/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "common/rect.h"
#include "common/scummsys.h"
#include "common/system.h"
#include "math/utils.h"
#include "zvision/graphics/render_table.h"
#include "zvision/scripting/script_manager.h"

namespace ZVision {

RenderTable::RenderTable(ZVision *engine, uint16 numColumns, uint16 numRows, const Graphics::PixelFormat &pixelFormat)
	: _engine(engine),
	  _system(engine->_system),
	  _numRows(numRows),
	  _numColumns(numColumns),
	  _renderState(FLAT),
	  _pixelFormat(pixelFormat) {
	assert(numRows != 0 && numColumns != 0);

	_internalBuffer = new FilterPixel[numRows * numColumns];

	memset(&_panoramaOptions, 0, sizeof(_panoramaOptions));
	memset(&_tiltOptions, 0, sizeof(_tiltOptions));
	_halfRows = floor((_numRows - 1) / 2);
	_halfColumns = floor((_numColumns - 1) / 2);
	_halfWidth = (float)_numColumns / 2.0f - 0.5f;
	_halfHeight = (float)_numRows / 2.0f - 0.5f;
}

RenderTable::~RenderTable() {
	delete[] _internalBuffer;
}

void RenderTable::setRenderState(RenderState newState) {
	_renderState = newState;

	switch (newState) {
	case PANORAMA:
		_panoramaOptions.verticalFOV = Math::deg2rad<float>(27.0f);
		_panoramaOptions.linearScale = 0.55f;
		_panoramaOptions.reverse = false;
		_panoramaOptions.zeroPoint = 0;
		break;
	case TILT:
		_tiltOptions.verticalFOV = Math::deg2rad<float>(27.0f);
		_tiltOptions.linearScale = 0.65f;
		_tiltOptions.reverse = false;
		break;
	case FLAT:
		// Intentionally left empty
		break;
	default:
		break;
	}
}

const Common::Point RenderTable::convertWarpedCoordToFlatCoord(const Common::Point &point) {
	// If we're outside the range of the RenderTable, no warping is happening. Return the maximum image coords
	if (point.x >= (int16)_numColumns || point.y >= (int16)_numRows || point.x < 0 || point.y < 0) {
		int16 x = CLIP<int16>(point.x, 0, (int16)_numColumns);
		int16 y = CLIP<int16>(point.y, 0, (int16)_numRows);
		return Common::Point(x, y);
	}
	
	uint32 index = point.y * _numColumns + point.x;

	Common::Point newPoint(point);
	newPoint.x += (_internalBuffer[index]._xDir ? _internalBuffer[index]._src.right : _internalBuffer[index]._src.left);
	newPoint.y += (_internalBuffer[index]._yDir ? _internalBuffer[index]._src.bottom : _internalBuffer[index]._src.top);

	return newPoint;
}

// Disused at present; potentially useful for future rendering efficient improvements.
/*/
void RenderTable::mutateImage(uint16 *sourceBuffer, uint16 *destBuffer, uint32 destWidth, const Common::Rect &subRect) {
    uint32 destOffset = 0;
  uint32 sourceXIndex = 0;
  uint32 sourceYIndex = 0;
  if(highQuality) {
    // TODO - convert to high quality pixel filtering
      for (int16 y = subRect.top; y < subRect.bottom; ++y) {
          uint32 sourceOffset = y * _numColumns;
          for (int16 x = subRect.left; x < subRect.right; ++x) {
              uint32 normalizedX = x - subRect.left;
              uint32 index = sourceOffset + x;
              // RenderTable only stores offsets from the original coordinates
              sourceYIndex = y + _internalBuffer[index]._src.top;
              sourceXIndex = x + _internalBuffer[index]._src.left;
              destBuffer[destOffset + normalizedX] = sourceBuffer[sourceYIndex * _numColumns + sourceXIndex];
          }
          destOffset += destWidth;
      }
  }
  else {
      for (int16 y = subRect.top; y < subRect.bottom; ++y) {
          uint32 sourceOffset = y * _numColumns;
          for (int16 x = subRect.left; x < subRect.right; ++x) {
              uint32 normalizedX = x - subRect.left;
              uint32 index = sourceOffset + x;
              // RenderTable only stores offsets from the original coordinates
              sourceYIndex = y + _internalBuffer[index]._src.top;
              sourceXIndex = x + _internalBuffer[index]._src.left;
              destBuffer[destOffset + normalizedX] = sourceBuffer[sourceYIndex * _numColumns + sourceXIndex];
          }
          destOffset += destWidth;
      }
  }
}
// */

