/* 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 <getopt.h>

#include "notmuch-client.h"

int
notmuch_restore_command (unused (void *ctx), int argc, char *argv[])
{
    notmuch_config_t *config;
    notmuch_database_t *notmuch;
    notmuch_bool_t synchronize_flags;
    notmuch_bool_t accumulate = FALSE;
    notmuch_bool_t match_enabled = FALSE;
    FILE *input = stdin;
    char *line = NULL;
    size_t line_size;
    ssize_t line_len;
    regex_t input_regex, match_regex;
    int rerr;

    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;

    synchronize_flags = notmuch_config_get_maildir_synchronize_flags (config);

    struct option options[] = {
	{ "accumulate",   no_argument,       0, 'a' },
	{ "match",	  required_argument, 0, 'm' },
	{ 0, 0, 0, 0}
    };

    int opt;
    do {
	opt = getopt_long (argc, argv, "", options, NULL);

	switch (opt) {
	case 'a':
	    accumulate = 1;
	    break;
	case 'm':
	    match_enabled = TRUE;
	    if ( xregcomp (&match_regex, optarg, REG_EXTENDED|REG_NOSUB) )
		return 1;
	    break;
	case '?':
	    return 1;
	    break;
	}

    } while (opt != -1);

    if (optind < argc) {
	input = fopen (argv[optind], "r");
	if (input == NULL) {
	    fprintf (stderr, "Error opening %s for reading: %s\n",
		     argv[optind], strerror (errno));
	    return 1;
	}
	optind++;
    }

    if (optind < argc) {
	fprintf (stderr,
	 "Cannot read dump from more than one file: %s\n",
		 argv[optind]);
	return 1;
    }

    /* 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 ')'. */
    if ( xregcomp (&input_regex,
		   "^([^ ]+) \\(([^)]*)\\)$",
		   REG_EXTENDED) )
	INTERNAL_ERROR("compile time constant regex failed.");

    while ((line_len = getline (&line, &line_size, input)) != -1) {
	regmatch_t match[3];
	char *message_id, *file_tags, *tag, *next;
	notmuch_message_t *message = NULL;
	notmuch_status_t status;
	notmuch_tags_t *db_tags;
	char *db_tags_str;

	chomp_newline (line);

	rerr = xregexec (&input_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);
	file_tags = xstrndup (line + match[2].rm_so,
			      match[2].rm_eo - match[2].rm_so);

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

	/* In order to detect missing messages, this check/optimization is
	 * intentionally done *after* first finding the message.  */
	if (accumulate && (file_tags == NULL || *file_tags == '\0'))
	{
	    goto NEXT_LINE;
	}

	db_tags_str = NULL;
	for (db_tags = notmuch_message_get_tags (message);
	     notmuch_tags_valid (db_tags);
	     notmuch_tags_move_to_next (db_tags))
	{
	    const char *tag = notmuch_tags_get (db_tags);

	    if (match_enabled && !accumulate &&
		!regexec (&match_regex, tag, 0, NULL, 0) )
		notmuch_message_remove_tag (message, tag);

	    if (db_tags_str)
		db_tags_str = talloc_asprintf_append (db_tags_str, " %s", tag);
	    else
		db_tags_str = talloc_strdup (message, tag);
	}

	if (((file_tags == NULL || *file_tags == '\0') &&
	     (db_tags_str == NULL || *db_tags_str == '\0')) ||
	    (!match_enabled && file_tags && db_tags_str && 
	     strcmp (file_tags, db_tags_str) == 0))
	{
	    goto NEXT_LINE;
	}

	notmuch_message_freeze (message);

	if (!accumulate && !match_enabled)
	    notmuch_message_remove_all_tags (message);

	next = file_tags;
	while (next) {
	    tag = strsep (&next, " ");
	    if (*tag == '\0')
		continue;

	    if (match_enabled &&
		regexec (&match_regex, tag, 0, NULL, 0))
		continue;

	    status = notmuch_message_add_tag (message, tag);
	    if (status) {
		fprintf (stderr,
			 "Error applying tag %s to message %s:\n",
			 tag, message_id);
		fprintf (stderr, "%s\n",
			 notmuch_status_to_string (status));
	    }
	}

	notmuch_message_thaw (message);

	if (synchronize_flags)
	    notmuch_message_tags_to_maildir_flags (message);

      NEXT_LINE:
	if (message)
	    notmuch_message_destroy (message);
	message = NULL;
	free (message_id);
	free (file_tags);
    }

    regfree (&input_regex);

    if (match_enabled)
	regfree (&match_regex);

    if (line)
	free (line);

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

    return 0;
}