/* Copyright (C) 1996-1997 Aleksey Volynskov
 * Copyright (C) 2011 Rambo
 * Copyright (C) 2020 SovietPony
 *
 * 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, version 3 of the License ONLY.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "glob.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef UNIX
#  include <sys/stat.h>
#endif
#include "files.h"
#include "map.h"
#include "my.h"
#include "game.h"
#include "view.h"
#include "dots.h"
#include "smoke.h"
#include "fx.h"
#include "items.h"
#include "monster.h"
#include "player.h"
#include "switch.h"
#include "weapons.h"
#include "error.h"
#include "cp866.h"

typedef struct {
  byte n, i, v, d;
} dmv;

int d_start, d_end;
mwad_t wad[MAX_WAD];
char wads[MAX_WADS][__MAX_PATH];
FILE* wadh[MAX_WADS];

static byte seq[255];
static byte seqn;
static int inum=0;
static dmv *pat=NULL;
static unsigned *patp;
static void **dmi;

static int m_start, m_end;
static int s_start, s_end;
static int wad_num;

static char f_drive[__MAX_DRIVE];
static char f_dir[__MAX_DIR];
static char f_name[__MAX_FNAME];
static char f_ext[__MAX_EXT];

void F_startup (void) {
  logo("F_startup: setup file system\n");
  memset(wads,0,sizeof(wads));
}

void F_addwad (const char *fn) {
  int i;

  for(i=0;i<MAX_WADS;++i) if(wads[i][0]==0) {
    strcpy(wads[i],fn);return;
  }
  ERR_failinit("Unable to add WAD %s",fn);
}

static int myfilelength (FILE *h) {
    int pos = ftell(h);
    fseek (h, 0, SEEK_END);
    int len = ftell(h);
    fseek (h, pos, SEEK_SET);
    return len;
}

// build wad directory
void F_initwads (void) {
  int i, j, k, p;
  FILE *h;
  char s[4];
  int n, o;
  wad_t w;

  logo("F_initwads: use WAD-files\n");
  for (i = 0; i < MAX_WAD; ++i) {
    wad[i].n[0] = 0;
  }

  logo("   add %s\n", wads[0]);
  if ((wadh[0] = h = fopen(wads[0], "rb")) == NULL) {
    ERR_failinit("Unable to open file: %s", wads[0]);
  }

  s[0] = '\0';
  myfread(s, 1, 4, h);
  if (strncmp(s, "IWAD", 4) != 0 && strncmp(s, "PWAD", 4) != 0) {
    ERR_failinit("Not IWAD or PWAD (1)");
  }

  p = 0; // wad number
  n = myfread32(h); // num
  o = myfread32(h); // offset
  fseek(h, o, SEEK_SET);
  for (j = 0; j < n; ++j) {
    w.o = myfread32(h); // offset
    w.l = myfread32(h); // len
    myfread(w.n, 1, 8, h); // name
    if (p >= MAX_WAD) {
      ERR_failinit("Too many entries in the WAD");
    }
    wad[p].o = w.o;
    wad[p].l = w.l;
    memcpy(wad[p].n, w.n, 8);
    wad[p].f = 0;
    ++p;
  }

  //fclose(h);

  for (i = 1; i < MAX_WADS; ++i) {
    if (wads[i][0] != 0) {
      logo("  add %s\n", wads[i]);
      if ((wadh[i] = h = fopen(wads[i], "rb")) == NULL) {
        ERR_failinit("Unable to open file (2):  %s", wads[i]);
      }
      mysplitpath(wads[i], f_drive, f_dir, f_name, f_ext);
      if (cp866_strcasecmp(f_ext, ".lmp") == 0) {
        for (k = 0; k < MAX_WAD; ++k) {
          if (cp866_strncasecmp(wad[k].n, f_name, 8) == 0) {
            wad[k].o = 0;
            wad[k].l = myfilelength(h);
            wad[k].f = i;
            break;
          }
          if (k >= MAX_WAD) {
            if (p >= MAX_WAD) {
              ERR_failinit("Too many entries in the WAD");
            }
            memset(wad[p].n, 0, 8);
            strncpy(wad[p].n, f_name, 8);
            wad[p].o = 0;
            wad[p].l = myfilelength(h);
            wad[p].f = i;
            ++p;
          }
        }

