// $Revision: 1.3 $
// Copyright (c) 1994-1995 Taligent, Inc.  All rights reserved.

#ifndef TaligentSamples_SCRAMBLETEXTCOMMAND
#include "ScrambleTextCommand.h"
#endif

#ifndef Taligent_RANDOMNUMBER
#include <Taligent/RandomNumber.h>
#endif

#ifndef Taligent_BREAKWORD
#include <Taligent/BreakWord.h>
#endif

#ifndef Taligent_ARRAYOF
#include <Taligent/ArrayOf.h>
#endif

#ifndef Taligent_ASSERTIONS
#include <Taligent/Assertions.h>
#endif

MCollectibleDefinitionsMacro(TScrambleTextCommand, 0);

TScrambleTextCommand::TScrambleTextCommand()
    : TReplaceTextCommand()
{
}

TScrambleTextCommand::~TScrambleTextCommand()
{
}

// Get the currently selected text first and scramble it, then
// use this to replace the text.  Support for discontiguous selections
// isn't really available yet, so we just use the first range of
// the current selection.

void
TScrambleTextCommand::HandleDoBegin(MTextSelection& selection)
{
    TStandardText text;
    TTextRange range;
    selection.GetFirstRange(range);
    
    {
        TTextRepresentationReadEntry entry(&selection);
        entry.GetTextForReading()->Extract(range, text);
    }

    ScrambleText(text);

    SetText(text);

    TReplaceTextCommand::HandleDoBegin(selection);
}

// Break the text into runs of words and punctuation and put the ranges into an 
// array. Shuffle the array, build new text from the shuffled ranges, then replace 
// the provided text.

void
TScrambleTextCommand::ScrambleText(TText& text)
{
    TTextChunkIterator* iter = TTextChunkIterator::CreatePreferredWordSelectionIterator(&text);
    Assertion(iter != NIL);

    TDeleterFor<TTextChunkIterator> deleter(iter);

    TTextRange range;
    if (!iter->First(range)) {
        return;
    }

    TArrayOf<TTextRange> ranges;

    TTextRange currentRange = range;
    while (iter->Next(range)) {
        bool joinRange = true;
        for (TTextOffset i = range.GetBegin(), e = range.GetEnd(); 
             (i < e) && joinRange;
             i++) {
        //
            UniChar c = text[TTextIndex(i)];
            joinRange = TUnicode::IsPunctuation(c) || TUnicode::IsASpace(c);
        }

        if (joinRange) {
            currentRange.SetEnd(currentRange.GetEnd() + range.GetLength());
        } else {
            ranges.Append(new TTextRange(currentRange));
            currentRange = range;
        }
    }
    ranges.Append(new TTextRange(currentRange));
        
    long limit = ranges.Count();
    if (limit > 1) {
        long maxindex = limit - 1;

        TUniformRandomInteger random;    // can't restrict random numbers to a range...
        unsigned long mask = 1;
        while (mask < maxindex) {
            mask = (mask << 1) + 1;
        }

        CollectionIndex i;
        for (i = 0; i < limit; i++) {
            CollectionIndex x;
            do {
                x = random.Next() & mask;
            } while (x > maxindex);

            if (i != x) {
                TTextRange* r = ranges.FastAt(i);
                ranges.FastAtPut(i, ranges.FastAt(x));
                ranges.FastAtPut(x, r);
            }
        }
        
        TStandardText scrambledText;
        for (i = 0; i < limit; i++) {
            scrambledText.Insert(text, ranges[i]);
        }

        text = scrambledText;
    }
    ranges.DeleteAll();
}