// qs_score - Quicksilver Score
//
// A port of the Quicksilver string ranking algorithm
//
// "hello world".score("axl") //=> 0.0
// "hello world".score("ow") //=> 0.6
// "hello world".score("hello world") //=> 1.0
//
// Tested in Firefox 2 and Safari 3
//
// The Quicksilver code is available here
// http://code.google.com/p/blacktree-alchemy/
// http://blacktree-alchemy.googlecode.com/svn/trunk/Crucible/Code/NSString+BLTRRanking.m
//
// The MIT License
//
// Copyright (c) 2008 Lachie Cox
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.


String.prototype.score = function (abbreviation,offset) {
    offset = offset || 0 // TODO: I think this is unused... remove
 
    if (abbreviation.length === 0) {
        return 0.9
    }
    if (abbreviation.length > this.length) {
        return 0.0
    }

    for (var i = abbreviation.length; i > 0; i--) {
        var sub_abbreviation = abbreviation.substring(0,i)
        var index = this.indexOf(sub_abbreviation)


        if (index < 0) {
            continue;
        }
        if (index + abbreviation.length > this.length + offset) {
            continue;
        }

        var next_string = this.substring(index + sub_abbreviation.length)
        var next_abbreviation = null

        if (i >= abbreviation.length) {
            next_abbreviation = ''
        } else {
            next_abbreviation = abbreviation.substring(i)
        }
 
        var remaining_score = next_string.score(next_abbreviation,offset + index)
 
        if (remaining_score > 0) {
            var score = this.length - next_string.length;

            if (index != 0) {
                var j = 0;
                var c = this.charCodeAt(index - 1)
                if ( c == 32 || c == 9) {
                    for (j = (index - 2); j >= 0; j--) {
                        c = this.charCodeAt(j)
                        score -= ((c == 32 || c == 9) ? 1 : 0.15)
                    }
                // XXX maybe not port this heuristic
                //
                // } else if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[self characterAtIndex:matchedRange.location]]) {
                //     for (j = matchedRange.location-1; j >= (int) searchRange.location; j--) {
                //         if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[self characterAtIndex:j]])
                //             score--;
                //         else
                //             score -= 0.15;
                //     }
                } else {
                    score -= index
                }
            }
   
            score += remaining_score * next_string.length
            score /= this.length;
            return score
        }
    }
    return 0.0
}
