/**

 * $Id: dreamcast.c,v 1.28 2007-10-31 11:53:35 nkeynes Exp $

 * Central switchboard for the system. This pulls all the individual modules

 * together into some kind of coherent structure. This is also where you'd

 * add Naomi support, if I ever get a board to play with...

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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 2 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.

 */

#include <errno.h>

#include "dream.h"

#include "config.h"

#include "mem.h"

#include "aica/aica.h"

#include "asic.h"

#include "dreamcast.h"

#include "gdrom/ide.h"

#include "maple/maple.h"

/**

 * Current state of the DC virtual machine

 */

#define STATE_UNINIT 0

#define STATE_RUNNING 1

#define STATE_STOPPING 2

#define STATE_STOPPED 3 

static volatile int dreamcast_state = STATE_UNINIT;

static uint32_t timeslice_length = DEFAULT_TIMESLICE_LENGTH;

const char *dreamcast_config = "DEFAULT";

#define MAX_MODULES 32

static int num_modules = 0;

dreamcast_module_t modules[MAX_MODULES];

/**

 * The unknown module is used for logging files without an actual module

 * declaration

 */

struct dreamcast_module unknown_module = { "****", NULL, NULL, NULL, NULL, 

					   NULL, NULL, NULL };

/**

 * This function is responsible for defining how all the pieces of the

 * dreamcast actually fit together. 

 *

 * Note currently the locations of the various MMIO pages are hard coded in

 * the MMIO definitions - they should probably be moved here.

 */

void dreamcast_configure( )

{

    dreamcast_register_module( &eventq_module );

    /* Register the memory framework */

    dreamcast_register_module( &mem_module );

    /* Setup standard memory map */

    mem_create_repeating_ram_region( 0x0C000000, 16 MB, MEM_REGION_MAIN, 0x01000000, 0x0F000000 );

    mem_create_ram_region( 0x00800000, 2 MB, MEM_REGION_AUDIO );

    mem_create_ram_region( 0x00703000, 8 KB, MEM_REGION_AUDIO_SCRATCH );

    mem_create_ram_region( 0x05000000, 8 MB, MEM_REGION_VIDEO );

    mem_load_rom( lxdream_get_config_value(CONFIG_BIOS_PATH),

		  0x00000000, 0x00200000, 0x89f2b1a1, MEM_REGION_BIOS );

    mem_create_ram_region( 0x00200000, 0x00020000, MEM_REGION_FLASH );

    mem_load_block( lxdream_get_config_value(CONFIG_FLASH_PATH),

		    0x00200000, 0x00020000 );

    /* Load in the rest of the core modules */

    dreamcast_register_module( &sh4_module );

    dreamcast_register_module( &asic_module );

    dreamcast_register_module( &pvr2_module );

    dreamcast_register_module( &aica_module );

    dreamcast_register_module( &maple_module );

    dreamcast_register_module( &ide_module );

}

void dreamcast_config_changed(void)

{

    mem_load_rom( lxdream_get_config_value(CONFIG_BIOS_PATH),

		  0x00000000, 0x00200000, 0x89f2b1a1, MEM_REGION_BIOS );

    mem_load_block( lxdream_get_config_value(CONFIG_FLASH_PATH),

		    0x00200000, 0x00020000 );

}

void dreamcast_save_flash()

{

    const char *file = lxdream_get_config_value(CONFIG_FLASH_PATH);

    mem_save_block( file, 0x00200000, 0x00020000 );

}

/**

 * Constructs a system configuration for the AICA in standalone mode,

 * ie sound chip only.

