#include "cache.h"
#include "commit.h"
#include "config.h"
#include "revision.h"
#include "argv-array.h"
#include "list-objects.h"
#include "list-objects-filter.h"
#include "list-objects-filter-options.h"
#include "trace.h"

static int parse_combine_filter(
	struct list_objects_filter_options *filter_options,
	const char *arg,
	struct strbuf *errbuf);

/*
 * Parse value of the argument to the "filter" keyword.
 * On the command line this looks like:
 *       --filter=<arg>
 * and in the pack protocol as:
 *       "filter" SP <arg>
 *
 * The filter keyword will be used by many commands.
 * See Documentation/rev-list-options.txt for allowed values for <arg>.
 *
 * Capture the given arg as the "filter_spec".  This can be forwarded to
 * subordinate commands when necessary (although it's better to pass it through
 * expand_list_objects_filter_spec() first).  We also "intern" the arg for the
 * convenience of the current command.
 */
static int gently_parse_list_objects_filter(
	struct list_objects_filter_options *filter_options,
	const char *arg,
	struct strbuf *errbuf)
{
	const char *v0;

	if (filter_options->choice)
		BUG("filter_options already populated");

	if (!strcmp(arg, "blob:none")) {
		filter_options->choice = LOFC_BLOB_NONE;
		return 0;

	} else if (skip_prefix(arg, "blob:limit=", &v0)) {
		if (git_parse_ulong(v0, &filter_options->blob_limit_value)) {
			filter_options->choice = LOFC_BLOB_LIMIT;
			return 0;
		}

	} else if (skip_prefix(arg, "tree:", &v0)) {
		if (!git_parse_ulong(v0, &filter_options->tree_exclude_depth)) {
			strbuf_addstr(errbuf, _("expected 'tree:<depth>'"));
			return 1;
		}
		filter_options->choice = LOFC_TREE_DEPTH;
		return 0;

	} else if (skip_prefix(arg, "sparse:oid=", &v0)) {
		struct object_context oc;
		struct object_id sparse_oid;

		/*
		 * Try to parse <oid-expression> into an OID for the current
		 * command, but DO NOT complain if we don't have the blob or
		 * ref locally.
		 */
		if (!get_oid_with_context(the_repository, v0, GET_OID_BLOB,
					  &sparse_oid, &oc))
			filter_options->sparse_oid_value = oiddup(&sparse_oid);
		filter_options->choice = LOFC_SPARSE_OID;
		return 0;

	} else if (skip_prefix(arg, "sparse:path=", &v0)) {
		filter_options->choice = LOFC_SPARSE_PATH;
		filter_options->sparse_path_value = strdup(v0);
		return 0;

	} else if (skip_prefix(arg, "combine:", &v0)) {
		return parse_combine_filter(filter_options, v0, errbuf);

	}
	/*
	 * Please update _git_fetch() in git-completion.bash when you
	 * add new filters
	 */

	strbuf_addf(errbuf, "invalid filter-spec '%s'", arg);

	memset(filter_options, 0, sizeof(*filter_options));
	return 1;
}

static int url_decode(struct strbuf *s, struct strbuf *errbuf)
{
	char *dest = s->buf;
	char *src = s->buf;
	size_t new_len;

	while (*src) {
		if (src[0] != '%') {
			*dest++ = *src++;
			continue;
		}

		if (hex_to_bytes((unsigned char *)dest, src + 1, 1)) {
			strbuf_addstr(errbuf,
				      "error in filter-spec - "
				      "invalid hex sequence after %");
			return 1;
		}

		if (!*dest) {
			strbuf_addstr(errbuf,
				      "error in filter-spec - unexpected %00");
			return 1;
		}

		src += 3;
		dest++;
	}
	new_len = dest - s->buf;
	strbuf_remove(s, new_len, s->len - new_len);

	return 0;
}

static const char *RESERVED_NON_WS = "~`!@#$^&*()[]{}\\;'\",<>?";

static int has_reserved_character(
	struct strbuf *sub_spec, struct strbuf *errbuf)
{
	const char *c = sub_spec->buf;
	while (*c) {
		if (*c <= ' ' || strchr(RESERVED_NON_WS, *c)) {
			strbuf_addf(errbuf,
				    "must escape char in sub-filter-spec: '%c'",
				    *c);
			return 1;
		}
		c++;
	}

	return 0;
}

static int parse_combine_subfilter(
	struct list_objects_filter_options *filter_options,
	struct strbuf *subspec,
	struct strbuf *errbuf)
{
	size_t new_index = filter_options->sub_nr;

	ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
		      filter_options->sub_alloc);

	return has_reserved_character(subspec, errbuf) ||
		url_decode(subspec, errbuf) ||
		gently_parse_list_objects_filter(
			&filter_options->sub[new_index], subspec->buf, errbuf);
}

static int parse_combine_filter(
	struct list_objects_filter_options *filter_options,
	const char *arg,
	struct strbuf *errbuf)
{
	struct strbuf **subspecs = strbuf_split_str(arg, '+', 0);
	size_t sub;
	int result;

	if (!subspecs[0]) {
		strbuf_addf(errbuf,
			    _("expected something after combine:"));
		result = 1;
		goto cleanup;
	}

	for (sub = 0; subspecs[sub]; sub++) {
		if (subspecs[sub + 1]) {
			/*
			 * This is not the last subspec. Remove trailing "+" so
			 * we can parse it.
			 */
			size_t last = subspecs[sub]->len - 1;
			assert(subspecs[sub]->buf[last] == '+');
			strbuf_remove(subspecs[sub], last, 1);
		}
		result = parse_combine_subfilter(
			filter_options, subspecs[sub], errbuf);
		if (result)
			goto cleanup;
	}

	filter_options->choice = LOFC_COMBINE;

cleanup:
	strbuf_list_free(subspecs);
	if (result) {
		list_objects_filter_release(filter_options);
		memset(filter_options, 0, sizeof(*filter_options));
	}
	return result;
}

static void add_url_encoded(struct strbuf *dest, const char *s)
{
	while (*s) {
		if (*s <= ' ' || strchr(RESERVED_NON_WS, *s) ||
			*s == '%' || *s == '+')
			strbuf_addf(dest, "%%%02X", (int)*s);
		else
			strbuf_addf(dest, "%c", *s);
		s++;
	}
}

/*
 * Changes filter_options into an equivalent LOFC_COMBINE filter options
 * instance. Does not do anything if filter_options is already LOFC_COMBINE.
 */
static void transform_to_combine_type(
	struct list_objects_filter_options *filter_options)
{
	assert(filter_options->choice);
	if (filter_options->choice == LOFC_COMBINE)
		return;
	{
		const int initial_sub_alloc = 2;
		struct list_objects_filter_options *sub_array =
			xcalloc(initial_sub_alloc, sizeof(*sub_array));
		sub_array[0] = *filter_options;
		memset(filter_options, 0, sizeof(*filter_options));
		filter_options->sub = sub_array;
		filter_options->sub_alloc = initial_sub_alloc;
	}
	filter_options->sub_nr = 1;
	filter_options->choice = LOFC_COMBINE;
	strbuf_init(&filter_options->filter_spec, 0);
	strbuf_addstr(&filter_options->filter_spec, "combine:");
	add_url_encoded(&filter_options->filter_spec,
			filter_options->sub[0].filter_spec.buf);
	/*
	 * We don't need the filter_spec strings for subfilter specs, only the
	 * top level.
	 */
	strbuf_release(&filter_options->sub[0].filter_spec);
}

void list_objects_filter_die_if_populated(
	struct list_objects_filter_options *filter_options)
{
	if (filter_options->choice)
		die(_("multiple filter-specs cannot be combined"));
}

void parse_list_objects_filter(
	struct list_objects_filter_options *filter_options,
	const char *arg)
{
	struct strbuf errbuf = STRBUF_INIT;
	int parse_error;

