/* Generator is (c) James Ponder, 1997-2001 http://www.squish.net/generator/ */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <ctype.h>
#include <signal.h>
#include <errno.h>

#include "generator.h"
#include "snprintf.h"

#include "ui.h"
#include "memz80.h"
#include "cpu68k.h"
#include "mem68k.h"
#include "cpuz80.h"
#include "vdp.h"
#include "gensound.h"

#ifdef ALLEGRO
#include "allegro.h"
#endif

/*** variables externed in generator.h ***/

unsigned int gen_quit = 0;
unsigned int gen_debugmode = 0;
unsigned int gen_loglevel = 1;  /* 2 = NORMAL, 1 = CRITICAL */
unsigned int gen_autodetect = 1; /* 0 = no, 1 = yes */
unsigned int gen_musiclog = 0; /* 0 = no, 1 = GYM, 2 = GNM */
unsigned int gen_modifiedrom = 0; /* 0 = no, 1 = yes */
t_cartinfo gen_cartinfo;
char gen_leafname[128];

static int gen_freerom = 0;

/*** forward references ***/

void gen_nicetext(char *out, char *in, unsigned int size);
uint16 gen_checksum(uint8 *start, unsigned int length);
void gen_setupcartinfo(void);

/*** Signal handler ***/

RETSIGTYPE gen_sighandler(int signum)
{
  if (gen_debugmode) {
    if (signum == SIGINT) {
      if (gen_quit) {
        LOG_CRITICAL(("Bye!"));
        ui_final();
        ui_err("Exiting");
      } else {
        LOG_REQUEST(("Ping - current PC = 0x%X", regs.pc));
      }
      gen_quit = 1;
    }
  } else {
    ui_final();
    exit(0);
  }
  signal(signum, gen_sighandler);
}

static char thing[] = ("\n\nIt's the year 2000 is there anyone out there?\n"
                       "\nIf you're from another planet put your hand in the "
                       "air, say yeah!\n\n");

/*** Program entry point ***/

int main(int argc, char *argv[])
{
  int retval;
  t_sr test;

  test.sr_int = 0;
  test.sr_struct.c = 1;
  if (test.sr_int != 1) {
    fprintf(stderr, "%s: compilation variable BYTES_HIGHFIRST not set "
            "correctly\n", argv[0]);
    return 1;
  }

  /* initialise user interface */
  if ((retval = ui_init(argc, argv)))
    return retval;

  /* initialise 68k memory system */
  if ((retval = mem68k_init()))
    ui_err("Failed to initialise mem68k module (%d)", retval);

  /* initialise z80 memory system */
  if ((retval = memz80_init()))
    ui_err("Failed to initialise memz80 module (%d)", retval);

  /* initialise vdp system */
  if ((retval = vdp_init()))
    ui_err("Failed to initialise vdp module (%d)", retval);

  /* initialise cpu system */
  if ((retval = cpu68k_init()))
    ui_err("Failed to initialise cpu68k module (%d)", retval);

  /* initialise z80 cpu system */
  if ((retval = cpuz80_init()))
    ui_err("Failed to initialise cpuz80 module (%d)", retval);

  /* initialise sound system */
  if ((retval = sound_init()))
    ui_err("Failed to initialise sound module (%d)", retval);

  signal(SIGINT, gen_sighandler);

  /* enter user interface loop */
  return ui_loop();
}

#ifdef ALLEGRO
END_OF_MAIN();
#endif

/*** gen_reset - reset system ***/

void gen_reset(void)
{
  vdp_reset();
  cpu68k_reset();
  cpuz80_reset();
  if (sound_reset()) {
    ui_err("sound failure");
  }
}

/*** gen_softreset - reset system ***/

void gen_softreset(void)
{
  cpu68k_reset();
}

/*** gen_loadimage - load ROM image ***/

char *gen_loadimage(const char *filename)
{
  int file, imagetype, bytes, bytesleft;
  struct stat statbuf;
  const char *extension;
  uint8 *buffer;
  unsigned int blocks, x, i;
  uint8 *new;
  char *p;

  /* Remove current file */
  if (cpu68k_rom) {
    if (gen_freerom)
      free(cpu68k_rom);
    cpu68k_rom = NULL;
  }

  /* Load file */
  if (stat(filename, &statbuf) != 0)
    return ("Unable to stat file.");
  cpu68k_romlen = statbuf.st_size;
  if (cpu68k_romlen < 0x200)
    return ("File is too small");

