112 lines
3.0 KiB
JavaScript
112 lines
3.0 KiB
JavaScript
var SecretSanta = function () {
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this.names = [];
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this.enforced = Object.create( null );
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this.blacklists = Object.create( null );
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};
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SecretSanta.prototype.add = function ( name ) {
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if ( this.names.indexOf( name ) !== -1 )
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throw new Error( 'Cannot redefine ' + name );
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this.names.push( name );
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var subapi = { };
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subapi.enforce = function ( other ) {
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this.enforced[ name ] = other;
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return subapi;
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}.bind( this );
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subapi.blacklist = function ( other ) {
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if ( ! Object.prototype.hasOwnProperty.call( this.blacklists, name ) )
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this.blacklists[ name ] = [];
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if ( this.blacklists[ name ].indexOf( other ) === -1 )
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this.blacklists[ name ].push( other );
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return subapi;
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}.bind( this );
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return subapi;
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};
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SecretSanta.prototype.generate = function () {
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var pairings = Object.create( null );
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var candidatePairings = Object.create( null );
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this.names.forEach( function ( name ) {
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if ( Object.prototype.hasOwnProperty.call( this.enforced, name ) ) {
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var enforced = this.enforced[ name ];
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if ( this.names.indexOf( enforced ) === -1 )
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throw new Error( name + ' is paired with ' + enforced + ', which hasn\'t been declared as a possible pairing' );
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Object.keys( pairings ).forEach( function ( name ) {
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if ( pairings[ name ] === enforced ) {
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throw new Error( 'Per your rules, multiple persons are paired with ' + enforced );
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}
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} );
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candidatePairings[ name ] = [ this.enforced[ name ] ];
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} else {
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var candidates = _.difference( this.names, [ name ] );
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if ( Object.prototype.hasOwnProperty.call( this.blacklists, name ) )
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candidates = _.difference( candidates, this.blacklists[ name ] );
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candidatePairings[ name ] = candidates;
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}
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}, this );
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var findNextGifter = function () {
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var names = Object.keys( candidatePairings );
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var minCandidateCount = _.min( names.map( function ( name ) { return candidatePairings[ name ].length; } ) );
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var potentialGifters = names.filter( function ( name ) { return candidatePairings[ name ].length === minCandidateCount; } );
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return _.sample( potentialGifters );
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};
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while ( Object.keys( candidatePairings ).length > 0 ) {
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var name = findNextGifter();
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if ( candidatePairings[ name ].length === 0 )
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throw new Error('We haven\'t been able to find a match for ' + name + '! Press "Generate" to try again and, if it still doesn\'t work, try removing some exclusions from your rules. Sorry for the inconvenience!');
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var pairing = _.sample( candidatePairings[ name ] );
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delete candidatePairings[ name ];
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Object.keys( candidatePairings ).forEach( function ( name ) {
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candidatePairings[ name ] = _.without( candidatePairings[ name ], pairing );
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} );
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pairings[ name ] = pairing;
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}
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return pairings;
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};
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