/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "device/device_network.h"
#include "device/device.h"
#include "device/device_intern.h"

#include "util/util_foreach.h"
#include "util/util_logging.h"

#if defined(WITH_NETWORK)

CCL_NAMESPACE_BEGIN

typedef map<device_ptr, device_ptr> PtrMap;
typedef vector<uint8_t> DataVector;
typedef map<device_ptr, DataVector> DataMap;

/* tile list */
typedef vector<RenderTile> TileList;

/* search a list of tiles and find the one that matches the passed render tile */
static TileList::iterator tile_list_find(TileList &tile_list, RenderTile &tile)
{
  for (TileList::iterator it = tile_list.begin(); it != tile_list.end(); ++it)
    if (tile.x == it->x && tile.y == it->y && tile.start_sample == it->start_sample)
      return it;
  return tile_list.end();
}

class NetworkDevice : public Device {
 public:
  boost::asio::io_service io_service;
  tcp::socket socket;
  device_ptr mem_counter;
  DeviceTask the_task; /* todo: handle multiple tasks */

  thread_mutex rpc_lock;

  virtual bool show_samples() const
  {
    return false;
  }

  NetworkDevice(DeviceInfo &info, Stats &stats, Profiler &profiler, const char *address)
      : Device(info, stats, profiler, true), socket(io_service)
  {
    error_func = NetworkError();
    stringstream portstr;
    portstr << SERVER_PORT;

    tcp::resolver resolver(io_service);
    tcp::resolver::query query(address, portstr.str());
    tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
    tcp::resolver::iterator end;

    boost::system::error_code error = boost::asio::error::host_not_found;
    while (error && endpoint_iterator != end) {
      socket.close();
      socket.connect(*endpoint_iterator++, error);
    }

    if (error)
      error_func.network_error(error.message());

    mem_counter = 0;
  }

  ~NetworkDevice()
  {
    RPCSend snd(socket, &error_func, "stop");
    snd.write();
  }

  virtual BVHLayoutMask get_bvh_layout_mask() const
  {
    return BVH_LAYOUT_BVH2;
  }

  void mem_alloc(device_memory &mem)
  {
    if (mem.name) {
      VLOG(1) << "Buffer allocate: " << mem.name << ", "
              << string_human_readable_number(mem.memory_size()) << " bytes. ("
              << string_human_readable_size(mem.memory_size()) << ")";
    }

    thread_scoped_lock lock(rpc_lock);

    mem.device_pointer = ++mem_counter;

    RPCSend snd(socket, &error_func, "mem_alloc");
    snd.add(mem);
    snd.write();
  }

  void mem_copy_to(device_memory &mem)
  {
    thread_scoped_lock lock(rpc_lock);

    RPCSend snd(socket, &error_func, "mem_copy_to");

    snd.add(mem);
    snd.write();
    snd.write_buffer(mem.host_pointer, mem.memory_size());
  }

  void mem_copy_from(device_memory &mem, int y, int w, int h, int elem)
  {
    thread_scoped_lock lock(rpc_lock);

    size_t data_size = mem.memory_size();

    RPCSend snd(socket, &error_func, "mem_copy_from");

    snd.add(mem);
    snd.add(y);
    snd.add(w);
    snd.add(h);
    snd.add(elem);
    snd.write();

    RPCReceive rcv(socket, &error_func);
    rcv.read_buffer(mem.host_pointer, data_size);
  }

  void mem_zero(device_memory &mem)
  {
    thread_scoped_lock lock(rpc_lock);

    RPCSend snd(socket, &error_func, "mem_zero");

    snd.add(mem);
    snd.write();
  }

  void mem_free(device_memory &mem)
  {
    if (mem.device_pointer) {
      thread_scoped_lock lock(rpc_lock);

      RPCSend snd(socket, &error_func, "mem_free");

      snd.add(mem);
      snd.write();

      mem.device_pointer = 0;
    }
  }

  void const_copy_to(const char *name, void *host, size_t size)
  {
    thread_scoped_lock lock(rpc_lock);

    RPCSend snd(socket, &error_func, "const_copy_to");

    string name_string(name);

    snd.add(name_string);
    snd.add(size);
    snd.write();
    snd.write_buffer(host, size);
  }

  bool load_kernels(const DeviceRequestedFeatures &requested_features)
  {
    if (error_func.have_error())
      return false;

    thread_scoped_lock lock(rpc_lock);

