/**
 * @file VirtualMatrixPanel_T.hpp
 * @brief TEMPLATED Virtual Matrix Panel class for HUB75 displays. Hence the '_T'.
 *
 * This header defines the VirtualMatrixPanel_T template class which maps virtual pixel
 * coordinates to physical LED coordinates. It supports compile‐time configuration for:
 *	 - Panel chain type (PANEL_CHAIN_TYPE)
 *	 - Scan type mapping (via a class, default is STANDARD_TWO_SCAN)
 *	 - A compile‐time scale factor (each virtual pixel is drawn as a block)
 *
 * Runtime rotation is supported via setRotation(). Depending on the build options,
 * the class conditionally inherits from Adafruit_GFX, GFX_Lite, or stands alone.
 * 
 * This class is used to accomplish two objectives:
 *	 1) Create a much larger display out of a number of physical LED panels
 *		chained in a various pattern.
 * 
 *	 2) Provide a way to deal with weird individual physical panels that 
 *		do not have a simple linear X, Y pixel mapping.
 *		i.e. Their DMA pixel mapping differs to the real world.
 *		i.e. Weird four-scan outdoor panels etc.
 *
 * @tparam ChainType	   Compile‐time panel chain configuration.
 * @tparam ScanType		   Policy type implementing a static apply() function for mapping.
 *						   Default is ScanTypeMapping<STANDARD_TWO_SCAN>.
 * @tparam ScaleFactor	   Compile‐time zoom factor (each virtual pixel becomes a
 *						   ScaleFactor x ScaleFactor block).
 *
 * @note The enum PANEL_SCAN_TYPE replaces the former PANEL_SCAN_RATE.
 */
 


#ifndef VIRTUAL_MATRIX_PANEL_TEMPLATE_H
#define VIRTUAL_MATRIX_PANEL_TEMPLATE_H

//#include <cstdint>
#include "ESP32-HUB75-MatrixPanel-I2S-DMA.h"

#ifdef USE_GFX_LITE
  #include "GFX_Lite.h"
#elif !defined(NO_GFX)
  #include "Adafruit_GFX.h"
#endif

// ----------------------------------------------------------------------
// Data structures and enums

/**
 * @brief Structure holding virtual/physical coordinate mapping.
 */
struct VirtualCoords {
	int16_t x;
	int16_t y;
	int16_t virt_row; // chain of panels row (optional)
	int16_t virt_col; // chain of panels col (optional)
	VirtualCoords() : x(0), y(0), virt_row(0), virt_col(0) {}
};

/**
 * @brief Panel scan types.
 *
 * Defines the different scanning modes.
 */
enum PANEL_SCAN_TYPE {
	STANDARD_TWO_SCAN,
	FOUR_SCAN_16PX_HIGH,			///< Four-scan mode, 16-pixel high panels.
	FOUR_SCAN_32PX_HIGH,			///< Four-scan mode, 32-pixel high panels.
	FOUR_SCAN_40PX_HIGH,			///< Four-scan mode, 40-pixel high panels.	
	FOUR_SCAN_40_80PX_HFARCAN,		///< Four-scan mode, 40-pixel high, 80px wide panel. Weird mapping: https://github.com/mrcodetastic/ESP32-HUB75-MatrixPanel-DMA/issues/759
	FOUR_SCAN_64PX_HIGH,			///< Four-scan mode, 64-pixel high panels.
};

/**
 * @brief Panel chain types.
 *
 * Defines the physical chain configuration for multiple panels.
 */
enum PANEL_CHAIN_TYPE {
	CHAIN_NONE,					///< No chaining.
	CHAIN_TOP_LEFT_DOWN,		///< Chain starting top-left, going down.
	CHAIN_TOP_RIGHT_DOWN,		///< Chain starting top-right, going down.
	CHAIN_BOTTOM_LEFT_UP,		///< Chain starting bottom-left, going up.
	CHAIN_BOTTOM_RIGHT_UP,		///< Chain starting bottom-right, going up.
	CHAIN_TOP_LEFT_DOWN_ZZ,		///< Zigzag chain starting top-left.
	CHAIN_TOP_RIGHT_DOWN_ZZ,	///< Zigzag chain starting top-right.
	CHAIN_BOTTOM_RIGHT_UP_ZZ,	///< Zigzag chain starting bottom-right.
	CHAIN_BOTTOM_LEFT_UP_ZZ		///< Zigzag chain starting bottom-left.
};

