#include "cache.h"
#include "dir.h"
#include "pathspec.h"

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * For each pathspec, sets the corresponding entry in the seen[] array
 * (which should be specs items long, i.e. the same size as pathspec)
 * to the nature of the "closest" (i.e. most specific) match found for
 * that pathspec in the index, if it was a closer type of match than
 * the existing entry.  As an optimization, matching is skipped
 * altogether if seen[] already only contains non-zero entries.
 *
 * If seen[] has not already been written to, it may make sense
 * to use find_pathspecs_matching_against_index() instead.
 */
void add_pathspec_matches_against_index(const struct pathspec *pathspec,
					char *seen)
{
	int num_unmatched = 0, i;

	/*
	 * Since we are walking the index as if we were walking the directory,
	 * we have to mark the matched pathspec as seen; otherwise we will
	 * mistakenly think that the user gave a pathspec that did not match
	 * anything.
	 */
	for (i = 0; i < pathspec->nr; i++)
		if (!seen[i])
			num_unmatched++;
	if (!num_unmatched)
		return;
	for (i = 0; i < active_nr; i++) {
		const struct cache_entry *ce = active_cache[i];
		ce_path_match(ce, pathspec, seen);
	}
}

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * This is a one-shot wrapper around add_pathspec_matches_against_index()
 * which allocates, populates, and returns a seen[] array indicating the
 * nature of the "closest" (i.e. most specific) matches which each of the
 * given pathspecs achieves against all items in the index.
 */
char *find_pathspecs_matching_against_index(const struct pathspec *pathspec)
{
	char *seen = xcalloc(pathspec->nr, 1);
	add_pathspec_matches_against_index(pathspec, seen);
	return seen;
}

/*
 * Magic pathspec
 *
 * Possible future magic semantics include stuff like:
 *
 *	{ PATHSPEC_RECURSIVE, '*', "recursive" },
 *	{ PATHSPEC_REGEXP, '\0', "regexp" },
 *
 */

static struct pathspec_magic {
	unsigned bit;
	char mnemonic; /* this cannot be ':'! */
	const char *name;
} pathspec_magic[] = {
	{ PATHSPEC_FROMTOP,  '/', "top" },
	{ PATHSPEC_LITERAL, '\0', "literal" },
	{ PATHSPEC_GLOB,    '\0', "glob" },
	{ PATHSPEC_ICASE,   '\0', "icase" },
	{ PATHSPEC_EXCLUDE,  '!', "exclude" },
};

static void prefix_magic(struct strbuf *sb, int prefixlen, unsigned magic)
{
	int i;
	strbuf_addstr(sb, ":(");
	for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
		if (magic & pathspec_magic[i].bit) {
			if (sb->buf[sb->len - 1] != '(')
				strbuf_addch(sb, ',');
			strbuf_addstr(sb, pathspec_magic[i].name);
		}
	strbuf_addf(sb, ",prefix:%d)", prefixlen);
}

static inline int get_literal_global(void)
{
	static int literal = -1;

	if (literal < 0)
		literal = git_env_bool(GIT_LITERAL_PATHSPECS_ENVIRONMENT, 0);

	return literal;
}

static inline int get_glob_global(void)
{
	static int glob = -1;

	if (glob < 0)
		glob = git_env_bool(GIT_GLOB_PATHSPECS_ENVIRONMENT, 0);

	return glob;
}

static inline int get_noglob_global(void)
{
	static int noglob = -1;

	if (noglob < 0)
		noglob = git_env_bool(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, 0);

	return noglob;
}

static inline int get_icase_global(void)
{
	static int icase = -1;

	if (icase < 0)
		icase = git_env_bool(GIT_ICASE_PATHSPECS_ENVIRONMENT, 0);

	return icase;
}

static int get_global_magic(int element_magic)
{
	int global_magic = 0;

	if (get_literal_global())
		global_magic |= PATHSPEC_LITERAL;

	/* --glob-pathspec is overridden by :(literal) */
	if (get_glob_global() && !(element_magic & PATHSPEC_LITERAL))
		global_magic |= PATHSPEC_GLOB;

	if (get_glob_global() && get_noglob_global())
		die(_("global 'glob' and 'noglob' pathspec settings are incompatible"));

	if (get_icase_global())
		global_magic |= PATHSPEC_ICASE;

	if ((global_magic & PATHSPEC_LITERAL) &&
	    (global_magic & ~PATHSPEC_LITERAL))
		die(_("global 'literal' pathspec setting is incompatible "
		      "with all other global pathspec settings"));