void RenderTable::mutateImage(Graphics::Surface *dstBuf, Graphics::Surface *srcBuf, bool highQuality) {
	uint32 destOffset = 0;
	uint32 sourceOffset = 0;
	uint16 *sourceBuffer = (uint16 *)srcBuf->getPixels();
	uint16 *destBuffer = (uint16 *)dstBuf->getPixels();
	if (highQuality != _highQuality) {
		_highQuality = highQuality;
		generateRenderTable();
	}
	uint32 mutationTime = _system->getMillis();
	if (_highQuality) {
		// Apply bilinear interpolation
		for (int16 y = 0; y < srcBuf->h; ++y) {
			sourceOffset = y * _numColumns;
			for (int16 x = 0; x < srcBuf->w; ++x) {
				const FilterPixel &curP = _internalBuffer[sourceOffset + x];
				const uint32 srcIndexYT = y + curP._src.top;
				const uint32 srcIndexYB = y + curP._src.bottom;
				const uint32 srcIndexXL = x + curP._src.left;
				const uint32 srcIndexXR = x + curP._src.right;
				uint32 rTL, rTR, rBL, rBR;
				uint32 gTL, gTR, gBL, gBR;
				uint32 bTL, bTR, bBL, bBR;
				splitColor(sourceBuffer[srcIndexYT * _numColumns + srcIndexXL], rTL, gTL, bTL);
				splitColor(sourceBuffer[srcIndexYT * _numColumns + srcIndexXR], rTR, gTR, bTR);
				splitColor(sourceBuffer[srcIndexYB * _numColumns + srcIndexXL], rBL, gBL, bBL);
				splitColor(sourceBuffer[srcIndexYB * _numColumns + srcIndexXR], rBR, gBR, bBR);
				const uint32 rF = curP._fTL * rTL + curP._fTR * rTR + curP._fBL * rBL + curP._fBR * rBR;
				const uint32 gF = curP._fTL * gTL + curP._fTR * gTR + curP._fBL * gBL + curP._fBR * gBR;
				const uint32 bF = curP._fTL * bTL + curP._fTR * bTR + curP._fBL * bBL + curP._fBR * bBR;
				destBuffer[destOffset] = mergeColor(rF, gF, bF);
				destOffset++;
			}
		}
	} else {
		// Apply nearest-neighbour interpolation
		for (int16 y = 0; y < srcBuf->h; ++y) {
			sourceOffset = y * _numColumns;
			for (int16 x = 0; x < srcBuf->w; ++x) {
				const uint32 index = sourceOffset + x;
				// RenderTable only stores offsets from the original coordinates
				const uint32 srcIndexX = x + (_internalBuffer[index]._xDir ? _internalBuffer[index]._src.right : _internalBuffer[index]._src.left);
				const uint32 srcIndexY = y + (_internalBuffer[index]._yDir ? _internalBuffer[index]._src.bottom : _internalBuffer[index]._src.top);
				destBuffer[destOffset] = sourceBuffer[srcIndexY * _numColumns + srcIndexX];
				destOffset++;
			}
		}
	}
	mutationTime = _system->getMillis() - mutationTime;
	debugC(5, kDebugGraphics, "\tPanorama mutation time %dms, %s quality", mutationTime, _highQuality ? "high" : "low");
}

void RenderTable::generateRenderTable() {
	switch (_renderState) {
	case RenderTable::PANORAMA: {
		generateLookupTable(false);
		break;
	}
	case RenderTable::TILT:
		generateLookupTable(true);
		break;
	case RenderTable::FLAT:
		// Intentionally left empty
		break;
	default:
		break;
	}
}

