#include "cache.h"
#include "commit.h"
#include "tree-walk.h"
#include "attr.h"
#include "archive.h"
#include "parse-options.h"
#include "unpack-trees.h"
#include "dir.h"

static char const * const archive_usage[] = {
        N_("git archive [<options>] <tree-ish> [<path>...]"),
        N_("git archive --list"),
        N_("git archive --remote <repo> [--exec <cmd>] [<options>] <tree-ish> [<path>...]"),
        N_("git archive --remote <repo> [--exec <cmd>] --list"),
        NULL
};

static const struct archiver **archivers;
static int nr_archivers;
static int alloc_archivers;
static int remote_allow_unreachable;

void register_archiver(struct archiver *ar)
{
        ALLOC_GROW(archivers, nr_archivers + 1, alloc_archivers);
        archivers[nr_archivers++] = ar;
}

static void format_subst(const struct commit *commit,
                         const char *src, size_t len,
                         struct strbuf *buf)
{
        char *to_free = NULL;
        struct strbuf fmt = STRBUF_INIT;
        struct pretty_print_context ctx = {0};
        ctx.date_mode = DATE_NORMAL;
        ctx.abbrev = DEFAULT_ABBREV;

        if (src == buf->buf)
                to_free = strbuf_detach(buf, NULL);
        for (;;) {
                const char *b, *c;

                b = memmem(src, len, "$Format:", 8);
                if (!b)
                        break;
                c = memchr(b + 8, '$', (src + len) - b - 8);
                if (!c)
                        break;

                strbuf_reset(&fmt);
                strbuf_add(&fmt, b + 8, c - b - 8);

                strbuf_add(buf, src, b - src);
                format_commit_message(commit, fmt.buf, buf, &ctx);
                len -= c + 1 - src;
                src  = c + 1;
        }
        strbuf_add(buf, src, len);
        strbuf_release(&fmt);
        free(to_free);
}

void *sha1_file_to_archive(const struct archiver_args *args,
                           const char *path, const unsigned char *sha1,
                           unsigned int mode, enum object_type *type,
                           unsigned long *sizep)
{
        void *buffer;
        const struct commit *commit = args->convert ? args->commit : NULL;

        path += args->baselen;
        buffer = read_sha1_file(sha1, type, sizep);
        if (buffer && S_ISREG(mode)) {
                struct strbuf buf = STRBUF_INIT;
                size_t size = 0;

                strbuf_attach(&buf, buffer, *sizep, *sizep + 1);
                convert_to_working_tree(path, buf.buf, buf.len, &buf);
                if (commit)
                        format_subst(commit, buf.buf, buf.len, &buf);
                buffer = strbuf_detach(&buf, &size);
                *sizep = size;
        }

        return buffer;
}

static void setup_archive_check(struct git_attr_check *check)
{
        static struct git_attr *attr_export_ignore;
        static struct git_attr *attr_export_subst;

        if (!attr_export_ignore) {
                attr_export_ignore = git_attr("export-ignore");
                attr_export_subst = git_attr("export-subst");
        }
        check[0].attr = attr_export_ignore;
        check[1].attr = attr_export_subst;
}

struct directory {
        struct directory *up;
        struct object_id oid;
        int baselen, len;
        unsigned mode;
        int stage;
        char path[FLEX_ARRAY];
};

struct archiver_context {
        struct archiver_args *args;
        write_archive_entry_fn_t write_entry;
        struct directory *bottom;
};

static int write_archive_entry(const unsigned char *sha1, const char *base,
                int baselen, const char *filename, unsigned mode, int stage,
                void *context)
{
        static struct strbuf path = STRBUF_INIT;
        struct archiver_context *c = context;
        struct archiver_args *args = c->args;
        write_archive_entry_fn_t write_entry = c->write_entry;
        struct git_attr_check check[2];
        const char *path_without_prefix;
        int err;

        args->convert = 0;
        strbuf_reset(&path);
        strbuf_grow(&path, PATH_MAX);
        strbuf_add(&path, args->base, args->baselen);
        strbuf_add(&path, base, baselen);
        strbuf_addstr(&path, filename);
        if (S_ISDIR(mode) || S_ISGITLINK(mode))
                strbuf_addch(&path, '/');
        path_without_prefix = path.buf + args->baselen;

        setup_archive_check(check);
        if (!git_check_attr(path_without_prefix, ARRAY_SIZE(check), check)) {
                if (ATTR_TRUE(check[0].value))
                        return 0;
                args->convert = ATTR_TRUE(check[1].value);
        }

