/*
 * GIT - the stupid content tracker
 *
 * Copyright (c) Junio C Hamano, 2006, 2009
 */
#include "builtin.h"
#include "quote.h"
#include "tree.h"
#include "parse-options.h"

static struct treeent {
        unsigned mode;
        unsigned char sha1[20];
        int len;
        char name[FLEX_ARRAY];
} **entries;
static int alloc, used;

static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
{
        struct treeent *ent;
        int len = strlen(path);
        if (strchr(path, '/'))
                die("path %s contains slash", path);

        if (alloc <= used) {
                alloc = alloc_nr(used);
                entries = xrealloc(entries, sizeof(*entries) * alloc);
        }
        ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
        ent->mode = mode;
        ent->len = len;
        hashcpy(ent->sha1, sha1);
        memcpy(ent->name, path, len+1);
}

static int ent_compare(const void *a_, const void *b_)
{
        struct treeent *a = *(struct treeent **)a_;
        struct treeent *b = *(struct treeent **)b_;
        return base_name_compare(a->name, a->len, a->mode,
                                 b->name, b->len, b->mode);
}

static void write_tree(unsigned char *sha1)
{
        struct strbuf buf;
        size_t size;
        int i;

        qsort(entries, used, sizeof(*entries), ent_compare);
        for (size = i = 0; i < used; i++)
                size += 32 + entries[i]->len;

        strbuf_init(&buf, size);
        for (i = 0; i < used; i++) {
                struct treeent *ent = entries[i];
                strbuf_addf(&buf, "%o %s%c", ent->mode, ent->name, '\0');
                strbuf_add(&buf, ent->sha1, 20);
        }

        write_sha1_file(buf.buf, buf.len, tree_type, sha1);
}

static const char *mktree_usage[] = {
        "git mktree [-z] [--missing] [--batch]",
        NULL
};

static void mktree_line(char *buf, size_t len, int line_termination, int allow_missing)
{
        char *ptr, *ntr;
        unsigned mode;
        enum object_type mode_type; /* object type derived from mode */
        enum object_type obj_type; /* object type derived from sha */
        char *path;
        unsigned char sha1[20];

        ptr = buf;
        /*
         * Read non-recursive ls-tree output format:
         *     mode SP type SP sha1 TAB name
         */
        mode = strtoul(ptr, &ntr, 8);
        if (ptr == ntr || !ntr || *ntr != ' ')
                die("input format error: %s", buf);
        ptr = ntr + 1; /* type */
        ntr = strchr(ptr, ' ');
        if (!ntr || buf + len <= ntr + 40 ||
            ntr[41] != '\t' ||
            get_sha1_hex(ntr + 1, sha1))
                die("input format error: %s", buf);

        /* It is perfectly normal if we do not have a commit from a submodule */
        if (S_ISGITLINK(mode))
                allow_missing = 1;


        *ntr++ = 0; /* now at the beginning of SHA1 */

        path = ntr + 41;  /* at the beginning of name */
        if (line_termination && path[0] == '"') {
                struct strbuf p_uq = STRBUF_INIT;
                if (unquote_c_style(&p_uq, path, NULL))
                        die("invalid quoting");
                path = strbuf_detach(&p_uq, NULL);
        }

        /*
         * Object type is redundantly derivable three ways.
         * These should all agree.
         */
        mode_type = object_type(mode);
        if (mode_type != type_from_string(ptr)) {
                die("entry '%s' object type (%s) doesn't match mode type (%s)",
                        path, ptr, typename(mode_type));
        }

        /* Check the type of object identified by sha1 */
        obj_type = sha1_object_info(sha1, NULL);
        if (obj_type < 0) {
                if (allow_missing) {
                        ; /* no problem - missing objects are presumed to be of the right type */
                } else {
                        die("entry '%s' object %s is unavailable", path, sha1_to_hex(sha1));
                }
        } else {
                if (obj_type != mode_type) {
                        /*
                         * The object exists but is of the wrong type.
                         * This is a problem regardless of allow_missing
                         * because the new tree entry will never be correct.
                         */
                        die("entry '%s' object %s is a %s but specified type was (%s)",
                                path, sha1_to_hex(sha1), typename(obj_type), typename(mode_type));
                }
        }

        append_to_tree(mode, sha1, path);
}

int cmd_mktree(int ac, const char **av, const char *prefix)
{
        struct strbuf sb = STRBUF_INIT;
        unsigned char sha1[20];
        int line_termination = '\n';
        int allow_missing = 0;
        int is_batch_mode = 0;
        int got_eof = 0;

        const struct option option[] = {
                OPT_SET_INT('z', NULL, &line_termination, "input is NUL terminated", '\0'),
                OPT_SET_INT( 0 , "missing", &allow_missing, "allow missing objects", 1),
                OPT_SET_INT( 0 , "batch", &is_batch_mode, "allow creation of more than one tree", 1),
                OPT_END()
        };

        ac = parse_options(ac, av, prefix, option, mktree_usage, 0);

        while (!got_eof) {
                while (1) {
                        if (strbuf_getline(&sb, stdin, line_termination) == EOF) {
                                got_eof = 1;
                                break;
                        }
                        if (sb.buf[0] == '\0') {
                                /* empty lines denote tree boundaries in batch mode */
                                if (is_batch_mode)
                                        break;
                                die("input format error: (blank line only valid in batch mode)");
                        }
                        mktree_line(sb.buf, sb.len, line_termination, allow_missing);
                }
                if (is_batch_mode && got_eof && used < 1) {
                        /*
                         * Execution gets here if the last tree entry is terminated with a
                         * new-line.  The final new-line has been made optional to be
                         * consistent with the original non-batch behaviour of mktree.
                         */
                        ; /* skip creating an empty tree */
                } else {
                        write_tree(sha1);
                        puts(sha1_to_hex(sha1));
                        fflush(stdout);
                }
                used=0; /* reset tree entry buffer for re-use in batch mode */
        }
        strbuf_release(&sb);
        exit(0);
}