        s[0] = '\0';
        myfread(s, 1, 4, h);
        if (strncmp(s, "IWAD", 4) != 0 && strncmp(s, "PWAD", 4) != 0) {
          ERR_failinit("Not IWAD or PWAD (2)");
        }
        n = myfread32(h); // num
        o = myfread32(h); // offset
        fseek(h, o, SEEK_SET);
        for (j = 0; j < n; ++j) {
          w.o = myfread32(h); // offset
          w.o = myfread32(h); // len
          myfread(w.n, 1, 8, h); // name
          for (k = 0; k < MAX_WAD; ++k) {
            if (cp866_strncasecmp(wad[k].n, w.n, 8) == 0) {
              wad[k].o = w.o;
              wad[k].l = w.l;
              wad[k].f = i;
              break;
            }
            if (k >= MAX_WAD) {
              if (p >= MAX_WAD) {
                ERR_failinit("Too many entries in the WAD");
              }
              memcpy(wad[p].n, w.n, 8);
              wad[p].o = w.o;
              wad[p].l = w.l;
              wad[p].f = i;
              ++p;
            }
          }
        }
      }
    }
	}

  wad_num = p;
}

// allocate resources
// (called from M_startup)
void F_allocres (void) {
  d_start=F_getresid("D_START");
  d_end=F_getresid("D_END");
  m_start=F_getresid("M_START");
  m_end=F_getresid("M_END");
  s_start=F_getresid("S_START");
  s_end=F_getresid("S_END");
}

// load resource
void F_loadres (int r, void *p, dword o, dword l) {

  int oo;
  FILE *fh;

  
  oo=ftell(fh=wadh[wad[r].f]);

  if(fseek(fh,wad[r].o+o,SEEK_SET)!=0)
    ERR_fatal("Error while file reading");

  if((dword)myfreadc(p,1,l,fh)!=l)
    ERR_fatal("Error while loading resource %.8s", wad[r].n);
  
  fseek(fh,oo,SEEK_SET);
  
}

/*
// unused
void F_saveres(int r, void *p, dword o, dword l) {
  FILE* fh = wadh[wad[r].f];
  int oo = ftell(fh);
  if (fseek(fh, wad[r].o + o, SEEK_SET) != 0) {
    ERR_fatal("Error while reading file");
  }
  myfwrite(p, l, 1, fh);
  fseek(fh, oo, SEEK_SET);
}
*/

// get resource id
int F_findres (const char n[8]) {
  int i;
  for (i = 0; i < wad_num; i++) {
    if (cp866_strncasecmp(wad[i].n, n, 8) == 0) {
      return i;
    }
  }
  return -1;
}

// get resource id
int F_getresid (const char n[8]) {
  int i = F_findres(n);
  if (i == -1) {
    ERR_fatal("F_getresid: resource %.8s not found", n);
  }
  return i;
}

void F_getresname (char n[8], int r) {
  memcpy(n, wad[r].n, 8);
}

// get sprite id
int F_getsprid (const char n[4], int s, int d, char *dir) {
  int i;
  byte a, b;
  s += 'A';
  d += '0';
  for (i = s_start + 1; i < s_end; i++) {
    if (cp866_strncasecmp(wad[i].n, n, 4) == 0 && (wad[i].n[4] == s || wad[i].n[6] == s)) {
      a = wad[i].n[4] == s ? wad[i].n[5] : 0;
      b = wad[i].n[6] == s ? wad[i].n[7] : 0;
      if (a == '0' || b == '0' || a == d || b == d) {
        if (dir != NULL) {
          *dir = a != '0' && b == '0' || a != d && b == d;
        }
        return i;
      }
    }
  }
  ERR_fatal("F_getsprid: image %.4s%c%c not found", n, s, d);
  return -1;
}

