/* The Ebb Web Server
 * Copyright (c) 2008 Ry Dahl. This software is released under the MIT 
 * License. See README file for details.
 */
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include <sys/un.h>
#include <netdb.h>
 
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <assert.h>
 
#include <pthread.h>
#include <glib.h>
 
#define EV_STANDALONE 1
#include <ev.c>
 
#include "parser.h"
#include "ebb.h"
 
#define min(a,b) (a < b ? a : b)
#define ramp(a) (a > 0 ? a : 0)
 
static int server_socket_unix(const char *path, int access_mask);
 
void env_add(ebb_client *client, const char *field, int flen, const char *value, int vlen)
{
  if(client->env_size >= EBB_MAX_ENV) {
    client->parser.overflow_error = TRUE;
    return;
  }
  client->env[client->env_size].type = EBB_FIELD_VALUE_PAIR;
  client->env[client->env_size].field = field;
  client->env[client->env_size].field_length = flen;
  client->env[client->env_size].value = value;
  client->env[client->env_size].value_length = vlen;
  client->env_size += 1;
}
 
 
void env_add_const(ebb_client *client, int type, const char *value, int vlen)
{
  if(client->env_size >= EBB_MAX_ENV) {
    client->parser.overflow_error = TRUE;
    return;
  }
  client->env[client->env_size].type = type;
  client->env[client->env_size].field = NULL;
  client->env[client->env_size].field_length = -1;
  client->env[client->env_size].value = value;
  client->env[client->env_size].value_length = vlen;
  client->env_size += 1;
}
 
 
void http_field_cb(void *data, const char *field, size_t flen, const char *value, size_t vlen)
{
  ebb_client *client = (ebb_client*)(data);
  assert(field != NULL);
  assert(value != NULL);
  env_add(client, field, flen, value, vlen);
}
 
 
void request_method_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_REQUEST_METHOD, at, length);
}
 
 
void request_uri_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_REQUEST_URI, at, length);
}
 
 
void fragment_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_FRAGMENT, at, length);
}
 
 
void request_path_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_REQUEST_PATH, at, length);
}
 
 
void query_string_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_QUERY_STRING, at, length);
}
 
 
void http_version_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_HTTP_VERSION, at, length);
}
 
 
void content_length_cb(void *data, const char *at, size_t length)
{
  ebb_client *client = (ebb_client*)(data);
  env_add_const(client, EBB_CONTENT_LENGTH, at, length);
  /* atoi_length - why isn't this in the statndard library? i hate c */
  assert(client->content_length == 0);
  int i, mult;
  for(mult=1, i=length-1; i>=0; i--, mult*=10)
    client->content_length += (at[i] - '0') * mult;
}
 
 
static void dispatch(ebb_client *client)
{
  ebb_server *server = client->server;
  
  if(client->open == FALSE)
    return;
  
  /* Set the env variables */
  if(server->port) {
    env_add_const(client, EBB_SERVER_PORT
                        , server->port
                        , strlen(server->port)
                        );
  }
  client->in_use = TRUE;
  server->request_cb(client, server->request_cb_data);
}
 
 
static void on_timeout(struct ev_loop *loop, ev_timer *watcher, int revents)
{
  ebb_client *client = (ebb_client*)(watcher->data);
  
  assert(client->server->loop == loop);
  assert(&(client->timeout_watcher) == watcher);
  
  ebb_client_close(client);
#ifdef DEBUG
  g_message("peer timed out");
#endif
}
 
#define client_finished_parsing http_parser_is_finished(&client->parser)
#define total_request_size (client->content_length + client->parser.nread)
 
static void* read_body_into_file(void *_client)
{
  ebb_client *client = (ebb_client*)_client;
  static unsigned int id;
  FILE *tmpfile;
  
  assert(client->open);
  assert(client->server->open);
  assert(client->content_length > 0);
  assert(client_finished_parsing);
  