 */

void dreamcast_configure_aica_only( )

{

    dreamcast_register_module( &mem_module );

    mem_create_ram_region( 0x00800000, 2 MB, MEM_REGION_AUDIO );

    mem_create_ram_region( 0x00703000, 8 KB, MEM_REGION_AUDIO_SCRATCH );

    dreamcast_register_module( &aica_module );

    aica_enable();

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_register_module( dreamcast_module_t module ) 

{

    modules[num_modules++] = module;

    if( module->init != NULL )

	module->init();

}

void dreamcast_init( void )

{

    dreamcast_configure();

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_reset( void )

{

    int i;

    for( i=0; i<num_modules; i++ ) {

	if( modules[i]->reset != NULL )

	    modules[i]->reset();

    }

}

void dreamcast_run( void )

{

    int i;

    if( dreamcast_state != STATE_RUNNING ) {

	for( i=0; i<num_modules; i++ ) {

	    if( modules[i]->start != NULL )

		modules[i]->start();

	}

    }

    dreamcast_state = STATE_RUNNING;

    while( dreamcast_state == STATE_RUNNING ) {

	int time_to_run = timeslice_length;

	for( i=0; i<num_modules; i++ ) {

	    if( modules[i]->run_time_slice != NULL )

		time_to_run = modules[i]->run_time_slice( time_to_run );

	}

    }

    for( i=0; i<num_modules; i++ ) {

	if( modules[i]->stop != NULL )

	    modules[i]->stop();

    }

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_run_for( unsigned int seconds, unsigned int nanosecs )

{

    int i;

    if( dreamcast_state != STATE_RUNNING ) {

	for( i=0; i<num_modules; i++ ) {

	    if( modules[i]->start != NULL )

		modules[i]->start();

	}

    }

    dreamcast_state = STATE_RUNNING;

    uint32_t nanos = 0;

    if( nanosecs != 0 ) {

        nanos = 1000000000 - nanosecs;

	seconds++;

    }

    while( dreamcast_state == STATE_RUNNING && seconds != 0 ) {

	int time_to_run = timeslice_length;

	for( i=0; i<num_modules; i++ ) {

	    if( modules[i]->run_time_slice != NULL )

		time_to_run = modules[i]->run_time_slice( time_to_run );

	}

	nanos += time_to_run;

	if( nanos >= 1000000000 ) {

	    nanos -= 1000000000;

	    seconds--;

	}

    }

    for( i=0; i<num_modules; i++ ) {

	if( modules[i]->stop != NULL )

	    modules[i]->stop();

    }

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_stop( void )

{

    if( dreamcast_state == STATE_RUNNING )

	dreamcast_state = STATE_STOPPING;

}

void dreamcast_shutdown()

{

    dreamcast_stop();

    dreamcast_save_flash();

}

gboolean dreamcast_is_running( void )

{

    return dreamcast_state == STATE_RUNNING;

}

/********************************* Save States *****************************/

struct save_state_header {

    char magic[16];

    uint32_t version;

    uint32_t module_count;

};

struct chunk_header {

    char marker[4]; /* Always BLCK */

    char name[8]; /* Block (module) name */

    uint32_t block_length;

};

/**

 * Check the save state header to ensure that it is a valid, supported

 * file. 

 * @return the number of blocks following, or 0 if the file is invalid.

 */

int dreamcast_read_save_state_header( FILE *f )

{

    struct save_state_header header;

    if( fread( &header, sizeof(header), 1, f ) != 1 ) {

	return 0;

    }

    if( strncmp( header.magic, DREAMCAST_SAVE_MAGIC, 16 ) != 0 ) {

	ERROR( "Not a %s save state file", APP_NAME );

	return 0;

    }

    if( header.version != DREAMCAST_SAVE_VERSION ) {

	ERROR( "%s save state version not supported", APP_NAME );

	return 0;

    }

    if( header.module_count > MAX_MODULES ) {

	ERROR( "%s save state is corrupted (bad module count)", APP_NAME );

	return 0;

    }

    return header.module_count;

}

int dreamcast_write_chunk_header( const gchar *name, uint32_t length, FILE *f )

{

    struct chunk_header head;

    memcpy( head.marker, "BLCK", 4 );

    memset( head.name, 0, 8 );

    memcpy( head.name, name, strlen(name) );

    head.block_length = length;

    return fwrite( &head, sizeof(head), 1, f );

}

frame_buffer_t dreamcast_load_preview( const gchar *filename )

{

    int i;

    FILE *f = fopen( filename, "r" );

    if( f == NULL ) return NULL;

    int module_count = dreamcast_read_save_state_header(f);

    if( module_count <= 0 ) {

	fclose(f);

	return NULL;

