#include "emul.h"

#include <stdio.h>
#include <stdlib.h>

void emul_init( emul_t *emul, cpu_6502_t *cpu, bus_t *bus, int width, int height )
{
	emul->cpu = cpu;
	emul->bus = bus;
	emul->gui = false;
	emul->width = width;
	emul->height = height;
	emul->debug = false;
	emul->paused = false;
	emul->speed = CPU_FREQUENCY;
}

void emul_start( emul_t *emul )
{
	if( emul->gui ) {
#ifdef WITH_GUI
		int rt = SDL_Init( SDL_INIT_TIMER | SDL_INIT_AUDIO | SDL_INIT_VIDEO );
		if( rt < 0 ) {
			fprintf( stderr, "ERROR: SDL_Init failed: %s\n", SDL_GetError( ) );
			exit( EXIT_FAILURE );
		}
		atexit( SDL_Quit );
		SDL_ShowCursor( SDL_ENABLE );
		
		int display = -1;
		for( int i = 0; i < SDL_GetNumVideoDisplays( ); i++ ) {
			SDL_Rect rect;
			if( SDL_GetDisplayBounds( i, &rect ) == 0 ) {
				fprintf( stderr, "INFO: display %d has dimensions %dx%d\n",
					i, rect.w, rect.h );
				display = i;
			} else {
				fprintf( stderr, "ERROR: SDL_GetDisplayBounds failed: %s\n", SDL_GetError( ) );
				exit( EXIT_FAILURE );
			}
		}
		if( display < 0 ) {
			fprintf( stderr, "ERROR: no video display found\n" );
			exit( EXIT_FAILURE );
		}
		
		emul->window = SDL_CreateWindow( "6502 emu",  
			SDL_WINDOWPOS_UNDEFINED_DISPLAY( display ),
			SDL_WINDOWPOS_UNDEFINED_DISPLAY( display ),
			emul->width, emul->height, 0 );
		if( emul->window == NULL ) {
			fprintf( stderr, "ERROR: SDL_CreateWindow failed: %s\n", SDL_GetError( ) );
			exit( EXIT_FAILURE );
		}

		emul->renderer = SDL_CreateRenderer( emul->window, -1, 0 );
		if( emul->renderer == NULL ) {
			fprintf( stderr, "ERROR: SDL_Renderer failed: %s\n", SDL_GetError( ) );
			exit( EXIT_FAILURE );
		}
		
		SDL_ShowWindow( emul->window );
		SDL_SetRenderDrawColor( emul->renderer, 0, 0, 0, 255 );
		SDL_RenderClear( emul->renderer );
		
		emul->background_image = SDL_LoadBMP( "../other/breadboard.bmp" );
		emul->background_texture = SDL_CreateTextureFromSurface( emul->renderer, emul->background_image );
		SDL_RenderCopy( emul->renderer, emul->background_texture, NULL, NULL );
				
		SDL_RenderPresent( emul->renderer );
#else
		fprintf( stderr, "WARN: gui enabled and not compiled with WITH_GUI (SDL2)\n" );
#endif
	}
}

static void print_help( void )
{
	fprintf( stderr, "CPU is paused, press\n"
		"(s) for single step\n"
		"(f) fini (continue to next rts)\n"
		"(c) for continue running\n"
		"(b) break to single stepping\n"
		"(+) speed up\n"
		"(-) speed down\n"
		"(q) or (ESC) for shutting down\n" );
}

void emul_run( emul_t *emul, int nof_steps )
{
#ifdef WITH_GUI
	if( emul->gui ) {
		SDL_Event event;
		bool done = false;

		if( emul->paused ) {
			print_help( );
		}

		while( !done && emul->cpu->error_state == ERROR_STATE_OK ) {
			uint32_t frame_start = SDL_GetTicks( );
						
			SDL_PollEvent( &event );
			
			switch( event.type ) {
				case SDL_KEYDOWN:
					switch( event.key.keysym.sym ) {
						case SDLK_ESCAPE:
						case SDLK_q:
							done = true;
							break;
						case SDLK_c:
							fprintf( stderr, "continuing at normal speed %1.6f MHz\n", ( (double)emul->speed / 1000000 ) );
							emul->paused = false;
							break;
						case SDLK_b:
							fprintf( stderr, "CPU paused (in single step mode)\n" );
							emul->paused = true;
							break;
						case SDLK_s:
							cpu_6502_run_steps( emul->cpu, 1 );
							break;
						case SDLK_EQUALS:
						case SDLK_KP_EQUALS:
						case SDLK_PLUS:
						case SDLK_KP_PLUS:
							emul->speed *= 10;
							if( emul->speed > CPU_FREQUENCY ) {
								emul->speed = CPU_FREQUENCY;
							}
							fprintf( stderr, "CPU speed  is %1.6f MHz now\n", ( (double)emul->speed / 1000000 ) );
							break;
						case SDLK_MINUS:
						case SDLK_KP_MINUS:
							emul->speed /= 10;
							if( emul->speed < 25 ) {
								emul->speed = 25;
							}
							fprintf( stderr, "CPU speed  is %1.6f MHz now\n", ( (double)emul->speed / 1000000 ) );
							break;
					}
					break;
				
				case SDL_QUIT:
					done = true;
					break;				
			}
			
			if( !emul->paused ) {
				cpu_6502_run_cycles( emul->cpu, emul->speed / DISPLAY_FPS );
			}
						
			SDL_RenderCopy( emul->renderer, emul->background_texture, NULL, NULL );

			emul->bus->base.vtable->draw( emul->bus, emul->renderer );
			//~ for( int i = 0; i < emul->bus->nof_devices; i++ ) {
				//~ device_t *device = emul->bus->devices[i].device;
				//~ device->vtable->draw( device, emul->renderer );
			//~ }

			SDL_RenderPresent( emul->renderer );

			uint32_t frame_end = SDL_GetTicks( );
			int delay = frame_start + 1000 / DISPLAY_FPS - frame_end;
			if( delay > 0 ) {
				SDL_Delay( delay );
			}
			
			if( nof_steps != -1 && emul->cpu->steps > nof_steps ) {
				fprintf( stderr, "INFO: final number of steps reached (%d), terminating now\n", emul->cpu->steps );
				done = true;
			}
		}
	} else {
		cpu_6502_run_steps( emul->cpu, nof_steps );
	}
#else
	cpu_6502_run( emul->cpu, nof_steps );
#endif
}

void emul_free( emul_t *emul )
{
#ifdef WITH_GUI
	if( emul->gui ) {
		SDL_DestroyTexture( emul->background_texture );
		SDL_FreeSurface( emul->background_image );
		SDL_DestroyRenderer( emul->renderer );
		SDL_DestroyWindow( emul->window );
	}
#endif
}