/* Pinos
 * Copyright (C) 2015 Wim Taymans <wim.taymans@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>

#include "config.h"

#include "pinos/client/pinos.h"
#include "pinos/client/log.h"
#include "pinos/client/interfaces.h"

#include "pinos/server/core.h"
#include "pinos/server/protocol-native.h"
#include "pinos/server/node.h"
#include "pinos/server/module.h"
#include "pinos/server/client-node.h"
#include "pinos/server/client.h"
#include "pinos/server/resource.h"
#include "pinos/server/link.h"
#include "pinos/server/node-factory.h"
#include "pinos/server/data-loop.h"
#include "pinos/server/main-loop.h"

#ifndef UNIX_PATH_MAX
#define UNIX_PATH_MAX   108
#endif

#define LOCK_SUFFIX     ".lock"
#define LOCK_SUFFIXLEN  5

typedef bool (*PinosDemarshalFunc) (void *object, void *data, size_t size);

typedef struct {
  int        fd;
  int        fd_lock;
  struct     sockaddr_un addr;
  char       lock_addr[UNIX_PATH_MAX + LOCK_SUFFIXLEN];
  PinosLoop *loop;
  SpaSource *source;
  char      *core_name;
  SpaList    link;
} Socket;

typedef struct {
  PinosCore   *core;
  SpaList      link;

  PinosProperties *properties;

  SpaList socket_list;
  SpaList client_list;

  PinosListener before_iterate;
} PinosProtocolNative;

typedef struct {
  PinosProtocolNative *impl;
  SpaList              link;
  PinosClient         *client;
  int                  fd;
  SpaSource           *source;
  PinosConnection     *connection;
  PinosListener        resource_added;
} PinosProtocolNativeClient;

static void
client_destroy (PinosProtocolNativeClient *this)
{
  pinos_loop_destroy_source (this->impl->core->main_loop->loop,
                             this->source);
  pinos_client_destroy (this->client);
  spa_list_remove (&this->link);

  pinos_connection_destroy (this->connection);
  close (this->fd);
  free (this);
}

static void
on_resource_added (PinosListener *listener,
                   PinosClient   *client,
                   PinosResource *resource)
{
  pinos_protocol_native_server_setup (resource);
}

static void
on_before_iterate (PinosListener *listener,
                   PinosLoop     *loop)
{
  PinosProtocolNative *this = SPA_CONTAINER_OF (listener, PinosProtocolNative, before_iterate);
  PinosProtocolNativeClient *client, *tmp;

  spa_list_for_each_safe (client, tmp, &this->client_list, link)
    pinos_connection_flush (client->connection);
}

static void
connection_data (SpaSource *source,
                 int        fd,
                 SpaIO      mask,
                 void      *data)
{
  PinosProtocolNativeClient *client = data;
  PinosConnection *conn = client->connection;
  uint8_t opcode;
  uint32_t id;
  uint32_t size;
  PinosClient *c = client->client;
  void *message;

  if (mask & (SPA_IO_ERR | SPA_IO_HUP)) {
    pinos_log_error ("protocol-native %p: got connection error", client->impl);
    client_destroy (client);
    return;
  }

  if (mask & SPA_IO_IN) {
    while (pinos_connection_get_next (conn, &opcode, &id, &message, &size)) {
      PinosResource *resource;
      const PinosDemarshalFunc *demarshal;

      pinos_log_trace ("protocol-native %p: got message %d from %u", client->impl, opcode, id);

      resource = pinos_map_lookup (&c->objects, id);
      if (resource == NULL) {
        pinos_log_error ("protocol-native %p: unknown resource %u", client->impl, id);
        continue;
      }
      if (opcode >= resource->iface->n_methods) {
        pinos_log_error ("protocol-native %p: invalid method %u", client->impl, opcode);
        client_destroy (client);
        break;
      }
      demarshal = resource->iface->methods;
      if (!demarshal[opcode] || !demarshal[opcode] (resource, message, size)) {
        pinos_log_error ("protocol-native %p: invalid message received", client->impl);
        client_destroy (client);
        break;
      }
    }
  }
}