  /* set blocking socket */
  int flags = fcntl(client->fd, F_GETFL, 0);
  assert(0 <= fcntl(client->fd, F_SETFL, flags & ~O_NONBLOCK));
  
  sprintf(client->upload_file_filename, "/tmp/ebb_upload_%010d", id++);
  tmpfile = fopen(client->upload_file_filename, "w+");
  if(tmpfile == NULL) g_message("Cannot open tmpfile %s", client->upload_file_filename);
  client->upload_file = tmpfile;
  
  size_t body_head_length = client->read - client->parser.nread;
  size_t written = 0, r;
  while(written < body_head_length) {
    r = fwrite( client->request_buffer + sizeof(char)*(client->parser.nread + written)
              , sizeof(char)
              , body_head_length - written
              , tmpfile
              );
    if(r <= 0) {
      ebb_client_close(client);
      return NULL;
    }
    written += r;
  }
  
  int bufsize = 5*1024;
  char buffer[bufsize];
  size_t received;
  while(written < client->content_length) {
    received = recv(client->fd
                   , buffer
                   , min(client->content_length - written, bufsize)
                   , 0
                   );
    if(received < 0) goto error;
    client->read += received;
    
    ssize_t w = 0;
    int rv;
    while(w < received) {
      rv = fwrite( buffer + w*sizeof(char)
                 , sizeof(char)
                 , received - w
                 , tmpfile
                 );
      if(rv <= 0) goto error;
      w += rv;
    }
    written += received;
  }
  rewind(tmpfile);
  // g_debug("%d bytes written to file %s", written, client->upload_file_filename);
  dispatch(client);
  return NULL;
error:
  ebb_client_close(client);
  return NULL;
}
 
 
static void on_client_readable(struct ev_loop *loop, ev_io *watcher, int revents)
{
  ebb_client *client = (ebb_client*)(watcher->data);
  
  assert(client->in_use == FALSE);
  assert(client->open);
  assert(client->server->open);
  assert(client->server->loop == loop);
  assert(&client->read_watcher == watcher);
  
  ssize_t read = recv( client->fd
                     , client->request_buffer + client->read
                     , EBB_BUFFERSIZE - client->read
                     , 0
                     );
  if(read < 0) goto error; 
  if(read == 0) goto error; /* XXX is this the right action to take for read==0 ? */
  client->read += read;
  ev_timer_again(loop, &client->timeout_watcher);
  
  if(client->read == EBB_BUFFERSIZE) goto error;
  
  if(FALSE == client_finished_parsing) {
    http_parser_execute( &client->parser
                       , client->request_buffer
                       , client->read
                       , client->parser.nread
                       );
    if(http_parser_has_error(&client->parser)) goto error;
  }
  
  if(client_finished_parsing) {
    if(total_request_size == client->read) {
      ev_io_stop(loop, watcher);
      client->nread_from_body = 0;
      dispatch(client);
      return;
    }
    if(total_request_size > EBB_BUFFERSIZE ) {
      /* read body into file - in a thread */
      ev_io_stop(loop, watcher);
      pthread_t thread;
      assert(0 <= pthread_create(&thread, NULL, read_body_into_file, client));
      pthread_detach(thread);
      return;
    }
  }
  return;
error:
  if(read < 0) g_message("Error recving data: %s", strerror(errno));
  ebb_client_close(client);
}
 
static client_init(ebb_server *server, ebb_client *client)
{
  assert(client->in_use == FALSE);
#ifdef DEBUG
  /* does ragel fuck up if request buffer isn't null? */
  for(i=0; i< EBB_BUFFERSIZE; i++)
    client->request_buffer[i] = 'A';
#endif
  
  client->open = TRUE;
  client->server = server;
  
  /* DO SOCKET STUFF */
  socklen_t len;
  client->fd = accept(server->fd, (struct sockaddr*)&(server->sockaddr), &len);
  assert(client->fd >= 0);
  int flags = fcntl(client->fd, F_GETFL, 0);
  assert(0 <= fcntl(client->fd, F_SETFL, flags | O_NONBLOCK));
  
  /* INITIALIZE http_parser */
  http_parser_init(&(client->parser));
  client->parser.data = client;
  client->parser.http_field     = http_field_cb;
  client->parser.request_method = request_method_cb;
  client->parser.request_uri    = request_uri_cb;
  client->parser.fragment       = fragment_cb;
  client->parser.request_path   = request_path_cb;
  client->parser.query_string   = query_string_cb;
  client->parser.http_version   = http_version_cb;
  client->parser.content_length = content_length_cb;
  
  /* OTHER */
  client->env_size = 0;
  client->read = client->nread_from_body = 0;
  client->response_buffer->len = 0; /* see note in ebb_client_close */
  client->content_length = 0;
  if(client->request_buffer == NULL) {
    client->request_buffer = (char*)malloc(EBB_BUFFERSIZE);
  }
  
  client->status_written = FALSE;
  client->headers_written = FALSE;
  client->body_written = FALSE;
  client->began_transmission = FALSE;
  
