// Copyright (c) 2014 Cesanta Software Limited
// All rights reserved
//
// This software is dual-licensed: you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation. For the terms of this
// license, see <http://www.gnu.org/licenses/>.
//
// You are free to use this software under the terms of the GNU General
// Public License, 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.
//
// Alternatively, you can license this software under a commercial
// license, as set out in <http://cesanta.com/>.
//
// $Date: 2014-09-09 17:09:33 UTC $

#ifndef NS_SKELETON_HEADER_INCLUDED
#define NS_SKELETON_HEADER_INCLUDED

#define NS_SKELETON_VERSION "2.0.0"

#undef UNICODE                  // Use ANSI WinAPI functions
#undef _UNICODE                 // Use multibyte encoding on Windows
#define _MBCS                   // Use multibyte encoding on Windows
#define _INTEGRAL_MAX_BITS 64   // Enable _stati64() on Windows
#define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005+
#undef WIN32_LEAN_AND_MEAN      // Let windows.h always include winsock2.h
#define _XOPEN_SOURCE 600       // For flockfile() on Linux
#define __STDC_FORMAT_MACROS    // <inttypes.h> wants this for C++
#define __STDC_LIMIT_MACROS     // C++ wants that for INT64_MAX
#ifndef _LARGEFILE_SOURCE
#define _LARGEFILE_SOURCE       // Enable fseeko() and ftello() functions
#endif
#define _FILE_OFFSET_BITS 64    // Enable 64-bit file offsets

#ifdef _MSC_VER
#pragma warning (disable : 4127)  // FD_SET() emits warning, disable it
#pragma warning (disable : 4204)  // missing c99 support
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <signal.h>

#ifdef _WIN32
#ifdef _MSC_VER
#pragma comment(lib, "ws2_32.lib")    // Linking with winsock library
#endif
#include <windows.h>
#include <process.h>
#ifndef EINPROGRESS
#define EINPROGRESS WSAEINPROGRESS
#endif
#ifndef EWOULDBLOCK
#define EWOULDBLOCK WSAEWOULDBLOCK
#endif
#ifndef __func__
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ __FILE__ ":" STR(__LINE__)
#endif
#ifndef va_copy
#define va_copy(x,y) x = y
#endif // MINGW #defines va_copy
#define snprintf _snprintf
#define vsnprintf _vsnprintf
#define sleep(x) Sleep((x) * 1000)
#define to64(x) _atoi64(x)
typedef int socklen_t;
typedef unsigned char uint8_t;
typedef unsigned int uint32_t;
typedef unsigned short uint16_t;
typedef unsigned __int64 uint64_t;
typedef __int64   int64_t;
typedef SOCKET sock_t;
#ifndef S_ISDIR
#define S_ISDIR(x) ((x) & _S_IFDIR)
#endif
#else
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pthread.h>
#include <stdarg.h>
#include <unistd.h>
#include <arpa/inet.h>  // For inet_pton() when NS_ENABLE_IPV6 is defined
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/select.h>
#define closesocket(x) close(x)
#define __cdecl
#define INVALID_SOCKET (-1)
#define to64(x) strtoll(x, NULL, 10)
typedef int sock_t;
#endif

#ifdef NS_ENABLE_DEBUG
#define DBG(x) do { printf("%-20s ", __func__); printf x; putchar('\n'); \
  fflush(stdout); } while(0)
#else
#define DBG(x)
#endif

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
#endif

#ifdef NS_ENABLE_SSL
#ifdef __APPLE__
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
#include <openssl/ssl.h>
#else
typedef void *SSL;
typedef void *SSL_CTX;
#endif

#ifdef __cplusplus
extern "C" {
#endif // __cplusplus

union socket_address {
  struct sockaddr sa;
  struct sockaddr_in sin;
#ifdef NS_ENABLE_IPV6
  struct sockaddr_in6 sin6;
#else
  struct sockaddr sin6;
#endif
};

// IO buffers interface
struct iobuf {
  char *buf;
  size_t len;
  size_t size;
};

void iobuf_init(struct iobuf *, size_t initial_size);
void iobuf_free(struct iobuf *);
size_t iobuf_append(struct iobuf *, const void *data, size_t data_size);
void iobuf_remove(struct iobuf *, size_t data_size);

