#include "cache.h"
#include "refs.h"
#include "refspec.h"

static struct refspec_item s_tag_refspec = {
	0,
	1,
	0,
	0,
	"refs/tags/*",
	"refs/tags/*"
};

/* See TAG_REFSPEC for the string version */
const struct refspec_item *tag_refspec = &s_tag_refspec;

/*
 * Parses the provided refspec 'refspec' and populates the refspec_item 'item'.
 * Returns 1 if successful and 0 if the refspec is invalid.
 */
static int parse_refspec(struct refspec_item *item, const char *refspec, int fetch)
{
	size_t llen;
	int is_glob;
	const char *lhs, *rhs;
	int flags;

	is_glob = 0;

	lhs = refspec;
	if (*lhs == '+') {
		item->force = 1;
		lhs++;
	}

	rhs = strrchr(lhs, ':');

	/*
	 * Before going on, special case ":" (or "+:") as a refspec
	 * for pushing matching refs.
	 */
	if (!fetch && rhs == lhs && rhs[1] == '\0') {
		item->matching = 1;
		return 1;
	}

	if (rhs) {
		size_t rlen = strlen(++rhs);
		is_glob = (1 <= rlen && strchr(rhs, '*'));
		item->dst = xstrndup(rhs, rlen);
	}

	llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
	if (1 <= llen && memchr(lhs, '*', llen)) {
		if ((rhs && !is_glob) || (!rhs && fetch))
			return 0;
		is_glob = 1;
	} else if (rhs && is_glob) {
		return 0;
	}

	item->pattern = is_glob;
	item->src = xstrndup(lhs, llen);
	flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);

	if (fetch) {
		struct object_id unused;

		/* LHS */
		if (!*item->src)
			; /* empty is ok; it means "HEAD" */
		else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(item->src, &unused))
			item->exact_sha1 = 1; /* ok */
		else if (!check_refname_format(item->src, flags))
			; /* valid looking ref is ok */
		else
			return 0;
		/* RHS */
		if (!item->dst)
			; /* missing is ok; it is the same as empty */
		else if (!*item->dst)
			; /* empty is ok; it means "do not store" */
		else if (!check_refname_format(item->dst, flags))
			; /* valid looking ref is ok */
		else
			return 0;
	} else {
		/*
		 * LHS
		 * - empty is allowed; it means delete.
		 * - when wildcarded, it must be a valid looking ref.
		 * - otherwise, it must be an extended SHA-1, but
		 *   there is no existing way to validate this.
		 */
		if (!*item->src)
			; /* empty is ok */
		else if (is_glob) {
			if (check_refname_format(item->src, flags))
				return 0;
		}
		else
			; /* anything goes, for now */
		/*
		 * RHS
		 * - missing is allowed, but LHS then must be a
		 *   valid looking ref.
		 * - empty is not allowed.
		 * - otherwise it must be a valid looking ref.
		 */
		if (!item->dst) {
			if (check_refname_format(item->src, flags))
				return 0;
		} else if (!*item->dst) {
			return 0;
		} else {
			if (check_refname_format(item->dst, flags))
				return 0;
		}
	}

	return 1;
}

static struct refspec_item *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
{
	int i;
	struct refspec_item *rs = xcalloc(nr_refspec, sizeof(*rs));

	for (i = 0; i < nr_refspec; i++) {
		if (!parse_refspec(&rs[i], refspec[i], fetch))
			goto invalid;
	}

	return rs;

 invalid:
	if (verify) {
		/*
		 * nr_refspec must be greater than zero and i must be valid
		 * since it is only possible to reach this point from within
		 * the for loop above.
		 */
		free_refspec(i+1, rs);
		return NULL;
	}
	die("Invalid refspec '%s'", refspec[i]);
}

int valid_fetch_refspec(const char *fetch_refspec_str)
{
	struct refspec_item *refspec;

	refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
	free_refspec(1, refspec);
	return !!refspec;
}

struct refspec_item *parse_fetch_refspec(int nr_refspec, const char **refspec)
{
	return parse_refspec_internal(nr_refspec, refspec, 1, 0);
}

struct refspec_item *parse_push_refspec(int nr_refspec, const char **refspec)
{
	return parse_refspec_internal(nr_refspec, refspec, 0, 0);
}

void free_refspec(int nr_refspec, struct refspec_item *refspec)
{
	int i;

	if (!refspec)
		return;

	for (i = 0; i < nr_refspec; i++) {
		free(refspec[i].src);
		free(refspec[i].dst);
	}
	free(refspec);
}