/**

  * $Id$

  * 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 "lxdream.h"

 #include "dream.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 "sh4/sh4.h"

 #include "sh4/sh4core.h"

 /**

  * 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_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;

 #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( )

 {

     const char *bios_path = lxdream_get_config_value(CONFIG_BIOS_PATH);

     const char *flash_path = lxdream_get_config_value(CONFIG_FLASH_PATH);

     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 );

     dreamcast_has_bios = mem_load_rom( bios_path, 0x00000000, 0x00200000, 0x89f2b1a1, MEM_REGION_BIOS );

     mem_create_ram_region( 0x00200000, 0x00020000, MEM_REGION_FLASH );

     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 );

 }

 void dreamcast_config_changed(void)

 {

     const char *bios_path = lxdream_get_config_value(CONFIG_BIOS_PATH);

     const char *flash_path = lxdream_get_config_value(CONFIG_FLASH_PATH);

     dreamcast_has_bios = mem_load_rom( bios_path, 0x00000000, 0x00200000, 0x89f2b1a1, MEM_REGION_BIOS );

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

         mem_load_block( flash_path, 0x00200000, 0x00020000 );

     }

 }

 void dreamcast_save_flash()

 {

     if( dreamcast_has_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_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( void )

 {

     dreamcast_configure();

     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_state != STATE_RUNNING ) {

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

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

                 modules[i]->start();

         }

     }

     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 );

             }

         }

     }

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

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

             modules[i]->stop();

     }

     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();

 #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);

     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 &&

     (dreamcast_has_bios || dreamcast_program_name != NULL);

 }

 /********************************* 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;

 }