/***********************************************************************/
/*                                                                     */
/*                                OCaml                                */
/*                                                                     */
/*            Jacob Navia, after Xavier Leroy                          */
/*                                                                     */
/*  Copyright 2001 Institut National de Recherche en Informatique et   */
/*  en Automatique.  All rights reserved.  This file is distributed    */
/*  under the terms of the GNU Library General Public License, with    */
/*  the special exception on linking described in file ../LICENSE.     */
/*                                                                     */
/***********************************************************************/

/***********************************************************************/
/* Changes made by Chris Watford to enhance the source editor          */
/* Began 14 Sept 2003 - watford@uiuc.edu                               */
/***********************************************************************/

#include "inria.h"
#include "history.h"

/*------------------------------------------------------------------------
Procedure:     AddToHistory ID:2
Author:        Chris Watford watford@uiuc.edu
Purpose:       Adds an edit buffer to the history control
Input:         Pointer to the edit buffer to add
Output:
Errors:
--------------------------------------------------------------------------
Edit History:
    15 Sept 2003 - Chris Watford watford@uiuc.edu
        - Complete rewrite
        - Got it to add the edit buffer to the history
    17 Sept 2003 - Chris Watford watford@uiuc.edu
        - Added doubly link list support
------------------------------------------------------------------------*/
void AddToHistory(EditBuffer *edBuf)
{
    StatementHistory *newLine;

    // sanity checks
    if(edBuf == NULL)
    {
        return;
    } else if (edBuf->LineCount == 0 || edBuf->Lines == NULL) {
        // fix any possible errors that may come from this
        edBuf->LineCount = 0;
        edBuf->Lines = NULL;
        return;
    }

    // setup newline and add as the front of the linked list
    newLine = SafeMalloc(sizeof(StatementHistory));
    newLine->Next = History;
    newLine->Prev = NULL;
    newLine->Statement = edBuf;

    // setup back linking
    if(History != NULL)
        History->Prev = newLine;

    // set the history up
    History = newLine;

    // search for the new history tail
    for(HistoryTail = (HistoryTail != NULL ? HistoryTail : History); HistoryTail->Next != NULL; HistoryTail = HistoryTail->Next);
}

/*------------------------------------------------------------------------
Procedure:     GetHistoryLine ID:2
Author:        Chris Watford watford@uiuc.edu
Purpose:       Returns an entry from the history table
Input:         Index of the history entry to return
Output:        The history entry as a single line
Errors:
--------------------------------------------------------------------------
Edit History:
    15 Sept 2003 - Chris Watford watford@uiuc.edu
        - Complete rewrite
    17 Sept 2003 - Chris Watford watford@uiuc.edu
        - Added doubly link list support
------------------------------------------------------------------------*/
char *GetHistoryLine(int n)
{
    StatementHistory *histentry = History;
    int i;

    // traverse linked list looking for member n
    for (i = 0; ((i < n) && (histentry != NULL)); i++, histentry = histentry->Next);

    // figure out what to return
    if (histentry != NULL)
    {
        return editbuffer_getasline(histentry->Statement);
    } else {
        return "";
    }
}