#include <stdio.h>
#include <string.h> /* strlen() */
#include <stdlib.h> /* exit() */

#include "version.h"

/* TODO */
/* match lowecase tokens as well as upper case ones */

/* Info from http://docs.info.apple.com/article.html?coll=ap&artnum=57 */

/* In memory, applesoft file starts at address $801        */
/* format is <LINE><LINE><LINE>$00$00                      */
/* Where <LINE> is:                                        */
/*    2 bytes (little endian) of LINK indicating addy of next line */
/*    2 bytes (little endian) giving the line number       */
/*    a series of bytes either ASCII or tokens (see below) */
/*    a $0 char indicating end of line                     */

#define NUM_TOKENS 107

   /* Starting at 0x80 */
char applesoft_tokens[][8]={

/* 80 */ "END","FOR","NEXT","DATA","INPUT","DEL","DIM","READ",
/* 88 */ "GR","TEXT","PR #","IN #","CALL","PLOT","HLIN","VLIN",
/* 90 */ "HGR2","HGR","HCOLOR=","HPLOT","DRAW","XDRAW","HTAB","HOME",
/* 98 */ "ROT=","SCALE=","SHLOAD","TRACE","NOTRACE","NORMAL","INVERSE","FLASH",
/* A0 */ "COLOR=","POP","VTAB ","HIMEM:","LOMEM:","ONERR","RESUME","RECALL",
/* A8 */ "STORE","SPEED=","LET","GOTO","RUN","IF","RESTORE","&",
/* B0 */ "GOSUB","RETURN","REM","STOP","ON","WAIT","LOAD","SAVE",
/* B8 */ "DEF FN","POKE","PRINT","CONT","LIST","CLEAR","GET","NEW",
/* C0 */ "TAB","TO","FN","SPC(","THEN","AT","NOT","STEP",
/* C8 */ "+","-","*","/","^","AND","OR",">",
/* D0 */ "=","<","SGN","INT","ABS","USR","FRE","SCRN (",
/* D8 */ "PDL","POS","SQR","RND","LOG","EXP","COS","SIN",
/* E0 */ "TAN","ATN","PEEK","LEN","STR$","VAL","ASC","CHR$",
/* E8 */ "LEFT$","RIGHT$","MID$","","","","","",
/* F0 */ "","","","","","","","",
/* F8 */ "","","","","","(","(","("
};

#define LOW(_x)  ((_x)&0xff)
#define HIGH(_x) (((_x)>>8)&0xff)
#define MAXSIZE 65535

/* File cannot be longer than 64k */
unsigned char output[MAXSIZE+1];

char *line_ptr;
int line=0;
char input_line[BUFSIZ];

static void show_problem(char *line_ptr) {

	int offset,i;

	offset=(int)(line_ptr-input_line);
	fprintf(stderr,"%s",input_line);
	for(i=0;i<offset;i++) fputc(' ',stderr);
	fprintf(stderr,"^\n");
}

static int getnum(void) {

	int num=0;

	/* skip any whitespace */
	while((*line_ptr<=' ') && (*line_ptr!=0)) line_ptr++;

	while (*line_ptr>' ') {
		if ((*line_ptr<'0')||(*line_ptr>'9')) {
			fprintf(stderr,"Invalid line number line %d\n",line);
			show_problem(line_ptr);
			exit(-1);
		}
		num*=10;
		num+=(*line_ptr)-'0';
		line_ptr++;
	}

	if (!(*line_ptr)) {
		fprintf(stderr,"Missing line number line %d\n",line);
		exit(-1);
	}

	return num;
}

static int in_quotes=0,in_rem=0;

/* note: try to find longest possible token */
/* otherwise ATN is turned into AT N */
static int find_token(void) {

	int ch,i;

	ch=*line_ptr;

	/* end remarks if end of line */
	if (in_rem && (ch=='\n')) {
		in_rem=0;
		return 0;
	}

	/* don't skip whitespace in quotes or remarks */
	if ((!in_quotes)&&(!in_rem)) {
		while(ch<=' ') {
			if ((ch=='\n') || (ch=='\r') || (ch=='\0')) {
				return 0;
			}
			line_ptr++;
			ch=*line_ptr;
		}
	}

	/* toggle quotes mode */
	if (ch=='\"') in_quotes=!in_quotes;

	/* don't tokenize if in quotes */
	if ((!in_quotes)&&(!in_rem)) {

//		fprintf(stderr,"%s",line_ptr);
		for(i=0;i<NUM_TOKENS;i++) {
			if (!strncmp(line_ptr,applesoft_tokens[i],
					strlen(applesoft_tokens[i]))) {

				/* HACK: special case to avoid AT/ATN problem */
				/* Update, apparently actual applesoft uses   */
				/*         a similar hack.  Also the 'A TO'   */
				/*         case which we don't handle because */
				/*         we like sane whitespace.           */
				if ((i==69) && (line_ptr[2]=='N')) continue;
//				fprintf(stderr,
//						"Found token %x (%s) %d\n",0x80+i,
//						applesoft_tokens[i],i);

				line_ptr+=strlen(applesoft_tokens[i]);

				/* REM is 0x32 */
				if (i==0x32) in_rem=1;

				return 0x80+i;
			}

			//fprintf(stderr,"%s ",applesoft_tokens[i]);
		}
	}

	//fprintf(stderr,"\n");

	/* not a token, just ascii */
	line_ptr++;
	return ch;
}

static void check_oflo(int size) {

	if (size>MAXSIZE) {
		fprintf(stderr,"Output file too big!\n");
		exit(-1);
	}
}

int main(int argc, char **argv) {

	int offset=2,i;

	int linenum=0,lastline=0,link_offset;
	int link_value=0x801; /* start of applesoft program */
	int token;

	while(1) {
		/* get line from input file */
		line_ptr=fgets(input_line,BUFSIZ,stdin);
		line++;
		if (line_ptr==NULL) break;

		/* VMW extension: use leading ' as a comment char */
		if (line_ptr[0]=='\'') continue;

		/* skip empty lines */
		if (line_ptr[0]=='\n') continue;

		linenum=getnum();
		if ((linenum>65535) || (linenum<0)) {
			fprintf(stderr,"Invalid line number %d\n",linenum);
			exit(-1);
		}
		if (linenum<lastline) {
			fprintf(stderr,"Line counted backwards %d->%d\n",
				lastline,linenum);
			exit(-1);
		}
		lastline=linenum;

		link_offset=offset;
		check_oflo(offset+4);
		output[offset+2]=LOW(linenum);
		output[offset+3]=HIGH(linenum);
		offset+=4;

		while(1) {
			token=find_token();
			output[offset]=token;
			offset++;
			check_oflo(offset);
			if (!token) break;
		}

		/* remarks end at end of line */
		in_rem=0;

		/* 2 bytes is to ignore size from beginning of file */
		link_value=0x801+(offset-2);

		/* point link value to next line */
		check_oflo(offset+2);
		output[link_offset]=LOW(link_value);
		output[link_offset+1]=HIGH(link_value);
	}
	/* set last link field to $00 $00 which indicates EOF */
	check_oflo(offset+2);
	output[offset]='\0';
	output[offset+1]='\0';
	offset+=2;

	/* Set filesize */
	/* -1 to match observed values */
	output[0]=LOW(offset-1);
	output[1]=HIGH(offset-1);
	/* output our file */
	for(i=0;i<offset;i++) putchar(output[i]);

	return 0;
}