    }

    for( i=0; i<module_count; i++ ) {

	struct chunk_header head;

	if( fread( &head, sizeof(head), 1, f ) != 1 ) {

	    fclose(f);

	    return NULL;

	}

	if( memcmp("BLCK", head.marker, 4) != 0 ) {

	    fclose(f);

	    return NULL;

	}

	if( strcmp("PVR2", head.name) == 0 ) {

	    uint32_t buf_count;

	    int has_front;

	    fread( &buf_count, sizeof(buf_count), 1, f );

	    fread( &has_front, sizeof(has_front), 1, f );

	    if( buf_count != 0 && has_front ) {

		frame_buffer_t result = read_png_from_stream(f);

		fclose(f);

		return result;

	    }

	    break;

	} else {

	    fseek( f, head.block_length, SEEK_CUR );

	}

    }

    return NULL;

}

int dreamcast_load_state( const gchar *filename )

{

    int i,j;

    int module_count;

    int have_read[MAX_MODULES];

    FILE *f = fopen( filename, "r" );

    if( f == NULL ) return errno;

    module_count = dreamcast_read_save_state_header(f);

    if( module_count <= 0 ) {

	fclose(f);

	return 1;

    }

    for( i=0; i<MAX_MODULES; i++ ) {

	have_read[i] = 0;

    }

    for( i=0; i<module_count; i++ ) {

	struct chunk_header chunk;

	fread( &chunk, sizeof(chunk), 1, f );

	if( strncmp(chunk.marker, "BLCK", 4) != 0 ) {

	    ERROR( "%s save state is corrupted (missing block header %d)", APP_NAME, i );

	    fclose(f);

	    return 2;

	}

	/* Find the matching module by name */

	for( j=0; j<num_modules; j++ ) {

	    if( strcmp(modules[j]->name,chunk.name) == 0 ) {

		have_read[j] = 1;

		if( modules[j]->load == NULL ) {

		    ERROR( "%s save state is corrupted (no loader for %s)", APP_NAME, modules[j]->name );

		    fclose(f);

		    return 2;

		} else if( modules[j]->load(f) != 0 ) {

		    ERROR( "%s save state is corrupted (%s failed)", APP_NAME, modules[j]->name );

		    fclose(f);

		    return 2;

		}

		break;

	    }

	}

	if( j == num_modules ) {

	    fclose(f);

	    ERROR( "%s save state contains unrecognized section", APP_NAME );

	    return 2;

	}

    }

    /* Any modules that we didn't load - reset to the default state.

     * (ie it's not an error to skip a module if you don't actually

     * care about its state).

     */

    for( j=0; j<num_modules; j++ ) {

	if( have_read[j] == 0 && modules[j]->reset != NULL ) {

	    modules[j]->reset();

	}

    }

    fclose(f);

    INFO( "Save state read from %s", filename );

    return 0;

}

int dreamcast_save_state( const gchar *filename )

{

    int i;

    FILE *f;

    struct save_state_header header;

    f = fopen( filename, "w" );

    if( f == NULL )

	return errno;

    strcpy( header.magic, DREAMCAST_SAVE_MAGIC );

    header.version = DREAMCAST_SAVE_VERSION;

    header.module_count = 0;

    for( i=0; i<num_modules; i++ ) {

	if( modules[i]->save != NULL )

	    header.module_count++;

    }

    fwrite( &header, sizeof(header), 1, f );

    for( i=0; i<num_modules; i++ ) {

	if( modules[i]->save != NULL ) {

	    uint32_t blocklen, posn1, posn2;

	    dreamcast_write_chunk_header( modules[i]->name, 0, f );

	    posn1 = ftell(f);

	    modules[i]->save(f);

	    posn2 = ftell(f);

	    blocklen = posn2 - posn1;

	    fseek( f, posn1-4, SEEK_SET );

	    fwrite( &blocklen, sizeof(blocklen), 1, f );

	    fseek( f, posn2, SEEK_SET );

	}

    }

    fclose( f );

    INFO( "Save state written to %s", filename );

    return 0;

}