#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>

#include "oper.h"
#include "panic.h"
#include "slice.h"

static struct slice xmalloc(size_t size)
{
	void *p = malloc(size);
	if (!p) {
		panicf("Out of memory!\n");
	}
	return (struct slice) {
		.buf = p,
		.size = size,
	};
}

static struct slice xrealloc(void *ptr, size_t size)
{
	void *p = realloc(ptr, size);
	if (!p) {
		panicf("Out of memory!\n");
	}
	return (struct slice) {
		.buf = p,
		.size = size,
	};
}

void read_file(struct slice *out, char *filename)
{
	FILE *f = fopen(filename, "r");
	if (!f) {
		panicf("File %s does not exit!\n", filename);
	}
	size_t offset = 0;
	while (true) {
		if (offset >= out->size) {
			size_t new_size = 2 * out->size;
			*out = xrealloc(out->buf, new_size);
		}
		size_t read_size = out->size - offset;
		size_t n = fread(out->buf + offset, 1, read_size, f);
		if (n < read_size) {
			if (ferror(f)) {
				panicf("Read error!\n");
			}
			out->size = offset + n;
			return;
		}
		offset += n;
	}
}

int main(int argc, char **argv)
{
	if (argc < 2) {
		printf("Usage error: need a filename.\n");
		return 1;
	}

	struct slice program = xmalloc(1);
	read_file(&program, argv[1]);

	run(program);

	free(program.buf);
}