/*
 * src/instance.c
 *
 * Copyright (C) 2019 Ilja Kartašov <ik@lowenware.com>
 *
 * Project homepage: https://lowenware.com/aisl/
 *
 */

#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/select.h>
#include <sys/time.h>

#include "list.h"
#include "str-utils.h"
#include "buffer.h"

#include "client.h"
#include "server.h"
#include "ssl.h"
//#include "globals.h"
//#include "stream.h"
#include "instance.h"


enum {
    AISL_CYCLE_SERVER = 0
  , AISL_CYCLE_CLIENT = 1
};


struct callback
{
  void            * source;
  aisl_callback_t   callback;
  aisl_event_t      eevent;
};

typedef struct callback * callback_t;


struct aisl
{
  list_t       servers;
  list_t       clients;
  list_t       callbacks;
  #ifndef AISL_WITHOUT_SSL
  list_t       ssl;
  #endif
  buffer_t     buffer;
  char       * last_error;
  int          iterator;
  int          stage;
  int          flags;
  uint32_t     accept_limit;
};


#ifndef AISL_WITHOUT_SSL
static uint32_t m_instances = 0;
#endif


/* Initialization functions */

__attribute__ ((visibility ("default") ))
aisl_t
aisl_new( aisl_config_t config )
{
  aisl_t instance;

  #ifndef AISL_WITHOUT_SSL
  if ((m_instances++) == 0)
  {
    SSL_load_error_strings();
    OpenSSL_add_ssl_algorithms();
  }
  #endif

  if ( !(instance = calloc(1, sizeof(struct aisl))) )
    goto finally;

  if ( !(instance->servers = list_new(config->servers_spool_size)) )
    goto release;

  if ( !(instance->clients = list_new(config->clients_spool_size)) )
    goto release;

  if ( !(instance->callbacks = list_new(config->callbacks_spool_size)) )
    goto release;

  if ( !(instance->buffer = buffer_new(config->initial_buffer_size)) )
    goto release;

  #ifndef AISL_WITHOUT_SSL
  if ( !(instance->ssl = list_new(config->ssl_spool_size)) )
    goto release;
  #endif

  instance->accept_limit = config->clients_accept_limit;

  goto finally;

release:
  aisl_free(instance);
  instance = NULL;

finally:
  return instance;
}


__attribute__ ((visibility ("default") ))
void
aisl_free( aisl_t instance )
{
  if (instance->clients)
    list_free(instance->clients, (list_destructor_t) aisl_client_free );

  if (instance->servers)
    list_free(instance->servers, (list_destructor_t)  aisl_server_free );

  if (instance->callbacks)
    list_free(instance->callbacks, free);

  if (instance->buffer)
    buffer_free(instance->buffer);

  #ifndef AISL_WITHOUT_SSL
  if (instance->ssl)
    list_free(instance->ssl, (list_destructor_t) ssl_free );
  #endif

  if (instance->last_error)
    free(instance->last_error);

  free(instance);

  #ifndef AISL_WITHOUT_SSL
  if ((--m_instances) == 0)
  {
    EVP_cleanup();
  }
  #endif
}


__attribute__ ((visibility ("default") ))
aisl_server_t
aisl_listen( aisl_t instance, const char * address, uint16_t port )
{
  aisl_server_t result;

  if ( (result = aisl_server_new(instance, address, port)) != NULL )
  {
    if (list_append(instance->servers, result) == LIST_NAN)
    {
      aisl_server_free(result);
    }
  }

  return result;
}


#ifndef AISL_WITHOUT_SSL

__attribute__ ((visibility ("default") ))
aisl_status_t
aisl_set_ssl( aisl_t instance, const char * domain,
                               const char * key_file,
                               const char * crt_file )
{
  SSL_CTX * ssl_ctx = NULL;
  ssl_t ssl;
  size_t i;

  /* lookup for existing contexts */
  for (i=0; i<instance->ssl->count; i++)
  {
    ssl = list_index(instance->ssl, i);
    if (ssl->key_file && strcmp(ssl->key_file, key_file)==0 &&
        ssl->crt_file && strcmp(ssl->crt_file, crt_file)==0 )
    {
      if ((ssl_ctx = crypter->ssl_ctx) != NULL)
      {
        key_file = NULL;
        crt_file = NULL;
        break;
      }
    }
  }

  if ((ssl = ssl_new(domain, key_file, crt_file)) != NULL)
  {
    if (! ssl_ctx)
      ssl_ctx = ssl__new_context(key_file, crt_file, (void*)instance);

