/*
 * Rangitaki Sync Library
 *
 * A program for downloading and uploading files over ssh.
 * Written for the Rangitaki blogging engine.
 *
 * Proudly written in C and with use of libssh (libssh.org)
 *
 * Version: 0.1
 *
 * COPYRIGHT (c) 2015 - 2016 The Rangitaki Project
 * COPYRIGHT (c) 2015 - 2016 Marcel Kapfer (mmk2410)
 *                           <marcelmichaelkapfer@yahoo.co.nz>
 *
 * MIT License
 *
 */

#include <libssh/libssh.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <assert.h>

#include "rangitaki-sync.h"
#include "dbg.h"

#define MAX_FILE_LENGTH 255

char * combine(char *begin, char *end){
    char *result;

    check(begin != NULL, "Begin can't be NULL.");
    check(end != NULL, "End can't be NULL.");

    size_t begin_length = strnlen(begin, MAX_FILE_LENGTH - 1);
    size_t end_length = strnlen(end, MAX_FILE_LENGTH - 1);

    assert(begin_length < MAX_FILE_LENGTH && "Got the begin too long.");
    assert(end_length < MAX_FILE_LENGTH && "Got the end to long.");

    result = malloc(begin_length + end_length + 1);
    check(result != NULL, "Failed to define result");

    strncpy(result, begin, MAX_FILE_LENGTH);
    check(result != NULL, "Failed to copy the string");

    strncat(result, end, MAX_FILE_LENGTH * 2);
    int rc = strncmp(result, begin, MAX_FILE_LENGTH * 2);
    check(rc <= 0, "Failed to concat string.");

    return result;

error:
    if (result) free(result);
    return NULL;
}

char * getFilename(char *input)
{
    check(input != NULL, "Input is NULL.");
    char* string;

    string = strdup(input);

    int buffer[100];
    int i = 0;
    int j = 0;
    for(i = 0; i <= strlen(string); i++) {
        if(string[i] == '/') {
            buffer[j] = i;
            j++;
        }
    }

    j--;
    int size = strlen(string) - buffer[j]; // Includes the \0
    char *result = malloc(size);
    strcpy(result, &string[buffer[j]+1]);
    result[size] = '\0';
    free(string);
    return result;

error:
    return NULL;
}

void ssh_initialize(const char *host, const char *user, const char *password,
        const char *remote_dir, const char *local_dir,
        const unsigned int port, ssh_data *data)
{
    data->host = strdup(host);
    data->user = strdup(user);
    data->password = strdup(password);
    data->remote_dir = strdup(remote_dir);
    data->local_dir = strdup(local_dir);
    data->port = port;
    data->verbosity = SSH_LOG_PROTOCOL;
}

int ssh_server_auth(ssh_session ssh)
{
    char *hexa;
    int state;
    unsigned char *hash = NULL;
    size_t hlen;
    ssh_key srv_pubkey;
    int rc;

    state = ssh_is_server_known(ssh);

    rc = ssh_get_publickey(ssh, &srv_pubkey);
    check(rc >= 0, "Couldn't not authenticate the server.");

    rc = ssh_get_publickey_hash(srv_pubkey,
                                SSH_PUBLICKEY_HASH_SHA1,
                                &hash,
                                &hlen);
    ssh_key_free(srv_pubkey);
    check(rc >= 0, "Couldn't not authenticate the server.");

    switch (state)
    {
        case SSH_SERVER_KNOWN_OK:
            log_info("Found host key");
            break;

        case SSH_SERVER_KNOWN_CHANGED:
            log_err("The host key of the server changed. Aborting connection.");
            ssh_print_hexa("Public key hash", hash, hlen);
            ssh_clean_pubkey_hash(&hash);
            return -1;

        case SSH_SERVER_FOUND_OTHER:
            log_err("The host key for this server was not found but an other. Aborting connection.");
            ssh_clean_pubkey_hash(&hash);
            return -1;

        case SSH_SERVER_FILE_NOT_FOUND:
            log_warn("Couldn't find known hosts file.");

        case SSH_SERVER_NOT_KNOWN:
            hexa = ssh_get_hexa(hash, hlen);
            log_info("Adding %s to known hosts.", hexa);
            free(hexa);
            if (ssh_write_knownhost(ssh) < 0) {
                log_err("Error adding server to known hosts file: %s", strerror(errno));
                ssh_clean_pubkey_hash(&hash);
                return -1;
            }
            break;

        default:
            log_err("%s", ssh_get_error(ssh));
            ssh_clean_pubkey_hash(&hash);
            return -1;
    }

    ssh_clean_pubkey_hash(&hash);
    return 0;

error:
    ssh_clean_pubkey_hash(&hash);
    return -1;
}

ssh_session ssh_open(ssh_data *data)
{
    int rc = 0;
    ssh_session ssh = ssh_new();

    if(ssh == NULL) {
        log_err("Failed th create ssh session.");
        return NULL;
    }

    if(ssh_options_set(ssh, SSH_OPTIONS_HOST, data->host) < 0) {
        ssh_free(ssh);
        log_err("Failed to set host.");
        return NULL;
    }