    RPCSend snd(socket, &error_func, "load_kernels");
    snd.add(requested_features.experimental);
    snd.add(requested_features.max_closure);
    snd.add(requested_features.max_nodes_group);
    snd.add(requested_features.nodes_features);
    snd.write();

    bool result;
    RPCReceive rcv(socket, &error_func);
    rcv.read(result);

    return result;
  }

  void task_add(DeviceTask &task)
  {
    thread_scoped_lock lock(rpc_lock);

    the_task = task;

    RPCSend snd(socket, &error_func, "task_add");
    snd.add(task);
    snd.write();
  }

  void task_wait()
  {
    thread_scoped_lock lock(rpc_lock);

    RPCSend snd(socket, &error_func, "task_wait");
    snd.write();

    lock.unlock();

    TileList the_tiles;

    /* todo: run this threaded for connecting to multiple clients */
    for (;;) {
      if (error_func.have_error())
        break;

      RenderTile tile;

      lock.lock();
      RPCReceive rcv(socket, &error_func);

      if (rcv.name == "acquire_tile") {
        lock.unlock();

        /* todo: watch out for recursive calls! */
        if (the_task.acquire_tile(this, tile)) { /* write return as bool */
          the_tiles.push_back(tile);

          lock.lock();
          RPCSend snd(socket, &error_func, "acquire_tile");
          snd.add(tile);
          snd.write();
          lock.unlock();
        }
        else {
          lock.lock();
          RPCSend snd(socket, &error_func, "acquire_tile_none");
          snd.write();
          lock.unlock();
        }
      }
      else if (rcv.name == "release_tile") {
        rcv.read(tile);
        lock.unlock();

        TileList::iterator it = tile_list_find(the_tiles, tile);
        if (it != the_tiles.end()) {
          tile.buffers = it->buffers;
          the_tiles.erase(it);
        }

        assert(tile.buffers != NULL);

        the_task.release_tile(tile);

        lock.lock();
        RPCSend snd(socket, &error_func, "release_tile");
        snd.write();
        lock.unlock();
      }
      else if (rcv.name == "task_wait_done") {
        lock.unlock();
        break;
      }
      else
        lock.unlock();
    }
  }

  void task_cancel()
  {
    thread_scoped_lock lock(rpc_lock);
    RPCSend snd(socket, &error_func, "task_cancel");
    snd.write();
  }

  int get_split_task_count(DeviceTask &)
  {
    return 1;
  }

 private:
  NetworkError error_func;
};

Device *device_network_create(DeviceInfo &info,
                              Stats &stats,
                              Profiler &profiler,
                              const char *address)
{
  return new NetworkDevice(info, stats, profiler, address);
}

void device_network_info(vector<DeviceInfo> &devices)
{
  DeviceInfo info;

  info.type = DEVICE_NETWORK;
  info.description = "Network Device";
  info.id = "NETWORK";
  info.num = 0;

  /* todo: get this info from device */
  info.has_volume_decoupled = false;
  info.has_adaptive_stop_per_sample = false;
  info.has_osl = false;
  info.denoisers = DENOISER_NONE;

  devices.push_back(info);
}

class DeviceServer {
 public:
  thread_mutex rpc_lock;

  void network_error(const string &message)
  {
    error_func.network_error(message);
  }

  bool have_error()
  {
    return error_func.have_error();
  }

  DeviceServer(Device *device_, tcp::socket &socket_)
      : device(device_), socket(socket_), stop(false), blocked_waiting(false)
  {
    error_func = NetworkError();
  }

  void listen()
  {
    /* receive remote function calls */
    for (;;) {
      listen_step();

      if (stop)
        break;
    }
  }

 protected:
  void listen_step()
  {
    thread_scoped_lock lock(rpc_lock);
    RPCReceive rcv(socket, &error_func);

    if (rcv.name == "stop")
      stop = true;
    else
      process(rcv, lock);
  }

  /* create a memory buffer for a device buffer and insert it into mem_data */
  DataVector &data_vector_insert(device_ptr client_pointer, size_t data_size)
  {
    /* create a new DataVector and insert it into mem_data */
    pair<DataMap::iterator, bool> data_ins = mem_data.insert(
        DataMap::value_type(client_pointer, DataVector()));

