/* 
 * (c) Philippe G. 2019, philippe_44@outlook.com
 *
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 * 
 */
 
#include <string.h>
#include "math.h"
#ifdef TJPGD_ROM
#include "esp32/rom/tjpgd.h"
#else
#include "tjpgd.h"
#endif
#include "esp_log.h"

#include "gds.h"
#include "gds_private.h"
#include "gds_image.h"

const static char TAG[] = "ImageDec";

#define SCRATCH_SIZE	3100

//Data that is passed from the decoder function to the infunc/outfunc functions.
typedef struct {
    const unsigned char *InData;	// Pointer to jpeg data
    int InPos;						// Current position in jpeg data
	int Width, Height;	
	uint8_t Mode;
	union {
		void *OutData;
		struct {						// DirectDraw
			struct GDS_Device *Device;
			int XOfs, YOfs;
			int XMin, YMin;
			int Depth;
		};	
	};	
} JpegCtx;

/****************************************************************************************
 * RGB conversion (24 bits 888: RRRRRRRRGGGGGGGGBBBBBBBB and 16 bits 565: RRRRRGGGGGGBBBBB = B31..B0)
 * so in other words for an array of 888 bytes: [0]=B, [1]=G, [2]=R, ...
 * monochrome (0.2125 * color.r) + (0.7154 * color.g) + (0.0721 * color.b)
 * grayscale (0.3 * R) + (0.59 * G) + (0.11 * B) )
 */
static inline int Scaler332(uint8_t *Pixels) {
	return (Pixels[2] & ~0x1f) | ((Pixels[1] & ~0x1f) >> 3) | (Pixels[0] >> 6);
}

static inline int Scaler444(uint8_t *Pixels) {
	return ((Pixels[2] & ~0x0f) << 4) | (Pixels[1] & ~0x0f) | (Pixels[0] >> 4);
}

static inline int Scaler555(uint8_t *Pixels) {
	return ((Pixels[2] & ~0x07) << 7) | ((Pixels[1] & ~0x07) << 2) | (Pixels[0] >> 3);
}

static inline int Scaler565(uint8_t *Pixels) {
	return ((Pixels[2] & ~0x07) << 8) | ((Pixels[1] & ~0x03) << 3) | (Pixels[0] >> 3);
}

static inline int Scaler666(uint8_t *Pixels) {
	return ((Pixels[2] & ~0x03) << 10) | ((Pixels[1] & ~0x03) << 4) | (Pixels[0] >> 2);
}

static inline int Scaler888(uint8_t *Pixels) {
	return (Pixels[2] << 16) | (Pixels[1] << 8) | Pixels[0];
}

static inline int ScalerGray(uint8_t *Pixels) {
	return (Pixels[2] * 14 + Pixels[1] * 76 + Pixels[0] * 38) >> 7;
}

static unsigned InHandler(JDEC *Decoder, uint8_t *Buf, unsigned Len) {
    JpegCtx *Context = (JpegCtx*) Decoder->device;
    if (Buf) memcpy(Buf, Context->InData +  Context->InPos, Len);
    Context->InPos += Len;
    return Len;
}

#define OUTHANDLER(F)										\
	for (int y = Frame->top; y <= Frame->bottom; y++) {		\
		for (int x = Frame->left; x <= Frame->right; x++) {	\
			OutData[Context->Width * y + x] = F(Pixels);	\
			Pixels += 3;									\
		}													\
	}	
	
#define OUTHANDLER24(F)													\
	for (int y = Frame->top; y <= Frame->bottom; y++) {					\
		uint8_t *p = OutData + (Context->Width * y + Frame->left) * 3;	\
		for (int c = Frame->right - Frame->left; c-- >= 0;) {			\
			uint32_t v = F(Pixels);										\
			*p++ = v; *p++ = v >> 8; *p++ = v >> 16;					\
			Pixels += 3;												\
		}																\
	}		

static unsigned OutHandler(JDEC *Decoder, void *Bitmap, JRECT *Frame) {
	JpegCtx *Context = (JpegCtx*) Decoder->device;
    uint8_t *Pixels = (uint8_t*) Bitmap;

