/*
 * xfer-file.c - file functions for xfer plugin
 *
 * Copyright (C) 2003-2019 Sébastien Helleu <flashcode@flashtux.org>
 *
 * This file is part of WeeChat, the extensible chat client.
 *
 * WeeChat 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.
 *
 * WeeChat 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 WeeChat.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <sys/wait.h>

#include "../weechat-plugin.h"
#include "xfer.h"
#include "xfer-file.h"
#include "xfer-buffer.h"
#include "xfer-config.h"


/*
 * Resumes a download.
 *
 * Returns:
 *   1: OK
 *   0: not resumable
 */

int
xfer_file_resume (struct t_xfer *xfer, const char *filename)
{
    struct stat st;

    if (!weechat_config_boolean (xfer_config_file_auto_resume))
        return 0;

    if (access (filename, W_OK) == 0)
    {
        if (stat (filename, &st) != -1)
        {
            if ((unsigned long long) st.st_size < xfer->size)
            {
                xfer->start_resume = (unsigned long long) st.st_size;
                xfer->pos = xfer->start_resume;
                xfer->last_check_pos = xfer->start_resume;
                return 1;
            }
        }
    }

    /* not resumable */
    return 0;
}

/*
 * Searches for local filename for a xfer.
 *
 * If type is file/recv, adds a suffix (like .1) if needed.
 * If download is resumable, sets "start_resume" to good value.
 */

void
xfer_file_find_filename (struct t_xfer *xfer)
{
    const char *dir_separator;
    char *path, *filename2;
    int length;

    if (!XFER_IS_FILE(xfer->type))
        return;

    path = weechat_string_eval_path_home (
        weechat_config_string (xfer_config_file_download_path),
        NULL, NULL, NULL);
    if (!path)
        return;

    xfer->local_filename = malloc (strlen (path) +
                                   strlen (xfer->remote_nick) +
                                   strlen (xfer->filename) + 4);
    if (!xfer->local_filename)
    {
        free (path);
        return;
    }

    strcpy (xfer->local_filename, path);
    dir_separator = weechat_info_get ("dir_separator", "");
    if (dir_separator
        && (xfer->local_filename[strlen (xfer->local_filename) - 1] != dir_separator[0]))
        strcat (xfer->local_filename, dir_separator);
    if (weechat_config_boolean (xfer_config_file_use_nick_in_filename))
    {
        strcat (xfer->local_filename, xfer->remote_nick);
        strcat (xfer->local_filename, ".");
    }
    strcat (xfer->local_filename, xfer->filename);

    free (path);

    /* file already exists? */
    if (access (xfer->local_filename, F_OK) == 0)
    {
        if (xfer_file_resume (xfer, xfer->local_filename))
            return;

        /* if auto rename is not set, then abort xfer */
        if (!xfer_config_file_auto_rename)
        {
            xfer_close (xfer, XFER_STATUS_FAILED);
            xfer_buffer_refresh (WEECHAT_HOTLIST_MESSAGE);
            return;
        }

        length = strlen (xfer->local_filename) + 16;
        filename2 = malloc (length);
        if (!filename2)
        {
            xfer_close (xfer, XFER_STATUS_FAILED);
            xfer_buffer_refresh (WEECHAT_HOTLIST_MESSAGE);
            return;
        }
        xfer->filename_suffix = 0;
        do
        {
            xfer->filename_suffix++;
            snprintf (filename2, length, "%s.%d",
                      xfer->local_filename,
                      xfer->filename_suffix);
            if (access (filename2, F_OK) == 0)
            {
                if (xfer_file_resume (xfer, filename2))
                    break;
            }
            else
                break;
        }
        while (1);

        free (xfer->local_filename);
        xfer->local_filename = strdup (filename2);
        free (filename2);
    }
}

/*
 * Calculates xfer speed (for files only).
 */

void
xfer_file_calculate_speed (struct t_xfer *xfer, int ended)
{
    time_t local_time, elapsed;
    unsigned long long bytes_per_sec_total;

    local_time = time (NULL);
    if (ended || local_time > xfer->last_check_time)
    {
        if (ended)
        {
            /* calculate bytes per second (global) */
            elapsed = local_time - xfer->start_transfer;
            if (elapsed == 0)
                elapsed = 1;
            xfer->bytes_per_sec = (xfer->pos - xfer->start_resume) / elapsed;
            xfer->eta = 0;
        }
        else
        {
            /* calculate ETA */
            elapsed = local_time - xfer->start_transfer;
            if (elapsed == 0)
                elapsed = 1;
            bytes_per_sec_total = (xfer->pos - xfer->start_resume) / elapsed;
            if (bytes_per_sec_total == 0)
                bytes_per_sec_total = 1;
            xfer->eta = (xfer->size - xfer->pos) / bytes_per_sec_total;

            /* calculate bytes per second (since last check time) */
            elapsed = local_time - xfer->last_check_time;
            if (elapsed == 0)
                elapsed = 1;
            xfer->bytes_per_sec = (xfer->pos - xfer->last_check_pos) / elapsed;
        }
        xfer->last_check_time = local_time;
        xfer->last_check_pos = xfer->pos;
    }
}