  /* allocate enough memory plus 16 bytes for disassembler to cope
     with the last instruction */
  if ((cpu68k_rom = malloc(cpu68k_romlen + 16)) == NULL) {
    cpu68k_romlen = 0;
    return ("Out of memory!");
  }
  gen_freerom = 1;
  memset(cpu68k_rom, 0, cpu68k_romlen + 16);
#ifdef ALLEGRO
  if ((file = open(filename, O_RDONLY | O_BINARY, 0)) == -1) {
#else
  if ((file = open(filename, O_RDONLY, 0)) == -1) {
#endif
    perror("open");
    cpu68k_rom = NULL;
    cpu68k_romlen = 0;
    return ("Unable to open file.");
  }
  buffer = cpu68k_rom;
  bytesleft = cpu68k_romlen;
  do {
    if ((bytes = read(file, buffer, bytesleft)) <= 0)
      break;
    buffer += bytes;
    bytesleft -= bytes;
  }
  while (bytesleft >= 0);
  close(file);
  if (bytes == -1)
    return (strerror(errno));
  else if (bytes != 0)
    return ("invalid return code from read()");
  if (bytesleft) {
    LOG_CRITICAL(("%d bytes left to read?!", bytesleft));
    return ("Error whilst loading file");
  }

  imagetype = 1;                /* BIN file by default */

  /* SMD file format check - Richard Bannister */
  if ((cpu68k_rom[8] == 0xAA) && (cpu68k_rom[9] == 0xBB) &&
      cpu68k_rom[10] == 0x06) {
    imagetype = 2;              /* SMD file */
  }
  /* check for interleaved 'SEGA' */
  if (cpu68k_rom[0x280] == 'E' && cpu68k_rom[0x281] == 'A' &&
      cpu68k_rom[0x2280] == 'S' && cpu68k_rom[0x2281] == 'G') {
    imagetype = 2;              /* SMD file */
  }
  /* Check extension is not wrong */
  extension = filename + strlen(filename) - 3;
  if (extension > filename) {
    if (!strcasecmp(extension, "smd") && (imagetype != 2))
      LOG_REQUEST(("File extension (smd) does not match detected "
                   "type (bin)"));
    if (!strcasecmp(extension, "bin") && (imagetype != 1))
      LOG_REQUEST(("File extension (bin) does not match detected "
                   "type (smd)"));
  }

  /* convert to standard BIN file format */

  switch (imagetype) {
  case 1:                      /* BIN */
    break;
  case 2:                      /* SMD */
    blocks = (cpu68k_romlen - 512) / 16384;
    if (blocks * 16384 + 512 != cpu68k_romlen)
      return ("Image is corrupt.");

    if ((new = malloc(cpu68k_romlen - 512)) == NULL) {
      cpu68k_rom = NULL;
      cpu68k_romlen = 0;
      return ("Out of memory!");
    }

    for (i = 0; i < blocks; i++) {
      for (x = 0; x < 8192; x++) {
        new[i * 16384 + x * 2 + 0] = cpu68k_rom[512 + i * 16384 + 8192 + x];
        new[i * 16384 + x * 2 + 1] = cpu68k_rom[512 + i * 16384 + x];
      }
    }
    free(cpu68k_rom);
    cpu68k_rom = new;
    cpu68k_romlen -= 512;
    break;
  default:
    return ("Unknown image type");
    break;
  }

  /* is this icky? */
  if ((p = strrchr(filename, '/')) == NULL &&
      (p = strrchr(filename, '\\')) == NULL) {
    snprintf(gen_leafname, sizeof(gen_leafname), "%s", filename);
  } else {
    snprintf(gen_leafname, sizeof(gen_leafname), "%s", p + 1);
  }
  if ((p = strrchr(gen_leafname, '.')) != NULL) {
    if ((!strcasecmp(p, ".smd")) || (!strcasecmp(p, ".bin")))
      *p = '\0';
  }
  if (gen_leafname[0] == '\0')
    snprintf(gen_leafname, sizeof(gen_leafname), "rom");


  if (gen_autodetect) {
    vdp_pal = (!gen_cartinfo.flag_usa && !gen_cartinfo.flag_japan &&
               gen_cartinfo.flag_europe) ? 1 : 0;
  }

  gen_setupcartinfo();

  /* reset system */
  gen_reset();

  if (gen_cartinfo.checksum != (cpu68k_rom[0x18e] << 8 | cpu68k_rom[0x18f]))
    LOG_REQUEST(("Warning: Checksum does not match in ROM (%04X)",
                 (cpu68k_rom[0x18e] << 8 | cpu68k_rom[0x18f])));