        if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
                if (args->verbose)
                        fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
                err = write_entry(args, sha1, path.buf, path.len, mode);
                if (err)
                        return err;
                return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
        }

        if (args->verbose)
                fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
        return write_entry(args, sha1, path.buf, path.len, mode);
}

static int write_archive_entry_buf(const unsigned char *sha1, struct strbuf *base,
                const char *filename, unsigned mode, int stage,
                void *context)
{
        return write_archive_entry(sha1, base->buf, base->len,
                                     filename, mode, stage, context);
}

static void queue_directory(const unsigned char *sha1,
                struct strbuf *base, const char *filename,
                unsigned mode, int stage, struct archiver_context *c)
{
        struct directory *d;
        d = xmallocz(sizeof(*d) + base->len + 1 + strlen(filename));
        d->up      = c->bottom;
        d->baselen = base->len;
        d->mode    = mode;
        d->stage   = stage;
        c->bottom  = d;
        d->len = sprintf(d->path, "%.*s%s/", (int)base->len, base->buf, filename);
        hashcpy(d->oid.hash, sha1);
}

static int write_directory(struct archiver_context *c)
{
        struct directory *d = c->bottom;
        int ret;

        if (!d)
                return 0;
        c->bottom = d->up;
        d->path[d->len - 1] = '\0'; /* no trailing slash */
        ret =
                write_directory(c) ||
                write_archive_entry(d->oid.hash, d->path, d->baselen,
                                    d->path + d->baselen, d->mode,
                                    d->stage, c) != READ_TREE_RECURSIVE;
        free(d);
        return ret ? -1 : 0;
}

static int queue_or_write_archive_entry(const unsigned char *sha1,
                struct strbuf *base, const char *filename,
                unsigned mode, int stage, void *context)
{
        struct archiver_context *c = context;

        while (c->bottom &&
               !(base->len >= c->bottom->len &&
                 !strncmp(base->buf, c->bottom->path, c->bottom->len))) {
                struct directory *next = c->bottom->up;
                free(c->bottom);
                c->bottom = next;
        }

        if (S_ISDIR(mode)) {
                queue_directory(sha1, base, filename,
                                mode, stage, c);
                return READ_TREE_RECURSIVE;
        }

        if (write_directory(c))
                return -1;
        return write_archive_entry(sha1, base->buf, base->len, filename, mode,
                                   stage, context);
}

int write_archive_entries(struct archiver_args *args,
                write_archive_entry_fn_t write_entry)
{
        struct archiver_context context;
        struct unpack_trees_options opts;
        struct tree_desc t;
        int err;

        if (args->baselen > 0 && args->base[args->baselen - 1] == '/') {
                size_t len = args->baselen;

                while (len > 1 && args->base[len - 2] == '/')
                        len--;
                if (args->verbose)
                        fprintf(stderr, "%.*s\n", (int)len, args->base);
                err = write_entry(args, args->tree->object.sha1, args->base,
                                  len, 040777);
                if (err)
                        return err;
        }

        memset(&context, 0, sizeof(context));
        context.args = args;
        context.write_entry = write_entry;

        /*
         * Setup index and instruct attr to read index only
         */
        if (!args->worktree_attributes) {
                memset(&opts, 0, sizeof(opts));
                opts.index_only = 1;
                opts.head_idx = -1;
                opts.src_index = &the_index;
                opts.dst_index = &the_index;
                opts.fn = oneway_merge;
                init_tree_desc(&t, args->tree->buffer, args->tree->size);
                if (unpack_trees(1, &t, &opts))
                        return -1;
                git_attr_set_direction(GIT_ATTR_INDEX, &the_index);
        }

        err = read_tree_recursive(args->tree, "", 0, 0, &args->pathspec,
                                  args->pathspec.has_wildcard ?
                                  queue_or_write_archive_entry :
                                  write_archive_entry_buf,
                                  &context);
        if (err == READ_TREE_RECURSIVE)
                err = 0;
        while (context.bottom) {
                struct directory *next = context.bottom->up;
                free(context.bottom);
                context.bottom = next;
        }
        return err;
}

static const struct archiver *lookup_archiver(const char *name)
{
        int i;

        if (!name)
                return NULL;

        for (i = 0; i < nr_archivers; i++) {
                if (!strcmp(name, archivers[i]->name))
                        return archivers[i];
        }
        return NULL;
}

