+# Fuzzy
+# https://github.com/myork/fuzzy
 #
-# * Fuzzy
-# * https://github.com/myork/fuzzy
-# *
-# * Copyright (c) 2012 Matt York
-# * Licensed under the MIT license.
+# Copyright (c) 2012 Matt York
+# Licensed under the MIT license.
 
 fuzzy = {}
-
-# Use in node or in browser
-if typeof exports isnt "undefined"
-  module.exports = fuzzy
-else
-  @fuzzy = fuzzy
+module.exports = fuzzy
 
 # Return all elements of `array` that have a fuzzy
 # match against `pattern`.

      ch = pre + ch + post
      patternIdx += 1

      # consecutive characters should increase the score more than linearly
      currScore += 1 + currScore
    else
      currScore = 0
    totalScore += currScore
    result[result.length] = ch
    idx++

  # return rendered string if we have a match for every char
  if patternIdx is pattern.length
    return (
      rendered: result.join("")
      score: totalScore
    )
  null


# The normal entry point. Filters `arr` for matches against `pattern`.
# It returns an array with matching values of the type:
#
#     [{
#         string:   '<b>lah' // The rendered string
#       , index:    2        // The index of the element in `arr`
#       , original: 'blah'   // The original element in `arr`
#     }]
#
# `opts` is an optional argument bag. Details:
#
#    opts = {
#        // string to put before a matching character
#        pre:     '<b>'
#
#        // string to put after matching character
#      , post:    '</b>'
#
#        // Optional function. Input is an element from the passed in
#        // `arr`, output should be the string to test `pattern` against.
#        // In this example, if `arr = [{crying: 'koala'}]` we would return
#        // 'koala'.
#      , extract: function(arg) { return arg.crying; }
#    }
fuzzy.filter = (pattern, arr, opts) ->
  opts = opts or {}

  # Sort by score. Browsers are inconsistent wrt stable/unstable
  # sorting, so force stable by using the index in the case of tie.
  # See http://ofb.net/~sethml/is-sort-stable.html
  arr.reduce(
    (prev, element, idx, arr) ->
      str = element
      str = opts.extract(element) if opts.extract

    compare = b.score - a.score
    return compare if compare
    a.index - b.index
  
  # No matches? Sort the original array using Damerau-Levenshtein.
  if highlighted.length < 1
    highlighted = arr.reduce(
      (prev, element, idx, arr) ->
        str = element
        str = opts.extract(element) if opts.extract
        prev[prev.length] =
          string: str
          score: DamerauLevenshtein(pattern, str)
          index: idx
          original: element
        prev
      ,[]
    ).sort (a, b) ->
      compare = a.score - b.score
      return compare if compare
      b.index - a.index
  highlighted
  
DamerauLevenshtein = (down, across, prices={}, damerau=true) ->
  # https://github.com/cbaatz/damerau-levenshtein
  switch typeof prices.insert
    when "function"
      insert = prices.insert
    when "number"
      insert = (c) ->
        prices.insert
    else
      insert = (c) ->
        1
  switch typeof prices.remove
    when "function"
      remove = prices.remove
    when "number"
      remove = (c) ->
        prices.remove
    else
      remove = (c) ->
        1
  switch typeof prices.substitute
    when "function"
      substitute = prices.substitute
    when "number"
      substitute = (from, to) ->
        prices.substitute
    else
      substitute = (from, to) ->
        1
  switch typeof prices.transpose
    when "function"
      transpose = prices.transpose
    when "number"
      transpose = (backward, forward) ->
        prices.transpose
    else
      transpose = (backward, forward) ->
        1
# ---------------------------------------------------------------------------- #
  ds = []
  if down is across
    return 0
  else
    down = down.split("")
    down.unshift null
    across = across.split("")
    across.unshift null
    down.forEach (d, i) ->
      ds[i] = []  unless ds[i]
      across.forEach (a, j) ->
        if i is 0 and j is 0
          ds[i][j] = 0
        else if i is 0
          ds[i][j] = ds[i][j - 1] + insert(a)
        else if j is 0
          ds[i][j] = ds[i - 1][j] + remove(d)
        else
          ds[i][j] = Math.min(ds[i - 1][j] + remove(d), ds[i][j - 1] + insert(a), ds[i - 1][j - 1] + ((if d is a then 0 else substitute(d, a))))
          ds[i][j] = Math.min(ds[i][j], ds[i - 2][j - 2] + ((if d is a then 0 else transpose(d, down[i - 1]))))  if damerau and i > 1 and j > 1 and down[i - 1] is a and d is across[j - 1]
    ds[down.length - 1][across.length - 1]
