/* sentence.c   by Michael Thorpe   2001-07-20 */

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

#define LINE_SIZE    4096
#define COMMENT_CHAR  '#'
#define SENTENCE_CHAR '-'
#define ADDCONST_CHAR '='

struct word {
	struct word *next;
	char word[1];
};

struct group {
	struct group *next;
	char name;
	int num;
	struct word *words;
};

struct group *groups=0;
int numsentences=0;
char curgroup='\0';
int numerrs=0;
int maxrecurse=10;

struct group *findgroup(char c) {
	struct group *g;

	for(g=groups;g;g=g->next)
		if(g->name==c)
			break;
	if(0==g) {
		if(0==(g=(struct group *)malloc(sizeof(struct group)))) {
			perror("malloc");
			exit(-1);
		}
		g->next=groups;
		g->name=c;
		g->num=0;
		g->words=0;
		groups=g;
	}
	return(g);
}

void addline(char *line) {
	struct group *g;
	struct word *w;

	g=findgroup(curgroup);
	if(0==(w=(struct word *)malloc(sizeof(struct word)+strlen(line)))) {
		perror("malloc");
		exit(-1);
	}
	w->next=g->words;
	strcpy(w->word,line);
	g->words=w;
	g->num++;
}

int readfile(FILE *f) {
	char line[LINE_SIZE];
	int i;

	while(line==fgets(line,LINE_SIZE,f)) {
		for(i=0;line[i] && COMMENT_CHAR != line[i] && '\n' != line[i];i++)
			;
		if(line[i])
			while(i>0 && isspace(line[i-1]))
				i--;
		line[i]='\0';
		if(i==0)
			continue;
		if(line[0]=='[' && line[1] && line[2]==']' && !line[3])
			curgroup=line[1];
		else if(curgroup)
			addline(line);
		else
			numerrs++;
	}
	return(0);
}

char *findword(char c) {
	struct group *g;
	struct word *w;
	int i;

	g=findgroup(c);
	if(0==g->num) {
		fprintf(stderr,"error: Couldn't find any appropriate words! (looking for '%c')\n",c);
		numerrs++;
		return(0);
	}
	w=g->words;
	i=rand()%g->num;
	while(i--)
		w=w->next;
	return(w->word);
}

void addconst(char c,char *s) {
	struct group *g;
	struct word *w;
	int i,j;

	g=findgroup(c);
	for(i=j=0;s[i];i++)
		if(s[i]=='%')
			j++;
	j+=i;
	if(0==(w=(struct word *)malloc(sizeof(struct word)+j))) {
		perror("malloc");
		exit(-1);
	}
	w->next=g->words;
	w->word[j]='\0';
	while(i>0) {
		if(s[--i]=='%')
			w->word[--j]='%';
		w->word[--j]=s[i];
	}
	g->words=w;
	g->num++;
}

void tackon(char **s,int *sl,char *t,int tl) {
	char *u;

	u=(char *)realloc(*s,*sl+tl);
	if(!u) {
		perror("malloc");
		exit(-1);
	}
	*s=u;
	memcpy(u+*sl,t,tl);
	*sl+=tl;
}

char *expandword(char *s) {
	char c,*e=0,*t;
	int capitalize=0,i,j,el=0;

	maxrecurse--;
	for(i=0;s[i];i++) {
		if(s[i]=='%' && s[i+1]) {
			i++;
			if(s[i]=='%')
				tackon(&e,&el,"%",1);
			else if(s[i]==SENTENCE_CHAR)
				capitalize=1;
			else {
				if(s[i]==ADDCONST_CHAR && s[i+1]) {
					c=s[++i];
					i++;
				}
				if((t=findword(s[i]))) {
					if(maxrecurse)
						t=expandword(t);
					if(i>1 && s[i-2]==ADDCONST_CHAR)
						addconst(c,t);
					j=strlen(t);
					if(capitalize) {
						c=toupper(t[0]);
						tackon(&e,&el,&c,1);
						t++;
						j--;
					}
					tackon(&e,&el,t,j);
					if(maxrecurse) {
						if(capitalize)
							t--;
						free(t);
					}
					capitalize=0;
				}
			}
		} else {
			for(j=i;s[j] && s[j] != '%';j++)
				;
			if(capitalize) {
				capitalize=0;
				c=toupper(s[i++]);
				tackon(&e,&el,&c,1);
			}
			tackon(&e,&el,s+i,j-i);
			i=j-1;
		}
	}
	maxrecurse++;
	tackon(&e,&el,"\0",1);
	return(e);
}

int main(int argc,char **argv) {
	int i=1;
	FILE *f;
	char *myenv=0;
	char *s;

	myenv=getenv("SENTENCE");
	if((argc<2 && !myenv) || (argc==2 && !strcmp(argv[i],"-h"))) {
		printf("usage: sentence [-h] [-r <#>] <file1> [<file2> [..]]  (or set $SENTENCE)\n");
		return(1);
	}
	if(argc>2 && !strcmp(argv[i],"-r") && isdigit(argv[i+1][0])) {
		maxrecurse=atoi(argv[++i]);
		i++;
	}
	if(argc<2 && myenv && (f=fopen(myenv,"r"))) {
		readfile(f);
		fclose(f);
	}
	for(;i<argc;i++) {
		if(0==(f=fopen(argv[i],"r"))) {
			numerrs++;
			perror("open");
			continue;
		}
		readfile(f);
		fclose(f);
	}
	srand(time(0)+getpid()+(getpid()<<15));
	rand();
	s=findword(SENTENCE_CHAR);
	if(0==s)
		return(numerrs);
	s=expandword(s);
	if(0==s)
		return(numerrs);
	fputs(s,stdout);
	putchar('\n');
	return(numerrs);
}