  LOG_REQUEST(("Loaded '%s'/'%s' (%s %04X %s)", gen_cartinfo.name_domestic,
               gen_cartinfo.name_overseas, gen_cartinfo.version,
               gen_cartinfo.checksum, gen_cartinfo.country));

  gen_modifiedrom = 0;
  return NULL;
}

/* setup to run from ROM in memory */

void gen_loadmemrom(const char *rom, int romlen)
{
  cpu68k_rom = (char *)rom; /* I won't alter it, promise */
  cpu68k_romlen = romlen;
  gen_freerom = 0;
  gen_setupcartinfo();
  gen_reset();
}

/* setup gen_cartinfo from current loaded rom */

void gen_setupcartinfo(void)
{
  unsigned int i;
  char *p;

  memset(&gen_cartinfo, 0, sizeof(gen_cartinfo));
  gen_nicetext(gen_cartinfo.console, (char *)(cpu68k_rom + 0x100), 16);
  gen_nicetext(gen_cartinfo.copyright, (char *)(cpu68k_rom + 0x110), 16);
  gen_nicetext(gen_cartinfo.name_domestic, (char *)(cpu68k_rom + 0x120), 48);
  gen_nicetext(gen_cartinfo.name_overseas, (char *)(cpu68k_rom + 0x150), 48);
  if (cpu68k_rom[0x180] == 'G' && cpu68k_rom[0x181] == 'M') {
    gen_cartinfo.prodtype = pt_game;
  } else if (cpu68k_rom[0x180] == 'A' && cpu68k_rom[0x181] == 'I') {
    gen_cartinfo.prodtype = pt_education;
  } else {
    gen_cartinfo.prodtype = pt_unknown;
  }
  gen_nicetext(gen_cartinfo.version, (char *)(cpu68k_rom + 0x182), 12);
  gen_cartinfo.checksum = gen_checksum(((uint8 *)cpu68k_rom) + 0x200,
                                       cpu68k_romlen - 0x200);
  gen_nicetext(gen_cartinfo.memo, (char *)(cpu68k_rom + 0x1C8), 28);
  for (i = 0x1f0; i < 0x1ff; i++) {
    if (cpu68k_rom[i] == 'J')
      gen_cartinfo.flag_japan = 1;
    if (cpu68k_rom[i] == 'U')
      gen_cartinfo.flag_usa = 1;
    if (cpu68k_rom[i] == 'E')
      gen_cartinfo.flag_europe = 1;
  }
  if (cpu68k_rom[0x1f0] >= '1' && cpu68k_rom[0x1f0] <= '9') {
    gen_cartinfo.hardware = cpu68k_rom[0x1f0] - '0';
  } else if (cpu68k_rom[0x1f0] >= 'A' && cpu68k_rom[0x1f0] <= 'F') {
    gen_cartinfo.hardware = cpu68k_rom[0x1f0] - 'A' + 10;
  }
  p = gen_cartinfo.country;
  for (i = 0x1f0; i < 0x200; i++) {
    if (cpu68k_rom[i] != 0 && cpu68k_rom[i] != 32)
      *p++ = cpu68k_rom[i];
  }
  *p = '\0';
}

/*** get_nicetext - take a string, remove spaces and capitalise ***/

void gen_nicetext(char *out, char *in, unsigned int size)
{
  int flag, i;
  int c;
  char *start = out;

  flag = 0;                     /* set if within word, e.g. make lowercase */
  i = size;                     /* maximum number of chars in input */
  while ((c = *in++) && --i > 0) {
    if (isalpha(c)) {
      if (!flag) {
        /* make uppercase */
        flag = 1;
        if (islower(c))
          *out++ = c - 'z' + 'Z';
        else
          *out++ = c;
      } else {
        /* make lowercase */
        if (isupper(c))
          *out++ = (c) - 'Z' + 'z';
        else
          *out++ = c;
      }
    } else if (c == ' ') {
      if (flag)
        *out++ = c;
      flag = 0;
    } else if (isprint(c) && c != '\t') {
      flag = 0;
      *out++ = c;
    }
  }
  while (out > start && out[-1] == ' ')
    out--;
  *out++ = '\0';
}

/*** gen_checksum - get Genesis-style checksum of memory block ***/

uint16 gen_checksum(uint8 *start, unsigned int length)
{
  uint16 checksum = 0;

  if (length & 1) {
    length &= ~1;
    LOG_VERBOSE(("checksum routines given odd length (%d)", length));
  }

  for (; length; length -= 2, start += 2) {
    checksum += start[0] << 8;
    checksum += start[1];
  }
  return checksum;
}