// Net skeleton interface
// Events. Meaning of event parameter (evp) is given in the comment.
enum ns_event {
  NS_POLL,     // Sent to each connection on each call to ns_mgr_poll()
  NS_ACCEPT,   // New connection accept()-ed. union socket_address *remote_addr
  NS_CONNECT,  // connect() succeeded or failed. int *success_status
  NS_RECV,     // Data has benn received. int *num_bytes
  NS_SEND,     // Data has been written to a socket. int *num_bytes
  NS_CLOSE     // Connection is closed. NULL
};

// Callback function (event handler) prototype, must be defined by user.
// Net skeleton will call event handler, passing events defined above.
struct ns_connection;
typedef void (*ns_callback_t)(struct ns_connection *, enum ns_event, void *evp);

struct ns_mgr {
  struct ns_connection *active_connections;
  ns_callback_t callback;           // Event handler function
  const char *hexdump_file;         // Debug hexdump file path
  sock_t ctl[2];                    // Socketpair for mg_wakeup()
  void *user_data;                  // User data
};

struct ns_connection {
  struct ns_connection *next, *prev;  // ns_mgr::active_connections linkage
  struct ns_connection *listener;     // Set only for accept()-ed connections
  struct ns_mgr *mgr;
  sock_t sock;
  union socket_address sa;
  struct iobuf recv_iobuf;
  struct iobuf send_iobuf;
  SSL *ssl;
  SSL_CTX *ssl_ctx;
  void *connection_data;
  time_t last_io_time;

  unsigned int flags;
#define NSF_FINISHED_SENDING_DATA   (1 << 0)
#define NSF_BUFFER_BUT_DONT_SEND    (1 << 1)
#define NSF_SSL_HANDSHAKE_DONE      (1 << 2)
#define NSF_CONNECTING              (1 << 3)
#define NSF_CLOSE_IMMEDIATELY       (1 << 4)
#define NSF_WANT_READ               (1 << 5)
#define NSF_WANT_WRITE              (1 << 6)
#define NSF_LISTENING               (1 << 7)
#define NSF_UDP                     (1 << 8)

#define NSF_USER_1                  (1 << 20)
#define NSF_USER_2                  (1 << 21)
#define NSF_USER_3                  (1 << 22)
#define NSF_USER_4                  (1 << 23)
#define NSF_USER_5                  (1 << 24)
#define NSF_USER_6                  (1 << 25)
};

void ns_mgr_init(struct ns_mgr *, void *data, ns_callback_t);
void ns_mgr_free(struct ns_mgr *);
int ns_mgr_poll(struct ns_mgr *, int milli);
void ns_broadcast(struct ns_mgr *, ns_callback_t, void *, size_t);

struct ns_connection *ns_next(struct ns_mgr *, struct ns_connection *);
struct ns_connection *ns_add_sock(struct ns_mgr *, sock_t sock, void *p);
struct ns_connection *ns_bind(struct ns_mgr *, const char *addr, void *p);
struct ns_connection *ns_connect(struct ns_mgr *, const char *addr, void *p);

int ns_send(struct ns_connection *, const void *buf, int len);
int ns_printf(struct ns_connection *, const char *fmt, ...);
int ns_vprintf(struct ns_connection *, const char *fmt, va_list ap);

// Utility functions
void *ns_start_thread(void *(*f)(void *), void *p);
int ns_socketpair(sock_t [2]);
int ns_socketpair2(sock_t [2], int sock_type);  // SOCK_STREAM or SOCK_DGRAM
void ns_set_close_on_exec(sock_t);
void ns_sock_to_str(sock_t sock, char *buf, size_t len, int flags);
int ns_hexdump(const void *buf, int len, char *dst, int dst_len);
int ns_avprintf(char **buf, size_t size, const char *fmt, va_list ap);
int ns_resolve(const char *domain_name, char *ip_addr_buf, size_t buf_len);

#ifdef __cplusplus
}
#endif // __cplusplus

#endif // NS_SKELETON_HEADER_INCLUDED