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

#include "interpreter.h"
#include "parser.h"
#include "util.h"


char* readfile(const char *fname,size_t *length){
	FILE *f=fopen(fname,"rb");
	if(!f)return NULL;
	if(fseek(f,0,SEEK_END)==-1){fclose(f); return NULL;}
	long flen=ftell(f);
	if(flen==-1){fclose(f); return NULL;}
	rewind(f);

	char *buf=malloc(flen+1,char);
	fread(buf,1,flen,f);
	if(ferror(f)){fclose(f); free(buf); return NULL;}
	if(memchr(buf,'\0',flen)!=NULL){
		fprintf(stderr,"Invalid null char in file '%s'\n",fname);
		exit(1);
	}
	buf[flen]='\0';
	fclose(f);

	*length=flen;
	return buf;
}

char *readstdin(size_t *length){
	int bufsz=1024,cursor=0;
	char *buf=malloc(bufsz,char);
	while(true){
		if(cursor==bufsz-1){
			bufsz*=2;
			buf=realloc(buf,bufsz,char);
		}
		int nread=fread(buf,1,bufsz-cursor-1,stdin);
		if(nread>0&&memchr(buf,'\0',nread)!=NULL){
			fprintf(stderr,"Invalid null char on stdin file\n");
			exit(1);
		}
		cursor+=nread;
		if(nread<bufsz-cursor-1){
			if(feof(stdin))break;
			if(ferror(stdin)){
				free(buf);
				return NULL;
			}
		}
	}
	buf[cursor]='\0';
	*length=cursor;
	return buf;
}


int main(int argc,char **argv){
	if(argc!=2){
		fprintf(stderr,"Pass source file (or '-') as a command-line argument.\n");
		return 1;
	}
	char *source;
	size_t length;
	if(strcmp(argv[1],"-")==0)source=readstdin(&length);
	else source=readfile(argv[1],&length);

	if((size_t)(int)length!=length){
		fprintf(stderr,"Source file too long!\n");
		return 2;
	}

	ParseRet pr=parse(source,length);
	if(pr.errstr){
		fprintf(stderr,"\x1B[1;31m%s\x1B[0m\n",pr.errstr);
		free(pr.errstr);
		return 1;
	}
	assert(pr.ast);
	char *s=ast_stringify(pr.ast);
	printf("%s\n",s);
	free(s);

	InterState *is=inter_make();
	inter_register_prelude(is);
	InterRet ir=inter_runcode(is,pr.ast);
	if(ir.errstr){
		fprintf(stderr,"\x1B[1;31m%s\x1B[0m\n",ir.errstr);
		free(ir.errstr);
		return 1;
	}
	s=ast_stringify(ir.ast);
	printf("%s\n",s);
	free(s);
	ast_free(ir.ast);
	inter_destroy(is);

	ast_free(pr.ast);
}