/*!@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, FPATH_MAX
#include <dirent.h>

/* 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
#ifndef MAX_ELENAME_LEN //max setname length
#define MAX_ELENAME_LEN 32
#endif
#define FNAME_MAX 1024
#define FPATH_MAX 8192

/* 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 //lexer_fsm.rl
int    lexer_setstr(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
uint8_t prev_setname[MAX_SETNAME_LEN];  
static
uint8_t prev_elename[MAX_ELENAME_LEN];
static
uint8_t map_key[] = "~";
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[FNAME_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,FNAME_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;
  printf("lexer_lexfilename(%s)\n",fname);
  return lexer_lexfilename(fname);
}

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

/* Returns 1 on success, 0 on failure */
int
lexer_ismapfile(uint8_t* str)
{
  int i, len;

  len = u8_strlen(str);
  for(i = 0; i < len; i++)
    if(str[i] == '~')
      return 1;
}


/* Scan filename and push the its tokens
   onto the stack */
int lexer_lexfilename
(uint8_t* str)
#define REF(STR) (STR[0] <= 0x39 && STR[0] >= 0x30)  
#define DEL_FTOK(STR) (STR = u8_strchr(STR, '_') + 1)
#define NEXT_TOK(STR) (u8_strchr(STR, '_') + 1)
#define SET_CURR_SETNAME(STR)                   \
  do {                                         \
  printf("setting curr_setname of str(%s)\n", STR); \
  setname_end = u8_chr(STR, FNAME_MAX, '_');   \
  setname_len = setname_end - str;             \
  u8_move(curr_setname, STR, setname_len);     \
  printf("curr_setname is now %s\n",curr_setname); \
   } while (0)
#define SET_CURR_ELENAME(STR) \
  do { \
    printf("setting curr_elename of str(%s)\n", STR); \
    setname_end = u8_chr(STR, FNAME_MAX, '_') + 1; \
    if(REF(setname_end)) \
      setname_end = u8_chr(setname_end, FNAME_MAX, '_') + 1; \
    elename_end = u8_chr(setname_end, FNAME_MAX, '_'); \
    elename_len = elename_end - setname_end; \
    u8_move(curr_elename, setname_end, elename_len); \
    printf("curr_elename is now %s\n", curr_elename); \
  } while (0) 
  
#define SETNAME_MATCHES()  (u8_strcmp(curr_setname, prev_setname) == 0)
#define ELENAME_MATCHES()  (u8_strcmp(curr_elename, prev_elename) == 0)
#define UPDATE_PREV_SETNAME(STR) \
  do { \
    printf("updating prev_setname from (%s)", prev_setname);		\
  u8_set(prev_setname , (ucs4_t) 0, MAX_SETNAME_LEN );  \
  u8_move(prev_setname, curr_setname, setname_len);  \
  printf(" to %s\n", prev_setname); \
  } while (0)
#define UPDATE_PREV_ELENAME(STR) \
  do { \
  u8_set(prev_elename , (ucs4_t) 0, MAX_ELENAME_LEN );  \
  u8_move(prev_elename, curr_elename, elename_len);  \
  } while (0)
#define PREV_MAPFILE() (TK_STACKX - 5)->tok_t == MOPEN || (TK_STACKX-3)->tok_t == MOPEN
#define SET_MAPSTR(STR)  (STR = u8_strstr(STR, map_key))

{ int ntok, len, newstrt;
  uint8_t *filepath;
  typedef enum filetypes {
    error = 0,
    set_model,
    set_map,
    ele_model,
    ele_map,
    ele_vlink,
    set_olink,
    set_vlink
  } filetypes;

  ntok = 0;

  printf("|---- Begin lexerfilename on %s ----|\n", str);
  
  if(*str == 0)
    perror("Lexfilename:: str is NULL so fail\n");

  /* Determine the filetype of str */
  len = u8_strlen(str);
  newstrt = lexer_setstr(str,len);

  str = str + newstrt;

  len = u8_strlen(str);
  
  ntok += lexer_lexstring(str, len);

  /* Need to add map variant name 'default' if user did not specify a
      map variant name */
  /* if(filetype == ele_map) */
  /*   { if(!u8_strchr(str, '_')) //map variant name not provided */
  /*      { yylval.str = "default"; */
  /* 	 lexer_pushtok(NAME, yylval); */
  /* 	 ntok++; */
  /* 	 printf("Pushing default ele_map name\n");     */
  /*      }	  */
  /*  } */