	if (!filter_options->choice) {
		strbuf_init(&filter_options->filter_spec, 0);
		strbuf_addstr(&filter_options->filter_spec, arg);

		parse_error = gently_parse_list_objects_filter(
			filter_options, arg, &errbuf);
	} else {
		/*
		 * Make filter_options an LOFC_COMBINE spec so we can trivially
		 * add subspecs to it.
		 */
		transform_to_combine_type(filter_options);

		strbuf_addstr(&filter_options->filter_spec, "+");
		add_url_encoded(&filter_options->filter_spec, arg);
		trace_printf("Generated composite filter-spec: %s\n",
			     filter_options->filter_spec.buf);
		ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
			      filter_options->sub_alloc);

		parse_error = gently_parse_list_objects_filter(
			&filter_options->sub[filter_options->sub_nr - 1], arg,
			&errbuf);
	}
	if (parse_error)
		die("%s", errbuf.buf);
}

int opt_parse_list_objects_filter(const struct option *opt,
				  const char *arg, int unset)
{
	struct list_objects_filter_options *filter_options = opt->value;

	if (unset || !arg)
		list_objects_filter_set_no_filter(filter_options);
	else
		parse_list_objects_filter(filter_options, arg);
	return 0;
}

void expand_list_objects_filter_spec(
	const struct list_objects_filter_options *filter,
	struct strbuf *expanded_spec)
{
	strbuf_init(expanded_spec, 0);
	if (filter->choice == LOFC_BLOB_LIMIT)
		strbuf_addf(expanded_spec, "blob:limit=%lu",
			    filter->blob_limit_value);
	else if (filter->choice == LOFC_TREE_DEPTH)
		strbuf_addf(expanded_spec, "tree:%lu",
			    filter->tree_exclude_depth);
	else
		strbuf_addstr(expanded_spec, filter->filter_spec.buf);
}

void list_objects_filter_release(
	struct list_objects_filter_options *filter_options)
{
	size_t sub;

	if (!filter_options)
		return;
	strbuf_release(&filter_options->filter_spec);
	free(filter_options->sparse_oid_value);
	free(filter_options->sparse_path_value);
	for (sub = 0; sub < filter_options->sub_nr; sub++)
		list_objects_filter_release(&filter_options->sub[sub]);
	free(filter_options->sub);
	memset(filter_options, 0, sizeof(*filter_options));
}

void partial_clone_register(
	const char *remote,
	const struct list_objects_filter_options *filter_options)
{
	/*
	 * Record the name of the partial clone remote in the
	 * config and in the global variable -- the latter is
	 * used throughout to indicate that partial clone is
	 * enabled and to expect missing objects.
	 */
	if (repository_format_partial_clone &&
	    *repository_format_partial_clone &&
	    strcmp(remote, repository_format_partial_clone))
		die(_("cannot change partial clone promisor remote"));

	git_config_set("core.repositoryformatversion", "1");
	git_config_set("extensions.partialclone", remote);

	repository_format_partial_clone = xstrdup(remote);

	/*
	 * Record the initial filter-spec in the config as
	 * the default for subsequent fetches from this remote.
	 */
	core_partial_clone_filter_default =
		xstrdup(filter_options->filter_spec.buf);
	git_config_set("core.partialclonefilter",
		       core_partial_clone_filter_default);
}

void partial_clone_get_default_filter_spec(
	struct list_objects_filter_options *filter_options)
{
	struct strbuf errbuf = STRBUF_INIT;

	/*
	 * Parse default value, but silently ignore it if it is invalid.
	 */
	if (!core_partial_clone_filter_default)
		return;

	if (!filter_options->filter_spec.buf)
		strbuf_init(&filter_options->filter_spec, 0);
	strbuf_addstr(&filter_options->filter_spec,
		      core_partial_clone_filter_default);
	gently_parse_list_objects_filter(filter_options,
					 core_partial_clone_filter_default,
					 &errbuf);
	strbuf_release(&errbuf);
}