/* notmuch - Not much of an email program, (just index and search)
 *
 * Copyright © 2009 Carl Worth
 *
 * 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 3 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, see http://www.gnu.org/licenses/ .
 *
 * Author: Carl Worth <cworth@cworth.org>
 */

#include "notmuch-client.h"
#include <stdlib.h>
#include <ctype.h>

#define DEFAULT_TAG_ARRAY_SIZE 2

static int 
strcmp_for_qsort (const void *ptr1, const void *ptr2)
{
    char * const * str1_p = ptr1;
    char * const * str2_p = ptr2;

    return strcmp(*str1_p, *str2_p);
}

int
notmuch_restore_command (void *ctx, int argc, char *argv[])
{
    notmuch_config_t *config;
    notmuch_database_t *notmuch;
    FILE *input;
    char *line = NULL;
    size_t line_size;
    ssize_t line_len;
    regex_t regex;
    int rerr;
    char **tag_array = NULL;
    int tag_array_size = DEFAULT_TAG_ARRAY_SIZE;

    config = notmuch_config_open (ctx, NULL, NULL);
    if (config == NULL)
	return 1;

    notmuch = notmuch_database_open (notmuch_config_get_database_path (config),
				     NOTMUCH_DATABASE_MODE_READ_WRITE);
    if (notmuch == NULL)
	return 1;

    if (argc) {
	input = fopen (argv[0], "r");
	if (input == NULL) {
	    fprintf (stderr, "Error opening %s for reading: %s\n",
		     argv[0], strerror (errno));
	    return 1;
	}
    } else {
	printf ("No filename given. Reading dump from stdin.\n");
	input = stdin;
    }

    /* Dump output is one line per message. We match a sequence of
     * non-space characters for the message-id, then one or more
     * spaces, then a list of space-separated tags as a sequence of
     * characters within literal '(' and ')'. */
    xregcomp (&regex,
	      "^([^ ]+) \\(([^)]*)\\)$",
	      REG_EXTENDED);

    /* Make an array of pointers to point to individual tokens */
    tag_array = talloc_array (ctx, char *, tag_array_size);
    if  (!tag_array) {
	fprintf (stderr, "fatal: overflow in talloc_array");
	exit(1);
    }
    
    while ((line_len = getline (&line, &line_size, input)) != -1) {
	regmatch_t match[3];
	char *message_id, *tags,  *next;
	notmuch_message_t *message;
	notmuch_status_t status;
	int tag_count;
	notmuch_tags_t *tag_list;
	int i;

	chomp_newline (line);

	rerr = xregexec (&regex, line, 3, match, 0);
	if (rerr == REG_NOMATCH)
	{
	    fprintf (stderr, "Warning: Ignoring invalid input line: %s\n",
		     line);
	    continue;
	}

	message_id = xstrndup (line + match[1].rm_so,
			       match[1].rm_eo - match[1].rm_so);
	tags = xstrndup (line + match[2].rm_so,
			 match[2].rm_eo - match[2].rm_so);

	message = notmuch_database_find_message (notmuch, message_id);
	if (message == NULL) {
	    fprintf (stderr, "Warning: Cannot apply tags to missing message: %s\n",
		     message_id);
	    goto NEXT_LINE;
	}

	next = tags;
	tag_count = 0;
	while (*next) {
	    while (*next && isspace(*next))
		next++;
	    if (*next) {
		while (tag_count >= tag_array_size) {
		    tag_array_size *= 2;
		    tag_array = talloc_realloc (ctx, tag_array, char *, 
						tag_array_size);
		    if  (!tag_array) {
			fprintf (stderr, "fatal: overflow in talloc_realloc");
			exit(1);
		    }
		} 
		tag_array[tag_count] = next;
		tag_count++;
	    }
	    while (*next && !isspace(*next))
		next++;
	    if (*next) {
		*next = '\0';
		next++;
	    }
	}

	qsort(tag_array,tag_count,sizeof(char*),strcmp_for_qsort);
	
	tag_list = notmuch_message_get_tags (message);
	i = 0;
	while (notmuch_tags_has_more (tag_list) && i < tag_count &&
	       (strcmp(notmuch_tags_get (tag_list),tag_array[i]) == 0))
	{
	    notmuch_tags_advance (tag_list);
	    i++;
	}

	/* the only success condition is for the tag list comparison is to run
	   off the end of both lists at the same time */
	if (notmuch_tags_has_more (tag_list) || i < tag_count ){
	    notmuch_message_freeze (message);
	    notmuch_message_remove_all_tags (message);

	    for (i=0; i < tag_count; i++) {
		status = notmuch_message_add_tag (message, tag_array[i]);
		if (status) {
		    fprintf (stderr,
			     "Error applying tag %s to message %s:\n",
			     tag_array[i], message_id);
		    fprintf (stderr, "%s\n",
			     notmuch_status_to_string (status));
		}
	    }
	    notmuch_message_thaw (message);
	}
	notmuch_message_destroy (message);
      NEXT_LINE:
	free (message_id);
	free (tags);
    }

    regfree (&regex);

    if (line)
	free (line);

    talloc_free (tag_array);

    notmuch_database_close (notmuch);
    if (input != stdin)
	fclose (input);

    return 0;
}