acuminous/yadda

'use strict';

var LevenshteinDistanceScore = require('./scores/LevenshteinDistanceScore');
var SameLibraryScore = require('./scores/SameLibraryScore');
var MultiScore = require('./scores/MultiScore');
var $ = require('./Array');

// Understands appropriateness of macros in relation to a specific step
var Competition = function (step, macros, last_macro) {
  var results = [];

  this.validate = function () {
    if (is_undefined()) return { step: step, valid: false, reason: 'Undefined Step' };
    if (is_ambiguous()) return { step: step, valid: false, reason: 'Ambiguous Step (Patterns [' + winning_patterns() + '] are all equally good candidates)' };
    return { step: step, valid: true, winner: this.winner() };
  };

  this.clear_winner = function () {
    if (is_undefined()) throw new Error('Undefined Step: [' + step + ']');
    if (is_ambiguous()) throw new Error('Ambiguous Step: [' + step + ']. Patterns [' + winning_patterns() + '] match equally well.');
    return this.winner();
  };

  function is_undefined() {
    return results.length === 0;
  }

  function is_ambiguous() {
    return results.length > 1 && results[0].score.equals(results[1].score);
  }

  this.winner = function () {
    return results[0].macro;
  };

  function winning_patterns() {
    return results.find_all(by_winning_score).collect(macro_signatures).join(', ');
  }

  function rank(step, macros) {
    results = macros
      .collect(function (macro) {
        return {
          macro: macro,
          score: new MultiScore([new LevenshteinDistanceScore(step, macro.levenshtein_signature()), new SameLibraryScore(macro, last_macro)]),
        };
      })
      .sort(by_ascending_score);
  }

  function by_ascending_score(a, b) {
    return b.score.compare(a.score);
  }

  function by_winning_score(result) {
    return result.score.equals(results[0].score);
  }

  function macro_signatures(result) {
    return result.macro.toString();
  }

  rank(step, $(macros));
};

module.exports = Competition;