/*
 * ZeroTier One - Network Virtualization Everywhere
 * Copyright (C) 2011-2015  ZeroTier, Inc.
 *
 * 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/>.
 *
 * --
 *
 * ZeroTier may be used and distributed under the terms of the GPLv3, which
 * are available at: http://www.gnu.org/licenses/gpl-3.0.html
 *
 * If you would like to embed ZeroTier into a commercial application or
 * redistribute it in a modified binary form, please contact ZeroTier Networks
 * LLC. Start here: http://www.zerotier.com/
 */

#if defined(__ANDROID__)
    #include <jni.h>
#endif

#include <dlfcn.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <pthread.h>

#include "OneService.hpp"
#include "Utils.hpp"
#include "OSUtils.hpp"

#include "SDK.h"
#include "SDK_Debug.h"
#include "SDK_ServiceSetup.hpp"

std::string service_path;
pthread_t intercept_thread;
int * intercept_thread_id;
pthread_key_t thr_id_key;
static ZeroTier::OneService *volatile zt1Service;

std::string localHomeDir; // Local shortened path
std::string givenHomeDir; // What the user/application provides as a suggestion
std::string homeDir; // The resultant platform-specific dir we *must* use internally
std::string netDir;

bool rpcEnabled;
std::string rpcNWID;

#ifdef __cplusplus
extern "C" {
#endif

void zt_init_rpc(const char * path, const char * nwid);

#if defined(__UNITY_3D__)
    // .NET Interop-friendly debug mechanism
    typedef void (*FuncPtr)( const char * );
    FuncPtr Debug;
    void SetDebugFunction( FuncPtr fp ) { Debug = fp; }
    
    // Starts a ZeroTier service at the given path
    void unity_start_service(char * path, int len) {
        std::string dstr = std::string(path);
        dstr = "unity_start_service(): path = " + dstr; 
        Debug(dstr.c_str());
        init_service(INTERCEPT_DISABLED, path);
    }
    // Starts a ZeroTier service and RPC
    void unity_start_service_and_rpc(char * path, char *nwid, int len) {
        std::string dstr = std::string(path);
        dstr = "unity_start_service_and_rpc(): path = " + dstr; 
        Debug(dstr.c_str());
        init_service_and_rpc(INTERCEPT_DISABLED, path, nwid);
    }
#endif
    
    void join_network(const char * nwid)
    {
        std::string confFile = zt1Service->givenHomePath() + "/networks.d/" + nwid + ".conf";
        LOGV("writing conf file = %s\n", confFile.c_str());
        if(!ZeroTier::OSUtils::mkdir(netDir)) {
            LOGV("unable to create %s\n", netDir.c_str());
        }
        if(!ZeroTier::OSUtils::writeFile(confFile.c_str(), "")) {
            LOGV("unable to write network conf file: %s\n", confFile.c_str());
        }
        // This provides the shim API with the RPC information
        zt_init_rpc(homeDir.c_str(), nwid); 
    }
    
    void leave_network(const char *nwid) { zt1Service->leave(nwid); }
    void zt_join_network(const char * nwid) { join_network(nwid); }
    void zt_leave_network(const char * nwid) { leave_network(nwid); }
    bool zt_is_running() { return zt1Service->isRunning(); }
    void zt_terminate() { zt1Service->terminate(); }


// Android JNI wrapper
#if defined(__ANDROID__)
    // JNI naming convention: Java_PACKAGENAME_CLASSNAME_METHODNAME
    JNIEXPORT void JNICALL Java_ZeroTier_SDK_joinNetwork(JNIEnv *env, jobject thisObj, jstring nwid) {
        const char *nwidstr;
        if(nwid) {
            nwidstr = env->GetStringUTFChars(nwid, NULL);
            zt_join_network(nwidstr);
        }
    }
    // JNI naming convention: Java_PACKAGENAME_CLASSNAME_METHODNAME
    JNIEXPORT void JNICALL Java_ZeroTier_SDK_leaveNetwork(JNIEnv *env, jobject thisObj, jstring nwid) {
        const char *nwidstr;
        if(nwid) {
            nwidstr = env->GetStringUTFChars(nwid, NULL);
            zt_leave_network(nwidstr);
        }
    }
    // JNI naming convention: Java_PACKAGENAME_CLASSNAME_METHODNAME
    JNIEXPORT jboolean JNICALL Java_ZeroTier_SDK_isRunning(JNIEnv *env, jobject thisObj) {
        if(zt1Service)
            return  zt1Service->isRunning();
        return false;
    }