	// decoded image is RGB888
	if (Context->Mode == GDS_RGB888) {
		uint8_t *OutData = (uint8_t*) Context->OutData;		
		OUTHANDLER24(Scaler888);
	} else if (Context->Mode == GDS_RGB666) {
		uint8_t *OutData = (uint8_t*) Context->OutData;		
		OUTHANDLER24(Scaler666);		
	} else if (Context->Mode == GDS_RGB565) {
		uint16_t *OutData = (uint16_t*) Context->OutData;
		OUTHANDLER(Scaler565);		
	} else if (Context->Mode == GDS_RGB555) {
		uint16_t *OutData = (uint16_t*) Context->OutData;
		OUTHANDLER(Scaler555);				
	} else if (Context->Mode == GDS_RGB444) {
		uint16_t *OutData = (uint16_t*) Context->OutData;
		OUTHANDLER(Scaler444);						
	} else if (Context->Mode == GDS_RGB332) {
		uint8_t *OutData = (uint8_t*) Context->OutData;
		OUTHANDLER(Scaler332);						
	} else if (Context->Mode <= GDS_GRAYSCALE) { 	 
		uint8_t *OutData = (uint8_t*) Context->OutData;		
		OUTHANDLER(ScalerGray);
	}
    
    return 1;
}

// Convert the RGB888 to destination color plane, use DrawPixel and not "fast" 
// version as X,Y may be beyond screen				
#define OUTHANDLERDIRECT(F,S)																		\
	for (int y = Frame->top; y <= Frame->bottom; y++) {												\
		if (y < Context->YMin) continue;															\
		for (int x = Frame->left; x <= Frame->right; x++) {											\
			if (x < Context->XMin) continue;														\
			DrawPixel( Context->Device, x + Context->XOfs, y + Context->YOfs, F(Pixels) >> S);	\
			Pixels += 3;																			\
		}																							\
	}
	
static unsigned OutHandlerDirect(JDEC *Decoder, void *Bitmap, JRECT *Frame) {
	JpegCtx *Context = (JpegCtx*) Decoder->device;
    uint8_t *Pixels = (uint8_t*) Bitmap;
	int Shift = 8 - Context->Depth;
	
	// decoded image is RGB888, shift only make sense for grayscale
	if (Context->Mode == GDS_RGB888) {
		OUTHANDLERDIRECT(Scaler888, 0);
	} else if (Context->Mode == GDS_RGB666) {
		OUTHANDLERDIRECT(Scaler666, 0);		
	} else if (Context->Mode == GDS_RGB565) {
		OUTHANDLERDIRECT(Scaler565, 0);		
	} else if (Context->Mode == GDS_RGB555) {
		OUTHANDLERDIRECT(Scaler555, 0);				
	} else if (Context->Mode == GDS_RGB444) {
		OUTHANDLERDIRECT(Scaler444, 0);						
	} else if (Context->Mode == GDS_RGB332) {
		OUTHANDLERDIRECT(Scaler332, 0);						
	} else if (Context->Mode <= GDS_GRAYSCALE) { 	 
		OUTHANDLERDIRECT(ScalerGray, Shift);
	}
    
    return 1;
}

//Decode the embedded image into pixel lines that can be used with the rest of the logic.
static void* DecodeJPEG(uint8_t *Source, int *Width, int *Height, float Scale, bool SizeOnly, int RGB_Mode) {
    JDEC Decoder;
    JpegCtx Context;
	char *Scratch = malloc(SCRATCH_SIZE);
	
    if (!Scratch) {
        ESP_LOGE(TAG, "Cannot allocate workspace");
        return NULL;
    }