  /* Pass back filepath as end of statment operator */
  filepath = u8_strdup(lexer_get_current_filepath());
  yylval.str = filepath;
  lexer_pushtok(NAME, yylval);
  printf("Pushing filepath %s\n", filepath);
  ntok++;
     
  printf("|---- Ending lexer_lexfilename on %s, %d tokens were lexed ----|\n", str, ntok);
  return ntok;
}

int
lexer_lexelemap
( uint8_t* str)
{ int setname_len, elename_len, strlen;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;
  
  SET_CURR_SETNAME(newstrt);
  SET_CURR_ELENAME(newstrt);
  if(PREV_MAPFILE())
    { printf("*previous file was mapfile*\n");
      SET_MAPSTR(newstrt);
    }
  else
    { 
      if(SETNAME_MATCHES())
	{ DEL_FTOK(newstrt);
	  if(REF(newstrt))
	    DEL_FTOK(newstrt);
	  printf("setname matches\n");
	  if(ELENAME_MATCHES())
	     DEL_FTOK(newstrt);
	  if(REF(str))
	    DEL_FTOK(newstrt);
	}	   
     }
  UPDATE_PREV_ELENAME(newstrt);
  UPDATE_PREV_SETNAME(newstrt);

  return newstrt - str;

  
}

int 
lexer_lexelemodel
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  printf("In lexelemodel, str is %s\n", str);

  newstrt = str;
  
  SET_CURR_SETNAME(newstrt);
  SET_CURR_ELENAME(newstrt);
  if(SETNAME_MATCHES())
    { printf("in ele_model: setname matches\n");
      DEL_FTOK(newstrt);
      printf("newstrt is now %s\n", newstrt);
      if(REF(newstrt))
	DEL_FTOK(newstrt);
      if(ELENAME_MATCHES())
	{ printf("in ele_model: elename matches\n");
	  DEL_FTOK(newstrt);
	  if(REF(newstrt))
	    DEL_FTOK(newstrt);
	}
    }
  UPDATE_PREV_ELENAME(newstrt);
  UPDATE_PREV_SETNAME(newstrt);

  return newstrt - str;
}

int
lexer_lexsetmap
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;
  
  SET_CURR_SETNAME(newstrt); 
  if(PREV_MAPFILE())
    SET_MAPSTR(newstrt);
  else
    if( SETNAME_MATCHES())
      DEL_FTOK(newstrt);
      if(REF(newstrt))
	DEL_FTOK(newstrt);

  UPDATE_PREV_SETNAME(newstrt);

  return newstrt - str;
}

int
lexer_lexsetmodel
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;

  SET_CURR_SETNAME(newstrt);
  if( SETNAME_MATCHES())
    DEL_FTOK(newstrt);
  if(REF(newstrt))
    DEL_FTOK(newstrt);
  UPDATE_PREV_SETNAME(newstrt);

  return newstrt - str;

}

int
lexer_lexsetvlink
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;

  SET_CURR_SETNAME(newstrt);
  if( SETNAME_MATCHES())
    DEL_FTOK(newstrt);
  if(REF((NEXT_TOK(newstrt)))) //if NAME REF REF
    DEL_FTOK(newstrt);
  UPDATE_PREV_SETNAME(newstrt);

  return newstrt - str;

}

int
lexer_lexelevlink
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;

  SET_CURR_SETNAME(newstrt);
  SET_CURR_ELENAME(newstrt);
  if(SETNAME_MATCHES())
    { DEL_FTOK(newstrt);
      if(REF(NEXT_TOK(newstrt))) //NAME REF REF, where  is set_label
        DEL_FTOK(newstrt);
    }
       
  return newstrt - str;
}

int
lexer_lexsetolink
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  return 0;

  //do nothing
}

int
lexer_lexeleolink
(uint8_t* str)
{ int setname_len, elename_len;
  uint8_t* setname_end, *elename_end, *newstrt;
  uint8_t curr_setname[MAX_SETNAME_LEN] = {0};
  uint8_t curr_elename[MAX_ELENAME_LEN] = {0};

  newstrt = str;
  
  SET_CURR_SETNAME(newstrt);
  printf("prev_setname %s, curr_setname %s\n", prev_setname, curr_setname);
  if(SETNAME_MATCHES())
    { DEL_FTOK(newstrt);
      if(REF(newstrt))
	DEL_FTOK(newstrt);
    }

  return newstrt - str;

  
}


/**************************/
/****Abandon All Hope******/
/**************************/
/***                    ***/
/***                    ***/       
/***                    ***/
/***                    ***/



/* 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 < FNAME_MAX; i += unit_size, fnp++) */
      /* 	{ unit_size = u8_mblen(fname_bytes + i, min(4, FNAME_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, FNAME_MAXy) == -1) */
      /*  	FAIL("Lexer failed to convert d_name into uint8_t\n"); */
      /* ulc_fprintf(stdout, "filename is %11U\n c", filename); */