    /* make sure it was a unique insertion */
    assert(data_ins.second);

    /* get a reference to the inserted vector */
    DataVector &data_v = data_ins.first->second;

    /* size the vector */
    data_v.resize(data_size);

    return data_v;
  }

  DataVector &data_vector_find(device_ptr client_pointer)
  {
    DataMap::iterator i = mem_data.find(client_pointer);
    assert(i != mem_data.end());
    return i->second;
  }

  /* setup mapping and reverse mapping of client_pointer<->real_pointer */
  void pointer_mapping_insert(device_ptr client_pointer, device_ptr real_pointer)
  {
    pair<PtrMap::iterator, bool> mapins;

    /* insert mapping from client pointer to our real device pointer */
    mapins = ptr_map.insert(PtrMap::value_type(client_pointer, real_pointer));
    assert(mapins.second);

    /* insert reverse mapping from real our device pointer to client pointer */
    mapins = ptr_imap.insert(PtrMap::value_type(real_pointer, client_pointer));
    assert(mapins.second);
  }

  device_ptr device_ptr_from_client_pointer(device_ptr client_pointer)
  {
    PtrMap::iterator i = ptr_map.find(client_pointer);
    assert(i != ptr_map.end());
    return i->second;
  }

  device_ptr device_ptr_from_client_pointer_erase(device_ptr client_pointer)
  {
    PtrMap::iterator i = ptr_map.find(client_pointer);
    assert(i != ptr_map.end());

    device_ptr result = i->second;

    /* erase the mapping */
    ptr_map.erase(i);

    /* erase the reverse mapping */
    PtrMap::iterator irev = ptr_imap.find(result);
    assert(irev != ptr_imap.end());
    ptr_imap.erase(irev);

    /* erase the data vector */
    DataMap::iterator idata = mem_data.find(client_pointer);
    assert(idata != mem_data.end());
    mem_data.erase(idata);

    return result;
  }

  /* note that the lock must be already acquired upon entry.
   * This is necessary because the caller often peeks at
   * the header and delegates control to here when it doesn't
   * specifically handle the current RPC.
   * The lock must be unlocked before returning */
  void process(RPCReceive &rcv, thread_scoped_lock &lock)
  {
    if (rcv.name == "mem_alloc") {
      string name;
      network_device_memory mem(device);
      rcv.read(mem, name);
      lock.unlock();

      /* Allocate host side data buffer. */
      size_t data_size = mem.memory_size();
      device_ptr client_pointer = mem.device_pointer;

      DataVector &data_v = data_vector_insert(client_pointer, data_size);
      mem.host_pointer = (data_size) ? (void *)&(data_v[0]) : 0;

      /* Perform the allocation on the actual device. */
      device->mem_alloc(mem);

      /* Store a mapping to/from client_pointer and real device pointer. */
      pointer_mapping_insert(client_pointer, mem.device_pointer);
    }
    else if (rcv.name == "mem_copy_to") {
      string name;
      network_device_memory mem(device);
      rcv.read(mem, name);
      lock.unlock();

      size_t data_size = mem.memory_size();
      device_ptr client_pointer = mem.device_pointer;

      if (client_pointer) {
        /* Lookup existing host side data buffer. */
        DataVector &data_v = data_vector_find(client_pointer);
        mem.host_pointer = (void *)&data_v[0];

        /* Translate the client pointer to a real device pointer. */
        mem.device_pointer = device_ptr_from_client_pointer(client_pointer);
      }
      else {
        /* Allocate host side data buffer. */
        DataVector &data_v = data_vector_insert(client_pointer, data_size);
        mem.host_pointer = (data_size) ? (void *)&(data_v[0]) : 0;
      }

      /* Copy data from network into memory buffer. */
      rcv.read_buffer((uint8_t *)mem.host_pointer, data_size);

      /* Copy the data from the memory buffer to the device buffer. */
      device->mem_copy_to(mem);

      if (!client_pointer) {
        /* Store a mapping to/from client_pointer and real device pointer. */
        pointer_mapping_insert(client_pointer, mem.device_pointer);
      }
    }
    else if (rcv.name == "mem_copy_from") {
      string name;
      network_device_memory mem(device);
      int y, w, h, elem;

      rcv.read(mem, name);
      rcv.read(y);
      rcv.read(w);
      rcv.read(h);
      rcv.read(elem);

      device_ptr client_pointer = mem.device_pointer;
      mem.device_pointer = device_ptr_from_client_pointer(client_pointer);

