/******************************************************************************
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Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.
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******************************************************************************/

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/un.h>
#include <unistd.h>
#include <dirent.h>
#include <pthread.h>
#include <stdbool.h>

#include <private/android_filesystem_config.h>
#include <android/log.h>

#include <cutils/log.h>

#define MAX_FILE_SIZE 1024*1024*20

#define LOGD0(t,s) __android_log_write(ANDROID_LOG_DEBUG, t, s)

static int file_descriptor = -1;
uint32_t file_size = 0;
pthread_t snoop_client_tid = -1;
int btsnoop_socket = -1;

#define LOCAL_SOCKET_NAME "bthcitraffic"
#define BTSNOOP_PATH "/data/media/0"
#define BTSOOP_PORT 8872

//#define __SNOOP_DUMP_DBG__

static void snoop_log(const char *fmt_str, ...)
{
    static char buffer[1024];
    va_list ap;

    va_start(ap, fmt_str);
    vsnprintf(buffer, 1024, fmt_str, ap);
    va_end(ap);

    LOGD0("btsnoop_dump: ", buffer);
}

int btsnoop_file_name (char file_name[256])
{
    struct tm *tmp;
    time_t t;
    char time_string[64];

    t = time(NULL);
    tmp = localtime(&t);
    if (tmp == NULL)
    {
        snoop_log("Error : get localtime");
        return -1;
    }

    if (strftime(time_string, 64, "%Y%m%d%H%M%S", tmp) == 0)
    {
        snoop_log("Error : strftime :");
        return -1;
    }
    snprintf(file_name, 256, BTSNOOP_PATH"/hci_snoop%s.cfa", time_string);
    return 0;
}

int snoop_open_file (void)
{
    char file_name[2][256];
    int snoop_files_found = 0;
    struct DIR* p_dir;
    struct dirent* p_dirent;

    p_dir = opendir(BTSNOOP_PATH);
    if(p_dir == NULL)
    {
        snoop_log("snoop_log_open: Unable to open the Dir entry\n");
        file_descriptor = -1;
        return -1;
    }
    while ((p_dirent = readdir(p_dir)) != NULL)
    {
        int ret;

        if ((ret = strncmp(p_dirent->d_name, "hci_snoop", strlen("hci_snoop"))) == 0)
        {
            snoop_files_found++;
        }
        if (snoop_files_found > 2)
        {
            snoop_log("snoop_log_open: Error : More than two snoop files : Abort");
            file_descriptor = -1;
            return -1;
        }
        else if (ret == 0)
        {
            strlcpy(file_name[snoop_files_found - 1], p_dirent->d_name, 256);
#ifdef __SNOOP_DUMP_DBG__
            snoop_log("snoop_log_open: snoop file found : %s", file_name[snoop_files_found - 1]);
#endif //__SNOOP_DUMP_DBG__
        }
    }
    closedir(p_dir);
    if (snoop_files_found == 2)
    {
        char del_file[256];

        /* Delete the oldest File */
        if (strncmp(file_name[0], file_name[1], 256) < 0)
        {
            snprintf(del_file, 256, BTSNOOP_PATH"/%s", file_name[0]);
#ifdef __SNOOP_DUMP_DBG__
            snoop_log("snoop_log_open: old file to delete : %s", del_file);
#endif //__SNOOP_DUMP_DBG__
            unlink(del_file);
        }
        else
        {
            snprintf(del_file, 256, BTSNOOP_PATH"/%s", file_name[1]);
#ifdef __SNOOP_DUMP_DBG__
            snoop_log("snoop_log_open: old file to delete : %s", del_file);
#endif //__SNOOP_DUMP_DBG__
            unlink(del_file);
        }
    }

    if (btsnoop_file_name(file_name[0]) != 0)
    {
        snoop_log("snoop_log_open: error : could not get snoop file name !!");
        return -1;
    }

    snoop_log("snoop_log_open: new file : %s", file_name[0]);
    file_descriptor = open(file_name[0], \
                              O_WRONLY|O_CREAT|O_TRUNC, \
                              S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH);
    if (file_descriptor == -1)
    {
        snoop_log("snoop_log_open: Unable to open snoop log file\n");
        file_descriptor = -1;
        return -1;
    }

    file_size = 0;
    write(file_descriptor, "btsnoop\0\0\0\0\1\0\0\x3\xea", 16);
    return 0;
}

int snoop_connect_to_source (void)
{
    struct sockaddr_un serv_addr;

    int ret, retry_count = 0, addr_len;

    snoop_log("snoop_connect_to_source :");
    /* Create Socket to connect to BT Traffic source*/
    btsnoop_socket = socket(AF_LOCAL, SOCK_STREAM, 0);
    if (btsnoop_socket < 0)
    {
        snoop_log("Can't create client socket : %s\n", strerror(errno));
        return -1;
    }
    else
    {
        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sun_family = AF_LOCAL;
        strlcpy(&serv_addr.sun_path[1], LOCAL_SOCKET_NAME, strlen(LOCAL_SOCKET_NAME) + 1);
        addr_len =  strlen(LOCAL_SOCKET_NAME) + 1;
        addr_len += sizeof(serv_addr.sun_family);
        do
        {
            ret = connect(btsnoop_socket, &serv_addr, addr_len);
            if (ret < 0)
            {
                snoop_log("Can't connect to BT traffic source : %s\n",strerror(errno));
                retry_count++;
                sleep (1);
            }
        } while((ret < 0) && (retry_count < 10));