// ----------------------------------------------------------------------
// Default Scan Rate Policy
/**
 * @brief Default policy for scan type mapping.
 *
 * This templated policy implements the static function apply() to remap
 * coordinates according to the panel scan type. It uses the panel's pixel base
 * to calculate offsets.
 *
 * @tparam Type The compile-time scan type (of type PANEL_SCAN_TYPE).
 */
template <PANEL_SCAN_TYPE ScanType>
struct ScanTypeMapping {
	static constexpr VirtualCoords apply(VirtualCoords coords, int virt_y, int panel_pixel_base) 
	{
		log_v("ScanTypeMapping: coords.x: %d, coords.y: %d, virt_y: %d, pixel_base: %d", coords.x, coords.y, virt_y, panel_pixel_base);

		// FOUR_SCAN_16PX_HIGH
		if constexpr (ScanType == FOUR_SCAN_16PX_HIGH) 
		{
			if ((coords.y & 4) == 0) {
				coords.x += (((coords.x / panel_pixel_base) + 1) * panel_pixel_base);
			} else {
				coords.x += ((coords.x / panel_pixel_base) * panel_pixel_base);
			}
			
			coords.y = (coords.y >> 3) * 4 + (coords.y & 0b00000011);
		}
		// FOUR_SCAN_40PX_HIGH
		else if constexpr (ScanType == FOUR_SCAN_40PX_HIGH) 
		{
			
			if (((coords.y) / 10) % 2 == 0) {				
				coords.x += (((coords.x / panel_pixel_base) + 1) * panel_pixel_base);
			} else {
				coords.x += ((coords.x / panel_pixel_base) * panel_pixel_base);
			}
			coords.y = (coords.y / 20) * 10 + (coords.y % 10);
		}
		else if constexpr (ScanType == FOUR_SCAN_40_80PX_HFARCAN) 
		{
			//  Weird mapping: https://github.com/mrcodetastic/ESP32-HUB75-MatrixPanel-DMA/issues/759
			panel_pixel_base = 16;

            // Mapping logic
            int panel_local_x = coords.x % 80; // Compensate for chain of panels

            if ((((coords.y) / 10) % 2) ^ ((panel_local_x / panel_pixel_base) % 2)) {
                coords.x += ((coords.x / panel_pixel_base) * panel_pixel_base);
            } else {
                coords.x += (((coords.x / panel_pixel_base) + 1) * panel_pixel_base);
            }

            coords.y = (coords.y % 10) + 10 * ((coords.y / 20) % 2);
			
		}		
		//	FOUR_SCAN_64PX_HIGH || FOUR_SCAN_32PX_HIGH
		else if constexpr (ScanType == FOUR_SCAN_64PX_HIGH || ScanType == FOUR_SCAN_32PX_HIGH) 
		{
			int adjusted_y = virt_y;
			if constexpr (ScanType == FOUR_SCAN_64PX_HIGH) 
			{
				// As in the original code (with extra remapping for 64px high panels)
				if ((virt_y & 8) != ((virt_y & 16) >> 1))
					adjusted_y = (((virt_y & 0b11000) ^ 0b11000) + (virt_y & 0b11100111));
			}

			if ((coords.y & 8) == 0) {
				coords.x += (((coords.x / panel_pixel_base) + 1) * panel_pixel_base);
			} else {
				coords.x += ((coords.x / panel_pixel_base) * panel_pixel_base);
			}
			
			coords.y = (adjusted_y >> 4) * 8 + (adjusted_y & 0b00000111);
		}

		// For STANDARD_TWO_SCAN / NORMAL_ONE_SIXTEEN no remapping is done.
		return coords;
	}
};

