#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"
#include "url.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)) {
                if (errbuf) {
                        strbuf_addstr(
                                errbuf,
                                _("sparse:path filters support has been dropped"));
                }
                return 1;

        } 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 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;
        char *decoded;
        int result;

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

        decoded = url_percent_decode(subspec->buf);

        result = has_reserved_character(subspec, errbuf) ||
                gently_parse_list_objects_filter(
                        &filter_options->sub[new_index], decoded, errbuf);

        free(decoded);
        return result;
}

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 = 0;

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

        for (sub = 0; subspecs[sub] && !result; 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);
        }

        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 int allow_unencoded(char ch)
{
        if (ch <= ' ' || ch == '%' || ch == '+')
                return 0;
        return !strchr(RESERVED_NON_WS, ch);
}

static void filter_spec_append_urlencode(
        struct list_objects_filter_options *filter, const char *raw)
{
        struct strbuf buf = STRBUF_INIT;
        strbuf_addstr_urlencode(&buf, raw, allow_unencoded);
        trace_printf("Add to combine filter-spec: %s\n", buf.buf);
        string_list_append(&filter->filter_spec, strbuf_detach(&buf, NULL));
}

/*
 * 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;
        string_list_append(&filter_options->filter_spec, xstrdup("combine:"));
        filter_spec_append_urlencode(
                filter_options,
                list_objects_filter_spec(&filter_options->sub[0]));
        /*
         * We don't need the filter_spec strings for subfilter specs, only the
         * top level.
         */
        string_list_clear(&filter_options->sub[0].filter_spec, /*free_util=*/0);
}

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) {
                string_list_append(&filter_options->filter_spec, xstrdup(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);

                string_list_append(&filter_options->filter_spec, xstrdup("+"));
                filter_spec_append_urlencode(filter_options, arg);
                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;
}

const char *list_objects_filter_spec(struct list_objects_filter_options *filter)
{
        if (!filter->filter_spec.nr)
                BUG("no filter_spec available for this filter");
        if (filter->filter_spec.nr != 1) {
                struct strbuf concatted = STRBUF_INIT;
                strbuf_add_separated_string_list(
                        &concatted, "", &filter->filter_spec);
                string_list_clear(&filter->filter_spec, /*free_util=*/0);
                string_list_append(
                        &filter->filter_spec, strbuf_detach(&concatted, NULL));
        }

        return filter->filter_spec.items[0].string;
}

const char *expand_list_objects_filter_spec(
        struct list_objects_filter_options *filter)
{
        if (filter->choice == LOFC_BLOB_LIMIT) {
                struct strbuf expanded_spec = STRBUF_INIT;
                strbuf_addf(&expanded_spec, "blob:limit=%lu",
                            filter->blob_limit_value);
                string_list_clear(&filter->filter_spec, /*free_util=*/0);
                string_list_append(
                        &filter->filter_spec,
                        strbuf_detach(&expanded_spec, NULL));
        }

        return list_objects_filter_spec(filter);
}

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

        if (!filter_options)
                return;
        string_list_clear(&filter_options->filter_spec, /*free_util=*/0);
        free(filter_options->sparse_oid_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,
        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(expand_list_objects_filter_spec(filter_options));
        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;

        string_list_append(&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);
}