/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#include "client.h"
#include "channels/audio-input/audio-buffer.h"
#include "channels/cliprdr.h"
#include "channels/disp.h"
#include "common/recording.h"
#include "config.h"
#include "fs.h"
#include "log.h"
#include "rdp.h"
#include "settings.h"
#include "user.h"

#ifdef ENABLE_COMMON_SSH
#include "common-ssh/sftp.h"
#include "common-ssh/ssh.h"
#include "common-ssh/user.h"
#endif

#include <guacamole/audio.h>
#include <guacamole/client.h>

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

/**
 * Tests whether the given path refers to a directory which the current user
 * can write to. If the given path is not a directory, is not writable, or is
 * not a link pointing to a writable directory, this test will fail, and
 * errno will be set appropriately.
 *
 * @param path
 *     The path to test.
 *
 * @return
 *     Non-zero if the given path is (or points to) a writable directory, zero
 *     otherwise.
 */
static int is_writable_directory(const char* path) {

    /* Verify path is writable */
    if (faccessat(AT_FDCWD, path, W_OK, 0))
        return 0;

    /* If writable, verify path is actually a directory */
    DIR* dir = opendir(path);
    if (!dir)
        return 0;

    /* Path is both writable and a directory */
    closedir(dir);
    return 1;

}

int guac_client_init(guac_client* client, int argc, char** argv) {

    /* Automatically set HOME environment variable if unset (FreeRDP's
     * initialization process will fail within freerdp_settings_new() if this
     * is unset) */
    const char* current_home = getenv("HOME");
    if (current_home == NULL) {

        /* Warn if the correct home directory cannot be determined */
        struct passwd* passwd = getpwuid(getuid());
        if (passwd == NULL)
            guac_client_log(client, GUAC_LOG_WARNING, "FreeRDP initialization "
                    "may fail: The \"HOME\" environment variable is unset and "
                    "its correct value could not be automatically determined: "
                    "%s", strerror(errno));

        /* Warn if the correct home directory could be determined but can't be
         * assigned */
        else if (setenv("HOME", passwd->pw_dir, 1))
            guac_client_log(client, GUAC_LOG_WARNING, "FreeRDP initialization "
                    "may fail: The \"HOME\" environment variable is unset "
                    "and its correct value (detected as \"%s\") could not be "
                    "assigned: %s", passwd->pw_dir, strerror(errno));

        /* HOME has been successfully set */
        else {
            guac_client_log(client, GUAC_LOG_DEBUG, "\"HOME\" "
                    "environment variable was unset and has been "
                    "automatically set to \"%s\"", passwd->pw_dir);
            current_home = passwd->pw_dir;
        }

    }

    /* Verify that detected home directory is actually writable and actually a
     * directory, as FreeRDP initialization will mysteriously fail otherwise */
    if (current_home != NULL && !is_writable_directory(current_home)) {
        if (errno == EACCES)
            guac_client_log(client, GUAC_LOG_WARNING, "FreeRDP initialization "
                    "may fail: The current user's home directory (\"%s\") is "
                    "not writable, but FreeRDP generally requires a writable "
                    "home directory for storage of configuration files and "
                    "certificates.", current_home);
        else if (errno == ENOTDIR)
            guac_client_log(client, GUAC_LOG_WARNING, "FreeRDP initialization "
                    "may fail: The current user's home directory (\"%s\") is "
                    "not actually a directory, but FreeRDP generally requires "
                    "a writable home directory for storage of configuration "
                    "files and certificates.", current_home);
        else
            guac_client_log(client, GUAC_LOG_WARNING, "FreeRDP initialization "
                    "may fail: Writability of the current user's home "
                    "directory (\"%s\") could not be determined: %s",
                    current_home, strerror(errno));
    }

    /* Set client args */
    client->args = GUAC_RDP_CLIENT_ARGS;

    /* Alloc client data */
    guac_rdp_client* rdp_client = calloc(1, sizeof(guac_rdp_client));
    client->data = rdp_client;

    /* Init clipboard */
    rdp_client->clipboard = guac_rdp_clipboard_alloc(client);

    /* Init display update module */
    rdp_client->disp = guac_rdp_disp_alloc();

    /* Redirect FreeRDP log messages to guac_client_log() */
    guac_rdp_redirect_wlog(client);

    /* Recursive attribute for locks */
    pthread_mutexattr_init(&(rdp_client->attributes));
    pthread_mutexattr_settype(&(rdp_client->attributes),
            PTHREAD_MUTEX_RECURSIVE);

    /* Set handlers */
    client->join_handler = guac_rdp_user_join_handler;
    client->free_handler = guac_rdp_client_free_handler;

#ifdef ENABLE_COMMON_SSH
    guac_common_ssh_init(client);
#endif

    return 0;

}

int guac_rdp_client_free_handler(guac_client* client) {

    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;

    /* Wait for client thread */
    pthread_join(rdp_client->client_thread, NULL);

    /* Free parsed settings */
    if (rdp_client->settings != NULL)
        guac_rdp_settings_free(rdp_client->settings);

    /* Clean up clipboard */
    guac_rdp_clipboard_free(rdp_client->clipboard);

    /* Free display update module */
    guac_rdp_disp_free(rdp_client->disp);

    /* Clean up filesystem, if allocated */
    if (rdp_client->filesystem != NULL)
        guac_rdp_fs_free(rdp_client->filesystem);

#ifdef ENABLE_COMMON_SSH
    /* Free SFTP filesystem, if loaded */
    if (rdp_client->sftp_filesystem)
        guac_common_ssh_destroy_sftp_filesystem(rdp_client->sftp_filesystem);

    /* Free SFTP session */
    if (rdp_client->sftp_session)
        guac_common_ssh_destroy_session(rdp_client->sftp_session);

    /* Free SFTP user */
    if (rdp_client->sftp_user)
        guac_common_ssh_destroy_user(rdp_client->sftp_user);

    guac_common_ssh_uninit();
#endif

    /* Clean up recording, if in progress */
    if (rdp_client->recording != NULL)
        guac_common_recording_free(rdp_client->recording);

    /* Clean up audio stream, if allocated */
    if (rdp_client->audio != NULL)
        guac_audio_stream_free(rdp_client->audio);

    /* Clean up audio input buffer, if allocated */
    if (rdp_client->audio_input != NULL)
        guac_rdp_audio_buffer_free(rdp_client->audio_input);

    /* Free client data */
    free(rdp_client);

    return 0;

}