/* 
 * Copyright (C) 2026 Peter Mikkelsen <petermikkelsen10@gmail.com>
 *
 * This file is part of aplwc.
 *
 * Aplwc is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Aplwc is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with aplwc.  If not, see <https://www.gnu.org/licenses/>.
 */

#define _POSIX_C_SOURCE 200809L
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include "aplwc_repl.h"

static void *
my_alloc(size_t size, size_t *actual)
{
	size_t target = size;
	void *p;
	int fail2;

	if(actual){
		if(NEVER(target == 0))
			target = 1;
		else{
			target--;
			target |= target >> 1;
			target |= target >> 2;
			target |= target >> 4;
			target |= target >> 8;
			target |= target >> 16;
			target |= target >> 32;
			target++;
		}
	}

	fail2 = aplwc_simulate_failure();

	p = FAILCASE(malloc(target), NULL);
	if((p == NULL) && (size < target)){
		target = size;
		p = FAILCASE_X(malloc(target), NULL, fail2);
	}

	if(actual)
		*actual = target;
	return p;
}

static void
my_dealloc(void *p)
{
	free(p);
}

int
main(int argc, char *argv[])
{
	struct aplwc_fns fns;
	struct aplwc *aplwc;
	enum aplwc_rc ret;
	AplwcLine line;
	AplwcValue value;
	char *input, *src;
	int exit_code, line_number;
	size_t input_size, src_size, i;
	int opt, xflag, input_file;
	long tmp;
	unsigned long print_failsims;
	FILE *f;

	aplwc_clear_line(&line);
	aplwc_clear_value(&value);
	input = NULL;
	xflag = 0;
	input_file = 0;
	exit_code = 0;
	line_number = 0;
	aplwc = NULL;

	aplwc_simulate_failure_at = getenv_ulong("APLWC_SIMULATE_FAILURE_AT", 0);
	print_failsims = getenv_ulong("APLWC_SIMULATE_FAILURE_PRINT_COUNT", 0);

	memset(&fns, 0, sizeof(fns));
	fns.alloc = my_alloc;
	fns.dealloc = my_dealloc;

	while((opt = getopt(argc, argv, "x")) != -1){
		switch(opt){
		case 'x':
			xflag = 1;
			break;
		default:
usage:
			fprintf(stderr, "Usage: %s [-x] [file]\n", argv[0]);
			exit_code = 1;
			goto end;
		}
	}

	if((optind+1) == argc){
		input_file = 1;
		f = fopen(argv[optind], "r");
		if(f == NULL){
			fprintf(stderr, "Could not open file: %s: %s\n", argv[optind], strerror(errno));
			exit_code = 1;
			goto end;
		}
	}else if(optind == argc)
		f = stdin;
	else
		goto usage;

	aplwc = aplwc_new(fns, &ret);
	if(ret){
		fprintf(stderr, "Couldn't create new aplwc instance: %s\n", aplwc_errstr_rc(ret));
		exit_code = 1;
		goto end;
	}

	if(input_file){
		if(FAILCASE(fseek(f, 0, SEEK_END), -1)){
file_size:
			fprintf(stderr, "Failed to determine file size\n");
			exit_code = 1;
			goto end;
		}
		tmp = FAILCASE(ftell(f), -1);
		if(tmp < 0)
			goto file_size;
		input_size = tmp;
		rewind(f);
		input = FAILCASE(malloc(input_size), NULL);
		if(input == NULL){
			fprintf(stderr, "Failed to allocate space for file contents\n");
			exit_code = 1;
			goto end;
		}
		if(FAILCASE(fread(input, 1, input_size, f), 0) < input_size){
			fprintf(stderr, "Failed to read file contents\n");
			exit_code = 1;
			goto end;
		}
		fclose(f);

		src = input;
		src_size = input_size;
		if((input_size > 2) && (input[0] == '#') && (input[1] == '!')){
			for(i = 0; i < input_size; i++){
				if(input[i] == '\n'){
					src += i;
					src_size -= i;
					xflag = 1;
					break;
				}
			}
		}

		ret = aplwc_load_module(aplwc, "Main", src, src_size);
		if(ret){
			fprintf(stderr, "Couldn't load Main module from file %s: %s\n", argv[optind], aplwc_errstr_rc(ret));
			exit_code = 1;
			goto end;
		}
		free(input);
		input = NULL;
	}

	if(xflag)
		goto end;

	for(;;){
		if(input)
			free(input);
		if(aplwc_valid_line(&line))
			aplwc_free_line(&line);
		if(aplwc_valid_value(&value))
			aplwc_free_value(&value);

		input = NULL;
		if(getline(&input, &input_size, stdin) < 0){
			free(input);
			input = NULL;
			break;
		}else{
			line_number++;
			aplwc_read(aplwc, input, &line);
			if(!aplwc_valid_line(&line)){
line_error:
				fprintf(stderr, "error on line %d: %s: %s\n", line_number, aplwc_errstr(aplwc), input);
				continue;
			}
			aplwc_eval(&line, &value);
			if(!aplwc_valid_value(&value))
				goto line_error;
			fprintf(stdout, "%s\n", aplwc_value_string(&value));
		}
	}

end:
	if(input)
		free(input);
	if(NEVER(aplwc_valid_line(&line)))
		aplwc_free_line(&line);
	if(NEVER(aplwc_valid_value(&value)))
		aplwc_free_value(&value);
	if(aplwc)
		aplwc_destroy(aplwc);

	if(print_failsims){
		f = fdopen(3, "w");
		if(f == NULL){
			fprintf(stderr, "Failed to open fd 3\n");
			exit_code = 1;
		}else{
			fprintf(f, "%ld\n", aplwc_simulate_failure_count);
			fclose(f);
		}
	}

	if((exit_code != 0) && aplwc_simulate_failure_at && (aplwc_simulate_failure_count >= aplwc_simulate_failure_at))
		exit_code = 0;

	return exit_code;
}