#include <stdio.h>
#include <io.h>
#include <string.h>
#include <windows.h>

struct idxentry {
  DWORD offset;
  DWORD size;
  BYTE unk;
  char filename[15];
};
struct idxFile {
  DWORD filecount;
  idxentry entries[0];
};

// Get filename with replaced extension
// e.g. samifilename = ChangeFileExt(filename, '.smi');
char* ChangeFileExt(const char* filename, const char* new_ext)
{
  char* p = strrchr(filename,'.');
  size_t n=strlen(filename);
  if (p) n=p-filename;
  char *result = (char*)malloc(n+strlen(new_ext));
  strncpy(result, filename ,n);
  strcpy(result+n, new_ext);
  return result;
}

void ListLb5(const char* lb5Filename)
{
  char* idxFilename = ChangeFileExt(lb5Filename,".idx");
  FILE* hIdxFile=fopen(idxFilename,"rb");
  if (hIdxFile)
  {
    fseek(hIdxFile,0,SEEK_END);
    size_t fsize=ftell(hIdxFile);
    fseek(hIdxFile,0,SEEK_SET);
    idxFile* idx = (idxFile*)malloc(fsize);
    fread(idx,fsize,1,hIdxFile);
    printf("file count: %d\n",idx->filecount);
    for (int i=0; i<idx->filecount; i++)
      printf("0x%08.8x %02.2x %-8d %s\n",idx->entries[i].offset,idx->entries[i].unk,idx->entries[i].size,idx->entries[i].filename);
    free(idx);
    fclose(hIdxFile);
  }
  else
  {
    printf("Couldn't open file '%s'\n",idxFilename);
  }
  free(idxFilename);
}
void decrypt(char* buf, size_t size)
{
  char c;
  while(size--)
  {
    c=*buf;
    if ((unsigned char)c>0xf) c=0xe-c;
    *buf=c;
    buf++;
  }
}
void ExtractLb5(const char* filename, const char* toExtract)
{
  char* idxFilename = ChangeFileExt(filename,".idx");
  char* lb5Filename = ChangeFileExt(filename,".lb5");
  FILE* hIdxFile=fopen(idxFilename,"rb");
  FILE* hLb5File=fopen(lb5Filename,"rb");
  char buffer[1024];
  if (!hLb5File)
  {
    printf("Couldn't open file '%s'\n",lb5Filename);
  }
  else if (hIdxFile)
  {
    fseek(hIdxFile,0,SEEK_END);
    size_t fsize=ftell(hIdxFile);
    fseek(hIdxFile,0,SEEK_SET);
    idxFile* idx = (idxFile*)malloc(fsize);
    fread(idx,fsize,1,hIdxFile);
    printf("file count: %d\n",idx->filecount);
    for (int i=0; i<idx->filecount; i++)
    {
      if (toExtract && strcmp(toExtract, idx->entries[i].filename))
        continue;
      printf("Extracting %s\n",idx->entries[i].filename);
      fseek(hLb5File,idx->entries[i].offset,SEEK_SET);
      FILE* curFile=fopen(idx->entries[i].filename,"wb");
      if (!curFile)
      {
        printf("Couldn't create file!\n");
        break;
      }
      size_t k=idx->entries[i].size,n=sizeof(buffer);
      while (k>0)
      {
        if (n>k) n=k;
        if (1!=fread(buffer,n,1,hLb5File))
        {
          printf("Read file error!\n");
          i=idx->filecount;
          break;
        };
        if (strstr(idx->entries[i].filename,".txt") || strstr(idx->entries[i].filename,".TXT"))
          decrypt(buffer,n);
        if (1!=fwrite(buffer,n,1,curFile))
        {
          printf("Write file error!\n");
          i=idx->filecount;
          break;
        };
        k-=n;
      }
      fclose(curFile);
      if (toExtract)
        break;
    }
    if (toExtract && i>=idx->filecount)
      printf("Couldn't find file '%s' in archive\n",toExtract);
    free(idx);
  }
  else
  {
    printf("Couldn't open file '%s'\n",idxFilename);
  }
  if(hIdxFile) fclose(hIdxFile);
  if(hLb5File)fclose(hLb5File);
  free(idxFilename);
  free(lb5Filename);
}

idxFile* genIdxFile(const char* filemask)
{
  long hFile;
  struct _finddata_t c_file;
  int total = 0;
  if( (hFile = _findfirst( filemask, &c_file )) != -1L )
  {
    do {
      total++;
    } while( _findnext( hFile, &c_file ) == 0 );
  }
  _findclose( hFile );
  if (total==0) return NULL;