      DataVector &data_v = data_vector_find(client_pointer);

      mem.host_pointer = (device_ptr) & (data_v[0]);

      device->mem_copy_from(mem, y, w, h, elem);

      size_t data_size = mem.memory_size();

      RPCSend snd(socket, &error_func, "mem_copy_from");
      snd.write();
      snd.write_buffer((uint8_t *)mem.host_pointer, data_size);
      lock.unlock();
    }
    else if (rcv.name == "mem_zero") {
      string name;
      network_device_memory mem(device);
      rcv.read(mem, name);
      lock.unlock();

      size_t data_size = mem.memory_size();
      device_ptr client_pointer = mem.device_pointer;

      if (client_pointer) {
        /* Lookup existing host side data buffer. */
        DataVector &data_v = data_vector_find(client_pointer);
        mem.host_pointer = (void *)&data_v[0];

        /* Translate the client pointer to a real device pointer. */
        mem.device_pointer = device_ptr_from_client_pointer(client_pointer);
      }
      else {
        /* Allocate host side data buffer. */
        DataVector &data_v = data_vector_insert(client_pointer, data_size);
        mem.host_pointer = (void *) ? (device_ptr) & (data_v[0]) : 0;
      }

      /* Zero memory. */
      device->mem_zero(mem);

      if (!client_pointer) {
        /* Store a mapping to/from client_pointer and real device pointer. */
        pointer_mapping_insert(client_pointer, mem.device_pointer);
      }
    }
    else if (rcv.name == "mem_free") {
      string name;
      network_device_memory mem(device);

      rcv.read(mem, name);
      lock.unlock();

      device_ptr client_pointer = mem.device_pointer;

      mem.device_pointer = device_ptr_from_client_pointer_erase(client_pointer);

      device->mem_free(mem);
    }
    else if (rcv.name == "const_copy_to") {
      string name_string;
      size_t size;

      rcv.read(name_string);
      rcv.read(size);

      vector<char> host_vector(size);
      rcv.read_buffer(&host_vector[0], size);
      lock.unlock();

      device->const_copy_to(name_string.c_str(), &host_vector[0], size);
    }
    else if (rcv.name == "load_kernels") {
      DeviceRequestedFeatures requested_features;
      rcv.read(requested_features.experimental);
      rcv.read(requested_features.max_closure);
      rcv.read(requested_features.max_nodes_group);
      rcv.read(requested_features.nodes_features);

      bool result;
      result = device->load_kernels(requested_features);
      RPCSend snd(socket, &error_func, "load_kernels");
      snd.add(result);
      snd.write();
      lock.unlock();
    }
    else if (rcv.name == "task_add") {
      DeviceTask task;

      rcv.read(task);
      lock.unlock();

      if (task.buffer)
        task.buffer = device_ptr_from_client_pointer(task.buffer);

      if (task.rgba_half)
        task.rgba_half = device_ptr_from_client_pointer(task.rgba_half);

      if (task.rgba_byte)
        task.rgba_byte = device_ptr_from_client_pointer(task.rgba_byte);

      if (task.shader_input)
        task.shader_input = device_ptr_from_client_pointer(task.shader_input);

      if (task.shader_output)
        task.shader_output = device_ptr_from_client_pointer(task.shader_output);

      task.acquire_tile = function_bind(&DeviceServer::task_acquire_tile, this, _1, _2);
      task.release_tile = function_bind(&DeviceServer::task_release_tile, this, _1);
      task.update_progress_sample = function_bind(&DeviceServer::task_update_progress_sample,
                                                  this);
      task.update_tile_sample = function_bind(&DeviceServer::task_update_tile_sample, this, _1);
      task.get_cancel = function_bind(&DeviceServer::task_get_cancel, this);

      device->task_add(task);
    }
    else if (rcv.name == "task_wait") {
      lock.unlock();

      blocked_waiting = true;
      device->task_wait();
      blocked_waiting = false;