    // JNI naming convention: Java_PACKAGENAME_CLASSNAME_METHODNAME
    JNIEXPORT void JNICALL Java_ZeroTier_SDK_terminate(JNIEnv *env, jobject thisObj) {
        if(zt1Service)
            zt1Service->terminate();
    }
#endif

    
// Typically used on iOS/OSX 
#if !defined(__ANDROID__)
    /*
     * Starts a service thread and performs basic setup tasks
     */
    void init_service(int key, const char * path) {
        givenHomeDir = path;
        pthread_key_create(&thr_id_key, NULL);
        intercept_thread_id = (int*)malloc(sizeof(int));
        *intercept_thread_id = key;
        pthread_create(&intercept_thread, NULL, startOneService, (void *)(intercept_thread_id));
    }
    void init_service_and_rpc(int key, const char * path, const char * nwid) {
        rpcEnabled = true;
        rpcNWID = nwid;
        init_service(key, path);
    }
    /*
     * Enables or disables intercept for current thread using key in thread-local storage
     */
    void set_intercept_status(int mode) {
        fprintf(stderr, "set_intercept_status(mode=%d): tid = %d\n", mode, pthread_mach_thread_np(pthread_self()));
        pthread_key_create(&thr_id_key, NULL);
        intercept_thread_id = (int*)malloc(sizeof(int));
        *intercept_thread_id = mode;
        pthread_setspecific(thr_id_key, intercept_thread_id);
    }
#endif

/*
 * Starts a new service instance
 */
#if defined(__ANDROID__)
    // JNI naming convention: Java_PACKAGENAME_CLASSNAME_METHODNAME
    JNIEXPORT void JNICALL Java_ZeroTier_SDK_startOneService(JNIEnv *env, jobject thisObj, jstring path) {
        if(path) {
            homeDir = env->GetStringUTFChars(path, NULL);
        }
#else
        void *startOneService(void *thread_id) {
#endif

    #if defined(SDK_BUNDLED) && !defined(__ANDROID__)
        // Don't intercept network calls originating from ZeroTier service
        set_intercept_status(INTERCEPT_DISABLED);
    #endif

        #if defined(__UNITY_3D__)
            int MAX_DIR_SZ = 256;
            char current_dir[MAX_DIR_SZ];
            getcwd(current_dir, MAX_DIR_SZ);
            chdir(service_path.c_str());
            homeDir = current_dir; // homeDir shall be current dir
        #endif

        #if defined(__APPLE__)
            #include "TargetConditionals.h"
            #if TARGET_IPHONE_SIMULATOR
                // homeDir = "dont/run/this/in/the/simulator/it/wont/work";
            #elif TARGET_OS_IPHONE
                localHomeDir = "ZeroTier/One";
                std::string del = givenHomeDir.length() && givenHomeDir[givenHomeDir.length()-1]!='/' ? "/" : "";
                homeDir = givenHomeDir + del + localHomeDir;
            #endif
        #endif

        #if defined(__ANDROID__)
            /* NOTE: Since on Android devices the sdcard is formatted as fat32, we can't use this 
            location to set up the RPC unix domain socket. Rather we must use the application's 
            specific data directory given by getApplicationContext().getFilesDir() */
            //rpcDir = homeDir; // Take given homeDir as rpcDir
            //homeDir = "/sdcard/zerotier"; // Use fat32-formatted sdcard for writing network conf & supporting files
        #endif