  size_t fsize = total*sizeof(idxentry)+sizeof(idxFile);
  int i=0;
  idxFile* idx = (idxFile*)malloc(fsize);
  idx->filecount = total;
  if( (hFile = _findfirst( filemask, &c_file )) != -1L )
  {
    do { 
      strncpy(idx->entries[i].filename, c_file.name, 15);
      idx->entries[i].filename[14]=0;
      idx->entries[i].size = c_file.size;
      idx->entries[i].unk = 0;
      i++;
    } while( _findnext( hFile, &c_file ) == 0 );
  }
  _findclose( hFile );
  return idx;
}
void CreateLb5(const char* filename, const char* filemask)
{
  char* idxFilename = ChangeFileExt(filename,".idx");
  char* lb5Filename = ChangeFileExt(filename,".lb5");
  char buffer[1024];

  idxFile* idx = genIdxFile(filemask);
  if (idx==NULL)
    printf("No files matching '%s' found.\n",filemask);

  FILE* hLb5File=fopen(lb5Filename,"wb");
  if (!hLb5File)
  {
    printf("Couldn't create file '%s'\n",lb5Filename);
  }
  else {
    printf("file count: %d\n",idx->filecount);
    size_t offset = 0;
    for (int i=0; i<idx->filecount; i++)
    {
      printf("Adding %s\n",idx->entries[i].filename);
      FILE* curFile=fopen(idx->entries[i].filename,"rb");
      if (!curFile)
      {
        printf("Couldn't open source file!\n");
        break;
      }
      idx->entries[i].offset = offset;
      size_t k=idx->entries[i].size,n=sizeof(buffer);
      offset += k;
      while (k>0)
      {
        if (n>k) n=k;
        if (1!=fread(buffer,n,1,curFile))
        {
          printf("Read file error!\n");
          i=idx->filecount;
          break;
        };
        if (strstr(idx->entries[i].filename,".txt") || strstr(idx->entries[i].filename,".TXT"))
          decrypt(buffer,n);
        if (1!=fwrite(buffer,n,1,hLb5File))
        {
          printf("Write file error!\n");
          i=idx->filecount;
          break;
        };
        k-=n;
      }
      fclose(curFile);
    }

    FILE* hIdxFile=fopen(idxFilename,"wb");
    if (!hIdxFile)
      printf("Couldn't create file '%s'\n",idxFilename);
    else {
      size_t fsize=idx->filecount*sizeof(idxentry)+sizeof(idxFile);
      if (1!=fwrite(idx,fsize,1,hIdxFile))
        printf("Error writing to file '%s'\n",idxFilename);
      fclose(hIdxFile);
    }
  }
  free(idx);
  if (hLb5File) fclose(hLb5File);
  free(idxFilename);
  free(lb5Filename);
}
#define STR_TEST(test, result, expected) if (strcmp(result,expected)) \
 printf("%s FAILED! (result: '%s', expected: '%s')\n", #test, result,expected);\
 else printf("%s PASSED (result: '%s', expected: '%s')\n", #test,result,expected);
void Test()
{
  printf("Testing...\n");
  char* tmp;
  tmp = ChangeFileExt("test.bmp",".ddwerwd");
  STR_TEST(ChangeFileExt("test.bmp",".ddwerwd"), tmp, "test.ddwerwd");
  free(tmp);
  tmp = ChangeFileExt("test2",".ddaa");
  STR_TEST(ChangeFileExt("test2",".ddaa"), tmp, "test2.ddaa");
  free(tmp);
  tmp = ChangeFileExt("test2.",".d");
  STR_TEST(ChangeFileExt("test2.",".d"), tmp, "test2.d");
  free(tmp);
};
int main(int argc, const char* argv[])
{
  //Test();
  if (argc<3)
  {
    printf("Usage: lb5 {l|x|c} file.lb5 [file (x)|filemask (c)]\n");
    return 1;
  }
  if (!strcmp(argv[1],"x"))
  { 
    if (argc>2)
      ExtractLb5(argv[2],argv[3]);
    else
      ExtractLb5(argv[2],NULL);
  }
  else if (!strcmp(argv[1],"l"))
  { 
    ListLb5(argv[2]);
  }
  else if (!strcmp(argv[1],"c"))
  { 
    CreateLb5(argv[2], argv[3]);
  }
  return 0;
}