/*
 * Android iodine client runner — uses VpnService TUN fd (no open_tun).
 */
#include <android/log.h>
#include <errno.h>
#include <jni.h>
#include <netdb.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "client.h"
#include "common.h"

#define IODINE_LOG_TAG "IodineNative"
#define ALOGI(...) __android_log_print(ANDROID_LOG_INFO, IODINE_LOG_TAG, __VA_ARGS__)
#define ALOGW(...) __android_log_print(ANDROID_LOG_WARN, IODINE_LOG_TAG, __VA_ARGS__)

static pthread_t iodine_thread;
static volatile int iodine_running;
static int iodine_dns_fd = -1;

struct iodine_run_args {
    int tun_fd;
    char nameserv_host[256];
    char topdomain[256];
    char password[33];
};

static void iodine_sighandler(int sig) {
    (void) sig;
    client_stop();
}

static void *iodine_thread_main(void *arg) {
    struct iodine_run_args *params = (struct iodine_run_args *) arg;

    int tun_fd = params->tun_fd;
    char *nameserv_host = params->nameserv_host;
    char *topdomain = params->topdomain;
    char *password = params->password;
    free(params);

    struct sockaddr_storage nameservaddr;
    int nameservaddr_len;
    int dns_fd = -1;
    int retval = 1;

    client_init();
    client_set_selecttimeout(4);
    client_set_lazymode(1);
    client_set_topdomain(topdomain);
    client_set_password(password);
    client_set_hostname_maxlen(0xFF);

    nameservaddr_len = get_addr(nameserv_host, DNS_PORT, AF_UNSPEC, 0, &nameservaddr);
    if (nameservaddr_len < 0) {
        ALOGW("nameserver lookup failed for %s", nameserv_host);
        iodine_running = 0;
        return NULL;
    }
    client_set_nameserver(&nameservaddr, nameservaddr_len);

    dns_fd = open_dns_from_host(NULL, 0, nameservaddr.ss_family, AI_PASSIVE);
    if (dns_fd < 0) {
        ALOGW("open_dns_from_host failed errno=%d", errno);
        iodine_running = 0;
        return NULL;
    }
    iodine_dns_fd = dns_fd;

    signal(SIGINT, iodine_sighandler);
    signal(SIGTERM, iodine_sighandler);

    ALOGI("iodine handshake %s via %s tun_fd=%d", topdomain, nameserv_host, tun_fd);
    if (client_handshake(dns_fd, 1, 1, 3072) != 0) {
        ALOGW("iodine handshake failed");
        goto cleanup;
    }

    ALOGI("iodine tunnel active");
    iodine_running = 1;
    client_tunnel(tun_fd, dns_fd);
    retval = 0;

cleanup:
    if (dns_fd >= 0) {
        close_dns(dns_fd);
        iodine_dns_fd = -1;
    }
    iodine_running = 0;
    ALOGI("iodine thread exit retval=%d", retval);
    return NULL;
}

static int start_iodine_thread(int tun_fd, const char *nameserv, const char *topdomain,
        const char *password) {
    if (iodine_running) {
        return 0;
    }
    struct iodine_run_args *params = calloc(1, sizeof(*params));
    if (!params) {
        return -1;
    }
    params->tun_fd = tun_fd;
    strncpy(params->nameserv_host, nameserv, sizeof(params->nameserv_host) - 1);
    strncpy(params->topdomain, topdomain, sizeof(params->topdomain) - 1);
    strncpy(params->password, password, sizeof(params->password) - 1);
    if (pthread_create(&iodine_thread, NULL, iodine_thread_main, params) != 0) {
        free(params);
        return -1;
    }
    pthread_detach(iodine_thread);
    return 0;
}

static void stop_iodine_thread(void) {
    if (!iodine_running) {
        return;
    }
    client_stop();
    if (iodine_dns_fd >= 0) {
        shutdown(iodine_dns_fd, SHUT_RDWR);
    }
    iodine_running = 0;
}

JNIEXPORT jboolean JNICALL
Java_com_foxx_androidcast_remoteaccess_IodineNative_start(
        JNIEnv *env, jclass clazz, jint tun_fd, jstring nameserv, jstring topdomain, jstring password) {
    (void) clazz;
    if (tun_fd < 0 || !nameserv || !topdomain || !password) {
        return JNI_FALSE;
    }
    const char *ns = (*env)->GetStringUTFChars(env, nameserv, NULL);
    const char *td = (*env)->GetStringUTFChars(env, topdomain, NULL);
    const char *pw = (*env)->GetStringUTFChars(env, password, NULL);
    if (!ns || !td || !pw) {
        if (ns) (*env)->ReleaseStringUTFChars(env, nameserv, ns);
        if (td) (*env)->ReleaseStringUTFChars(env, topdomain, td);
        if (pw) (*env)->ReleaseStringUTFChars(env, password, pw);
        return JNI_FALSE;
    }
    int rc = start_iodine_thread((int) tun_fd, ns, td, pw);
    (*env)->ReleaseStringUTFChars(env, nameserv, ns);
    (*env)->ReleaseStringUTFChars(env, topdomain, td);
    (*env)->ReleaseStringUTFChars(env, password, pw);
    return rc == 0 ? JNI_TRUE : JNI_FALSE;
}

JNIEXPORT void JNICALL
Java_com_foxx_androidcast_remoteaccess_IodineNative_stop(JNIEnv *env, jclass clazz) {
    (void) env;
    (void) clazz;
    stop_iodine_thread();
}

JNIEXPORT jboolean JNICALL
Java_com_foxx_androidcast_remoteaccess_IodineNative_isRunning(JNIEnv *env, jclass clazz) {
    (void) env;
    (void) clazz;
    return iodine_running ? JNI_TRUE : JNI_FALSE;
}