	/* --noglob-pathspec adds :(literal) _unless_ :(glob) is specified */
	if (get_noglob_global() && !(element_magic & PATHSPEC_GLOB))
		global_magic |= PATHSPEC_LITERAL;

	return global_magic;
}

/*
 * Parse the pathspec element looking for long magic
 *
 * saves all magic in 'magic'
 * if prefix magic is used, save the prefix length in 'prefix_len'
 * returns the position in 'elem' after all magic has been parsed
 */
static const char *parse_long_magic(unsigned *magic, int *prefix_len,
				    const char *elem)
{
	const char *pos;
	const char *nextat;

	for (pos = elem + 2; *pos && *pos != ')'; pos = nextat) {
		size_t len = strcspn(pos, ",)");
		int i;

		if (pos[len] == ',')
			nextat = pos + len + 1; /* handle ',' */
		else
			nextat = pos + len; /* handle ')' and '\0' */

		if (!len)
			continue;

		if (starts_with(pos, "prefix:")) {
			char *endptr;
			*prefix_len = strtol(pos + 7, &endptr, 10);
			if (endptr - pos != len)
				die(_("invalid parameter for pathspec magic 'prefix'"));
			continue;
		}

		for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
			if (strlen(pathspec_magic[i].name) == len &&
			    !strncmp(pathspec_magic[i].name, pos, len)) {
				*magic |= pathspec_magic[i].bit;
				break;
			}
		}

		if (ARRAY_SIZE(pathspec_magic) <= i)
			die(_("Invalid pathspec magic '%.*s' in '%s'"),
			    (int) len, pos, elem);
	}

	if (*pos != ')')
		die(_("Missing ')' at the end of pathspec magic in '%s'"),
		    elem);
	pos++;

	return pos;
}

/*
 * Parse the pathspec element looking for short magic
 *
 * saves all magic in 'magic'
 * returns the position in 'elem' after all magic has been parsed
 */
static const char *parse_short_magic(unsigned *magic, const char *elem)
{
	const char *pos;

	for (pos = elem + 1; *pos && *pos != ':'; pos++) {
		char ch = *pos;
		int i;

		if (!is_pathspec_magic(ch))
			break;

		for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
			if (pathspec_magic[i].mnemonic == ch) {
				*magic |= pathspec_magic[i].bit;
				break;
			}
		}

		if (ARRAY_SIZE(pathspec_magic) <= i)
			die(_("Unimplemented pathspec magic '%c' in '%s'"),
			    ch, elem);
	}

	if (*pos == ':')
		pos++;

	return pos;
}

static const char *parse_element_magic(unsigned *magic, int *prefix_len,
				       const char *elem)
{
	if (elem[0] != ':' || get_literal_global())
		return elem; /* nothing to do */
	else if (elem[1] == '(')
		/* longhand */
		return parse_long_magic(magic, prefix_len, elem);
	else
		/* shorthand */
		return parse_short_magic(magic, elem);
}

static void strip_submodule_slash_cheap(struct pathspec_item *item)
{
	if (item->len >= 1 && item->match[item->len - 1] == '/') {
		int i = cache_name_pos(item->match, item->len - 1);

		if (i >= 0 && S_ISGITLINK(active_cache[i]->ce_mode)) {
			item->len--;
			item->match[item->len] = '\0';
		}
	}
}

static void strip_submodule_slash_expensive(struct pathspec_item *item)
{
	int i;

	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		int ce_len = ce_namelen(ce);

		if (!S_ISGITLINK(ce->ce_mode))
			continue;

		if (item->len <= ce_len || item->match[ce_len] != '/' ||
		    memcmp(ce->name, item->match, ce_len))
			continue;

		if (item->len == ce_len + 1) {
			/* strip trailing slash */
			item->len--;
			item->match[item->len] = '\0';
		} else {
			die(_("Pathspec '%s' is in submodule '%.*s'"),
			    item->original, ce_len, ce->name);
		}
	}
}

static void die_inside_submodule_path(struct pathspec_item *item)
{
	int i;

	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		int ce_len = ce_namelen(ce);

		if (!S_ISGITLINK(ce->ce_mode))
			continue;

		if (item->len < ce_len ||
		    !(item->match[ce_len] == '/' || item->match[ce_len] == '\0') ||
		    memcmp(ce->name, item->match, ce_len))
			continue;

		die(_("Pathspec '%s' is in submodule '%.*s'"),
		    item->original, ce_len, ce->name);
	}
}