        if (ret < 0)
        {
            close(btsnoop_socket);
            return -1;
        }

        snoop_log("Connected to bthcitraffic : sock fd : %d", btsnoop_socket);
        return btsnoop_socket;
    }
}

int read_block (int sock, unsigned char *pBuf, int len)
{
    int bytes_recv = 0, ret;
    do
    {
#ifdef __SNOOP_DUMP_DBG__
        snoop_log("read_block : waiting to read");
#endif //__SNOOP_DUMP_DBG__

        ret = recv(sock, &pBuf[bytes_recv], len - bytes_recv, 0);
#ifdef __SNOOP_DUMP_DBG__
        snoop_log("read_block : read returned %d", ret);
#endif //__SNOOP_DUMP_DBG__
        if ( (ret == -1) && (errno != EAGAIN) )
        {
            bytes_recv = ret;
            snoop_log("Error Packet header : Connection Closed : %s\n", strerror(errno));
            break;
        }
        else if (ret == 0)
        {
            snoop_log("Disconnected from bthcitraffic : Exiting...");
            close (sock);
            break;
        }
        bytes_recv += ret;
    } while(bytes_recv < len);

#ifdef __SNOOP_DUMP_DBG__
    snoop_log("bytes read = %d", bytes_recv);
#endif //__SNOOP_DUMP_DBG__
    return bytes_recv;
}

static unsigned char read_buf[1200];

int snoop_process (int sk)
{
    int bytes_recv = 0;
    struct stat st;
    uint32_t sizeoffile = 0, length;

    if (file_descriptor == -1)
    {
        if (snoop_open_file() != 0)
        {
            return -1;
        }
    }

/*
    24 Bytes snoop Header
    Initial 4 bytes have the length of the HCI packet
    Read 8 bytes which have orignal length and included length
*/
    bytes_recv = read_block (sk, &read_buf[0], 8);
    if ((bytes_recv == 0) || (bytes_recv == -1))
    {
        snoop_log("Error in reading the Header : ");
        return -1;
    }

    length = read_buf[0] << 24 | read_buf[1] << 16 | read_buf[2] << 8 | read_buf[3];

#if 1
#ifdef __SNOOP_DUMP_DBG__
    snoop_log("Length of Frame %ld : byte %0x %0x %0x %0x", length,
        read_buf[0], read_buf[1], read_buf[2], read_buf[3]);

    snoop_log("File Size = %d", file_size);
#endif //__SNOOP_DUMP_DBG__

    if (file_size > MAX_FILE_SIZE)
    {
        if (file_descriptor != -1)
        {
            close(file_descriptor);
            file_descriptor = -1;
            if (snoop_open_file() != 0)
            {
                return -1;
            }
        }
    }
#endif

/*
    Read rest of snoop header(16 Bytes) and HCI Packet
*/
    bytes_recv = read_block (sk, &read_buf[8], length + 16);
    if ((bytes_recv == 0) || (bytes_recv == -1))
    {
        snoop_log("Error reading snoop packet : ");
        return -1;
    }

    file_size += (bytes_recv + 8);

    write(file_descriptor, read_buf, bytes_recv + 8);

    return 0;
}

void *snoop_dump_thread( void *context)
{
    int sk, ret, bytes_recv;

    snoop_log ("snoop_dump_thread starting");

    sk = snoop_connect_to_source();

/*
       16 Bytes : Read and discard snoop file header
*/
    bytes_recv = read_block (sk, &read_buf[0], 16);
    if ((bytes_recv == 0) || (bytes_recv == -1))
    {
        snoop_log("Error in reading the snoop file Header : ");
        exit(0);
    }

    if (snoop_open_file() != 0)
    {
        exit(0);
    }

    if (sk != -1)
    {
        do
        {
            ret = snoop_process(sk);
        } while(ret != -1);
    }

    snoop_log("snoop_dump_thread  terminated");
    return NULL;
}

void start_snoop_logging ()
{
    bool snoop_thread_valid = false;

    snoop_log("starting snoop logging");
    snoop_thread_valid = (pthread_create(&snoop_client_tid, NULL, snoop_dump_thread, NULL) == 0);

    if (!snoop_thread_valid) {
        snoop_log("pthread_create failed: %s", strerror(errno));
    } else {
        snoop_log(" snoop_dump_thread is initialized");
    }
}

static void close_fd(int *fd) {
  if (*fd != -1) {
    close(*fd);
    *fd = -1;
  }
}

void snoop_thread_cleanup()
{
  close_fd(&file_descriptor);
  if (btsnoop_socket != -1) {
    shutdown(btsnoop_socket, SHUT_RDWR);
    close_fd(&btsnoop_socket);
  }
}

void stop_snoop_logging ()
{
  if ( snoop_client_tid != -1)
  {
    snoop_log(" stop_snoop_logging is called");
    snoop_thread_cleanup();
    pthread_join(snoop_client_tid, NULL);
    snoop_client_tid = -1;
  }
}