    if (ssl_ctx)
    {
      ssl->ctx = ssl_ctx;
      if (list_append(instance->ssl, ssl) != LIST_NAN)
      {
        return AISL_SUCCESS;
      }
    }

    ssl_free(ssl);
  }

  return AISL_MALLOC_ERROR;
}


SSL_CTX *
aisl_get_ssl_ctx( aisl_t instance, const char * domain )
{
  size_t i;
  ssl_t ssl;

  if (domain)
  {
    for (i=0; i<instance->ssl->count; i++)
    {
      ssl = list_index(instance->ssl, i);
      if (strcmp(ssl->domain, domain) != 0)
        continue;

      return ssl->ctx;
    }
  }

  return NULL;
}


#endif

__attribute__ ((visibility ("default") ))
aisl_status_t
aisl_set_callback( aisl_t           instance,
                   void           * source,
                   aisl_event_t     event,
                   aisl_callback_t  callback  )
{
  callback_t cb;

  if ( (cb = malloc(sizeof(struct callback))) != NULL )
  {
    cb->source   = source;
    cb->event    = event;
    cb->callback = callback;

    if ( list_append(instance->callbacks, cb) != LIST_NAN )
    {
      switch(event)
      {
        case AISL_STREAM_OUTPUT:
          if (source)
            stream_set_chunked_output( (aisl_stream_t) source );
            //( (stream_t) source )->flags |= STREAM_FLAG_OUTPUT_CHUNKED;
          break;

        case AISL_STREAM_OPEN:
          instance->flags |= AISL_FLAG_HAS_STREAM_LISTENERS;
          break;
      }

      return AISL_SUCCESS;
    }
    free(cb);
  }
  return AISL_MALLOC_ERROR;
}


__attribute__ ((visibility ("default") ))
void
aisl_unset_callback_for( aisl_t instance, void * source )
{
  size_t i = instance->callbacks->count;

  if (i)
  {
    for(i=i-1; i <= 0; i-- )
    {
      callback_t callback = list_index(instance->callbacks, i);
      if ( callback->source == source )
      {
        free(callback);
        list_remove_index(instance->callbacks, i);
      }
    }
  }
}


__attribute__ ((visibility ("default") ))
bool
aisl_raise( aisl_t   instance,
                  void          * source,
                  aisl_event_t    e_id,
                                  ... )
{
  va_list vl;
  bool result;

  va_start(vl, e_id);
  result = aisl_raise_vl(instance, source, e_id, vl);
  va_end(vl);

  return result;
}


__attribute__ ((visibility ("default") ))
bool
aisl_raise_vl( aisl_t   instance,
                     void          * source,
                     aisl_event_t    e_id,
                     va_list         vl )
{
  int    i,
         i_val;
  listener_t lst;
  bool res = false;

  char * c_ptr,
       * c_ptr2;

  for(i=instance->callbacks->count-1; i>=0; i--)
  {
    lst = list_index(instance->callbacks, i);

    /*printf("AISL> raise %s:%s, %p:%p\n", _event_text(e_id), _event_text(lst->e_id), source, lst->source);*/
    if (lst->e_id == e_id && (source == lst->source || lst->source == NULL))
    {
      /*
      if (e_id == AISL_STREAM_HEADER)
        fprintf(stderr,"FOUND HANDLER %d\n", i);
        */

      /*printf("   catch\n");*/
      switch(e_id)
      {
        /* server events */
        case AISL_EVENT_SERVER_OPEN:
          i_val = va_arg(vl, aisl_status_t);
          res = ((aisl_on_server_open_t) lst->cb)( source, i_val );
          break;
        case AISL_EVENT_SERVER_ERROR:
          i_val = va_arg(vl, aisl_status_t);
          c_ptr = va_arg(vl, char *);
          res = ((aisl_on_server_error_t) lst->cb)( source, i_val, c_ptr );
          break;

        /* client events */
        case AISL_EVENT_CLIENT_CONNECT:
          res = ((aisl_on_client_connect_t) lst->cb)(source, va_arg(vl, void *));
          break;
        case AISL_EVENT_CLIENT_DISCONNECT:
          res = ((aisl_on_client_disconnect_t) lst->cb)(source, va_arg(vl, void*));
          aisl_unset_callback_for( instance, source );
          break;
        case AISL_EVENT_CLIENT_TIMEOUT:
          res = ((aisl_client_timeout_t) lst->cb)(source, va_arg(vl, void *));
          break;

