/**

 * $Id$

 * 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 <glib.h>

#include <unistd.h>

#include "lxdream.h"

#include "lxpaths.h"

#include "dream.h"

#include "eventq.h"

#include "mem.h"

#include "dreamcast.h"

#include "asic.h"

#include "syscall.h"

#include "gui.h"

#include "aica/aica.h"

#include "gdrom/ide.h"

#include "maple/maple.h"

#include "pvr2/pvr2.h"

#include "sh4/sh4.h"

#include "sh4/sh4core.h"

#include "vmu/vmulist.h"

static gboolean dreamcast_load_bios( const gchar *filename );

/**

 * Current state of the DC virtual machine

 */

typedef enum { STATE_UNINIT=0, STATE_RUNNING, 

               STATE_STOPPING, STATE_STOPPED } dreamcast_state_t;

static volatile dreamcast_state_t dreamcast_state = STATE_UNINIT;

static gboolean dreamcast_use_bios = TRUE;

static gboolean dreamcast_has_bios = FALSE;

static gboolean dreamcast_has_flash = FALSE;

static gboolean dreamcast_exit_on_stop = FALSE;

static gchar *dreamcast_program_name = NULL;

static sh4addr_t dreamcast_entry_point = 0xA0000000;

static uint32_t timeslice_length = DEFAULT_TIMESLICE_LENGTH;

static uint64_t run_time_nanosecs = 0;

static unsigned int quick_save_state = -1;

#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 };

extern struct mem_region_fn mem_region_sdram;

extern struct mem_region_fn mem_region_vram32;

extern struct mem_region_fn mem_region_vram64;

extern struct mem_region_fn mem_region_audioram;

extern struct mem_region_fn mem_region_audioscratch;

extern struct mem_region_fn mem_region_flashram;

extern struct mem_region_fn mem_region_bootrom;

extern struct mem_region_fn mem_region_pvr2ta;

extern struct mem_region_fn mem_region_pvr2yuv;

extern struct mem_region_fn mem_region_pvr2vdma1;

extern struct mem_region_fn mem_region_pvr2vdma2;

unsigned char dc_main_ram[16 MB];

unsigned char dc_boot_rom[2 MB];

unsigned char dc_flash_ram[128 KB];

/**

 * 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( gboolean use_bootrom )

{

    char *bios_path = lxdream_get_global_config_path_value(CONFIG_BIOS_PATH);

    char *flash_path = lxdream_get_global_config_path_value(CONFIG_FLASH_PATH);

    /* Initialize the event queue first */

    event_init();

    /* Register the memory framework */

    dreamcast_register_module( &mem_module );

    /* Setup standard memory map */

    mem_map_region( dc_boot_rom,     0x00000000, 2 MB,   MEM_REGION_BIOS,         &mem_region_bootrom, MEM_FLAG_ROM, 2 MB, 0 );

    mem_map_region( dc_flash_ram,    0x00200000, 128 KB, MEM_REGION_FLASH,        &mem_region_flashram, MEM_FLAG_RAM, 128 KB, 0 );

    mem_map_region( aica_main_ram,   0x00800000, 2 MB,   MEM_REGION_AUDIO,        &mem_region_audioram, MEM_FLAG_RAM, 2 MB, 0 );

    mem_map_region( aica_scratch_ram,0x00703000, 8 KB,   MEM_REGION_AUDIO_SCRATCH,&mem_region_audioscratch, MEM_FLAG_RAM, 8 KB, 0 );

    mem_map_region( NULL,            0x04000000, 8 MB,   MEM_REGION_VIDEO64,      &mem_region_vram64, 0, 8 MB, 0 );

    mem_map_region( pvr2_main_ram,   0x05000000, 8 MB,   MEM_REGION_VIDEO,        &mem_region_vram32, MEM_FLAG_RAM, 8 MB, 0 ); 

    mem_map_region( dc_main_ram,     0x0C000000, 16 MB,  MEM_REGION_MAIN,         &mem_region_sdram, MEM_FLAG_RAM, 0x01000000, 0x0F000000 );

    mem_map_region( NULL,            0x10000000, 8 MB,   MEM_REGION_PVR2TA,       &mem_region_pvr2ta, 0, 0x02000000, 0x12000000 );

    mem_map_region( NULL,            0x10800000, 8 MB,   MEM_REGION_PVR2YUV,      &mem_region_pvr2yuv, 0, 0x02000000, 0x12800000 );

    mem_map_region( NULL,            0x11000000, 16 MB,  MEM_REGION_PVR2VDMA1,    &mem_region_pvr2vdma1, 0, 16 MB, 0 );

    mem_map_region( NULL,            0x13000000, 16 MB,  MEM_REGION_PVR2VDMA2,    &mem_region_pvr2vdma2, 0, 16 MB, 0 );

    dreamcast_use_bios = use_bootrom;

    dreamcast_has_bios = dreamcast_load_bios( bios_path );

    if( !dreamcast_has_bios ) {

        dreamcast_load_fakebios();

