/**
  3D renderer: implements 3D rendering.
*/

#ifndef _LCR_RENDERER_H
#define _LCR_RENDERER_H

#define S3L_RESOLUTION_X LCR_SETTING_RESOLUTION_X
#define S3L_RESOLUTION_Y LCR_SETTING_RESOLUTION_Y
#define S3L_PIXEL_FUNCTION LCR_pixelFunc3D

#define S3L_Z_BUFFER 2

#include "small3dlib.h"

/// Renderer specific unit, length of one map square.
#define LCR_RENDERER_UNIT S3L_FRACTIONS_PER_UNIT

struct LCR_Renderer
{
  // TODO
};

S3L_Scene LCR_scene3D;
S3L_Model3D LCR_models3D[3]; // TODO

S3L_Model3D *LCR_mapModel;
S3L_Unit LCR_mapVertices[LCR_SETTING_MAX_MAP_VERTICES * 3];
S3L_Index LCR_mapTriangles[LCR_SETTING_MAX_MAP_TRIANGLES * 3];

void LCR_pixelFunc3D(S3L_PixelInfo *pixel)
{
  LCR_drawPixelXYSafe(pixel->x,pixel->y,0xff00 + (pixel->triangleID % 16) * 16 );
}

S3L_Index _LCR_addMapVertex(S3L_Unit x, S3L_Unit y, S3L_Unit z)
{
  S3L_Index index = 0;
  S3L_Unit *vertices = LCR_mapVertices;

  while (index < LCR_mapModel->vertexCount) // if exists, return vertex index
  {
    if (vertices[0] == x && vertices[1] == y && vertices[2] == z)
      return index;

    vertices += 3;
    index++;
  }

  // if it doesn't exist, add it
  if (LCR_mapModel->vertexCount < LCR_SETTING_MAX_MAP_VERTICES)
  {
    *vertices = x;
    vertices++;
    *vertices = y;
    vertices++;
    *vertices = z;
    LCR_mapModel->vertexCount++;
    return LCR_mapModel->vertexCount - 1;
  }

  // TODO: error print
  return 0;  
}

void _LCR_addMapTriangle(S3L_Index a, S3L_Index b, S3L_Index c)
{
  if (LCR_mapModel->triangleCount < LCR_SETTING_MAX_MAP_TRIANGLES)
  {
    S3L_Index *t = &(LCR_mapTriangles[LCR_mapModel->triangleCount * 3]);

    *t = a;
    t++;
    *t = b;
    t++;
    *t = c;

    LCR_mapModel->triangleCount++;
  }
}

/**
  Builds an internal 3D model of the currently loaded map. Returns 1 on success,
  otherwise 0 (e.g. not enough space).
*/
uint8_t _LCR_rendererBuildMapModel(void)
{
  uint8_t blockShapeBytes[LCR_MAP_BLOCK_SHAPE_MAX_BYTES];
  uint8_t blockShapeByteCount;

  S3L_model3DInit(LCR_mapVertices,0,LCR_mapTriangles,0,LCR_mapModel);

  for (int j = 0; j < LCR_currentMap.blockCount; ++j)
  {
    uint8_t bx, by, bz;
    LCR_mapBlockGetCoords(LCR_currentMap.blocks + j * LCR_BLOCK_SIZE,&bx,&by,&bz);

    LCR_mapGetBlockShape(LCR_currentMap.blocks[j * LCR_BLOCK_SIZE],0,
      blockShapeBytes,&blockShapeByteCount);

    uint8_t vx, vy, vz, vi = 0;
    uint8_t *bytes = blockShapeBytes;
    S3L_Index triangleIndices[3];

    S3L_Unit originOffset = -1 * LCR_MAP_SIZE_BLOCKS / 2 * LCR_RENDERER_UNIT;

    for (int i = 0; i < blockShapeByteCount; ++i)
    {
      LCR_decodeMapBlockCoords(blockShapeBytes[i],&vx,&vy,&vz);

      triangleIndices[vi] = _LCR_addMapVertex(
        originOffset + (((S3L_Unit) bx) * LCR_RENDERER_UNIT) +       (LCR_RENDERER_UNIT * ((S3L_Unit) vx)) / 12,
        (originOffset + (((S3L_Unit) by) * LCR_RENDERER_UNIT)) / 2 + (LCR_RENDERER_UNIT / 2 * ((S3L_Unit) vy)) / 12,
        originOffset + (((S3L_Unit) bz) * LCR_RENDERER_UNIT) +       (LCR_RENDERER_UNIT * ((S3L_Unit) vz)) / 12);

      if (vi < 2)
        vi++;
      else
      {
        _LCR_addMapTriangle(
          triangleIndices[0],triangleIndices[1],triangleIndices[2]);
        vi = 0;
      }
    }
  }

  return 1;
}

uint8_t LCR_rendererInit(void)
{
  LCR_mapModel = LCR_models3D;

  if (!_LCR_rendererBuildMapModel())
    return 0;