static int reject_entry(const unsigned char *sha1, struct strbuf *base,
                        const char *filename, unsigned mode,
                        int stage, void *context)
{
        int ret = -1;
        if (S_ISDIR(mode)) {
                struct strbuf sb = STRBUF_INIT;
                strbuf_addbuf(&sb, base);
                strbuf_addstr(&sb, filename);
                if (!match_pathspec(context, sb.buf, sb.len, 0, NULL, 1))
                        ret = READ_TREE_RECURSIVE;
                strbuf_release(&sb);
        }
        return ret;
}

static int path_exists(struct tree *tree, const char *path)
{
        const char *paths[] = { path, NULL };
        struct pathspec pathspec;
        int ret;

        parse_pathspec(&pathspec, 0, 0, "", paths);
        pathspec.recursive = 1;
        ret = read_tree_recursive(tree, "", 0, 0, &pathspec,
                                  reject_entry, &pathspec);
        free_pathspec(&pathspec);
        return ret != 0;
}

static void parse_pathspec_arg(const char **pathspec,
                struct archiver_args *ar_args)
{
        /*
         * must be consistent with parse_pathspec in path_exists()
         * Also if pathspec patterns are dependent, we're in big
         * trouble as we test each one separately
         */
        parse_pathspec(&ar_args->pathspec, 0,
                       PATHSPEC_PREFER_FULL,
                       "", pathspec);
        ar_args->pathspec.recursive = 1;
        if (pathspec) {
                while (*pathspec) {
                        if (**pathspec && !path_exists(ar_args->tree, *pathspec))
                                die(_("pathspec '%s' did not match any files"), *pathspec);
                        pathspec++;
                }
        }
}

static void parse_treeish_arg(const char **argv,
                struct archiver_args *ar_args, const char *prefix,
                int remote)
{
        const char *name = argv[0];
        const unsigned char *commit_sha1;
        time_t archive_time;
        struct tree *tree;
        const struct commit *commit;
        struct object_id oid;

        /* Remotes are only allowed to fetch actual refs */
        if (remote && !remote_allow_unreachable) {
                char *ref = NULL;
                const char *colon = strchrnul(name, ':');
                int refnamelen = colon - name;

                if (!dwim_ref(name, refnamelen, oid.hash, &ref))
                        die("no such ref: %.*s", refnamelen, name);
                free(ref);
        }

        if (get_sha1(name, oid.hash))
                die("Not a valid object name");

        commit = lookup_commit_reference_gently(oid.hash, 1);
        if (commit) {
                commit_sha1 = commit->object.sha1;
                archive_time = commit->date;
        } else {
                commit_sha1 = NULL;
                archive_time = time(NULL);
        }

        tree = parse_tree_indirect(oid.hash);
        if (tree == NULL)
                die("not a tree object");

        if (prefix) {
                struct object_id tree_oid;
                unsigned int mode;
                int err;

                err = get_tree_entry(tree->object.sha1, prefix,
                                     tree_oid.hash, &mode);
                if (err || !S_ISDIR(mode))
                        die("current working directory is untracked");

                tree = parse_tree_indirect(tree_oid.hash);
        }
        ar_args->tree = tree;
        ar_args->commit_sha1 = commit_sha1;
        ar_args->commit = commit;
        ar_args->time = archive_time;
}

#define OPT__COMPR(s, v, h, p) \
        { OPTION_SET_INT, (s), NULL, (v), NULL, (h), \
          PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, (p) }
#define OPT__COMPR_HIDDEN(s, v, p) \
        { OPTION_SET_INT, (s), NULL, (v), NULL, "", \
          PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN, NULL, (p) }

