#include "cache.h"
#include "repository.h"
#include "config.h"
#include "submodule-config.h"

/* The main repository */
static struct repository the_repo;
struct repository *the_repository;

void initialize_the_repository(void)
{
        the_repository = &the_repo;

        the_repo.index = &the_index;
        repo_set_hash_algo(&the_repo, GIT_HASH_SHA1);
}

static char *git_path_from_env(const char *envvar, const char *git_dir,
                               const char *path, int fromenv)
{
        if (fromenv) {
                const char *value = getenv(envvar);
                if (value)
                        return xstrdup(value);
        }

        return xstrfmt("%s/%s", git_dir, path);
}

static int find_common_dir(struct strbuf *sb, const char *gitdir, int fromenv)
{
        if (fromenv) {
                const char *value = getenv(GIT_COMMON_DIR_ENVIRONMENT);
                if (value) {
                        strbuf_addstr(sb, value);
                        return 1;
                }
        }

        return get_common_dir_noenv(sb, gitdir);
}

static void expand_base_dir(char **out, const char *in,
                            const char *base_dir, const char *def_in)
{
        free(*out);
        if (in)
                *out = xstrdup(in);
        else
                *out = xstrfmt("%s/%s", base_dir, def_in);
}

static void repo_set_commondir(struct repository *repo,
                               const char *commondir)
{
        struct strbuf sb = STRBUF_INIT;

        free(repo->commondir);

        if (commondir) {
                repo->different_commondir = 1;
                repo->commondir = xstrdup(commondir);
                return;
        }

        repo->different_commondir = get_common_dir_noenv(&sb, repo->gitdir);
        repo->commondir = strbuf_detach(&sb, NULL);
}

void repo_set_gitdir(struct repository *repo,
                     const char *root,
                     const struct set_gitdir_args *o)
{
        const char *gitfile = read_gitfile(root);
        /*
         * repo->gitdir is saved because the caller could pass "root"
         * that also points to repo->gitdir. We want to keep it alive
         * until after xstrdup(root). Then we can free it.
         */
        char *old_gitdir = repo->gitdir;

        repo->gitdir = xstrdup(gitfile ? gitfile : root);
        free(old_gitdir);

        repo_set_commondir(repo, o->commondir);
        expand_base_dir(&repo->objectdir, o->object_dir,
                        repo->commondir, "objects");
        expand_base_dir(&repo->graft_file, o->graft_file,
                        repo->commondir, "info/grafts");
        expand_base_dir(&repo->index_file, o->index_file,
                        repo->gitdir, "index");
}

void repo_set_hash_algo(struct repository *repo, int hash_algo)
{
        repo->hash_algo = &hash_algos[hash_algo];
}

/*
 * Attempt to resolve and set the provided 'gitdir' for repository 'repo'.
 * Return 0 upon success and a non-zero value upon failure.
 */
static int repo_init_gitdir(struct repository *repo, const char *gitdir)
{
        int ret = 0;
        int error = 0;
        char *abspath = NULL;
        const char *resolved_gitdir;
        struct set_gitdir_args args = { NULL };

        abspath = real_pathdup(gitdir, 0);
        if (!abspath) {
                ret = -1;
                goto out;
        }

        /* 'gitdir' must reference the gitdir directly */
        resolved_gitdir = resolve_gitdir_gently(abspath, &error);
        if (!resolved_gitdir) {
                ret = -1;
                goto out;
        }

        repo_set_gitdir(repo, resolved_gitdir, &args);

out:
        free(abspath);
        return ret;
}

void repo_set_worktree(struct repository *repo, const char *path)
{
        repo->worktree = real_pathdup(path, 1);
}

static int read_and_verify_repository_format(struct repository_format *format,
                                             const char *commondir)
{
        int ret = 0;
        struct strbuf sb = STRBUF_INIT;

        strbuf_addf(&sb, "%s/config", commondir);
        read_repository_format(format, sb.buf);
        strbuf_reset(&sb);

        if (verify_repository_format(format, &sb) < 0) {
                warning("%s", sb.buf);
                ret = -1;
        }

        strbuf_release(&sb);
        return ret;
}

/*
 * Initialize 'repo' based on the provided 'gitdir'.
 * Return 0 upon success and a non-zero value upon failure.
 */
static int repo_init(struct repository *repo,
                     const char *gitdir,
                     const char *worktree)
{
        struct repository_format format;
        memset(repo, 0, sizeof(*repo));

        repo->ignore_env = 1;

        if (repo_init_gitdir(repo, gitdir))
                goto error;

        if (read_and_verify_repository_format(&format, repo->commondir))
                goto error;

        repo_set_hash_algo(repo, format.hash_algo);

        if (worktree)
                repo_set_worktree(repo, worktree);

        return 0;

error:
        repo_clear(repo);
        return -1;
}

/*
 * Initialize 'submodule' as the submodule given by 'path' in parent repository
 * 'superproject'.
 * Return 0 upon success and a non-zero value upon failure.
 */
int repo_submodule_init(struct repository *submodule,
                        struct repository *superproject,
                        const char *path)
{
        const struct submodule *sub;
        struct strbuf gitdir = STRBUF_INIT;
        struct strbuf worktree = STRBUF_INIT;
        int ret = 0;

        sub = submodule_from_cache(superproject, &null_oid, path);
        if (!sub) {
                ret = -1;
                goto out;
        }

        strbuf_repo_worktree_path(&gitdir, superproject, "%s/.git", path);
        strbuf_repo_worktree_path(&worktree, superproject, "%s", path);

        if (repo_init(submodule, gitdir.buf, worktree.buf)) {
                /*
                 * If initilization fails then it may be due to the submodule
                 * not being populated in the superproject's worktree.  Instead
                 * we can try to initilize the submodule by finding it's gitdir
                 * in the superproject's 'modules' directory.  In this case the
                 * submodule would not have a worktree.
                 */
                strbuf_reset(&gitdir);
                strbuf_repo_git_path(&gitdir, superproject,
                                     "modules/%s", sub->name);

                if (repo_init(submodule, gitdir.buf, NULL)) {
                        ret = -1;
                        goto out;
                }
        }

        submodule->submodule_prefix = xstrfmt("%s%s/",
                                              superproject->submodule_prefix ?
                                              superproject->submodule_prefix :
                                              "", path);

out:
        strbuf_release(&gitdir);
        strbuf_release(&worktree);
        return ret;
}

void repo_clear(struct repository *repo)
{
        FREE_AND_NULL(repo->gitdir);
        FREE_AND_NULL(repo->commondir);
        FREE_AND_NULL(repo->objectdir);
        FREE_AND_NULL(repo->graft_file);
        FREE_AND_NULL(repo->index_file);
        FREE_AND_NULL(repo->worktree);
        FREE_AND_NULL(repo->submodule_prefix);

        if (repo->config) {
                git_configset_clear(repo->config);
                FREE_AND_NULL(repo->config);
        }

        if (repo->submodule_cache) {
                submodule_cache_free(repo->submodule_cache);
                repo->submodule_cache = NULL;
        }

        if (repo->index) {
                discard_index(repo->index);
                FREE_AND_NULL(repo->index);
        }
}

int repo_read_index(struct repository *repo)
{
        if (!repo->index)
                repo->index = xcalloc(1, sizeof(*repo->index));

        return read_index_from(repo->index, repo->index_file, repo->gitdir);
}