    }

    if( flash_path != NULL && flash_path[0] != '\0' ) {

        mem_load_block( flash_path, 0x00200000, 0x00020000 );

    }

    dreamcast_has_flash = TRUE;

    /* 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 );

    dreamcast_register_module( &eventq_module );

    g_free(bios_path);

    g_free(flash_path);

}

static gboolean dreamcast_load_bios( const gchar *filename )

{

    if( dreamcast_use_bios ) {

        dreamcast_has_bios = mem_load_rom( dc_boot_rom, filename, 2 MB, 0x89f2b1a1 );

    } else {

        dreamcast_has_bios = FALSE;

    }

    return dreamcast_has_bios;

}

static const char fakebios[] = {

        0x00, 0xd1, /* movl $+4, r1 */

        0x2b, 0x41, /* jmp @r1 */

        0xa0, 0xff, /* .long 0xffffffa0 */

        0xff, 0xff };

gboolean dreamcast_load_fakebios( )

{

    memset( dc_boot_rom, 0, 2 MB );

    memcpy( dc_boot_rom, fakebios, sizeof(fakebios) );

    syscall_add_hook( 0xA0, bios_boot );

    dreamcast_has_bios = TRUE;

    return TRUE;

}

gboolean dreamcast_load_flash( const gchar *filename )

{

    if( filename != NULL && filename[0] != '\0' ) {

        return mem_load_block( filename, 0x00200000, 0x00020000 ) == 0;

    }

    return FALSE;

}

gboolean dreamcast_config_changed(void *data, struct lxdream_config_group *group, unsigned item,

                                       const gchar *oldval, const gchar *newval)

{

    gchar *tmp;

    switch(item) {

    case CONFIG_BIOS_PATH:

        tmp = get_expanded_path(newval);

        dreamcast_load_bios(tmp);

        g_free(tmp);

        break;

    case CONFIG_FLASH_PATH:

        tmp = get_expanded_path(newval);

        dreamcast_load_flash(tmp);

        g_free(tmp);

        break;

    }

    reset_gui_paths();

    return TRUE;

}

void dreamcast_save_flash()

{

    if( dreamcast_has_flash ) {

        char *file = lxdream_get_global_config_path_value(CONFIG_FLASH_PATH);

        mem_save_block( file, 0x00200000, 0x00020000 );

        g_free(file);

    }

}

/**

 * 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_map_region( aica_main_ram, 0x00800000, 2 MB, MEM_REGION_AUDIO, &mem_region_audioram, MEM_FLAG_RAM, 2 MB, 0 );

    mem_map_region( aica_scratch_ram, 0x00703000, 8 KB, MEM_REGION_AUDIO_SCRATCH, &mem_region_audioscratch, MEM_FLAG_RAM, 8 KB, 0 );

    dreamcast_register_module( &aica_module );

    aica_enable();

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_register_module( dreamcast_module_t module ) 

{

    assert( num_modules < MAX_MODULES );

    modules[num_modules++] = module;

    if( module->init != NULL )

        module->init();

}

void dreamcast_set_run_time( uint32_t secs, uint32_t nanosecs )

{

    run_time_nanosecs = (((uint64_t)secs) * 1000000000) + nanosecs;

}

void dreamcast_set_exit_on_stop( gboolean flag )

{

    dreamcast_exit_on_stop = flag;

}

void dreamcast_init( gboolean use_bootrom )

{

    dreamcast_configure( use_bootrom );

    dreamcast_state = STATE_STOPPED;

}

void dreamcast_reset( void )

{

    sh4_core_exit(CORE_EXIT_SYSRESET);

    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_can_run() ) {

        ERROR(_("No program is loaded, and no BIOS is configured (required to boot a CD image). To continue, either load a binary program, or set the path to your BIOS file in the Path Preferences"));

        return;

    }

    if( dreamcast_state != STATE_RUNNING ) {

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

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

                modules[i]->start();