void RenderTable::generateLookupTable(bool tilt) {
	debugC(1, kDebugGraphics, "Generating %s lookup table.", tilt ? "tilt" : "panorama");
	debugC(5, kDebugGraphics, "_halfWidth %f, _halfHeight %f", _halfWidth, _halfHeight);
	debugC(5, kDebugGraphics, "_halfRows %d, _halfColumns %d", _halfRows, _halfColumns);
	uint32 generationTime = _system->getMillis();
	float cosAlpha, polarCoordInCylinderCoords, cylinderRadius, xOffset, yOffset;
	uint32 indexTL, indexBL, indexTR, indexBR;
	auto outerLoop = [&](uint & polarCoord, float & halfPolarSize, float & scale) {
		// polarCoord is the coordinate of the working window pixel parallel to the direction of camera rotation
		// halfPolarSize is the distance from the central axis to the outermost working window pixel in the direction of camera rotation
		// alpha represents the angle in the direction of camera rotation between the view axis and the centre of a pixel at the given polar coordinate
		const float alpha = atan(((float)polarCoord - halfPolarSize) / cylinderRadius);
		// To map the polar coordinate to the cylinder surface coordinates, we just need to calculate the arc length
		// We also scale it by linearScale
		polarCoordInCylinderCoords = (cylinderRadius * scale * alpha) + halfPolarSize;
		cosAlpha = cos(alpha);
	};
	auto innerLoop = [&](uint & polarCoord, uint & linearCoord, float & halfLinearSize,  float & polarOffset, float & linearOffset) {
		// To calculate linear coordinate in cylinder coordinates, we can do similar triangles comparison,
		// comparing the triangle from the center to the screen and from the center to the edge of the cylinder
		const float linearCoordInCylinderCoords = halfLinearSize + ((float)linearCoord - halfLinearSize) * cosAlpha;
		linearOffset = linearCoordInCylinderCoords - linearCoord;
		polarOffset = polarCoordInCylinderCoords - polarCoord;
		_internalBuffer[indexTL] = FilterPixel(xOffset, yOffset, _highQuality);
		// Transformation is both horizontally and vertically symmetrical about the camera axis,
		// We can thus save on trigonometric calculations by computing one quarter of the transformation matrix and then mirroring it in both X & Y:
		_internalBuffer[indexBL] = _internalBuffer[indexTL];
		_internalBuffer[indexBL].flipV();
		_internalBuffer[indexTR] = _internalBuffer[indexTL];
		_internalBuffer[indexTR].flipH();
		_internalBuffer[indexBR] = _internalBuffer[indexBL];
		_internalBuffer[indexBR].flipH();
	};
	if (tilt) {
		cylinderRadius = (_halfWidth + 0.5f) / tan(_tiltOptions.verticalFOV);
		_tiltOptions.gap = cylinderRadius * atan2((float)(_halfHeight / cylinderRadius), 1.0f) * _tiltOptions.linearScale;
		for (uint y = 0; y <= _halfRows; ++y) {
			outerLoop(y, _halfHeight, _tiltOptions.linearScale);
			const uint32 columnIndexTL = y * _numColumns;
			const uint32 columnIndexBL = (_numRows - (y + 1)) * _numColumns;
			const uint32 columnIndexTR = columnIndexTL + (_numColumns - 1);
			const uint32 columnIndexBR = columnIndexBL + (_numColumns - 1);
			for (uint x = 0; x <= _halfColumns; ++x) {
				indexTL = columnIndexTL + x;
				indexBL = columnIndexBL + x;
				indexTR = columnIndexTR - x;
				indexBR = columnIndexBR - x;
				innerLoop(y, x, _halfWidth, yOffset, xOffset);
			}
		}
	} else {
		cylinderRadius = (_halfHeight + 0.5f) / tan(_panoramaOptions.verticalFOV);
		for (uint x = 0; x <= _halfColumns; ++x) {
			const uint32 columnIndexL = x;
			const uint32 columnIndexR = (_numColumns - 1) - x;
			uint32 rowIndexT = 0;
			uint32 rowIndexB = _numColumns * (_numRows - 1);
			outerLoop(x, _halfWidth, _panoramaOptions.linearScale);
			for (uint y = 0; y <= _halfRows; ++y) {
				indexTL = rowIndexT + columnIndexL;
				indexBL = rowIndexB + columnIndexL;
				indexTR = rowIndexT + columnIndexR;
				indexBR = rowIndexB + columnIndexR;
				innerLoop(x, y, _halfHeight, xOffset, yOffset);
				rowIndexT += _numColumns;
				rowIndexB -= _numColumns;
			}
		}
	}
	generationTime = _system->getMillis() - generationTime;
	debugC(1, kDebugGraphics, "Render table generated, %s quality", _highQuality ? "high" : "low");
	debugC(1, kDebugGraphics, "\tRender table generation time %dms", generationTime);
}

void RenderTable::setPanoramaFoV(float fov) {
	assert(fov > 0.0f);

	_panoramaOptions.verticalFOV = Math::deg2rad<float>(fov);
}

void RenderTable::setPanoramaScale(float scale) {
	assert(scale > 0.0f);

	_panoramaOptions.linearScale = scale;
}

void RenderTable::setPanoramaReverse(bool reverse) {
	_panoramaOptions.reverse = reverse;
}

bool RenderTable::getPanoramaReverse() {
	return _panoramaOptions.reverse;
}

void RenderTable::setPanoramaZeroPoint(uint16 point) {
	_panoramaOptions.zeroPoint = point;
}

uint16 RenderTable::getPanoramaZeroPoint() {
	return _panoramaOptions.zeroPoint;
}

void RenderTable::setTiltFoV(float fov) {
	assert(fov > 0.0f);

	_tiltOptions.verticalFOV = Math::deg2rad<float>(fov);
}

void RenderTable::setTiltScale(float scale) {
	assert(scale > 0.0f);

	_tiltOptions.linearScale = scale;
}

void RenderTable::setTiltReverse(bool reverse) {
	_tiltOptions.reverse = reverse;
}

float RenderTable::getTiltGap() {
	return _tiltOptions.gap;
}

float RenderTable::getAngle() {
	switch (_renderState) {
	case TILT:
		return Math::rad2deg<float>(_tiltOptions.verticalFOV);
	case PANORAMA:
		return Math::rad2deg<float>(_panoramaOptions.verticalFOV);
	default:
		return 1.0f;
	}
}

float RenderTable::getLinscale() {
	switch (_renderState) {
	case TILT:
		return _tiltOptions.linearScale;
	case PANORAMA:
		return _panoramaOptions.linearScale;
	default:
		return 1.0f;
	}
}

} // End of namespace ZVision