  S3L_sceneInit(LCR_models3D,1,&LCR_scene3D);

  return 1;
}

void LCR_rendererMoveCamera(LCR_SpaceUnit forwRightUpOffset[3],
  LCR_SpaceUnit yawPitchOffset[2])
{  
  S3L_Vec4 f, r, u;

  S3L_rotationToDirections(LCR_scene3D.camera.transform.rotation,
    S3L_FRACTIONS_PER_UNIT,&f,&r,&u);

  LCR_scene3D.camera.transform.translation.x +=
    ((f.x * forwRightUpOffset[0] + r.x * forwRightUpOffset[1] + 
    u.x * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      
 
  LCR_scene3D.camera.transform.translation.y +=
    ((f.y * forwRightUpOffset[0] + r.y * forwRightUpOffset[1] + 
    u.y * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      

  LCR_scene3D.camera.transform.translation.z +=
    ((f.z * forwRightUpOffset[0] + r.z * forwRightUpOffset[1] + 
    u.z * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      
  
  LCR_scene3D.camera.transform.rotation.y +=
    (yawPitchOffset[0] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;
  
  LCR_scene3D.camera.transform.rotation.x +=
    (yawPitchOffset[1] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;

  if (LCR_scene3D.camera.transform.rotation.x > S3L_FRACTIONS_PER_UNIT / 4)
    LCR_scene3D.camera.transform.rotation.x = S3L_FRACTIONS_PER_UNIT / 4;

  if (LCR_scene3D.camera.transform.rotation.x < -1 * S3L_FRACTIONS_PER_UNIT / 4)
    LCR_scene3D.camera.transform.rotation.x = -1 * S3L_FRACTIONS_PER_UNIT / 4;
}

void LCR_rendererDraw(void)
{
  S3L_newFrame();
  S3L_drawScene(LCR_scene3D);
}

void LCR_drawBackground(int verticalOffset)
{

// TODO

for (int y = 0; y < LCR_EFFECTIVE_RESOLUTION_Y; ++y)
  for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
    LCR_drawPixelXYUnsafe(x,y,0xffff);

/*
  uint16_t color = LCR_skyImages[LCR_skyImages[256] & 0x00ff]  ; // TODO
  int limit = verticalOffset - LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE / 2;

  if (limit >= LCR_EFFECTIVE_RESOLUTION_Y)
    limit = LCR_EFFECTIVE_RESOLUTION_Y - 1;

  for (int y = 0; y <= limit; ++y)
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
      LCR_drawPixelUnsafe(x,y,color);

  color = LCR_skyImages[LCR_skyImages[255 + (128 * 128) / 2] >> 8]; // TODO
  limit = verticalOffset + LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE / 2 -
    LCR_SETTING_SKY_SIZE;

  if (limit < 0)
    limit = 0;

  for (int y = LCR_EFFECTIVE_RESOLUTION_Y - 1; y >= limit; --y)
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
      LCR_drawPixelUnsafe(x,y,color);
*/
}

void LCR_drawSkyStrip(int verticalOffset, uint8_t horizontalOffset)
{
#if LCR_SETTING_SKY_SIZE != 0
/*
  verticalOffset -= (LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE) / 2; 

  int finalY = verticalOffset + LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE;

  finalY = (finalY / LCR_SETTING_SKY_SIZE) * LCR_SETTING_SKY_SIZE;

  if (finalY >= LCR_EFFECTIVE_RESOLUTION_Y)
    finalY = LCR_EFFECTIVE_RESOLUTION_Y - 1;

  const uint16_t *skyLine = LCR_skyImages + 256;

  if (verticalOffset < 0)
  {
    skyLine += (-1 * verticalOffset / LCR_SETTING_SKY_SIZE) * (LCR_SKY_IMAGE_SIZE / 2);
    verticalOffset = 0;
  }

  while (verticalOffset < finalY)
  {
    for (int i = 0; i < LCR_EFFECTIVE_RESOLUTION_X; ++i)
    {
      // only diraw background on empty pixels
      if (S3L_zBufferRead(i,verticalOffset) == S3L_MAX_DEPTH)
      {
        int offsetX = (i / LCR_SETTING_SKY_SIZE + horizontalOffset)
          % LCR_SKY_IMAGE_SIZE;

        uint16_t pixel = *(skyLine + offsetX / 2);

        pixel = offsetX % 2 ? (pixel >> 8) : (pixel & 0x00ff);

        LCR_drawPixelUnsafe(i,verticalOffset,LCR_skyImages[pixel]); 
      }
    }

    verticalOffset++;

    if (verticalOffset % LCR_SETTING_SKY_SIZE == 0)
      skyLine += LCR_SKY_IMAGE_SIZE / 2;
  }
*/
#endif
}

LCR_SpaceUnit LCR_rendererGetCameraYaw(void)
{
  return (LCR_scene3D.camera.transform.rotation.y * LCR_SQUARE_SIDE_LEN) /
    S3L_FRACTIONS_PER_UNIT;
}

LCR_SpaceUnit LCR_rendererGetCameraPitch(void)
{
  return (LCR_scene3D.camera.transform.rotation.x * LCR_SQUARE_SIDE_LEN) /
    S3L_FRACTIONS_PER_UNIT;
}

#endif // guard