#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);
                }
        }
}

/*
 * Take an element of a pathspec and check for magic signatures.
 * Append the result to the prefix. Return the magic bitmap.
 *
 * For now, we only parse the syntax and throw out anything other than
 * "top" magic.
 *
 * NEEDSWORK: This needs to be rewritten when we start migrating
 * get_pathspec() users to use the "struct pathspec" interface.  For
 * example, a pathspec element may be marked as case-insensitive, but
 * the prefix part must always match literally, and a single stupid
 * string cannot express such a case.
 */
static unsigned prefix_pathspec(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);
        }

        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);

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

        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 */
        assert(item->nowildcard_len <= item->len &&
               item->prefix         <= item->len);
        return magic;
}

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];

                item[i].magic = prefix_pathspec(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;
}