/*
 * Perform the initialization of a pathspec_item based on a pathspec element.
 */
static void init_pathspec_item(struct pathspec_item *item, unsigned flags,
			       const char *prefix, int prefixlen,
			       const char *elt)
{
	unsigned magic = 0, element_magic = 0;
	const char *copyfrom = elt;
	char *match;
	int pathspec_prefix = -1;

	/* PATHSPEC_LITERAL_PATH ignores magic */
	if (flags & PATHSPEC_LITERAL_PATH) {
		magic = PATHSPEC_LITERAL;
	} else {
		copyfrom = parse_element_magic(&element_magic,
					       &pathspec_prefix,
					       elt);
		magic |= element_magic;
		magic |= get_global_magic(element_magic);
	}

	item->magic = magic;

	if (pathspec_prefix >= 0 &&
	    (prefixlen || (prefix && *prefix)))
		die("BUG: 'prefix' magic is supposed to be used at worktree's root");

	if ((magic & PATHSPEC_LITERAL) && (magic & PATHSPEC_GLOB))
		die(_("%s: 'literal' and 'glob' are incompatible"), elt);

	/* Create match string which will be used for pathspec matching */
	if (pathspec_prefix >= 0) {
		match = xstrdup(copyfrom);
		prefixlen = pathspec_prefix;
	} else if (magic & PATHSPEC_FROMTOP) {
		match = xstrdup(copyfrom);
		prefixlen = 0;
	} else {
		match = prefix_path_gently(prefix, prefixlen,
					   &prefixlen, copyfrom);
		if (!match)
			die(_("%s: '%s' is outside repository"), elt, copyfrom);
	}

	item->match = match;
	item->len = strlen(item->match);
	item->prefix = prefixlen;

	/*
	 * Prefix the pathspec (keep all magic) and assign to
	 * original. Useful for passing to another command.
	 */
	if ((flags & PATHSPEC_PREFIX_ORIGIN) &&
	    prefixlen && !get_literal_global()) {
		struct strbuf sb = STRBUF_INIT;

		/* Preserve the actual prefix length of each pattern */
		prefix_magic(&sb, prefixlen, element_magic);

		strbuf_addstr(&sb, match);
		item->original = strbuf_detach(&sb, NULL);
	} else {
		item->original = xstrdup(elt);
	}

	if (flags & PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP)
		strip_submodule_slash_cheap(item);

	if (flags & PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE)
		strip_submodule_slash_expensive(item);

	if (magic & PATHSPEC_LITERAL) {
		item->nowildcard_len = item->len;
	} else {
		item->nowildcard_len = simple_length(item->match);
		if (item->nowildcard_len < prefixlen)
			item->nowildcard_len = prefixlen;
	}

	item->flags = 0;
	if (magic & PATHSPEC_GLOB) {
		/*
		 * FIXME: should we enable ONESTAR in _GLOB for
		 * pattern "* * / * . c"?
		 */
	} else {
		if (item->nowildcard_len < item->len &&
		    item->match[item->nowildcard_len] == '*' &&
		    no_wildcard(item->match + item->nowildcard_len + 1))
			item->flags |= PATHSPEC_ONESTAR;
	}

	/* sanity checks, pathspec matchers assume these are sane */
	if (item->nowildcard_len > item->len ||
	    item->prefix         > item->len) {
		/*
		 * This case can be triggered by the user pointing us to a
		 * pathspec inside a submodule, which is an input error.
		 * Detect that here and complain, but fallback in the
		 * non-submodule case to a BUG, as we have no idea what
		 * would trigger that.
		 */
		die_inside_submodule_path(item);
		die ("BUG: item->nowildcard_len > item->len || item->prefix > item->len)");
	}
}

static int pathspec_item_cmp(const void *a_, const void *b_)
{
	struct pathspec_item *a, *b;

	a = (struct pathspec_item *)a_;
	b = (struct pathspec_item *)b_;
	return strcmp(a->match, b->match);
}

static void NORETURN unsupported_magic(const char *pattern,
				       unsigned magic)
{
	struct strbuf sb = STRBUF_INIT;
	int i;
	for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
		const struct pathspec_magic *m = pathspec_magic + i;
		if (!(magic & m->bit))
			continue;
		if (sb.len)
			strbuf_addstr(&sb, ", ");

		if (m->mnemonic)
			strbuf_addf(&sb, _("'%s' (mnemonic: '%c')"),
				    m->name, m->mnemonic);
		else
			strbuf_addf(&sb, "'%s'", m->name);
	}
	/*
	 * We may want to substitute "this command" with a command
	 * name. E.g. when add--interactive dies when running
	 * "checkout -p"
	 */
	die(_("%s: pathspec magic not supported by this command: %s"),
	    pattern, sb.buf);
}