int F_getreslen (int r) {
  return wad[r].l;
}

void F_nextmus (char *s) {
  int i;
  i=F_findres(s);
  if(i<=m_start || i>=m_end) i=m_start;
  for(++i;;++i) {
    if(i>=m_end) i=m_start+1;

    if (cp866_strcasecmp(wad[i].n,"MENU") == 0 ||
        cp866_strcasecmp(wad[i].n,"INTERMUS") == 0 ||
        cp866_strcasecmp(wad[i].n,"\x8a\x8e\x8d\x85\x96\x0") == 0)
        continue;

    if(cp866_strncasecmp(wad[i].n,"DMI",3)!=0) break;
  }
  memcpy(s,wad[i].n,8);
}

void F_randmus (char *s) {
  int i;
  int n = myrand(10);
  for (i = 0; i < n; i++) {
    F_nextmus(s);
  }
}

// reads bytes from file until CR
void F_readstr (FILE* h, char *s, int m) {
  int i = 0;
  size_t len = 0;
  static char c = 0;
  while (i < m) {
    c = 13;
    len = myfreadc(&c, 1, 1, h);
    if (len == 0 || c == 13 || c == 10) {
      break;
    }
    s[i] = c;
    i++;
  }
  s[i] = 0;
}

/*
// unused
// reads bytes from file until NUL
void F_readstrz (FILE* h,char *s,int m) {
  int i = 0;
  size_t len = 0;
  static char c = 0;
  while (i < m) {
    c = 0;
    len = myfreadc(&c, 1, 1, h);
    if (len == 0 || c == 0) {
      break;
    }
    s[i] = c;
    i++;
  }
  s[i] = 0;
}
*/

/*void F_freemus(void) {

  int i;

  if(!pat) return;
  S_stopmusic();
  free(pat);free(patp);
  for(i=0;i<inum;++i) if(dmi[i]!=NULL) free(dmi[i]);
  free(dmi);
  pat=NULL;

}
*/

/*void F_loadmus(char n[8]) {
  int r,i,j;
  FILE *h;
  int o;
  struct{
	char id[4];
	byte ver,pat;
	word psz;
  }d;
  struct{byte t;char n[13];word r;}di;

  if((r=F_findres(n))==-1) return;
  fseek(h=wadh[wad[r].f],wad[r].o,SEEK_SET);
  myfread(&d,1,sizeof(d),h);
  if(memcmp(d.id,"DMM",4)!=0) return;
  if(!(pat=malloc(d.psz<<2))) return;
  myfread(pat,1,d.psz<<2,h);
  myfread(&seqn,1,1,h);if(seqn) myfread(seq,1,seqn,h);
  inum=0;myfread(&inum,1,1,h);
  if(!(dmi=malloc(inum*4))) {free(pat);pat=NULL;return;}
  if(!(patp=malloc((word)d.pat*32))) {free(pat);free(dmi);pat=NULL;return;}
  for(i=0;i<inum;++i) {
	dmi[i]=NULL;
	myfread(&di,1,16,h);o=ftell(h);
	for(r=0;r<12;++r) if(di.n[r]=='.') di.n[r]=0;
	if((r=F_findres(di.n))==-1) continue;
	if(!(dmi[i]=malloc(wad[r].l+8))) continue;
	memset(dmi[i],0,16);
	F_loadres(r,dmi[i],0,2);
	F_loadres(r,(int*)dmi[i]+1,2,2);
	F_loadres(r,(int*)dmi[i]+2,4,2);
	F_loadres(r,(int*)dmi[i]+3,6,2);
	F_loadres(r,(int*)dmi[i]+4,8,wad[r].l-8);
	fseek(h,o,SEEK_SET);
  }
  for(i=r=0,j=(word)d.pat<<3;i<j;++i) {
	patp[i]=r<<2;
	while(pat[r++].v!=0x80);
  }
 }
*/