    if(ssh_options_set(ssh, SSH_OPTIONS_USER, data->user) < 0) {
        ssh_free(ssh);
        log_err("Failed to set user.");
        return NULL;
    }

    if(ssh_options_set(ssh, SSH_OPTIONS_PORT, &data->port)) {
        ssh_free(ssh);
        log_err("Failed to set port.");
        return NULL;
    }

    if(ssh_options_set(ssh, SSH_OPTIONS_LOG_VERBOSITY, &data->verbosity)) {
        ssh_free(ssh);
        log_err("Failed to set verbosity.");
        return NULL;
    }

    if(ssh_connect(ssh)) {
        log_err("Connection failed: %s.", ssh_get_error(ssh));
        ssh_disconnect(ssh);
        ssh_free(ssh);
        return NULL;
    }

    if(ssh_server_auth < 0) {
        log_err("Couldn't authenticate the server.");
        ssh_disconnect(ssh);
        ssh_free(ssh);
        return NULL;
    }

    rc = ssh_userauth_password(ssh, data->user, data->password);
    if(rc == SSH_AUTH_SUCCESS) {
        return ssh;
    } else if(rc == SSH_AUTH_DENIED) {
        log_err("Authentication failed.");
    } else {
        log_err("Error while authenticating");
    }

    return NULL;

}

int ssh_close(ssh_session ssh)
{
    ssh_disconnect(ssh);
    ssh_free(ssh);
    return 0;
}

ssh_scp scp_open(ssh_session ssh, ssh_data *data, int mode)
{
    int rc = 0;
    ssh_scp scp = ssh_scp_new(ssh, mode, data->remote_dir);
    check(scp != NULL, "Failed to create the scp session: %s", ssh_get_error(ssh));

    rc = ssh_scp_init(scp);
    if(rc == -1)
    {
        log_err("Failed to initialize the scp connection.");
        goto error;
    }
    check(rc == SSH_OK, "Failed to initialize the scp session: %s", ssh_get_error(ssh));

    return scp;

error:
    if(scp) ssh_scp_free(scp);
    return NULL;

}

int scp_close(ssh_scp scp)
{
    ssh_scp_close(scp);
    ssh_scp_free(scp);
    return 0;
}

int scp_download(ssh_session ssh, ssh_scp scp, ssh_data *data)
{
    int rc;
    int rv;
    int size, mode;
    char buffer[16384];
    char *local_dir = strdup(data->local_dir);

    do {
        rc = ssh_scp_pull_request(scp);

        switch (rc) {
            case SSH_SCP_REQUEST_NEWFILE:
                size = ssh_scp_request_get_size(scp);
                mode = ssh_scp_request_get_permissions(scp);
                char *filename = strdup(ssh_scp_request_get_filename(scp));
                check(filename != NULL, "Couldn't get the filename.");
                printf("DOWNLOAD: %s %d %d\n", filename, size, mode);
                char *dir = combine(local_dir, filename);
                FILE *output = fopen(dir, "w+");
                check(output != NULL, "FILE couldn't be created");
                ssh_scp_accept_request(scp);
                rc = ssh_scp_read(scp, buffer, sizeof(buffer));
                check(rc != SSH_ERROR, "Error downloading the file. %s",
                        ssh_get_error(ssh));
                rv = fwrite(buffer, size, 1, output);
                check(rv != 0, "Failed to write file");
                rv = fclose(output);
                free(dir);
                free(filename);
                check(rv == 0, "Failed to close FILE");
                printf("Done.\n");
                break;

            case SSH_ERROR:
                log_err("Error: %s", ssh_get_error(ssh));
                goto error;

            case SSH_SCP_REQUEST_WARNING:
                log_warn("Warning: %s", ssh_scp_request_get_warning(scp));
                break;

            case SSH_SCP_REQUEST_NEWDIR:
                filename = strdup(ssh_scp_request_get_filename(scp));
                mode = ssh_scp_request_get_permissions(scp);
                printf("DOWNLOAD: %s %d\n", filename, mode);
                ssh_scp_accept_request(scp);
                break;

            case SSH_SCP_REQUEST_ENDDIR:
                break;

            case SSH_SCP_REQUEST_EOF:
                log_info("DONE");
                return 0;

        }
    } while (1);

error:
    return -1;
}

int scp_upload(ssh_session ssh, ssh_scp scp, ssh_data *data)
{
    int rc = 0;
    FILE *fisz = fopen(data->local_dir, "rb");
    fseek(fisz, 0L, SEEK_END);
    int size = ftell(fisz);
    fclose(fisz);

    rc = ssh_scp_push_file64(scp, getFilename(data->local_dir), size,
            S_IRUSR |  S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH);
    check(rc == SSH_OK, "Failed to create file: %s", ssh_get_error(ssh));

    char *buffer = malloc(size + 100);
    FILE *file = fopen(data->local_dir, "r");
    check(file != NULL, "Error opening local file.");
    rc = 0;
    rc = fread(buffer, size, 1, file);
    rc = ssh_scp_write(scp, buffer, size);
    check(rc == SSH_OK, "Error while writing remote file: %s", ssh_get_error(ssh));

    return 0;

error:
    return -1;
}