// ----------------------------------------------------------------------
// VirtualMatrixPanel_T Declaration
//
// Template parameters:
//	 - ChainScanType: compile–time panel chain configuration.
//	 - ScanTypeMapping: a policy type implementing a static "apply" function 
//					   (default is ScanTypeMapping<STANDARD_TWO_SCAN>).
//	 - ScaleFactor: a compile–time zoom factor (must be >= 1).
#ifdef USE_GFX_LITE
template <PANEL_CHAIN_TYPE ChainScanType,
		  class ScanTypeMapping = ScanTypeMapping<STANDARD_TWO_SCAN>,
		  int ScaleFactor = 1>
class VirtualMatrixPanel_T : public GFX {
public:
#elif !defined(NO_GFX)
template <PANEL_CHAIN_TYPE ChainScanType,
		  class ScanTypeMapping = ScanTypeMapping<STANDARD_TWO_SCAN>,
		  int ScaleFactor = 1>
class VirtualMatrixPanel_T : public Adafruit_GFX {
public:
#else
template <PANEL_CHAIN_TYPE ChainScanType,
		  class ScanTypeMapping = ScanTypeMapping<STANDARD_TWO_SCAN>,
		  int ScaleFactor = 1>
class VirtualMatrixPanel_T {
public:
#endif

	// Constructor: pass the underlying MatrixPanel_I2S_DMA display,
	// virtual module dimensions, and physical panel resolution.
	// (Chain type is chosen at compile time.)
	VirtualMatrixPanel_T(uint8_t _vmodule_rows,
						uint8_t _vmodule_cols,
						uint8_t _panel_res_x,
						uint8_t _panel_res_y)
#ifdef USE_GFX_LITE
	  : GFX(_vmodule_cols * _panel_res_x, _vmodule_rows * _panel_res_y),
#elif !defined(NO_GFX)
	  : Adafruit_GFX(_vmodule_cols * _panel_res_x, _vmodule_rows * _panel_res_y),
#endif
		panel_res_x(_panel_res_x),
		panel_res_y(_panel_res_y),
		panel_pixel_base(_panel_res_x), // default pixel base is panel_res_x
		vmodule_rows(_vmodule_rows),
		vmodule_cols(_vmodule_cols),
		virtual_res_x(_vmodule_cols * _panel_res_x),
		virtual_res_y(_vmodule_rows * _panel_res_y),
		dma_res_x(_panel_res_x * _vmodule_rows * _vmodule_cols - 1),
		_virtual_res_x(virtual_res_x),
		_virtual_res_y(virtual_res_y),
		_rotate(0)
	{
		// Initialize with an invalid coordinate.
		coords.x = coords.y = -1;
	}

	// ------------------------------------------------------------------
	// Drawing methods
	inline void drawPixel(int16_t x, int16_t y, uint16_t color) {
		if constexpr (ScaleFactor > 1) 
		{
			for (int dx = 0; dx < ScaleFactor; dx++) {
				for (int dy = 0; dy < ScaleFactor; dy++) {
					//irtualCoords v = getCoords(x * ScaleFactor + dx, y * ScaleFactor + dy);
					// display->drawPixel(v.x, v.y, color);
					calcPhysicalToElectricalCoords(x * ScaleFactor + dx, y * ScaleFactor + dy);
					display->drawPixel(coords.x, coords.y, color);
					
				}
			}
		} else {
			//VirtualCoords v = getCoords(x, y);
			//display->drawPixel(v.x, v.y, color);
			
			calcPhysicalToElectricalCoords(x , y);
			display->drawPixel(coords.x, coords.y, color);			
		}

		log_v("x: %d, y: %d -> coords.x: %d, coords.y: %d", x, y, coords.x, coords.y);
	}

	inline void fillScreen(uint16_t color) {
		display->fillScreen(color);
	}

	inline void fillScreenRGB888(uint8_t r, uint8_t g, uint8_t b) {
		display->fillScreenRGB888(r, g, b);
	}

	inline void drawPixelRGB888(int16_t x, int16_t y, uint8_t r, uint8_t g, uint8_t b) {
		//VirtualCoords v = getCoords(x, y);
		//display->drawPixelRGB888(v.x, v.y, r, g, b);
		
		calcPhysicalToElectricalCoords(x , y);
		display->drawPixelRGB888(coords.x, coords.y, r, g, b);	
	}

#ifdef USE_GFX_LITE
	inline void drawPixel(int16_t x, int16_t y, CRGB color) {
		//VirtualCoords v = getCoords(x, y);
		//display->drawPixel(v.x, v.y, color);
		
		calcPhysicalToElectricalCoords(x , y);
		display->drawPixel(coords.x, coords.y, color);
		