static PinosProtocolNativeClient *
client_new (PinosProtocolNative *impl,
            int                  fd)
{
  PinosProtocolNativeClient *this;
  PinosClient *client;
  socklen_t len;
  struct ucred ucred, *ucredp;

  this = calloc (1, sizeof (PinosProtocolNativeClient));
  if (this == NULL)
    goto no_native_client;

  this->impl = impl;
  this->fd = fd;
  this->source = pinos_loop_add_io (impl->core->main_loop->loop,
                                    this->fd,
                                    SPA_IO_IN | SPA_IO_ERR | SPA_IO_HUP,
                                    false,
                                    connection_data,
                                    this);
  if (this->source == NULL)
    goto no_source;

  this->connection = pinos_connection_new (fd);
  if (this->connection == NULL)
    goto no_connection;

  len = sizeof (ucred);
  if (getsockopt (fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len) < 0) {
    pinos_log_error ("no peercred: %m");
    ucredp = NULL;
  } else {
    ucredp = &ucred;
  }

  client = pinos_client_new (impl->core, ucredp, NULL);
  if (client == NULL)
    goto no_client;

  client->protocol_private = this->connection;

  this->client = client;

  spa_list_insert (impl->client_list.prev, &this->link);

  pinos_signal_add (&client->resource_added,
                    &this->resource_added,
                    on_resource_added);

  pinos_global_bind (impl->core->global,
                     client,
                     0,
                     0);
  return this;

no_client:
  pinos_connection_destroy (this->connection);
no_connection:
  pinos_loop_destroy_source (impl->core->main_loop->loop,
                             this->source);
no_source:
  free (this);
no_native_client:
  return NULL;
}

static Socket *
create_socket (void)
{
  Socket *s;

  if ((s = calloc(1, sizeof (Socket))) == NULL)
    return NULL;

  s->fd = -1;
  s->fd_lock = -1;
  return s;
}

static void
destroy_socket (Socket *s)
{
  if (s->source)
    pinos_loop_destroy_source (s->loop, s->source);
  if (s->addr.sun_path[0])
    unlink (s->addr.sun_path);
  if (s->fd >= 0)
    close (s->fd);
  if (s->lock_addr[0])
    unlink (s->lock_addr);
  if (s->fd_lock >= 0)
    close (s->fd_lock);
  free (s);
}

static bool
init_socket_name (Socket *s, const char *name)
{
  int name_size;
  const char *runtime_dir;

  if ((runtime_dir = getenv ("XDG_RUNTIME_DIR")) == NULL) {
    pinos_log_error ("XDG_RUNTIME_DIR not set in the environment");
    return false;
  }

  s->addr.sun_family = AF_LOCAL;
  name_size = snprintf (s->addr.sun_path, sizeof (s->addr.sun_path),
                        "%s/%s", runtime_dir, name) + 1;

  s->core_name = (s->addr.sun_path + name_size - 1) - strlen (name);

  if (name_size > (int)sizeof (s->addr.sun_path)) {
    pinos_log_error ("socket path \"%s/%s\" plus null terminator exceeds 108 bytes",
                     runtime_dir, name);
    *s->addr.sun_path = 0;
    return false;
  }
  return true;
}

static bool
lock_socket (Socket *s)
{
  struct stat socket_stat;

  snprintf (s->lock_addr, sizeof (s->lock_addr),
            "%s%s", s->addr.sun_path, LOCK_SUFFIX);

  s->fd_lock = open (s->lock_addr, O_CREAT | O_CLOEXEC,
                     (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));

  if (s->fd_lock < 0) {
    pinos_log_error ("unable to open lockfile %s check permissions", s->lock_addr);
    goto err;
  }