        #if defined(__APPLE__) && !defined(__IOS__)
            homeDir = givenHomeDir;
            localHomeDir = givenHomeDir; // Used for RPC and *can* differ from homeDir on some platforms
        #endif

        LOGV("homeDir = %s", givenHomeDir.c_str());
        // Where network .conf files will be stored
        netDir = homeDir + "/networks.d";
        zt1Service = (ZeroTier::OneService *)0;
        
        // Construct path for network config and supporting service files
        if (!homeDir.length()) {
            #if defined(__ANDROID__)
                return;
            #else
                return NULL;
            #endif
        } else {
            LOGV("startOneService(): constructing path...\n");
            std::vector<std::string> hpsp(ZeroTier::Utils::split(homeDir.c_str(),ZT_PATH_SEPARATOR_S,"",""));
            std::string ptmp;
            if (homeDir[0] == ZT_PATH_SEPARATOR)
                ptmp.push_back(ZT_PATH_SEPARATOR);
            for(std::vector<std::string>::iterator pi(hpsp.begin());pi!=hpsp.end();++pi) {
                if (ptmp.length() > 0)
                    ptmp.push_back(ZT_PATH_SEPARATOR);
                ptmp.append(*pi);
                if ((*pi != ".")&&(*pi != "..")) {
                    if (!ZeroTier::OSUtils::mkdir(ptmp)) {
                        LOGV("startOneService(): home path does not exist, and could not create\n");
                    }
                }
            }
        }

        #if defined(__IOS__)
            // Go to the app's data directory so we can shorten the sun_path we bind to
            int MAX_DIR_SZ = 256;
            char current_dir[MAX_DIR_SZ];
            getcwd(current_dir, MAX_DIR_SZ);
            std::string targetDir = homeDir + "/../../";
            chdir(targetDir.c_str());
            homeDir = localHomeDir;
        #endif

        //chdir(current_dir); // Return to previous current working directory (at the request of Unity3D)
        #if defined(__UNITY_3D__)
            Debug("Starting service...\n");
        #endif

        // Initialize RPC 
        if(rpcEnabled) {
            zt_init_rpc(localHomeDir.c_str(), rpcNWID.c_str());
        }

        // Generate random port for new service instance
        unsigned int randp = 0;
        ZeroTier::Utils::getSecureRandom(&randp,sizeof(randp));
        int servicePort = 9000 + (randp % 1000);
            
        for(;;) {
            zt1Service = ZeroTier::OneService::newInstance(homeDir.c_str(),servicePort);
            switch(zt1Service->run()) {
                case ZeroTier::OneService::ONE_STILL_RUNNING: // shouldn't happen, run() won't return until done
                case ZeroTier::OneService::ONE_NORMAL_TERMINATION:
                    break;
                case ZeroTier::OneService::ONE_UNRECOVERABLE_ERROR:
                    //fprintf(stderr,"%s: fatal error: %s" ZT_EOL_S,argv[0],zt1Service->fatalErrorMessage().c_str());
                    //returnValue = 1;
                    break;
                case ZeroTier::OneService::ONE_IDENTITY_COLLISION: {
                    delete zt1Service;
                    zt1Service = (ZeroTier::OneService *)0;
                    std::string oldid;
                    //OSUtils::readFile((homeDir + ZT_PATH_SEPARATOR_S + "identity.secret").c_str(),oldid);
                    if (oldid.length()) {
                        //OSUtils::writeFile((homeDir + ZT_PATH_SEPARATOR_S + "identity.secret.saved_after_collision").c_str(),oldid);
                        //OSUtils::rm((homeDir + ZT_PATH_SEPARATOR_S + "identity.secret").c_str());
                        //OSUtils::rm((homeDir + ZT_PATH_SEPARATOR_S + "identity.public").c_str());
                    }
                }   continue; // restart!
            }
            break; // terminate loop -- normally we don't keep restarting
        }
        #if defined(__ANDROID__)
            return;
        #else
            return NULL;
        #endif
    }

#ifdef __cplusplus
}
#endif