/*!@file
  \brief   lexical analyzer implementation for APC
  \details The lexer manages two FIFO stacks.  One for maintaining tokens, the
           other for maintaining a list of files to be scanned.  During
           execution, the lexer will return a token from its token queue if any
           are present.  If not, the lexer will will pop an element from its
           file queue to 'scanner' to be tokenized.  If the file queue is empty,
           the lexer will instead call 'parsedir' to traverse the directory tree
           and tokenize the results.  If 'parsedir' does not generate any new
           tokens, we are done.
  \author  Jordan Lavatai
  \date    Aug 2016
  ----------------------------------------------------------------------------*/
/* Standard */
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
/* Posix */
#include <unistd.h>
#include <unitypes.h>
#include <unistr.h>
#include <uniconv.h>
#include <uniname.h>
#include <unistdio.h>
#include <stdlib.h>
#include <limits.h> //realpath, NAME_MAX, PATH_MAX
#include <dirent.h>
/* Redefinitions of NAME_MAX and PATH_MAX */
//#define NAME_MAX NAME_MAX/4
//#define PATH_MAX PATH_MAX/4

/* Local */
#include "parser.tab.h"
#ifndef DE_STACKSIZE
#define DE_STACKSIZE 1024
#endif
#ifndef TK_STACKSIZE
#define TK_STACKSIZE 1024
#endif
#ifndef MAX_SETNAME_LEN //max setname length
#define MAX_SETNAME_LEN 32
#endif

/* Public */
int         lexer_init(void);
int         lexer(void);
int         lexer_lexfile(const uint8_t*);
void        lexer_pushtok(int, YYSTYPE);
uint8_t const* lexer_get_current_filepath(void);
int         lexer_lexfilename(uint8_t*);
struct dirent* lexer_direntpa[DE_STACKSIZE],** lexer_direntpp,** lexer_direntpb;
/* Private */
extern //lexer_fsm.rl
int         lexer_lexstring(uint8_t*, int);
extern //scanner.c
int         scanner_init(void);
extern //scanner.c
int         scanner(void);
static inline
int         dredge_current_depth(void);
extern //bison
YYSTYPE     yylval;
static
uint8_t const* current_filename;
static
struct tok
{ YYSTYPE lval;  //token val
  int     tok_t; //token type
} token_stack[TK_STACKSIZE], *tsp, *tsx;

/* Directory Entity Array/Stack
   Simple array for keeping track of dirents yet to be processed by the scanner.
   If this list is empty and there are no tokens, the lexer is done.
   This array is populated by the scanner as an array, and popped locally by the
   lexer as a stack, and is popped as a FIFO stack.
*/
#define DE_STACK    (lexer_direntpa)
#define DE_STACKP   (lexer_direntpp)
#define DE_STACKB   (lexer_direntpb)
#define DE_LEN()    (DE_STACKP - DE_STACKB)
#define DE_INIT()   (DE_STACKP = DE_STACKB = DE_STACK)
#define DE_POP()    (*DE_STACKB++)

/* Token Stack
   This is a FIFO stack whose pointers are a union of either a pointer to an
   integer, or a pointer to two integers (a struct tok).  This way, integers may
   be added or removed from the stack either singularly (IPUSH/IPOP), or as a
   full token of two integers (PUSH/POP).
   An alignment error will occur if IPOP or IPUSH are used a non-even number of
   times in a sequence!
*/
#define TK_STACK     (token_stack)
#define TK_STACKP    (tsp)
#define TK_STACKX    (tsx)
#define TK_LEN()     (TK_STACKX - TK_STACKP)
#define TK_INIT()    (TK_STACKP = TK_STACKX = TK_STACK)
#define TK_POP()     (*TK_STACKP++)
#define TK_PUSH(T,L) (*TK_STACKX++ = (struct tok){L,T})

/* Initializer
   The initializer returns boolean true if an error occurs, which may be handled
   with standard errno.
*/
int lexer_init
()
{ TK_INIT();
  DE_INIT();
  return scanner_init();
}

/* Lexer
   If the token buffer is empty, 'lexer' will initialize the token buffer and
   call 'lexer_scandir'.  If SCAN_ERROR is returned, an error is printed
   before sending a null return to bison.  If 0 tokens are generated, the error
   printing is skipped.  In all other cases, 'yylval' is set, and the token's
   integer representation is returned.
*/
int lexer
#define $($)#$
#define SCAN_ERROR -1
#define TK_EMPTY   (TK_STACKP == TK_STACKX)
#define FAIL(...)				\
  do {						\
    fprintf(stderr,__VA_ARGS__);		\
    goto done;					\
  } while (0)
()
{ struct tok token;
   start:
  while (DE_LEN() > 0)//lex any directory entries in our stack
    {
      if (lexer_lexfile(DE_POP()->d_name) == 0)
       FAIL("Lexer failed to tokenize [%s]\n",(*DE_STACKB)->d_name);
    }
  if (TK_EMPTY)           //if there are no tokens,
    { TK_INIT();            //initialize the token stack back to 0
      switch (scanner())
        { case SCAN_ERROR:    //if an error occurred,
	    FAIL("Scanner error\n");
	  case 0:             //if the the scanner finds no dirents,
	    goto done;        //then we are done
          default:            //if we found some elements to scan,
	    goto start;       //start over and lex them
        }
    }
  token = TK_POP();
  yylval = token.lval;
  return token.tok_t;
 done:
  yylval.val = 0;
  return 0;
}


