/*!@file
  \brief   APC main driver
  \details The driver assumes the existence of a bison-generated parser,
           referenced by the external function 'yyparse'.
           It also assumes the existence of a lexer which must be initialized
           before parsing, referenced by the external function 'lexer_init'
           which assumes standard error handling.
           All input arguments are made available through the exposed (that is,
           non-static) array of character pointers 'cargs', which point
           to the non-duplicated strings in 'argv' directly from the system.
  \author  Jordan Lavatai
  \date    Aug 2016
  ----------------------------------------------------------------------------*/
/* Standard */
#include <stdio.h>  //print
#include <errno.h>  //errors
#include <string.h> //strndupa
/* Posix */
#include <stdlib.h> //exit
#include <unistd.h> //getopt, sysconf
#include <dirent.h> //opendir
/* Internal */
#include "apc.h"
#include "parser.tab.h" //bison
#include "ir.h"
#include "print.h"

#define DEFAULT_PAGESIZE 4096
const char** cargs;
const uint8_t*  apc_package_name;
long  sys_pagesize;
  
int main(int, char*[]);

extern //lexer.c
int  lexer_init(void);
extern //scanner.c
int  scanner_init(void);
extern //scanner.c
void scanner_quit(void);
extern //scanner.c
int  scanner_scandir(DIR*);
extern //ir.c
int  ir_init(void);
extern //ir.c
int  ir_linker(void);
extern //ir.c
int  ir_condenser(void);
extern
void ir_test(void);

static
char* getcwd_basename(void);

#define $($)#$ //stringifier
#define MAXSTR 4096
#define MAXERR "-%c allows at most " $(MAXSTR) " input characters\n", opt
#define OPTS  "d:o:h-"
#define USAGE "Usage %s [-d dir_root][-o output_file][-h]\n", argv[0]
#define USAGE_LONG					\
  "\tOptions:\n"					\
  "\t\t-d\tRoot directory to parse from \t[./]\n"	\
  "\t\t-o\tOutput filename \t\t[a.asspak]\n"		\
  "\t\t-h\tPrint this help\n"
#define DONE   -1
#undef eprintf_callback
#define free_and_exit(ecode) do {		\
    free(cargs);				\
    exit(ecode);				\
  } while(0)
#define eprintf_callback(...) free_and_exit(EXIT_FAILURE)
/* Main entry from terminal
   parses the command line and kicks off recursive scanning
*/
int main
( int   argc,
  char* argv[]
)
{ int   opt;
  DIR*  dirp;
  const char* scanpath;
  char*       path_iter;
  cargs = (const char**) malloc('Z');
 getopt:
  switch (opt = getopt(argc, argv, OPTS))
  { case 'd' :
      path_iter = optarg;
      while (*path_iter++ != '\0');
      path_iter -= 2;
      if (*path_iter == '/')
	*path_iter = '\0';
    case 'o' :
      if (strnlen(optarg, MAXSTR) != MAXSTR)
        { cargs[opt] = optarg;
          goto getopt;
        }
      fprintf(stderr, MAXERR);
    default :
      eprintf(USAGE);
    case 'h' :
      printf(USAGE);
      printf(USAGE_LONG);
      free_and_exit(EXIT_SUCCESS);
    case DONE:
      break;
  }
  if ((sys_pagesize = sysconf(_SC_PAGESIZE)) == 0)
    sys_pagesize = DEFAULT_PAGESIZE;
  if (ir_init())
    { perror("init");
      free_and_exit(EXIT_FAILURE);
    }
  scanpath = cargs['d'] ? cargs['d'] : "./";
  errno = 0;
  dirp = opendir(scanpath);
  if (dirp == NULL || errno)
    eprintf("Path %s could not be accessed: %s\n", scanpath, strerror(errno));
  errno = 0;
  if (chdir(scanpath) || errno)
    eprintf("Could not change directory to %s: %s\n", scanpath, strerror(errno));
  apc_package_name = (uint8_t*) getcwd_basename();
  if (scanner_scandir(dirp))
    eprintf(strerror(errno));
  ir_test();
  ir_linker();
  ir_condenser();
  free_and_exit(EXIT_SUCCESS);
}

static
char* getcwd_basename
( void )
{ char* path_iter,* path_buf,* path;
  int   pages;
  path = NULL;
  pages = 1;
 try_cwd:
  path_buf = (char*) malloc(MAXSTR * pages);
  errno = 0;
  getcwd(path_buf, MAXSTR * pages);
  if (errno == ERANGE)
    { pages++;
      free(path_buf);
      goto try_cwd;
    }
  else if (errno)
    { perror(NULL);
      free(path_buf);
      return NULL;
    }
  path = path_iter = path_buf;
  while (*path_iter != '\0')
    { if (*path_iter == '/')
	path = path_iter + 1;
      path_iter++;
    }
  return path;
}