/*
 * 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.
 */

#ifndef __SESSION_H__
#define __SESSION_H__

#include "device/device.h"
#include "render/buffers.h"
#include "render/shader.h"
#include "render/stats.h"
#include "render/tile.h"

#include "util/util_progress.h"
#include "util/util_stats.h"
#include "util/util_thread.h"
#include "util/util_vector.h"

CCL_NAMESPACE_BEGIN

class BufferParams;
class Device;
class DeviceScene;
class DeviceRequestedFeatures;
class DisplayBuffer;
class Progress;
class RenderBuffers;
class Scene;

/* Session Parameters */

class SessionParams {
 public:
  DeviceInfo device;
  bool background;
  bool progressive_refine;

  bool progressive;
  bool experimental;
  int samples;
  int2 tile_size;
  TileOrder tile_order;
  int start_resolution;
  int denoising_start_sample;
  int pixel_size;
  int threads;
  bool adaptive_sampling;

  bool use_profiling;

  bool display_buffer_linear;

  DenoiseParams denoising;

  double cancel_timeout;
  double reset_timeout;
  double text_timeout;
  double progressive_update_timeout;

  ShadingSystem shadingsystem;

  function<bool(const uchar *pixels, int width, int height, int channels)> write_render_cb;

  SessionParams()
  {
    background = false;
    progressive_refine = false;

    progressive = false;
    experimental = false;
    samples = 1024;
    tile_size = make_int2(64, 64);
    start_resolution = INT_MAX;
    denoising_start_sample = 0;
    pixel_size = 1;
    threads = 0;
    adaptive_sampling = false;

    use_profiling = false;

    display_buffer_linear = false;

    cancel_timeout = 0.1;
    reset_timeout = 0.1;
    text_timeout = 1.0;
    progressive_update_timeout = 1.0;

    shadingsystem = SHADINGSYSTEM_SVM;
    tile_order = TILE_CENTER;
  }

  bool modified(const SessionParams &params)
  {
    /* Modified means we have to recreate the session, any parameter changes
     * that can be handled by an existing Session are omitted. */
    return !(device == params.device && background == params.background &&
             progressive_refine == params.progressive_refine &&
             progressive == params.progressive && experimental == params.experimental &&
             tile_size == params.tile_size && start_resolution == params.start_resolution &&
             pixel_size == params.pixel_size && threads == params.threads &&
             adaptive_sampling == params.adaptive_sampling &&
             use_profiling == params.use_profiling &&
             display_buffer_linear == params.display_buffer_linear &&
             cancel_timeout == params.cancel_timeout && reset_timeout == params.reset_timeout &&
             text_timeout == params.text_timeout &&
             progressive_update_timeout == params.progressive_update_timeout &&
             tile_order == params.tile_order && shadingsystem == params.shadingsystem &&
             denoising.type == params.denoising.type &&
             (denoising.use == params.denoising.use || (device.denoisers & denoising.type)));
  }
};

/* Session
 *
 * This is the class that contains the session thread, running the render
 * control loop and dispatching tasks. */

class Session {
 public:
  Device *device;
  Scene *scene;
  RenderBuffers *buffers;
  DisplayBuffer *display;
  Progress progress;
  SessionParams params;
  TileManager tile_manager;
  Stats stats;
  Profiler profiler;

  function<void(RenderTile &)> write_render_tile_cb;
  function<void(RenderTile &, bool)> update_render_tile_cb;
  function<void(RenderTile &)> read_bake_tile_cb;

  explicit Session(const SessionParams &params);
  ~Session();

  void start();
  void cancel();
  bool draw(BufferParams &params, DeviceDrawParams &draw_params);
  void wait();

  bool ready_to_reset();
  void reset(BufferParams &params, int samples);
  void set_pause(bool pause);
  void set_samples(int samples);
  void set_denoising(const DenoiseParams &denoising);
  void set_denoising_start_sample(int sample);

  bool update_scene();

  void device_free();

  /* Returns the rendering progress or 0 if no progress can be determined
   * (for example, when rendering with unlimited samples). */
  float get_progress();

  void collect_statistics(RenderStats *stats);

 protected:
  struct DelayedReset {
    thread_mutex mutex;
    bool do_reset;
    BufferParams params;
    int samples;
  } delayed_reset;

  void run();

  bool run_update_for_next_iteration();
  bool run_wait_for_work(bool no_tiles);

  void update_status_time(bool show_pause = false, bool show_done = false);

  void render(bool use_denoise);
  void copy_to_display_buffer(int sample);

  void reset_(BufferParams &params, int samples);

  void run_cpu();
  bool draw_cpu(BufferParams &params, DeviceDrawParams &draw_params);
  void reset_cpu(BufferParams &params, int samples);

  void run_gpu();
  bool draw_gpu(BufferParams &params, DeviceDrawParams &draw_params);
  void reset_gpu(BufferParams &params, int samples);

  bool render_need_denoise(bool &delayed);

  bool steal_tile(RenderTile &tile, Device *tile_device, thread_scoped_lock &tile_lock);
  bool get_tile_stolen();
  bool acquire_tile(RenderTile &tile, Device *tile_device, uint tile_types);
  void update_tile_sample(RenderTile &tile);
  void release_tile(RenderTile &tile, const bool need_denoise);

  void map_neighbor_tiles(RenderTileNeighbors &neighbors, Device *tile_device);
  void unmap_neighbor_tiles(RenderTileNeighbors &neighbors, Device *tile_device);

  bool device_use_gl;

  thread *session_thread;

  volatile bool display_outdated;

  volatile bool gpu_draw_ready;
  volatile bool gpu_need_display_buffer_update;
  thread_condition_variable gpu_need_display_buffer_update_cond;

  bool pause;
  thread_condition_variable pause_cond;
  thread_mutex pause_mutex;
  thread_mutex tile_mutex;
  thread_mutex buffers_mutex;
  thread_mutex display_mutex;
  thread_condition_variable denoising_cond;
  thread_condition_variable tile_steal_cond;

  double reset_time;
  double last_update_time;
  double last_display_time;

  RenderTile stolen_tile;
  typedef enum {
    NOT_STEALING,     /* There currently is no tile stealing in progress. */
    WAITING_FOR_TILE, /* A device is waiting for another device to release a tile. */
    RELEASING_TILE,   /* A device has releasing a stealable tile. */
    GOT_TILE /* A device has released a stealable tile, which is now stored in stolen_tile. */
  } TileStealingState;
  std::atomic<TileStealingState> tile_stealing_state;
  int stealable_tiles;

  /* progressive refine */
  bool update_progressive_refine(bool cancel);
};

CCL_NAMESPACE_END

#endif /* __SESSION_H__ */