	Context.OutData = NULL;
    Context.InData = Source;
    Context.InPos = 0;
	        
    //Prepare and decode the jpeg.
    int Res = jd_prepare(&Decoder, InHandler, Scratch, SCRATCH_SIZE, (void*) &Context);
	if (Width) *Width = Decoder.width;
	if (Height) *Height = Decoder.height;
	Decoder.scale = Scale;

    if (Res == JDR_OK && !SizeOnly) {
		if (RGB_Mode <= GDS_RGB332) Context.OutData = malloc(Decoder.width * Decoder.height);
		else if (RGB_Mode < GDS_RGB666) Context.OutData = malloc(Decoder.width * Decoder.height * 2);
		else if (RGB_Mode <= GDS_RGB888) Context.OutData = malloc(Decoder.width * Decoder.height * 3);
		
		// find the scaling factor
		uint8_t N = 0, ScaleInt =  ceil(1.0 / Scale);
		ScaleInt--; ScaleInt |= ScaleInt >> 1; ScaleInt |= ScaleInt >> 2; ScaleInt++;
		while (ScaleInt >>= 1) N++;
		if (N > 3) {
			ESP_LOGW(TAG, "Image will not fit %dx%d", Decoder.width, Decoder.height);
			N = 3;
		}	
		
		// ready to decode		
		if (Context.OutData) {
			Context.Width = Decoder.width / (1 << N);
			Context.Height = Decoder.height / (1 << N);
			Context.Mode = RGB_Mode;
			if (Width) *Width = Context.Width;
			if (Height) *Height = Context.Height;
			Res = jd_decomp(&Decoder, OutHandler, N);
			if (Res != JDR_OK) {
				ESP_LOGE(TAG, "Image decoder: jd_decode failed (%d)", Res);
			}	
		} else {
			ESP_LOGE(TAG, "Can't allocate bitmap %dx%d or invalid mode %d", Decoder.width, Decoder.height, RGB_Mode);			
		}	
	} else if (!SizeOnly) {
        ESP_LOGE(TAG, "Image decoder: jd_prepare failed (%d)", Res);
    }    

	// free scratch area
    if (Scratch) free(Scratch);
    return Context.OutData;
}

void* GDS_DecodeJPEG(uint8_t *Source, int *Width, int *Height, float Scale, int RGB_Mode) {
	return DecodeJPEG(Source, Width, Height, Scale, false, RGB_Mode);
}	

void GDS_GetJPEGSize(uint8_t *Source, int *Width, int *Height) {
	DecodeJPEG(Source, Width, Height, 1, true, -1);
}	

/****************************************************************************************
 * RGB conversion (24 bits: RRRRRRRRGGGGGGGGBBBBBBBB and 16 bits 565: RRRRRGGGGGGBBBBB = B31..B0)
 * so in other words for an array of 888 bytes: [0]=B, [1]=G, [2]=R, ...
 * monochrome (0.2125 * color.r) + (0.7154 * color.g) + (0.0721 * color.b)
 * grayscale (0.3 * R) + (0.59 * G) + (0.11 * B) )
 */
 
static inline int ToGray888(uint8_t **Pixel) {
	uint32_t v = *(*Pixel)++; v |= *(*Pixel)++ << 8; v |= *(*Pixel)++ << 16; 
	return (((v & 0xff) * 14) + ((v >> 8) & 0xff) * 76 + ((v >> 16) * 38) + 1) >> 7;
} 
 
static inline int ToGray666(uint8_t **Pixel) {
	uint32_t v = *(*Pixel)++; v |= *(*Pixel)++ << 8; v |= *(*Pixel)++ << 16; 
	return (((v & 0x3f) * 14) + ((v >> 6) & 0x3f) * 76 + ((v >> 12) * 38) + 1) >> 7;
}

