/*
 * Builtin "git branch"
 *
 * Copyright (c) 2006 Kristian Høgsberg <krh@redhat.com>
 * Based on git-branch.sh by Junio C Hamano.
 */

#include "cache.h"
#include "refs.h"
#include "commit.h"
#include "builtin.h"

static const char builtin_branch_usage[] =
"git-branch (-d | -D) <branchname> | [-l] [-f] <branchname> [<start-point>] | [-r]";


static const char *head;
static unsigned char head_sha1[20];

static int in_merge_bases(const unsigned char *sha1,
                          struct commit *rev1,
                          struct commit *rev2)
{
        struct commit_list *bases, *b;
        int ret = 0;

        bases = get_merge_bases(rev1, rev2, 1);
        for (b = bases; b; b = b->next) {
                if (!hashcmp(sha1, b->item->object.sha1)) {
                        ret = 1;
                        break;
                }
        }

        free_commit_list(bases);
        return ret;
}

static void delete_branches(int argc, const char **argv, int force)
{
        struct commit *rev, *head_rev;
        unsigned char sha1[20];
        char *name;
        int i;

        head_rev = lookup_commit_reference(head_sha1);
        for (i = 0; i < argc; i++) {
                if (!strcmp(head, argv[i]))
                        die("Cannot delete the branch you are currently on.");

                name = xstrdup(mkpath("refs/heads/%s", argv[i]));
                if (!resolve_ref(name, sha1, 1, NULL))
                        die("Branch '%s' not found.", argv[i]);

                rev = lookup_commit_reference(sha1);
                if (!rev || !head_rev)
                        die("Couldn't look up commit objects.");

                /* This checks whether the merge bases of branch and
                 * HEAD contains branch -- which means that the HEAD
                 * contains everything in both.
                 */

                if (!force &&
                    !in_merge_bases(sha1, rev, head_rev)) {
                        fprintf(stderr,
                                "The branch '%s' is not a strict subset of your current HEAD.\n"
                                "If you are sure you want to delete it, run 'git branch -D %s'.\n",
                                argv[i], argv[i]);
                        exit(1);
                }

                if (delete_ref(name, sha1))
                        printf("Error deleting branch '%s'\n", argv[i]);
                else
                        printf("Deleted branch %s.\n", argv[i]);

                free(name);
        }
}

static int ref_index, ref_alloc;
static char **ref_list;

static int append_ref(const char *refname, const unsigned char *sha1, int flags,
                void *cb_data)
{
        if (ref_index >= ref_alloc) {
                ref_alloc = alloc_nr(ref_alloc);
                ref_list = xrealloc(ref_list, ref_alloc * sizeof(char *));
        }

        ref_list[ref_index++] = xstrdup(refname);

        return 0;
}

static int ref_cmp(const void *r1, const void *r2)
{
        return strcmp(*(char **)r1, *(char **)r2);
}

static void print_ref_list(int remote_only)
{
        int i;

        if (remote_only)
                for_each_remote_ref(append_ref, NULL);
        else
                for_each_branch_ref(append_ref, NULL);

        qsort(ref_list, ref_index, sizeof(char *), ref_cmp);

        for (i = 0; i < ref_index; i++) {
                if (!strcmp(ref_list[i], head))
                        printf("* %s\n", ref_list[i]);
                else
                        printf("  %s\n", ref_list[i]);
        }
}

static void create_branch(const char *name, const char *start,
                          int force, int reflog)
{
        struct ref_lock *lock;
        struct commit *commit;
        unsigned char sha1[20];
        char ref[PATH_MAX], msg[PATH_MAX + 20];

        snprintf(ref, sizeof ref, "refs/heads/%s", name);
        if (check_ref_format(ref))
                die("'%s' is not a valid branch name.", name);

        if (resolve_ref(ref, sha1, 1, NULL)) {
                if (!force)
                        die("A branch named '%s' already exists.", name);
                else if (!strcmp(head, name))
                        die("Cannot force update the current branch.");
        }

        if (get_sha1(start, sha1) ||
            (commit = lookup_commit_reference(sha1)) == NULL)
                die("Not a valid branch point: '%s'.", start);
        hashcpy(sha1, commit->object.sha1);

        lock = lock_any_ref_for_update(ref, NULL);
        if (!lock)
                die("Failed to lock ref for update: %s.", strerror(errno));

        if (reflog) {
                log_all_ref_updates = 1;
                snprintf(msg, sizeof msg, "branch: Created from %s", start);
        }

        if (write_ref_sha1(lock, sha1, msg) < 0)
                die("Failed to write ref: %s.", strerror(errno));
}

int cmd_branch(int argc, const char **argv, const char *prefix)
{
        int delete = 0, force_delete = 0, force_create = 0, remote_only = 0;
        int reflog = 0;
        int i;

        git_config(git_default_config);

        for (i = 1; i < argc; i++) {
                const char *arg = argv[i];

                if (arg[0] != '-')
                        break;
                if (!strcmp(arg, "--")) {
                        i++;
                        break;
                }
                if (!strcmp(arg, "-d")) {
                        delete = 1;
                        continue;
                }
                if (!strcmp(arg, "-D")) {
                        delete = 1;
                        force_delete = 1;
                        continue;
                }
                if (!strcmp(arg, "-f")) {
                        force_create = 1;
                        continue;
                }
                if (!strcmp(arg, "-r")) {
                        remote_only = 1;
                        continue;
                }
                if (!strcmp(arg, "-l")) {
                        reflog = 1;
                        continue;
                }
                usage(builtin_branch_usage);
        }

        head = xstrdup(resolve_ref("HEAD", head_sha1, 0, NULL));
        if (!head)
                die("Failed to resolve HEAD as a valid ref.");
        if (strncmp(head, "refs/heads/", 11))
                die("HEAD not found below refs/heads!");
        head += 11;

        if (delete)
                delete_branches(argc - i, argv + i, force_delete);
        else if (i == argc)
                print_ref_list(remote_only);
        else if (i == argc - 1)
                create_branch(argv[i], head, force_create, reflog);
        else if (i == argc - 2)
                create_branch(argv[i], argv[i + 1], force_create, reflog);
        else
                usage(builtin_branch_usage);

        return 0;
}