#include <stdio.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <exception>
#include <stdlib.h>
#include <unistd.h>
#include <augeas.h>

// set wifi client data; DHCP, IP, ...
int setWifiParameter(int DHCP, std::string sIP, std::string sSubnet, std::string sRouter){
    std::stringstream buffer;
    buffer << "/etc/network/interfaces" << std::flush; // +++ IMPORTANT: no SLASH at the end of path, otherwise it will not work but there won't be an error message
    std::string sPathExec = buffer.str();
    std::cout << "Execution path is: " << sPathExec << std::endl;

    augeas *myAug = NULL;
    std::string sPath;
    int ret = 0;
    int iMatches = 0;
    unsigned int flags = AUG_NO_MODL_AUTOLOAD;  // AUG_NO_MODL_AUTOLOAD: really do not load // AUG_NO_LOAD: do not load/scan files // 0
    const char *root = NULL; //sRoot.c_str();
    const char *path = NULL;
    char **matches = NULL;
    const char *value = NULL;
    char **pathsErrors = NULL;

    // ==================
    // Initialization of augeas
    // ==================

    std::cout << std::endl << "Here we start the initialization." << std::endl;

    // Terminal: augtool --noautoload
    // The flag is set to --noautoload in order to speed up the initialization.
    // If the flag is not set, the standard config files are loaded which takes a while.
    // The commands after aug_init() then set the specific files which should be loaded.
    myAug = aug_init(root, "/usr/share/augeas/lenses", flags);

    // Set lens which should be loaded
    // Terminal: augtool> set /augeas/load/Interfaces/lens "Interfaces.lns"
    ret = aug_set(myAug, "/augeas/load/Interfaces/lens", "Interfaces.lns");
    std::cout << "Set lens: " << ret << std::endl;

    // Set incl(ude) path which should be parsed
    // Terminal: augtool> set /augeas/load/Interfaces/incl "/etc/network/interfaces"
    path = sPathExec.c_str();
    ret = aug_set(myAug, "/augeas/load/Interfaces/incl", path);
    std::cout << "Set incl: " << ret << std::endl;

    // Load/parse config files
    // Terminal: augtool> load
    ret = aug_load(myAug);
    std::cout << "Load augeas: " << ret << std::endl;

    // Reading and showing error messages
    iMatches = aug_match(myAug, "/augeas//error/*", &pathsErrors);
    std::cout << "Number of errors: " << std::to_string(iMatches) << std::endl;
    for (int j = 0; j < iMatches; j++) {
        ret = aug_get(myAug, pathsErrors[j], &value);
        std::cout << pathsErrors[j] << std::endl;
        if (value!=NULL){
            std::cout << value << std::endl;
        }else{
            std::cout << "Null" << std::endl;
        }
    }

    // ==================
    // Checking for specific nodes
    // ==================

    std::cout << std::endl << "Here we start searching for a specific node." << std::endl;

    // Check for matches
    sPath= "/files" + sPathExec + "/iface";
    path = sPath.c_str();
    iMatches = aug_match(myAug, path, &matches);
    std::cout << "Number of matches: " << iMatches << std::endl;

    // Check which network interface is the wifi interface (wlan0)
    // todo: simplify by using XPath
    int iWlanInterface = -1;

    std::cout << "The following paths have been found:" << std::endl;

    for (int i=1; i<=iMatches; i++){
        sPath = "/files" + sPathExec + "/iface[" + std::to_string(i) + "]";
        std::cout << sPath << std::endl;
        path = sPath.c_str();
        const char *value;
        ret = aug_get(myAug, path, &value);  // todo: ret has to be 1, otherwise value is NULL
        if (ret==1){
            buffer.str(std::string()); // clear stream "buffer"
            buffer << value << std::flush;
            if (buffer.str()=="wlan0"){
                iWlanInterface = i;
                std::cout << "Interface number of wlan0: " << std::to_string(iWlanInterface) << std::endl;
            }
        }else{
            std::cout << "no value" << std::endl;
        }
    }

    // ==================
    // Changing value of nodes
    // ==================

    std::cout << std::endl << "Here we start changing the value of the node."  <<std::endl;

    // Reading values before changing
    sPath= "/files" + sPathExec + "/iface[" + std::to_string(iWlanInterface) + "]/method";
    path = sPath.c_str();
    ret = aug_get(myAug, path, &value);
    std::cout << "The value read from node before changing: " << value << std::endl;

    // Terminal: augtool > set /files/home/pi/AugeasDemoC/network/interfaces/iface[3]/method dhcp
    sPath= "/files" + sPathExec + "/iface[" + std::to_string(iWlanInterface) + "]/method";
    path = sPath.c_str();
    ret = aug_set(myAug, path, "dhcp");
    std::cout << "Set value: " << ret << std::endl;

    // Reading version of augeas
    ret = aug_get(myAug, "/augeas/version", &value);
    std::cout << "Augeas version: " << value << std::endl;

    // Reading values; just for debugging
    sPath= "/files" + sPathExec + "/iface[" + std::to_string(iWlanInterface) + "]/method";
    path = sPath.c_str();
    ret = aug_get(myAug, path, &value);
    std::cout << "The value read from node after changing: " << value << std::endl;

    // ==================
    // Saving changes back to file
    // ==================

    std::cout << std::endl << "Here we start saving changes back to files." << std::endl;

    // Set the save mode: overwrite/backup/newfile/noop
    ret = aug_set(myAug, "/augeas/save", "overwrite");
    std::cout << "Save mode set: " << ret << std::endl;

    // Reading and showing saved files
    // Terminal: augtool> print /augeas/events/saved
    char **pathSaved= NULL;
    ret = aug_match(myAug, "/augeas/events/saved", &pathSaved);
    std::cout << "Number of changed files: " << std::to_string(ret) << std::endl;
    for (int j = 0; j < ret; j++) {
        aug_get(myAug, pathSaved[j], &value);
        std::cout << pathSaved[j] << std::endl;
    }

    // Save the changed config files
    // Terminal: augtool > save
    ret = aug_save(myAug);
    std::cout << "File saved: " << ret << std::endl;

    // Reading and showing saved files
    // Terminal: augtool> print /augeas/events/saved
    ret = aug_match(myAug, "/augeas/events/saved", &pathSaved);
    std::cout << "Number of changed files: " << std::to_string(ret) << std::endl;
    for (int j = 0; j < ret; j++) {
        aug_get(myAug, pathSaved[j], &value);
        std::cout << pathSaved[j] << std::endl;
    }

    // Reading and showing error messages
    iMatches = aug_match(myAug, "/augeas//error/*", &pathsErrors);
    std::cout << "Number of errors: " << std::to_string(iMatches) << std::endl;
    for (int j = 0; j < iMatches; j++) {
        ret = aug_get(myAug, pathsErrors[j], &value);
        std::cout << pathsErrors[j] << std::endl;
        if (value!=NULL){
            std::cout << value << std::endl;
        }else{
            std::cout << "Null" << std::endl;
        }
    }

    aug_close(myAug);

    return 0;
}

/**
 * This is the main method which creates and sets consumer instance.
 * @Looping is essential for this MQTT library to work.
 * @Exceptions on connection and subscription error.
 */
int main(int argc, char *argv[]) {

    // write config files related to wifi
    int ret = setWifiParameter(1, "192.168.178.123", "255.255.255.0", "192.168.178.1");
    std::cout << "Return: " << ret << std::endl;

    return 0;
}