  if (flock (s->fd_lock, LOCK_EX | LOCK_NB) < 0) {
    pinos_log_error ("unable to lock lockfile %s, maybe another daemon is running", s->lock_addr);
    goto err_fd;
  }

  if (stat (s->addr.sun_path, &socket_stat) < 0 ) {
    if (errno != ENOENT) {
      pinos_log_error ("did not manage to stat file %s\n", s->addr.sun_path);
      goto err_fd;
    }
  } else if (socket_stat.st_mode & S_IWUSR ||
             socket_stat.st_mode & S_IWGRP) {
    unlink (s->addr.sun_path);
  }
  return true;

err_fd:
  close (s->fd_lock);
  s->fd_lock = -1;
err:
  *s->lock_addr = 0;
  *s->addr.sun_path = 0;
  return false;
}

static void
socket_data (SpaSource *source,
             int        fd,
             SpaIO      mask,
             void      *data)
{
  PinosProtocolNative *impl = data;
  struct sockaddr_un name;
  socklen_t length;
  int client_fd;

  length = sizeof (name);
  client_fd = accept4 (fd, (struct sockaddr *) &name, &length, SOCK_CLOEXEC);
  if (client_fd < 0) {
    pinos_log_error ("failed to accept: %m");
    return;
  }

  if (client_new (impl, client_fd) == NULL) {
    pinos_log_error ("failed to create client");
    close (client_fd);
    return;
  }
}

static bool
add_socket (PinosProtocolNative *impl, Socket *s)
{
  socklen_t size;

  if ((s->fd = socket (PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)) < 0)
    return false;

  size = offsetof (struct sockaddr_un, sun_path) + strlen (s->addr.sun_path);
  if (bind (s->fd, (struct sockaddr *) &s->addr, size) < 0) {
    pinos_log_error ("bind() failed with error: %m");
    return false;
  }

  if (listen (s->fd, 128) < 0) {
    pinos_log_error ("listen() failed with error: %m");
    return false;
  }

  s->loop = impl->core->main_loop->loop;
  s->source = pinos_loop_add_io (s->loop,
                                 s->fd,
                                 SPA_IO_IN,
                                 false,
                                 socket_data,
                                 impl);
  if (s->source == NULL)
    return false;

  spa_list_insert (impl->socket_list.prev, &s->link);

  return true;
}


static PinosProtocolNative *
pinos_protocol_native_new (PinosCore       *core,
                           PinosProperties *properties)
{
  PinosProtocolNative *impl;
  Socket *s;
  const char *name;

  impl = calloc (1, sizeof (PinosProtocolNative));
  pinos_log_debug ("protocol-native %p: new", impl);

  impl->core = core;
  impl->properties = properties;

  name = NULL;
  if (impl->properties)
    name = pinos_properties_get (impl->properties, "pinos.core.name");
  if (name == NULL)
    name = getenv ("PINOS_CORE");
  if (name == NULL)
    name = "pinos-0";

  s = create_socket ();

  spa_list_init (&impl->socket_list);
  spa_list_init (&impl->client_list);

  if (!init_socket_name (s, name))
    goto error;

  if (!lock_socket (s))
    goto error;

  if (!add_socket (impl, s))
    goto error;

  pinos_signal_add (&impl->core->main_loop->loop->before_iterate,
                    &impl->before_iterate,
                    on_before_iterate);

  return impl;

error:
  destroy_socket (s);
  free (impl);
  return NULL;
}

#if 0
static void
pinos_protocol_native_destroy (PinosProtocolNative *impl)
{
  PinosProtocolNativeObject *object, *tmp;

  pinos_log_debug ("protocol-native %p: destroy", impl);

  pinos_signal_remove (&impl->before_iterate);

  pinos_global_destroy (impl->global);

  spa_list_for_each_safe (object, tmp, &impl->object_list, link)
    object_destroy (object);

  free (impl);
}
#endif

bool
pinos__module_init (PinosModule * module, const char * args)
{
  pinos_protocol_native_new (module->core, NULL);
  return true;
}