#include "7seg.h"

#include <stdio.h>
#include <stdbool.h>

#ifdef WITH_GUI
#include <SDL.h>
#include <SDL2_gfxPrimitives.h>
#endif

static device_vtable_t const seg7_vtable = {
	seg7_read,
	seg7_write,
#ifdef WITH_GUI
	seg7_draw,
#endif
	seg7_deinit
};

void seg7_init( seg7_t *seg, bool initialize )
{
	device_init( &seg->base, "seg7" );
	seg->base.vtable = (device_vtable_t *)&seg7_vtable;

	seg->debug = false;
	
	if( initialize ) {
		seg->latch = 0x0000;
		seg->shift = 0x0000;
	}
}

uint8_t seg7_read( void *obj, uint16_t addr )
{
	// device is a write-only device
	return 0;
}

void seg7_write( void *obj, uint16_t addr, uint8_t data )
{
	seg7_t *seg = (seg7_t *)obj;

	// address is not relevant, PORTA is connected to our signals
	// via a databus
	
	// write bits from SER into shift register on positive SRCLK
	if( data & SRCLK ) {
		seg->shift = ( seg->shift << 1 ) | ( data & SER );
		if( seg->debug ) {
			fprintf( stderr, "7seg shifting data, data is now %02X\n", seg->shift );
		}
	}
	
	// copy shift to latch register on positive RCLK
	if( data & RCLK ) {
		seg->latch = seg->shift;
		if( seg->debug ) {
			fprintf( stderr, "7seg copying %02X from shift to latch\n", seg->latch );
		}
	}
			
	// ignore writes to other addresses
}

#ifdef WITH_GUI

enum {
	NOF_DIGITS = 16,
	NOF_SEGS = 7,
	// direction of the segment (vertical or horizontal)
	H = 0,
	V = 1,
	// segment positions in the segs array (bit)
	A = 6,
	B = 5,
	C = 4,
	D = 3,
	E = 2,
	F = 1,
	G = 0
};

static int segs[NOF_DIGITS] = {
	0x7E, 0x30, 0x6D, 0x79, 0x33,
	0x5B, 0x5F, 0x70, 0x7F, 0x7B,
	0x77, 0x1F, 0x4E, 0x3D, 0x4F,
	0x47
};

static int x_pos[NOF_SEGS] = {
	5, 45, 45,  5,  5,  5 , 5 
};

static int y_pos[NOF_SEGS] = 
{
	5,  5, 45, 90, 45,  5, 45
};

static int direction[NOF_SEGS] =
{
	H, V, V, H, V, V, H
};

static void printSegment( SDL_Renderer *renderer, int x, int y, int direction, bool enabled )
{
	int r = 80;
	
	if( enabled ) {
		r = 255;
	}
			
	switch( direction ) {
		case H:
			boxRGBA( renderer, x-3, y-3, x+40, y+3, r, 0x00, 0x00, 0xFF );	
			break;
		
		case V:
			boxRGBA( renderer, x-3, y-3, x+3, y+40, r, 0x00, 0x00, 0xFF );	
			break;
	}
}

static void printDigit( SDL_Renderer *renderer, int x, int y, int digit )
{
	int v = ( 1 << 6 );
	for( int i = 0; i < 7; i++ ) {
		printSegment( renderer, x + x_pos[i], y + y_pos[i], direction[i], v & segs[digit] );
		v >>= 1;
	}
}	

void seg7_draw( void *obj, SDL_Renderer *renderer )
{
	seg7_t *seg = (seg7_t *)obj;
	
	boxRGBA( renderer, 10, 10, 110, 110, 0x00, 0x00, 0x00, 0xFF );
	
	printDigit( renderer, 10, 10, ( seg->latch & 0x00F0 ) >> 4 );
	printDigit( renderer, 60, 10, seg->latch & 0x000F );
}
#endif

void seg7_deinit( void *obj )
{
	seg7_t *seg = (seg7_t *)obj;

	device_deinit( &seg->base );
}