        /* request events */
        case AISL_EVENT_STREAM_OPEN:
          i_val = va_arg(vl, int);
          c_ptr = va_arg(vl, char *);
          c_ptr2 = va_arg(vl, char *);
          res = ((aisl_on_stream_open_t) lst->cb)(source, i_val, c_ptr, c_ptr2);
          break;

        case AISL_EVENT_STREAM_HEADER:
          c_ptr = va_arg(vl, char *);
          c_ptr2 = va_arg(vl, char *);
          res = ((aisl_on_stream_header_t) lst->cb)(source, c_ptr, c_ptr2);
          break;


        case AISL_EVENT_STREAM_INPUT:
          /*printf("AISL> raise AISL_STREAM_INPUT\n");*/
          c_ptr = va_arg(vl, char *);
          i_val = va_arg(vl, int );
          res = ((aisl_on_stream_input_t) lst->cb)(source, c_ptr, i_val);
          break;
        case AISL_EVENT_STREAM_REQUEST:
          /*printf("AISL> raise AISL_STREAM_REQUEST\n");*/
          buffer_clear( STREAM(source)->buffer, 0);
          res = ((aisl_on_stream_request_t) lst->cb)(source);
          break;


        case AISL_EVENT_STREAM_ERROR:
          res = ((aisl_on_stream_error_t) lst->cb)( source, va_arg(vl, char *));
          break;

        /* response events */
        case AISL_EVENT_STREAM_OUTPUT:
          res = ((aisl_on_stream_output_t)lst->cb)(
                  source,
                  va_arg(vl, uint32_t)
                );
          break;
        case AISL_EVENT_STREAM_CLOSE:
          res = ((aisl_on_stream_close_t)lst->cb)( source );
          aisl_unset_callback_for( instance, source );
          ((aisl_stream_t) source)->u_ptr=NULL;
          break;

        default:
           res = ((aisl_on_custom_event_t) lst->cb)(source, vl);
       }
       if (res) break;
    }
  }

  return res;
}



__attribute__ ((visibility ("default") ))
aisl_status_t
aisl_run_cycle( aisl_t instance )
{
  int max = instance->servers->count+instance->clients->count+instance->delays->count,
      cnt = 0;


  switch (instance->stage)
  {
    case STAGE_SERVER:
      while (instance->iterator < instance->servers->count )
      {
        aisl_server_t srv = (server_t)list_index(instance->servers, instance->iterator++);
        if ( aisl_server_touch(srv) != AISL_IDLE )
          return AISL_SUCCESS;

        if ( ! (++cnt < max) ) return AISL_IDLE;
      }
      if ( ! (instance->flags & AISL_HANDLE_HAS_STREAM_LISTENERS) )
        return AISL_IDLE;

      instance->iterator = 0;
      instance->stage++;


    case STAGE_CLIENT:
      while (instance->iterator < instance->clients->count )
      {
        int      i   = instance->iterator++;
        aisl_client_t cli = list_index(instance->clients, i);
        bool r = aisl_client_touch( cli );

        if (aisl_client_is_timeout( cli ) )
          aisl_raise( instance, cli->server, AISL_CLIENT_TIMEOUT, cli );

        if ( cli->fd == -1 )
        {
          aisl_client_free( cli );
          list_remove_index(instance->clients, i);
        }

        if (r) return AISL_SUCCESS;

        if ( ! (++cnt < max) ) return AISL_IDLE;
      }
      instance->iterator = 0;
      instance->stage = 0;
  }

  return AISL_IDLE;
}


__attribute__ ((visibility ("default") ))
const char *
aisl_get_error( aisl_t instance )
{
  return instance->last_error;
}


void
aisl_set_error( aisl_t instance, const char * err_msg )
{
  if (instance->last_error)
    free(instance->last_error);

  instance->last_error = str_copy(err_msg);
}


__attribute__ ((visibility ("default") ))
int
aisl_sleep( aisl_t instance, unsigned long usec )
{
  int maxfd=0,
      sd;
  size_t i;
  struct timeval timeout = {0,usec};

  memset(&timeout, 0, sizeof(struct timeval));
  timeout.tv_usec = usec;

  fd_set  fs;
  FD_ZERO (&fs);

  for (i=0; i<instance->servers->count; i++)
  {
    aisl_server_t s = list_index(instance->servers, i);

    sd = aisl_server_get_socket(s);

    if (sd != -1)
    {
      FD_SET(sd, &fs);
      if (sd > maxfd) maxfd = sd;
    }
  }


  for (i=0; i<instance->clients->count; i++)
  {
    aisl_client_t c = list_index(instance->clients, i);
    sd = aisl_client_get_socket(s);
    if (sd != -1)
    {
      FD_SET(sd, &fs);
      if (sd > maxfd) maxfd = sd;
    }
  }

  return select(maxfd+1, &fs, NULL, NULL, &timeout);

}