/*
@file generation.cpp
*/

#include <cstdlib>
#include <cstring>
#include <iostream>

#include <arpa/inet.h>
#include <errno.h>
#include <malloc.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <unistd.h>

#define MAX_LEN 1024
#define PORT 5000

using namespace std;

class Generation
{
    struct sockaddr_in server;
    int sock;
    uint8_t *buffer;

   public:
    Generation(void);
    ~Generation(void);
    int gen(void);
    int reproduce(void *pic_address, int pic_size);
};

string b2a_hex(uint8_t *buffer, int len)
{
    char const hex_char[16] = {'0', '1', '2', '3', '4', '5', '6', '7',
                               '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    string ascii;
    for (int iter = 0; iter < len; iter++)
    {
        const char character = buffer[iter];
        ascii.append("\\x");
        ascii.append(&hex_char[(character & 0xF0) >> 4], 1);
        ascii.append(&hex_char[character & 0xF], 1);
    }

    return ascii;
}

Generation::Generation(void)
{
    cout << __func__ << "\n";

    struct sockaddr_in server;
    server.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    server.sin_family = AF_INET;
    server.sin_port = htons(PORT);
    sock = socket(AF_INET, SOCK_STREAM, 0);
}

Generation::~Generation(void)
{
    cout << __func__ << "\n";

    if (sock)
    {
        close(sock);
    }

    if (buffer)
    {
        free(buffer);
    }
}

int Generation::reproduce(void *pic_address, int pic_size)
{
    cout << __func__ << "\n";

    int status = 0;

    printf("{\"address\":\"%p\",\"size\":\"%d\"}\n", pic_address, pic_size);

    status = connect(sock, (struct sockaddr *)&server, sizeof(server));
    status = write(sock, pic_address, pic_size);

    status = 1;
    return status;
}

int Generation::gen(void)
{
    cout << __func__ << "\n";

    int status = 0;

    while (1)
    {
        status = connect(sock, (struct sockaddr *)&server, sizeof(server));
        if (0 == status)
        {
            cout << "connected [" << status << "]\n";
            break;
        }
    }

    buffer = (uint8_t *)calloc(1, MAX_LEN);

    while (1)
    {
        status = read(sock, buffer, MAX_LEN);
        if (0 <= status)
        {
            cout << "recv len [" << status << "]\n";
            break;
        }
    }

    cout << "recv\n" << b2a_hex(buffer, sizeof(int)) << "\n";

    int child_len = *(int *)buffer;

    cout << "seed len [" << child_len << "]\n";

    int prot = (PROT_READ | PROT_WRITE | PROT_EXEC);
    int flags = (MAP_ANON | MAP_PRIVATE);
    uint8_t *pic_buffer = (uint8_t *)mmap(NULL, child_len, prot, flags, -1, 0);

    if (MAP_FAILED == pic_buffer)
    {
        throw runtime_error("mmap fail");
    }

    int iter = child_len;
    while (1)
    {
        status = read(sock, buffer, MAX_LEN);

        if (!status)
        {
            continue;
        }

        memcpy(&pic_buffer[iter - child_len], buffer, status);

        if ((status + iter) >= child_len)
        {
            break;
        }

        iter -= status;
    }
    void (*pic_function)(void *, int, void *);
    pic_function = reinterpret_cast<void (*)(void *, int, void *)>(pic_buffer);

    cout << "child spawn\n";
    pic_function(pic_buffer, child_len, (void *)&Generation::reproduce);

    status = 1;
    return status;
}

int main(int argc, const char **argv)
{
    cout << __func__ << "\n";

    pid_t process_id;
    int status = 0;

    process_id = fork();

    if (0 == process_id)
    {
        Generation *gen = new Generation();
        status = gen->gen();
        if (status)
        {
            return 1;
        }
    }

    return 0;
}