	}

	inline void fillScreen(CRGB color) {
		display->fillScreen(color);
	}
#endif

#ifndef NO_GFX
	inline void drawDisplayTest() {

		// Call ourself as we need to re-map pixels if we're using our own ScanTypeMapping
		// Note: Will mean this display test will be impacted by chaining approach etc.
		// this->setFont(&FreeSansBold12pt7b);	
		this->setTextColor(display->color565(255, 255, 0));
		// this->setTextSize(1);
		for (int col = 0; col < vmodule_cols; col++) {
			for (int row = 0; row < vmodule_rows; row++) {

				int start_x = col * panel_res_x;
				int start_y = row * panel_res_y;

				int panel_id = col + (row * vmodule_cols) + 1;
				//int top_left_x = panel * panel_res_x;
				this->drawRect(start_x, start_y, panel_res_x, panel_res_y, this->color565(0, 255, 0));
				this->setCursor(start_x + panel_res_x/2 - 2, start_y + panel_res_y/2 - 4);
				this->print(panel_id);

				log_d("drawDisplayTest() Panel: %d, start_x: %d, start_y: %d", panel_id, start_x, start_y);
			}
		}  
		
	}

	inline void drawDisplayTestDMA()
	{
		// Write to the underlying panels only via the dma_display instance.
		// This only works on standard panels with a linear mapping (i.e. two-scan).
		this->display->setTextColor(this->display->color565(255, 255, 0));
		this->display->setTextSize(1);
	
		for (int panel = 0; panel < vmodule_cols * vmodule_rows; panel++)
		{
			int top_left_x = panel * panel_res_x;
			this->display->drawRect(top_left_x, 0, panel_res_x, panel_res_y, this->display->color565(0, 255, 0));
			this->display->setCursor((panel * panel_res_x) + 6, panel_res_y - 12);
			this->display->print((vmodule_cols * vmodule_rows) - panel);
		}
	}

#endif

	inline void clearScreen() { display->clearScreen(); }

	inline uint16_t color444(uint8_t r, uint8_t g, uint8_t b) { return display->color444(r, g, b); }
	inline uint16_t color565(uint8_t r, uint8_t g, uint8_t b) { return display->color565(r, g, b); }

	inline void flipDMABuffer() { display->flipDMABuffer(); }

	// ------------------------------------------------------------------
	// Rotation (runtime)
	inline void setRotation(uint8_t rotate) {
		if (rotate < 4)
			_rotate = rotate;
#ifdef NO_GFX
		// When NO_GFX is defined, update _virtual_res_x/_virtual_res_y as needed.
#else
		uint8_t rotation = (rotate & 3);
		switch (rotation) {
			case 0:
			case 2:
				_virtual_res_x = virtual_res_x;
				_virtual_res_y = virtual_res_y;
				_width = virtual_res_x;
				_height = virtual_res_y;
				break;
			case 1:
			case 3:
				_virtual_res_x = virtual_res_y;
				_virtual_res_y = virtual_res_x;
				_width = virtual_res_y;
				_height = virtual_res_x;
				break;
		}
#endif
	}

	// ------------------------------------------------------------------
	// Panel scan–type configuration (runtime adjustment of pixel base)
	inline void setPixelBase(uint8_t pixel_base) {
		panel_pixel_base = pixel_base;
	}

	// ------------------------------------------------------------------
	// calcPhysicalToElectricalCoords() maps a virtual (x,y) coordinate to a physical coordinate.
	// VirtualCoords getCoords(int16_t virt_x, int16_t virt_y) {
	void calcPhysicalToElectricalCoords(int16_t virt_x, int16_t virt_y) {
		
#ifdef NO_GFX
		if (virt_x < 0 || virt_x >= _virtual_res_x || virt_y < 0 || virt_y >= _virtual_res_y) {
#else
		if (virt_x < 0 || virt_x >= _width || virt_y < 0 || virt_y >= _height) {
#endif
			coords.x = coords.y = -1;
			return;
			//return coords;
		}

		//log_d("calcCoords pre-chain: virt_x: %d, virt_y: %d", virt_x, virt_y);

		// --- Runtime rotation ---
		switch (_rotate) {
			case 1: {
				int16_t temp = virt_x;
				virt_x = virt_y;
				virt_y = virtual_res_y - 1 - temp;
				break;
			}
			case 2: {
				virt_x = virtual_res_x - 1 - virt_x;
				virt_y = virtual_res_y - 1 - virt_y;
				break;
			}
			case 3: {
				int16_t temp = virt_x;
				virt_x = virtual_res_x - 1 - virt_y;
				virt_y = temp;
				break;
			}
			default:
				break;
		}

