#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

static void
usage() {
        printf("Clear text from lib.ru for Pocket PC, Version 0.2.\n");
        printf("Author: Teodor Sigaev <teodor@sigaev.ru>\n");
        printf("Usage:\n   clrlibru [-i INPUTFILE] [-o OUTPUT] [-l NUMSPACE]\n");
        exit(0);
}

char* RemoveTag[]={
	"select",
	"head",
	"div",
	"a",
	"form",
	NULL
};

static int
is_rtag(char *tag, int len) {
	char **ptr=RemoveTag;

	tag[len]='\0';
	while( *ptr ) {
		if ( strcmp(tag, *ptr) == 0 ) 
			return 1;
		ptr++;
	} 
	return 0;
}


static char *optarg = NULL;
static int current=1;

int
mgetopt(int argn, char* argv[], char *option) {
	char key;

	if ( current >= argn ) return -1;

	key = *(argv[current]+1);
	if ( *(argv[current]) == '-' || *(argv[current]) == '/' ) {
		char *ptr = strchr( option, key );
		if ( ptr == NULL ) {
			printf( "Unknown option: %s\n", argv[current]);
			exit(1);
		}
		current++;
		if ( *(ptr+1) == ':' ) {
			if (current < argn) {
				optarg=argv[current];
				current++;
			} else {
				printf("No value for -%c\n" ,key);
				exit(1);
			}
		} else
			optarg=NULL;
	} else {
		printf("Unknown option: %s\n", argv[current]);
		exit(1);
	}
	return (int)key;
}

#define INTXT	0
#define INTAG	1
#define FINDEND	2
#define INDROPTAG	3
#define INDROPINTAG	4
#define INHEADTAG	5
#define INDROPINCLSTAG	6


int 
main(int argn, char *argv[]) {
	int ch;
	FILE	*in=stdin, *out=stdout;
	int state=INTXT;
	char	buf[8192];
	int lenbuf=0,closelen=0;
        int spacelen=4;

	while((ch = mgetopt(argn, argv, "l:i:o:h?"))!=-1) {
		switch (ch) {
			case 'i':
				if ( (in=fopen(optarg, "r"))==NULL) {
					printf("Can't open file %s\n", optarg);
					exit(1);
				}
				break;
			case 'o':
				if ( (out=fopen(optarg, "w"))==NULL) {
					printf("Can't open file %s\n",optarg);
					exit(1);
				}
				break;
			case 'l':
				spacelen = atoi(optarg);
				if ( spacelen < 0 ) {
					printf("-l should be >= 0\n");
					exit(1);
				}
				break;
			case 'h':
			case '?':
			default:
				usage();
		}
	}
	
	while( (ch=getc(in)) != EOF ) {
		if ( state==INTXT ) {
			if ( ch == '<' ) {
				state=INHEADTAG;
				lenbuf=0;
			} else if ( ch == '\n' ) {
				state=FINDEND;
				lenbuf=1;
				*buf = ch;
			} else if ( ch != '\r' )
				fputc(ch,out);
		} else if ( state==INHEADTAG ) {
			if ( isalpha(ch) ) {
				buf[ lenbuf ] = tolower(ch);
				lenbuf++;
			} else if ( ch == '>' ) {
				if ( is_rtag(buf,lenbuf) ) {
					state = INDROPTAG;
					closelen=0;
				} else {
					state=INTXT;
					fputc(' ',out);
				}
			} else if ( lenbuf == 0 && ch != '/' ) {
				fputc('<',out); fputc(ch,out); 
				state=INTXT;
			} else { 
				if ( is_rtag(buf,lenbuf) ) {
					state = INDROPTAG;
					closelen=0;
				} else {
					state=INTAG;
					fputc(' ',out);
				}
			}
		} else if ( state==INTAG ) {
			if ( ch == '>' ) {
				state=INTXT;
				fputc(' ',out);
			}	
		} else if ( state == INDROPTAG ) {
			if ( ch == '<' ) {
				state=INDROPINTAG;
				closelen=0;
			}
		} else if ( state == INDROPINTAG ) {
			if ( ch == '/' )
				state=INDROPINCLSTAG;
			else
				state=INDROPTAG;
		} else if ( state == INDROPINCLSTAG ) {
			if ( isalpha(ch) ) {
				if ( closelen < lenbuf && tolower(ch) == buf[closelen] ) {
					closelen++;
					if ( closelen==lenbuf )
						state=INTAG;
				} else 
					state=INDROPTAG;
			} else
				state=INDROPTAG;
		} else if ( state==FINDEND ) {
			if ( ch == ' ' ) {
				buf[ lenbuf ] = ch;
				lenbuf++;
				if ( lenbuf > spacelen ) {
					fwrite(buf, sizeof(char), lenbuf, out);
					state=INTXT;
				}
			} else if ( ch=='\n' ) {
				buf[ lenbuf ] = ch;
				lenbuf++;
				fwrite(buf, sizeof(char), lenbuf, out);
				state=INTXT;
			} else if ( ch !='\r' ) {
				state=INTXT;
				fputc(' ',out);
				ungetc(ch,in);
			} 
		} else {
			printf("Unknown state: %d\n", state);
			exit(1);
		}
	} 
			
	if ( in!=stdin )
		fclose(in);
	if ( out!=stdout )
		fclose(out);

	return 0;	
}