/*
 * Given command line arguments and a prefix, convert the input to
 * pathspec. die() if any magic in magic_mask is used.
 */
void parse_pathspec(struct pathspec *pathspec,
		    unsigned magic_mask, unsigned flags,
		    const char *prefix, const char **argv)
{
	struct pathspec_item *item;
	const char *entry = argv ? *argv : NULL;
	int i, n, prefixlen, warn_empty_string, nr_exclude = 0;

	memset(pathspec, 0, sizeof(*pathspec));

	if (flags & PATHSPEC_MAXDEPTH_VALID)
		pathspec->magic |= PATHSPEC_MAXDEPTH;

	/* No arguments, no prefix -> no pathspec */
	if (!entry && !prefix)
		return;

	if ((flags & PATHSPEC_PREFER_CWD) &&
	    (flags & PATHSPEC_PREFER_FULL))
		die("BUG: PATHSPEC_PREFER_CWD and PATHSPEC_PREFER_FULL are incompatible");

	/* No arguments with prefix -> prefix pathspec */
	if (!entry) {
		if (flags & PATHSPEC_PREFER_FULL)
			return;

		if (!(flags & PATHSPEC_PREFER_CWD))
			die("BUG: PATHSPEC_PREFER_CWD requires arguments");

		pathspec->items = item = xcalloc(1, sizeof(*item));
		item->match = xstrdup(prefix);
		item->original = xstrdup(prefix);
		item->nowildcard_len = item->len = strlen(prefix);
		item->prefix = item->len;
		pathspec->nr = 1;
		return;
	}

	n = 0;
	warn_empty_string = 1;
	while (argv[n]) {
		if (*argv[n] == '\0' && warn_empty_string) {
			warning(_("empty strings as pathspecs will be made invalid in upcoming releases. "
				  "please use . instead if you meant to match all paths"));
			warn_empty_string = 0;
		}
		n++;
	}

	pathspec->nr = n;
	ALLOC_ARRAY(pathspec->items, n);
	item = pathspec->items;
	prefixlen = prefix ? strlen(prefix) : 0;

	for (i = 0; i < n; i++) {
		entry = argv[i];

		init_pathspec_item(item + i, flags, prefix, prefixlen, entry);

		if (item[i].magic & PATHSPEC_EXCLUDE)
			nr_exclude++;
		if (item[i].magic & magic_mask)
			unsupported_magic(entry, item[i].magic & magic_mask);

		if ((flags & PATHSPEC_SYMLINK_LEADING_PATH) &&
		    has_symlink_leading_path(item[i].match, item[i].len)) {
			die(_("pathspec '%s' is beyond a symbolic link"), entry);
		}

		if (item[i].nowildcard_len < item[i].len)
			pathspec->has_wildcard = 1;
		pathspec->magic |= item[i].magic;
	}

	if (nr_exclude == n)
		die(_("There is nothing to exclude from by :(exclude) patterns.\n"
		      "Perhaps you forgot to add either ':/' or '.' ?"));


	if (pathspec->magic & PATHSPEC_MAXDEPTH) {
		if (flags & PATHSPEC_KEEP_ORDER)
			die("BUG: PATHSPEC_MAXDEPTH_VALID and PATHSPEC_KEEP_ORDER are incompatible");
		QSORT(pathspec->items, pathspec->nr, pathspec_item_cmp);
	}
}

void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
{
	int i;

	*dst = *src;
	ALLOC_ARRAY(dst->items, dst->nr);
	COPY_ARRAY(dst->items, src->items, dst->nr);

	for (i = 0; i < dst->nr; i++) {
		dst->items[i].match = xstrdup(src->items[i].match);
		dst->items[i].original = xstrdup(src->items[i].original);
	}
}

void clear_pathspec(struct pathspec *pathspec)
{
	int i;

	for (i = 0; i < pathspec->nr; i++) {
		free(pathspec->items[i].match);
		free(pathspec->items[i].original);
	}
	free(pathspec->items);
	pathspec->items = NULL;
	pathspec->nr = 0;
}