  /* SETUP READ AND TIMEOUT WATCHERS */
  client->read_watcher.data = client;
  ev_init(&client->read_watcher, on_client_readable);
  ev_io_set(&client->read_watcher, client->fd, EV_READ | EV_ERROR);
  ev_io_start(server->loop, &client->read_watcher);
  
  client->timeout_watcher.data = client;  
  ev_timer_init(&client->timeout_watcher, on_timeout, EBB_TIMEOUT, EBB_TIMEOUT);
  ev_timer_start(server->loop, &client->timeout_watcher);
}
 
static void on_request(struct ev_loop *loop, ev_io *watcher, int revents)
{
  ebb_server *server = (ebb_server*)(watcher->data);
  assert(server->open);
  assert(server->loop == loop);
  assert(&server->request_watcher == watcher);
  
  if(EV_ERROR & revents) {
    g_message("on_request() got error event, closing server.");
    ebb_server_unlisten(server);
    return;
  }
  /* Now we're going to initialize the client 
   * and set up her callbacks for read and write
   * the client won't get passed back to the user, however,
   * until the request is complete and parsed.
   */
  int i;
  ebb_client *client;
  /* Get next availible peer */
  for(i=0; i < EBB_MAX_CLIENTS; i++)
    if(!server->clients[i].in_use && !server->clients[i].open) {
      client = &(server->clients[i]);
      break;
    }
  if(client == NULL) {
    g_message("Too many peers. Refusing connections.");
    return;
  }
  
#ifdef DEBUG
  int count = 0;
  for(i = 0; i < EBB_MAX_CLIENTS; i++)
    if(server->clients[i].open) count += 1;
  g_debug("%d open connections", count);
#endif
  
  client_init(server, client);
}
 
 
ebb_server* ebb_server_alloc()
{
  ebb_server *server = g_new0(ebb_server, 1);
  return server;
}
 
 
void ebb_server_init( ebb_server *server
                    , struct ev_loop *loop
                    , ebb_request_cb request_cb
                    , void *request_cb_data
                    )
{
  int i;
  for(i=0; i < EBB_MAX_CLIENTS; i++) {
    server->clients[i].request_buffer = NULL;
    server->clients[i].response_buffer = g_string_new("");
    server->clients[i].open = FALSE;
    server->clients[i].in_use = FALSE;
  }
  
  server->request_cb = request_cb;
  server->request_cb_data = request_cb_data;
  server->loop = loop;
  server->open = FALSE;
  server->fd = -1;
  return;
error:
  ebb_server_free(server);
  return;
}
 
 
void ebb_server_free(ebb_server *server)
{
  ebb_server_unlisten(server);
  
  int i; 
  for(i=0; i < EBB_MAX_CLIENTS; i++)
    g_string_free(server->clients[i].response_buffer, TRUE);
  if(server->port)
    free(server->port);
  if(server->socketpath)
    free(server->socketpath);
  free(server);
}
 
 
void ebb_server_unlisten(ebb_server *server)
{
  if(server->open) {
    int i;
    ebb_client *client;
    ev_io_stop(server->loop, &server->request_watcher);
    close(server->fd);
    if(server->socketpath)
      unlink(server->socketpath);
    server->open = FALSE;
  }
}
 
int ebb_server_listen_on_port(ebb_server *server, const int port)
{
  int sfd = -1;
  struct linger ling = {0, 0};
  struct sockaddr_in addr;
  int flags = 1;
  
  if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
    perror("socket()");
    goto error;
  }
  
  flags = fcntl(sfd, F_GETFL, 0);
  if(fcntl(sfd, F_SETFL, flags | O_NONBLOCK) < 0) {
    perror("setting O_NONBLOCK");
    goto error;
  }
  
  flags = 1;
  setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, (void *)&flags, sizeof(flags));
  setsockopt(sfd, SOL_SOCKET, SO_KEEPALIVE, (void *)&flags, sizeof(flags));
  setsockopt(sfd, SOL_SOCKET, SO_LINGER, (void *)&ling, sizeof(ling));
  setsockopt(sfd, IPPROTO_TCP, TCP_NODELAY, (void *)&flags, sizeof(flags));
  
  /*
   * the memset call clears nonstandard fields in some impementations
   * that otherwise mess things up.