static int parse_archive_args(int argc, const char **argv,
                const struct archiver **ar, struct archiver_args *args,
                const char *name_hint, int is_remote)
{
        const char *format = NULL;
        const char *base = NULL;
        const char *remote = NULL;
        const char *exec = NULL;
        const char *output = NULL;
        int compression_level = -1;
        int verbose = 0;
        int i;
        int list = 0;
        int worktree_attributes = 0;
        struct option opts[] = {
                OPT_GROUP(""),
                OPT_STRING(0, "format", &format, N_("fmt"), N_("archive format")),
                OPT_STRING(0, "prefix", &base, N_("prefix"),
                        N_("prepend prefix to each pathname in the archive")),
                OPT_STRING('o', "output", &output, N_("file"),
                        N_("write the archive to this file")),
                OPT_BOOL(0, "worktree-attributes", &worktree_attributes,
                        N_("read .gitattributes in working directory")),
                OPT__VERBOSE(&verbose, N_("report archived files on stderr")),
                OPT__COMPR('0', &compression_level, N_("store only"), 0),
                OPT__COMPR('1', &compression_level, N_("compress faster"), 1),
                OPT__COMPR_HIDDEN('2', &compression_level, 2),
                OPT__COMPR_HIDDEN('3', &compression_level, 3),
                OPT__COMPR_HIDDEN('4', &compression_level, 4),
                OPT__COMPR_HIDDEN('5', &compression_level, 5),
                OPT__COMPR_HIDDEN('6', &compression_level, 6),
                OPT__COMPR_HIDDEN('7', &compression_level, 7),
                OPT__COMPR_HIDDEN('8', &compression_level, 8),
                OPT__COMPR('9', &compression_level, N_("compress better"), 9),
                OPT_GROUP(""),
                OPT_BOOL('l', "list", &list,
                        N_("list supported archive formats")),
                OPT_GROUP(""),
                OPT_STRING(0, "remote", &remote, N_("repo"),
                        N_("retrieve the archive from remote repository <repo>")),
                OPT_STRING(0, "exec", &exec, N_("command"),
                        N_("path to the remote git-upload-archive command")),
                OPT_END()
        };

        argc = parse_options(argc, argv, NULL, opts, archive_usage, 0);

        if (remote)
                die("Unexpected option --remote");
        if (exec)
                die("Option --exec can only be used together with --remote");
        if (output)
                die("Unexpected option --output");

        if (!base)
                base = "";

        if (list) {
                for (i = 0; i < nr_archivers; i++)
                        if (!is_remote || archivers[i]->flags & ARCHIVER_REMOTE)
                                printf("%s\n", archivers[i]->name);
                exit(0);
        }

        if (!format && name_hint)
                format = archive_format_from_filename(name_hint);
        if (!format)
                format = "tar";

        /* We need at least one parameter -- tree-ish */
        if (argc < 1)
                usage_with_options(archive_usage, opts);
        *ar = lookup_archiver(format);
        if (!*ar || (is_remote && !((*ar)->flags & ARCHIVER_REMOTE)))
                die("Unknown archive format '%s'", format);

        args->compression_level = Z_DEFAULT_COMPRESSION;
        if (compression_level != -1) {
                if ((*ar)->flags & ARCHIVER_WANT_COMPRESSION_LEVELS)
                        args->compression_level = compression_level;
                else {
                        die("Argument not supported for format '%s': -%d",
                                        format, compression_level);
                }
        }
        args->verbose = verbose;
        args->base = base;
        args->baselen = strlen(base);
        args->worktree_attributes = worktree_attributes;

        return argc;
}

int write_archive(int argc, const char **argv, const char *prefix,
                  int setup_prefix, const char *name_hint, int remote)
{
        int nongit = 0;
        const struct archiver *ar = NULL;
        struct archiver_args args;

        if (setup_prefix && prefix == NULL)
                prefix = setup_git_directory_gently(&nongit);

        git_config_get_bool("uploadarchive.allowunreachable", &remote_allow_unreachable);
        git_config(git_default_config, NULL);

        init_tar_archiver();
        init_zip_archiver();

        argc = parse_archive_args(argc, argv, &ar, &args, name_hint, remote);
        if (nongit) {
                /*
                 * We know this will die() with an error, so we could just
                 * die ourselves; but its error message will be more specific
                 * than what we could write here.
                 */
                setup_git_directory();
        }

        parse_treeish_arg(argv, &args, prefix, remote);
        parse_pathspec_arg(argv + 1, &args);

        return ar->write_archive(ar, &args);
}

static int match_extension(const char *filename, const char *ext)
{
        int prefixlen = strlen(filename) - strlen(ext);

        /*
         * We need 1 character for the '.', and 1 character to ensure that the
         * prefix is non-empty (k.e., we don't match .tar.gz with no actual
         * filename).
         */
        if (prefixlen < 2 || filename[prefixlen - 1] != '.')
                return 0;
        return !strcmp(filename + prefixlen, ext);
}

const char *archive_format_from_filename(const char *filename)
{
        int i;

        for (i = 0; i < nr_archivers; i++)
                if (match_extension(filename, archivers[i]->name))
                        return archivers[i]->name;
        return NULL;
}