/* Token Receiver
   This receiver takes a struct tok and pushes it to the FIFO stack.
*/
void lexer_pushtok
#define $($)#$ //stringifier
#define ERR_TK "Fatal: Generated over " $(TK_STACKSIZE) " tokens in one pass."
( int tok, YYSTYPE lval )
{ if (TK_LEN() >= TK_STACKSIZE)
    { fprintf(stderr, ERR_TK);
      exit(EXIT_FAILURE);
    }
  TK_PUSH(tok, lval);
}

/* Lexical analysis of a file
   Strips a filename to its base name, then sends it to lexer_lex
*/
int lexer_lexfile
#define HIDDEN_WARNING "%s is hidden and will not be parsed!\n", filename
( const uint8_t  *filename
)
{ static uint8_t fname[NAME_MAX];
  uint8_t        *last_period = NULL, *iter;

  if (*filename ==  '.')
    { fprintf (stderr, HIDDEN_WARNING);
      return 0;
    }
  /* Copy the filename and remove its suffix */
  u8_strncpy(fname,filename,NAME_MAX);
  last_period = NULL;
  for (iter = fname; *iter; iter++)  //find the last '.' char
    if (*iter ==  '.')
      last_period = iter;
  if (last_period)                   //if we found one,
    *last_period =  0;             //truncate the string there
  /* Register the current_filename */
  current_filename = filename;
  
  return lexer_lexfilename(fname);
}

uint8_t const* lexer_get_current_filepath
()
{ static uint8_t        current_path[PATH_MAX];
  static uint8_t const* last_filename;
  if ((!last_filename || last_filename != current_filename) &&
      (realpath(current_filename, current_path) != (char*) current_path))
    { perror("realpath: ");
      return NULL;
    }
  return (const char*)current_path;
}

/* Scan filename and push the its tokens
   onto the stack */
int lexer_lexfilename
(uint8_t* str)
{
  int ntok, i, cmp, len, set_len, height, width;
  char map_key[] = "_m_";
  static uint8_t set_name[MAX_SETNAME_LEN] = {0};
  uint8_t *first, *map_begin;

  printf("Starting lexerfilename on %s\n", str);
  

  if(*str == 0)
    printf("Lexfilename:: str is NULL so fail\n");
  printf("setname is %s\n", set_name);
  
  /* If last file was a mapfile, then its 5th to last token should
  be a MOPEN. If this is the case, then we only pass MOPEN, height,
  weight and name of the current file. */
  if( (TK_STACKX - 5)->tok_t == MOPEN )
    { printf("The last file was a mapfile\n");
      if( (map_begin = strstr(map_key, str)) ) //if the current file is a mapfile
	{ printf("The current file is a variant of the last mapfile\n");
	  printf("Start lexing mapfile %s\n", str);
	  ntok += lexer_lexstring(map_begin, strlen(map_begin));
	}
      printf("Current file is not a variant of the last mapfile\n");      
    }
  else //last file was not a mapfile
    { printf("Last file was not a mapfile\n");

      first = (uint8_t*) u8_strchr(str,  '_'); //find the first '_' to find where str set_name ends    
      
      if(set_name[0] != 0) //if there is a set_name from last str     
	{ printf("There is a set_name (%s) present\n", set_name);
          set_len = first - str;
           
	  if(u8_strncmp(str, set_name, set_len) == 0) //check if it matches the current set_name
	    { str = str + set_len + 1;                    //if so, remove it from str
	      printf("str set_name matched last set_name, set str to %s\n", str);
	    }
	  else //update set_name to be str set_name
	    { u8_cpy(set_name, str, set_len);
	      set_name[set_len] = 0;
	      
	    }
        }
      else //set set_name
	{ u8_cpy(set_name, str, first-str);
	} 
      /* Call lexer_lexstring to tokenize the string */
      printf("calling lexstring to tokenize str (%s) of len %d\n", str, u8_strlen(str));
      ntok += lexer_lexstring(str, u8_strlen(str));
    }
    
  /*TODO: if regfile, store full path for later */

  printf("Ending lexer_lex on %s, %d tokens were lexed\n", str, ntok);
  return ntok;
}

/* int lexer_lexmapfile */
/* #define INC_X() */
/* (int height, int width) */
/* { */
/*   int x, y; */

/*   /\* Give scanner_scanpixels a buffer and a len. Iterate through */
/*      buf with buf[n]. If n == 0, do nothing. if n has a value, push x, */
/*      push y, push (z = n << 24), push (ref_id = n >> 8) *\/ */
/*   //scanner_scanpixels() */

/*   for(i = 0; i < len; i++) */
/*     if(buf[i] == 0) */
/*       if(x == width) */
/* 	x = 0; */
/*       else */
	
	  
      

/* } */
/* fname_bytes = (uint8_t*)(DE_POP()->d_name); */
      /* printf("d_name is %s\n", fname_bytes); */
      /* for (fnp = filename, i = 0; i < NAME_MAX; i += unit_size, fnp++) */
      /* 	{ unit_size = u8_mblen(fname_bytes + i, min(4, NAME_MAX - i)); */
      /* 	  if (u8_mbtouc(fnp, fname_bytes + i, unit_size) == -1) //add ucs4 char to the filename */
      /* 	    FAIL("Lexer failed to convert ^%s to unicode\n", (fname_bytes + i)); */
      /* 	  if (*fnp == 0) //added a terminating char */
      /* 	    break; */
      /* 	} */
      /* if(u8_mbtouc(filename, DE_POP()->d_name, NAME_MAX) == -1) */
      /*  	FAIL("Lexer failed to convert d_name into uint8_t\n"); */
      /* ulc_fprintf(stdout, "filename is %11U\n c", filename); */