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

#include "buffer.h"
#include "util.h"

static void buf_realloc(struct buffer *buf, size_t new_size) {
	if (new_size > buf->size) {
		buf->size = new_size + 1;
		buf->data = realloc(buf->data, buf->size);
	}
}

struct buffer *buf_new(const char *init) {
	struct buffer *buf = malloc(sizeof(struct buffer));
	if (init) {
		buf->data = strdup(init);
		buf->len = strlen(init);
		buf->size = buf->len + 1;
	} else {
		buf->size = 1024;
		buf->data = malloc(buf->size);
		*buf->data = '\0';
		buf->len = 0;
	}

	return buf;
}

void buf_del(struct buffer **buf) {
	assert(*buf);
	struct buffer *tmp = *buf;
	free(tmp->data);
	free(tmp);
	*buf = NULL;
}

struct buffer *buf_dup(struct buffer *src) {
	struct buffer *dest = malloc(sizeof(struct buffer));
	dest->len = src->len;
	dest->size = src->size;
	dest->data = malloc(dest->size);
	memcpy(dest->data, src->data, dest->size);
	return dest;
}

char *buf_strdup(struct buffer *buf) {
	return strdup(buf->data);
}

void buf_append(struct buffer *buf, const char *str) {
	size_t len = strlen(str);
	buf_realloc(buf, buf->len + len + 1);
	strncat(buf->data, str, buf->size);
}

void buf_printf(struct buffer *buf, char *fmt, ...) {
	va_list ap;
	ssize_t len;

	va_start(ap, fmt);
	len = vsnprintf(buf->data, buf->size, fmt, ap);
	va_end(ap);

	if (len >= buf->size) {
		buf_realloc(buf, len + 1);
		va_start(ap, fmt);
		len = vsnprintf(buf->data, buf->size, fmt, ap);
		va_end(ap);
	}

	if (len < 0 || len >= buf->size) {
		fprintf(stderr, "buf_printf: failed to format str");
		exit(EXIT_FAILURE);
	}

	buf->len = len;
}