/* patch-parser.c:
 *
 * vim:smartindent ts=8:sts=2:sta:et:ai:shiftwidth=2
 ****************************************************************
 * Copyright (C) 2005 Canonical Limited
 *        Authors: Robert Collins <robert.collins@canonical.com>
 *
 * See the file "COPYING" for further information about
 * the copyright and warranty status of this work.
 *
 * Portions Copyright (C) 2001, 2002, 2003, 2004 Tim Waugh <twaugh@redhat.com>
 */


#include "hackerlab/bugs/panic.h"
#include "hackerlab/char/str.h"
#include "hackerlab/vu/safe-printfmt.h"
#include "libawk/relational.h"
#include "libarch/patch-parser.h"

/* FROM PatchUtils */
static int read_atatline (const char *atatline,
		   unsigned long *orig_offset,
		   unsigned long *orig_count,
		   unsigned long *new_offset,
		   unsigned long *new_count);
/**
 * \@brief parse patch_contents and return a list of the 
 * dels and adds in the patch, adjusted for use with the
 * file_offset_mapper api
 *
 * we parse in the 'be generous in what you accept style:
 * we will parse invalid patches and do our best.
 */
patch_line_changes_list
patch_parser_parse(t_uchar const * patch_content)
{
    rel_table lines = rel_nl_split (patch_content);
    int line;
    patch_line_changes_list result = NULL;
    int current_state = 0; /* 0 = want --, 1 = want ++, 2 = want @@, 3= want @@ or hunks */
    int current_adjusted_line = 0;
    int hunk_adjustment = 0;
    for (line = 0; line < rel_n_records (lines); ++line)
      {
        switch (current_state) 
          {
          case 0:
            if (!str_cmp_prefix ("---", lines[line][0]))
              {
                ++current_state;
                continue;
              }
          case 1:
            if (!str_cmp_prefix ("+++", lines[line][0]))
              {
                ++current_state;
                continue;
              }
          case 2:
            if (!str_cmp_prefix ("@@", lines[line][0]))
              {
                unsigned long curr_offset;
                read_atatline(lines[line][0], &curr_offset, NULL, NULL, NULL);
                current_adjusted_line = (int) curr_offset; // + hunk_adjustment;
                ++current_state;
                hunk_adjustment = 0;
                continue;
              }
          case 3:
            if (!str_cmp_prefix ("@@", lines[line][0]))
              {
                unsigned long curr_offset;
                read_atatline(lines[line][0], &curr_offset, NULL, NULL, NULL);
                current_adjusted_line = (int) curr_offset; // + hunk_adjustment;
                hunk_adjustment = 0;
                continue;
              }
            else if (lines[line][0][0] == '-')
              {
                patch_line_change_t * change = ar_ref_patch_line_change(&result, ar_size_patch_line_change(result));
                change->offset = current_adjusted_line++ - 1;
                change->operation = PATCH_DEL_LINE;
                ++hunk_adjustment; /* carry out adjustment to the next hunk */
                invariant (change->offset > -1);
              }
            else if (lines[line][0][0] == '+')
              {
                patch_line_change_t * change = ar_ref_patch_line_change(&result, ar_size_patch_line_change(result));
                change->offset = current_adjusted_line - 1;
                change->operation = PATCH_ADD_LINE;
                if (change->offset == -1)
                  {
                    /* special case BOGON: new files are -0,0 +1,length */
                    change->offset = 0;
                  }
              }
            else if (lines[line][0][0] == ' ')
              {
                ++current_adjusted_line;
              }
          }
      }
    rel_free_table (lines);
    return result;
}

void
ar_print_patch_line_change (int fd, patch_line_changes_list changes)
{
    int line;
    for (line = 0; line < ar_size_patch_line_change (changes); ++line)
        safe_printfmt (2, "%d %d\n", changes[line].offset, changes[line].operation);
}

/* librarising is too hard right now:
 * so we use one function from patchutils
 */
/*
 * diff.c - diff specific util functions
 * Copyright (C) 2001, 2002, 2003, 2004 Tim Waugh <twaugh@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


#include <string.h>
#include <stdlib.h>
static unsigned long calculate_num_lines (const char *atatline, char which)
{
        char *p = strchr (atatline, which);
        if (!p)
                return 1;
        while (*p && *p != ',' && *p != ' ') p++;
        if (!*p || *p == ' ')
                return 1;
        return strtoul (p + 1, NULL, 10);
}

static unsigned long orig_num_lines (const char *atatline)
{
        return calculate_num_lines (atatline, '-');
}

static unsigned long new_num_lines (const char *atatline)
{
        return calculate_num_lines (atatline, '+');
}

/* Parse an @@ line. */
int read_atatline (const char *atatline,
		   unsigned long *orig_offset,
		   unsigned long *orig_count,
		   unsigned long *new_offset,
		   unsigned long *new_count)
{
	char *endptr;
	unsigned long res;
	char *p;

	if (orig_offset) {
		p = strchr (atatline, '-');
		if (!p)
			return 1;
		p++;
		res = strtoul (p, &endptr, 0);
		if (p == endptr)
			return 1;
		*orig_offset = res;
	}

	if (orig_count)
		*orig_count = orig_num_lines (atatline);

	if (new_offset) {
		p = strchr (atatline, '+');
		if (!p)
			return 1;
		p++;
		res = strtoul (p, &endptr, 0);
		if (p == endptr)
			return 1;
		*new_offset = res;
	}

	if (new_count)
		*new_count = new_num_lines (atatline);

	return 0;
}