		// --- Chain mapping ---
		int row = virt_y / panel_res_y; // 0-indexed row in the virtual module
		if constexpr (ChainScanType == CHAIN_TOP_RIGHT_DOWN) {
			if ((row & 1) == 1) {
				coords.x = dma_res_x - virt_x - (row * virtual_res_x);
				coords.y = panel_res_y - 1 - (virt_y % panel_res_y);
			} else {
				coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
				coords.y = (virt_y % panel_res_y);
			}
		}
		else if constexpr (ChainScanType == CHAIN_TOP_RIGHT_DOWN_ZZ) {
			coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
			coords.y = (virt_y % panel_res_y);
		}
		else if constexpr (ChainScanType == CHAIN_TOP_LEFT_DOWN) {
			if ((row & 1) == 0) {
				coords.x = dma_res_x - virt_x - (row * virtual_res_x);
				coords.y = panel_res_y - 1 - (virt_y % panel_res_y);
			} else {
				coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
				coords.y = (virt_y % panel_res_y);
			}
		}
		else if constexpr (ChainScanType == CHAIN_TOP_LEFT_DOWN_ZZ) {
			coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
			coords.y = (virt_y % panel_res_y);
		}
		else if constexpr (ChainScanType == CHAIN_BOTTOM_LEFT_UP) {
			row = vmodule_rows - row - 1;
			if ((row & 1) == 1) {
				coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
				coords.y = (virt_y % panel_res_y);
			} else {
				coords.x = dma_res_x - (row * virtual_res_x) - virt_x;
				coords.y = panel_res_y - 1 - (virt_y % panel_res_y);
			}
		}
		else if constexpr (ChainScanType == CHAIN_BOTTOM_LEFT_UP_ZZ) {
			row = vmodule_rows - row - 1;
			coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
			coords.y = (virt_y % panel_res_y);
		}
		else if constexpr (ChainScanType == CHAIN_BOTTOM_RIGHT_UP) {
			row = vmodule_rows - row - 1;
			if ((row & 1) == 0) {
				coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
				coords.y = (virt_y % panel_res_y);
			} else {
				coords.x = dma_res_x - (row * virtual_res_x) - virt_x;
				coords.y = panel_res_y - 1 - (virt_y % panel_res_y);
			}
		}
		else if constexpr (ChainScanType == CHAIN_BOTTOM_RIGHT_UP_ZZ) {
			row = vmodule_rows - row - 1;
			coords.x = ((vmodule_rows - (row + 1)) * virtual_res_x) + virt_x;
			coords.y = (virt_y % panel_res_y);
		}
		else { // CHAIN_NONE (default)
			coords.x = virt_x;
			coords.y = virt_y;
		}

		//log_d("calcCoords post-chain: virt_x: %d, virt_y: %d", virt_x, virt_y);  

		// --- Apply physical LED panel scan–type mapping / fix ---
		coords = ScanTypeMapping::apply(coords, virt_y, panel_pixel_base);

	}

#ifdef NO_GFX
	inline uint16_t width()	 const { return _virtual_res_x; }
	inline uint16_t height() const { return _virtual_res_y; }
#endif

	// ------------------------------------------------------------------
	// Data members (public for compatibility)
	VirtualCoords coords;
	
	uint8_t panel_res_x;	   // physical panel resolution X
	uint8_t panel_res_y;	   // physical panel resolution Y
	uint8_t panel_pixel_base; // used for scan–type mapping

	inline void setDisplay(MatrixPanel_I2S_DMA &disp) {
		display = &disp;
	}

private:
	MatrixPanel_I2S_DMA *display;
	// Note: panel_chain_type is now fixed via the compile–time template parameter 'ChainScanType'.
	uint16_t virtual_res_x;	   // virtual display width (combination of panels)
	uint16_t virtual_res_y;	   // virtual display height (combination of panels)
	uint16_t _virtual_res_x;   // width adjusted by current rotation
	uint16_t _virtual_res_y;   // height adjusted by current rotation
	uint8_t	 vmodule_rows;	  // virtual module rows
	uint8_t	 vmodule_cols;	  // virtual module columns
	uint16_t dma_res_x;		   // width as seen by the DMA engine

	int _rotate;			 // runtime rotation (0 to 3)
};

#endif	// VIRTUAL_MATRIX_PANEL_TEMPLATE_H