      lock.lock();
      RPCSend snd(socket, &error_func, "task_wait_done");
      snd.write();
      lock.unlock();
    }
    else if (rcv.name == "task_cancel") {
      lock.unlock();
      device->task_cancel();
    }
    else if (rcv.name == "acquire_tile") {
      AcquireEntry entry;
      entry.name = rcv.name;
      rcv.read(entry.tile);
      acquire_queue.push_back(entry);
      lock.unlock();
    }
    else if (rcv.name == "acquire_tile_none") {
      AcquireEntry entry;
      entry.name = rcv.name;
      acquire_queue.push_back(entry);
      lock.unlock();
    }
    else if (rcv.name == "release_tile") {
      AcquireEntry entry;
      entry.name = rcv.name;
      acquire_queue.push_back(entry);
      lock.unlock();
    }
    else {
      cout << "Error: unexpected RPC receive call \"" + rcv.name + "\"\n";
      lock.unlock();
    }
  }

  bool task_acquire_tile(Device *, RenderTile &tile)
  {
    thread_scoped_lock acquire_lock(acquire_mutex);

    bool result = false;

    RPCSend snd(socket, &error_func, "acquire_tile");
    snd.write();

    do {
      if (blocked_waiting)
        listen_step();

      /* todo: avoid busy wait loop */
      thread_scoped_lock lock(rpc_lock);

      if (!acquire_queue.empty()) {
        AcquireEntry entry = acquire_queue.front();
        acquire_queue.pop_front();

        if (entry.name == "acquire_tile") {
          tile = entry.tile;

          if (tile.buffer)
            tile.buffer = ptr_map[tile.buffer];

          result = true;
          break;
        }
        else if (entry.name == "acquire_tile_none") {
          break;
        }
        else {
          cout << "Error: unexpected acquire RPC receive call \"" + entry.name + "\"\n";
        }
      }
    } while (acquire_queue.empty() && !stop && !have_error());

    return result;
  }

  void task_update_progress_sample()
  {
    ; /* skip */
  }

  void task_update_tile_sample(RenderTile &)
  {
    ; /* skip */
  }

  void task_release_tile(RenderTile &tile)
  {
    thread_scoped_lock acquire_lock(acquire_mutex);

    if (tile.buffer)
      tile.buffer = ptr_imap[tile.buffer];

    {
      thread_scoped_lock lock(rpc_lock);
      RPCSend snd(socket, &error_func, "release_tile");
      snd.add(tile);
      snd.write();
      lock.unlock();
    }

    do {
      if (blocked_waiting)
        listen_step();

      /* todo: avoid busy wait loop */
      thread_scoped_lock lock(rpc_lock);

      if (!acquire_queue.empty()) {
        AcquireEntry entry = acquire_queue.front();
        acquire_queue.pop_front();

        if (entry.name == "release_tile") {
          lock.unlock();
          break;
        }
        else {
          cout << "Error: unexpected release RPC receive call \"" + entry.name + "\"\n";
        }
      }
    } while (acquire_queue.empty() && !stop);
  }

  bool task_get_cancel()
  {
    return false;
  }

  /* properties */
  Device *device;
  tcp::socket &socket;

  /* mapping of remote to local pointer */
  PtrMap ptr_map;
  PtrMap ptr_imap;
  DataMap mem_data;

  struct AcquireEntry {
    string name;
    RenderTile tile;
  };

  thread_mutex acquire_mutex;
  list<AcquireEntry> acquire_queue;

  bool stop;
  bool blocked_waiting;

 private:
  NetworkError error_func;

  /* todo: free memory and device (osl) on network error */
};

void Device::server_run()
{
  try {
    /* starts thread that responds to discovery requests */
    ServerDiscovery discovery;

    for (;;) {
      /* accept connection */
      boost::asio::io_service io_service;
      tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), SERVER_PORT));

      tcp::socket socket(io_service);
      acceptor.accept(socket);

      string remote_address = socket.remote_endpoint().address().to_string();
      printf("Connected to remote client at: %s\n", remote_address.c_str());

      DeviceServer server(this, socket);
      server.listen();

      printf("Disconnected.\n");
    }
  }
  catch (exception &e) {
    fprintf(stderr, "Network server exception: %s\n", e.what());
  }
}

CCL_NAMESPACE_END

#endif