static inline int ToGray565(uint16_t **Pixel) {
	uint16_t v = *(*Pixel)++; 
	return ((((v & 0x1f) * 14) << 1) + ((v >> 5) & 0x3f) * 76 + (((v >> 11) * 38) << 1) + 1) >> 7;
}

static inline int ToGray555(uint16_t **Pixel) {
	uint16_t v = *(*Pixel)++; 
	return ((v & 0x1f) * 14 + ((v >> 5) & 0x1f) * 76 + (v >> 10) * 38) >> 7;
}

static inline int ToGray444(uint16_t **Pixel) {
	uint16_t v = *(*Pixel)++; 
	return ((v & 0x0f) * 14 + ((v >> 4) & 0x0f) * 76 + (v >> 8) * 38) >> 7;
}

static inline int ToGray332(uint8_t **Pixel) {
	uint8_t v = *(*Pixel)++; 
	return ((((v & 0x3) * 14) << 1) + ((v >> 2) & 0x7) * 76 + (v >> 5) * 38 + 1) >> 7;
}

static inline int ToSelf(uint8_t **Pixel) {
	return *(*Pixel)++; 
}
	
#define DRAW_GRAYRGB(S,F)													\
	if (Scale > 0) {														\
		for (int r = 0; r < Height; r++) {									\
			for (int c = 0; c < Width; c++) {								\
				DrawPixel( Device, c + x, r + y, F(S) >> Scale);		\
			}																\
		}																	\
	} else {																\
		for (int r = 0; r < Height; r++) {									\
			for (int c = 0; c < Width; c++) {								\
				DrawPixel( Device, c + x, r + y, F(S) << -Scale);	\
			}																\
		}																	\
	}									
	
#define DRAW_RGB(T)										\
	T *S = (T*) Image;									\
	for (int r = 0; r < Height; r++) {					\
		for (int c = 0; c < Width; c++) {				\
			DrawPixel(Device, c + x, r + y, *S++);	\
		}												\
	}																	
	
#define DRAW_RGB24													\
	uint8_t *S = (uint8_t*) Image;									\
	for (int r = 0; r < Height; r++) {								\
		for (int c = 0; c < Width; c++) {							\
			uint32_t v = *S++; v |= *S++ << 8; v |= *S++ << 16;		\
			DrawPixel(Device, c + x, r + y, v);					\
		}															\
	}	

/****************************************************************************************
 *  Decode the embedded image into pixel lines that can be used with the rest of the logic.
 */
void GDS_DrawRGB( struct GDS_Device* Device, uint8_t *Image, int x, int y, int Width, int Height, int RGB_Mode ) {

	// don't do anything if driver supplies a draw function
	if (Device->DrawRGB) {
		Device->DrawRGB( Device, Image, x, y, Width, Height, RGB_Mode );
		Device->Dirty = true;	
		return;
	}
	
	// RGB type displays
	if (Device->Mode > GDS_GRAYSCALE) {
		// image must match the display mode!
		if (Device->Mode != RGB_Mode) {
			ESP_LOGE(TAG, "non-matching display & image mode %u %u", Device->Mode, RGB_Mode);
			return;
		}	
		
		if (RGB_Mode == GDS_RGB332) {
			DRAW_RGB(uint8_t);
		} else if (RGB_Mode < GDS_RGB666) {
			DRAW_RGB(uint16_t);
		} else {
			DRAW_RGB24;
		}	
		
