiki.api", "mediawiki.util" ], function () {
            var diff = window.location.search.match( /diff=(\d+|\w+)?/ )[1];
            var oldid = window.location.search.match( /oldid=(\d+|\w+)?/ )[1];
            var revids = "";
            if( Number( oldid ) ) {
                revids += oldid;
            }
            if( Number( diff ) ) {
                if( revids ) {
                    revids += "|";
                }
                revids += diff;
            }
            var getPrev = !oldid;
            getTimestamps( revids, getPrev ).then( function ( data ) {
                var oldidTimestamp = oldid && data.timestamps[oldid];
                if( !oldid ) {
                    for( var revid in data.timestamps ) {
                        if( revid !== diff ) {
                            oldidTimestamp = data.timestamps[revid];
                        }
                    }
                }
                status.empty().append( $( "<p>" )
                    .append( $( "<strong>" )
                        .append( $( "<a>" )
                            .attr( "href", mw.util.getUrl( "Special:Undelete", {
                                target: data.title,
                                timestamp: oldidTimestamp,
                                diff: data.timestamps[diff] || diff,
                            } ) )
                            .text( "You can view it here" ) )
                        .append( "." ) ) );
            } );
        } );
    } else if( window.location.search.indexOf( "oldid=" ) >= 0 &&
            document.getElementsByClassName( "mw-revision" ).length === 0 &&
            !document.querySelector( "table.diff" ) ) {
        var status = $( "<p>" )
            .text( "Loading diff link..." )
            .appendTo( "#mw-content-text" );
        mw.loader.using( [ "mediawiki.api", "mediawiki.util" ], function () {
            var oldid = window.location.search.match( /oldid=(\d+)/ )[1];
            getTimestamps( oldid ).then( function ( data ) {
                status.empty().append( $( "<p>" )
                    .append( $( "<strong>" )
                        .append( $( "<a>" )
                            .attr( "href", mw.util.getUrl( "Special:Undelete", {
                                target: data.title,
                                timestamp: data.timestamps[oldid],
                            } ) )
                            .text( "You can view it here" ) )
                        .append( "." ) ) );
            } )
        } );
    }
} );