        }

    }

    if( maple_should_grab() ) {

        gui_set_use_grab(TRUE);

    }

    dreamcast_state = STATE_RUNNING;

    if( run_time_nanosecs != 0 ) {

        while( dreamcast_state == STATE_RUNNING ) {

            uint32_t time_to_run = timeslice_length;

            if( run_time_nanosecs < time_to_run ) {

                time_to_run = (uint32_t)run_time_nanosecs;

            }

            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 );

            }

            if( run_time_nanosecs > time_to_run ) {

                run_time_nanosecs -= time_to_run;

            } else {

                run_time_nanosecs = 0; // Finished

                break;

            }

        }

    } else {

        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 );

            }

        }

    }

    gui_set_use_grab(FALSE);

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

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

            modules[i]->stop();

    }

    vmulist_save_all();

    dreamcast_state = STATE_STOPPED;

    if( dreamcast_exit_on_stop ) {

        dreamcast_shutdown();

        exit(0);

    }

}

void dreamcast_stop( void )

{

    sh4_core_exit(CORE_EXIT_HALT); // returns only if not inside SH4 core

    if( dreamcast_state == STATE_RUNNING )

        dreamcast_state = STATE_STOPPING;

}

void dreamcast_shutdown()

{

    // Don't do a dreamcast_stop - if we're calling this out of SH4 code,

    // it's a shutdown-and-quit event

    if( dreamcast_state == STATE_RUNNING )

        dreamcast_state = STATE_STOPPING;

    dreamcast_save_flash();

    vmulist_save_all();

#ifdef ENABLE_SH4STATS

    sh4_stats_print(stdout);

#endif

}

void dreamcast_program_loaded( const gchar *name, sh4addr_t entry_point )

{

    if( dreamcast_program_name != NULL ) {

        g_free(dreamcast_program_name);

    }

    dreamcast_program_name = g_strdup(name);

    dreamcast_entry_point = entry_point;

    sh4_set_pc(entry_point);

    sh4_write_sr( sh4_read_sr() & (~SR_BL) ); /* Unmask interrupts */

    bios_install();

    dcload_install();

    gui_update_state();

}

gboolean dreamcast_is_running( void )

{

    return dreamcast_state == STATE_RUNNING;

}

gboolean dreamcast_can_run(void)

{

    return dreamcast_state != STATE_UNINIT;

}

/********************************* 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, char *error, int errorlen )

{

    struct save_state_header header;

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

        return 0;

    }

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

    	if( error != NULL )

    		snprintf( error, errorlen, _("File is not a %s save state"), APP_NAME );

        return 0;

    }

    if( header.version != DREAMCAST_SAVE_VERSION ) {

    	if( error != NULL )

    		snprintf( error, errorlen, _("Unsupported %s save state version"), APP_NAME );

        return 0;

    }

    if( header.module_count > MAX_MODULES ) {

    	if( error != NULL )

    		snprintf( error, errorlen, _("%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, NULL, 0);

    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;

}

gboolean dreamcast_load_state( const gchar *filename )

{

    int i,j;

    int module_count;

    char error[128];

    int have_read[MAX_MODULES];

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

    if( f == NULL ) return FALSE;

    module_count = dreamcast_read_save_state_header(f, error, sizeof(error));

    if( module_count <= 0 ) {

    	ERROR( error );

        fclose(f);

        return FALSE;

    }

    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 FALSE;

        }

        /* 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 FALSE;

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

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

                    fclose(f);

                    return FALSE;

                }

                break;

            }

        }

        if( j == num_modules ) {

            fclose(f);

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

            return FALSE;

        }

    }

    /* 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 TRUE;

}

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;

}

/********************** Quick save state support ***********************/

/* This section doesn't necessarily belong here, but it probably makes the

 * most sense here next to the regular save/load functions

 */

static gchar *get_quick_state_filename( int state )

{

    gchar *path = lxdream_get_global_config_path_value(CONFIG_SAVE_PATH);

    gchar *str = g_strdup_printf( QUICK_STATE_FILENAME, path, state );

    g_free( path );

    return str;

}

static void dreamcast_quick_state_init()

{

    const char *state = lxdream_get_global_config_value(CONFIG_QUICK_STATE);

    if( state != NULL ) {

        quick_save_state = atoi(state);

        if( quick_save_state > MAX_QUICK_STATE ) {

            quick_save_state = 0;

        }

    } else {

        quick_save_state = 0;