		Device->Dirty = true;
		return;
	}
	
	// set the right scaler when displaying grayscale
	if (RGB_Mode <= GDS_GRAYSCALE) {
		int Scale = 8 - Device->Depth;
		DRAW_GRAYRGB(&Image,ToSelf);
	} else if (RGB_Mode == GDS_RGB332) {
		int Scale = 3 - Device->Depth;		
		DRAW_GRAYRGB(&Image,ToGray332);
	} else if (RGB_Mode < GDS_RGB666)	{
		if (RGB_Mode == GDS_RGB565) {
			int Scale = 6 - Device->Depth;
			DRAW_GRAYRGB((uint16_t**)&Image,ToGray565);
		} else if (RGB_Mode == GDS_RGB555) {
			int Scale = 5 - Device->Depth;
			DRAW_GRAYRGB((uint16_t**)&Image,ToGray555);
		} else if (RGB_Mode == GDS_RGB444) {
			int Scale = 4 - Device->Depth; 
			DRAW_GRAYRGB((uint16_t**)&Image,ToGray444)
		}	
	} else {
		if (RGB_Mode == GDS_RGB666) {
			int Scale = 6 - Device->Depth;
			DRAW_GRAYRGB(&Image,ToGray666);
		} else if (RGB_Mode == GDS_RGB888) {
			int Scale = 8 - Device->Depth;
			DRAW_GRAYRGB(&Image,ToGray888);
		}	
	} 
	
	Device->Dirty = true;	
}

/****************************************************************************************
 *  Decode the embedded image into pixel lines that can be used with the rest of the logic.
 */
bool GDS_DrawJPEG(struct GDS_Device* Device, uint8_t *Source, int x, int y, int Fit) {
    JDEC Decoder;
    JpegCtx Context;
	bool Ret = false;
	char *Scratch = malloc(SCRATCH_SIZE);
	
    if (!Scratch) {
        ESP_LOGE(TAG, "Cannot allocate workspace");
        return NULL;
    }

    // Populate fields of the JpegCtx struct.
    Context.InData = Source;
    Context.InPos = 0;
	Context.XOfs = x;
	Context.YOfs = y;
	Context.Device = Device;
	Context.Depth = Device->Depth;
        
    //Prepare and decode the jpeg.
    int Res = jd_prepare(&Decoder, InHandler, Scratch, SCRATCH_SIZE, (void*) &Context);
	Context.Width = Decoder.width;
	Context.Height = Decoder.height;
	
    if (Res == JDR_OK) {
		uint8_t N = 0;
		
		// do we need to fit the image
		if (Fit & GDS_IMAGE_FIT) {
			float XRatio = (Device->Width - x) / (float) Decoder.width, YRatio = (Device->Height - y) / (float) Decoder.height;
			uint8_t Ratio = XRatio < YRatio ? ceil(1/XRatio) : ceil(1/YRatio);
			Ratio--; Ratio |= Ratio >> 1; Ratio |= Ratio >> 2; Ratio++;
			while (Ratio >>= 1) N++;
			if (N > 3) {
				ESP_LOGW(TAG, "Image will not fit %dx%d", Decoder.width, Decoder.height);
				N = 3;
			}	
			Context.Width /= 1 << N;
			Context.Height /= 1 << N;
		} 
		
		// then place it
		if (Fit & GDS_IMAGE_CENTER_X) Context.XOfs = (Device->Width + x - Context.Width) / 2;
		else if (Fit & GDS_IMAGE_RIGHT) Context.XOfs = Device->Width - Context.Width;
		if (Fit & GDS_IMAGE_CENTER_Y) Context.YOfs = (Device->Height + y - Context.Height) / 2;
		else if (Fit & GDS_IMAGE_BOTTOM) Context.YOfs = Device->Height - Context.Height;

		Context.XMin = x - Context.XOfs;
		Context.YMin = y - Context.YOfs;
		Context.Mode = Device->Mode;
					
		// do decompress & draw
		Res = jd_decomp(&Decoder, OutHandlerDirect, N);
		if (Res == JDR_OK) {
			Device->Dirty = true;
			Ret = true;
		} else {	
			ESP_LOGE(TAG, "Image decoder: jd_decode failed (%d)", Res);
		}	
	} else {	
        ESP_LOGE(TAG, "Image decoder: jd_prepare failed (%d)", Res);
    }    
      
	// free scratch area
    if (Scratch) free(Scratch);
	return Ret;
}

