#include <stdio.h>
#include <stddef.h>
#include <string.h>

int usage(int argc, char** argv, int argerr, const char* error) {
  FILE* o = error ? stderr : stdout;
  char* progname = argv[0];
  fprintf(o, "This program '%s' loads arbitrary files and outputs them as C code which loads them in the style of 'program resources'.\n", progname);
  fprintf(o, "It is particularly designed for loading one or more ramdisks, init programs or other arbitrary 'blobs' in kernel boot images.\n\n");
  fprintf(o, "By default it will produce a function which calls another function to register each resource.\n");
  fprintf(o, "Using the --nofunctions option and setting the name with --arrayname you can also get it to just produce arrays similar to a simple 'bin2c' program.\n\n");
  fprintf(o, "USAGE:\n");
  fprintf(o, "  %s [--output <filename>] [--allowempty] [--nofunctions] [--defaulttype <name>] [--loadfunction <functionname>] [--registerfunction <functionname>] [[--type <typestring>] [--arrayname <name>] [--filename <name>] resource1 [[--type <typestring>] [--arrayname <name>] [--filename <name>] resource2 [...]]]\n\n", progname);
  fprintf(o, "EXAMPLES:\n");
  fprintf(o, "  %s --output gamemods_autogenerated.c --loadfunction mods_init --allowempty --defaulttype GAME_MOD *.mod\n\n", progname);
  fprintf(o, "  %s --output mybootscripts.c --type SCRIPT --name bootscript startup.script --type RAMDISK --name initramdisk startup.image\n\n", progname);
  fprintf(o, "  %s --allowempty\n\n", progname);
  return error == NULL ? 0 : -1;
}

#define MAX_RESOURCES 100
FILE* files[MAX_RESOURCES];
char* types[MAX_RESOURCES];
char* arraynames[MAX_RESOURCES];
char* filenames[MAX_RESOURCES];
unsigned long sizes[MAX_RESOURCES];
    
    unsigned char buffer[256];
  
int main(int argc, char** argv) {
  char* defaulttype = "RESOURCE";
  char* nexttype = NULL;
  char* nextarrayname = NULL;
  char* nextfilename = NULL;
  int nresources = 0;
  int allowempty = 0;
  int nofunctions = 0;
  char* loadfunction = "resources_init";
  char* registerfunction = "resources_register";
  char* progname = argv[0];
  int bytesperline = 16;
  
  char* outputname = NULL;
  
  char simplenamebuff[6];
  simplenamebuff[0] = '_';
  simplenamebuff[1] = 'r';
  simplenamebuff[2] = 'e';
  simplenamebuff[3] = 's';
  simplenamebuff[5] = 0;
  
  int argi = 1;
  while (argi < argc) {
    if (!strcmp(argv[argi], "--usage")) {
      usage(argc, argv, argi, NULL);
      return 0;
    } else if (!strcmp(argv[argi], "--type")) {
      if (argi + 1 >= argc) {
        return usage(argc, argv, argi, "Missing argument after --type");
      }
      argi++;
      nexttype = argv[argi];
    } else if (!strcmp(argv[argi], "--arrayname")) {
      if (argi + 1 >= argc) {
        return usage(argc, argv, argi, "Missing argument after --arrayname");
      }
      argi++;
      nextarrayname = argv[argi];
    } else if (!strcmp(argv[argi], "--filename")) {
      if (argi + 1 >= argc) {
        return usage(argc, argv, argi, "Missing argument after --filename");
      }
      argi++;
      nextfilename = argv[argi];
    } else if (!strcmp(argv[argi], "--output") || (argv[argi][0] == '-' && argv[argi][1] == 'o' && argv[argi][2] == 0)) {
      if (outputname != NULL) {
        usage(argc, argv, argi, "Can't specify output more than once");
        return -1;
      }
      if (argi + 1 >= argc) {
        usage(argc, argv, argi, "Missing argument after --output");
        return -1;
      }
      argi++;
      outputname = argv[argi];
    } else if (argv[argi][0] == '-' && argv[argi][1] == 'o') {
      if (outputname != NULL) {
        usage(argc, argv, argi, "Can't specify output more than once");
        return -1;
      }
      outputname = argv[argi]+2;
    } else if (!strcmp(argv[argi], "--allowempty")) {
      allowempty = 1;
    } else if (!strcmp(argv[argi], "--nofunctions")) {
      nofunctions = 1;
    } else {
      if (nresources + 1 >= MAX_RESOURCES) {
        return usage(argc, argv, argi, "Too many resources");
      }
      files[nresources] = fopen(argv[argi], "rb");
      if (nexttype) {
        types[nresources] = nexttype;
        nexttype = NULL;
      } else {
        types[nresources] = defaulttype;
      }
      if (nextarrayname) {
        arraynames[nresources] = nextarrayname;
        nextarrayname = NULL;
      } else {
        simplenamebuff[4] = (char)('A' + nresources);
        arraynames[nresources] = strdup(simplenamebuff);
      }
      if (nextfilename) {
        filenames[nresources] = nextfilename;
        nextfilename = NULL;
      } else {
        char* lastsegment = argv[argi];
        char* s = lastsegment;
        while (*s) { 
          if (*s == '/' || *s == '\\' || *s == ':') {
            lastsegment = s+1;
          }
          s++;
        }
        filenames[nresources] = lastsegment;
      }
      nresources++;
    }
    argi++;
  }
  
  if (nresources < 1 && !allowempty) {
    return usage(argc, argv, argi, "Expected some resources to add or --allowempty to allow an empty resource structure");
  }
  
  FILE* output = stdout;
  
  if (outputname != NULL) { 
    output = fopen(outputname, "w");
    if (output == NULL) {
      fprintf(stderr, "ERROR: Failed to open output file '%s'\n", outputname);
      return -1;
    }
  }
  
  fprintf(output, "// This file is autogenerated by '%s'\n\n", progname);
  char* hex = "0123456789ABCDEF";
  for (int resi = 0; resi < nresources; resi++) {
    FILE* f = files[resi];
    unsigned long sz = 0;
    size_t nread;
    fprintf(output, "unsigned char %s[] = {\n", arraynames[resi]);
    while ((nread = fread(buffer, 1, bytesperline, f)) > 0) {
      if (sz > 0) {
        fprintf(output, ",\n");
      }
      sz += (unsigned long) nread;
      for (size_t bytei = 0; bytei < nread; bytei++) {
        int b = ((int) buffer[bytei]) & 0xFF;
        fprintf(output, "%s0x%c%c", bytei > 0 ? ", " : "  ", hex[b>>4], hex[b&0xF]);
      }
    }
    fprintf(output, "\n}; // end of %s\n\n", arraynames[resi]);
    
    sizes[resi] = sz;
    fclose(f);
  }
  
  if (!nofunctions) {
    fprintf(output, "// This function should be implemented in the program code, the name can be changed with using --registerfunction <name> when generating this code\n");
    fprintf(output, "void %s(const char* type, const char* name, unsigned char* data, unsigned long size);\n\n", registerfunction);
    
    fprintf(output, "// This function should be invoked from the program code, the name can be changed with using --loadfunction <name> when generating this code\n");
    fprintf(output, "void %s() {\n", loadfunction);
    for (int resi = 0; resi < nresources; resi++) {
      fprintf(output, "  %s(\"%s\", \"%s\", %s, %lu);\n", registerfunction, types[resi], filenames[resi], arraynames[resi], sizes[resi]);
    }
    fprintf(output, "}\n\n");
  }
  
  if (outputname != NULL) {
    fclose(output);
  }
}