    }

}

void dreamcast_quick_save()

{

    if( quick_save_state == -1 ) 

        dreamcast_quick_state_init();

    gchar *str = get_quick_state_filename(quick_save_state);

    dreamcast_save_state(str);

    g_free(str);

}

void dreamcast_quick_load()

{

    if( quick_save_state == -1 ) 

        dreamcast_quick_state_init();

    gchar *str = get_quick_state_filename(quick_save_state);

    dreamcast_load_state(str);

    g_free(str);

}

unsigned int dreamcast_get_quick_state( )

{

    if( quick_save_state == -1 ) 

        dreamcast_quick_state_init();

    return quick_save_state;

}

void dreamcast_set_quick_state( unsigned int state )

{

    if( state <= MAX_QUICK_STATE && state != quick_save_state ) {

        quick_save_state = state;

        char buf[3];

        sprintf( buf, "%d", quick_save_state );

        lxdream_set_global_config_value(CONFIG_QUICK_STATE, buf);

        lxdream_save_config();

    }

}

gboolean dreamcast_has_quick_state( unsigned int state )

{

    gchar *str = get_quick_state_filename(state);

    int result = access(str, R_OK);

    g_free(str);

    return result == 0 ? TRUE : FALSE;

}

/********************* The Boot ROM address space **********************/

static int32_t FASTCALL ext_bootrom_read_long( sh4addr_t addr )

{

    return *((int32_t *)(dc_boot_rom + (addr&0x001FFFFF)));

}

static int32_t FASTCALL ext_bootrom_read_word( sh4addr_t addr )

{

    return SIGNEXT16(*((int16_t *)(dc_boot_rom + (addr&0x001FFFFF))));

}

static int32_t FASTCALL ext_bootrom_read_byte( sh4addr_t addr )

{

    return SIGNEXT8(*((int16_t *)(dc_boot_rom + (addr&0x001FFFFF))));

}

static void FASTCALL ext_bootrom_read_burst( unsigned char *dest, sh4addr_t addr )

{

    memcpy( dest, dc_boot_rom +(addr&0x001FFFFF), 32 );

}

struct mem_region_fn mem_region_bootrom = { 

        ext_bootrom_read_long, unmapped_write_long, 

        ext_bootrom_read_word, unmapped_write_long, 

        ext_bootrom_read_byte, unmapped_write_long, 

        ext_bootrom_read_burst, unmapped_write_burst }; 

/********************* The Flash RAM address space **********************/

static int32_t FASTCALL ext_flashram_read_long( sh4addr_t addr )

{

    return *((int32_t *)(dc_flash_ram + (addr&0x0001FFFF)));

}

static int32_t FASTCALL ext_flashram_read_word( sh4addr_t addr )

{

    return SIGNEXT16(*((int16_t *)(dc_flash_ram + (addr&0x0001FFFF))));

}

static int32_t FASTCALL ext_flashram_read_byte( sh4addr_t addr )

{

    return SIGNEXT8(*((int16_t *)(dc_flash_ram + (addr&0x0001FFFF))));

}

static void FASTCALL ext_flashram_write_long( sh4addr_t addr, uint32_t val )

{

    *(uint32_t *)(dc_flash_ram + (addr&0x0001FFFF)) = val;

    asic_g2_write_word();

}

static void FASTCALL ext_flashram_write_word( sh4addr_t addr, uint32_t val )

{

    *(uint16_t *)(dc_flash_ram + (addr&0x0001FFFF)) = (uint16_t)val;

    asic_g2_write_word();

}

static void FASTCALL ext_flashram_write_byte( sh4addr_t addr, uint32_t val )

{

    *(uint8_t *)(dc_flash_ram + (addr&0x0001FFFF)) = (uint8_t)val;

    asic_g2_write_word();

}

static void FASTCALL ext_flashram_read_burst( unsigned char *dest, sh4addr_t addr )

{

    memcpy( dest, dc_flash_ram+(addr&0x0001FFFF), 32 );

}

static void FASTCALL ext_flashram_write_burst( sh4addr_t addr, unsigned char *src )

{

    memcpy( dc_flash_ram+(addr&0x0001FFFF), src, 32 );

}

struct mem_region_fn mem_region_flashram = { ext_flashram_read_long, ext_flashram_write_long, 

        ext_flashram_read_word, ext_flashram_write_word, 

        ext_flashram_read_byte, ext_flashram_write_byte, 

        ext_flashram_read_burst, ext_flashram_write_burst };