/*

 * Copyright (C) the libgit2 contributors. All rights reserved.

 *

 * This file is part of libgit2, distributed under the GNU GPL v2 with

 * a Linking Exception. For full terms see the included COPYING file.

 */

#include "common.h"

#include "commit.h"

#include "tag.h"

#include "merge.h"

#include "diff.h"

#include "annotated_commit.h"

#include "git2/reset.h"

#include "git2/checkout.h"

#include "git2/merge.h"

#include "git2/refs.h"

#define ERROR_MSG "Cannot perform reset"

int git_reset_default(

	git_repository *repo,

	git_object *target,

	git_strarray* pathspecs)

{

	git_object *commit = NULL;

	git_tree *tree = NULL;

	git_diff *diff = NULL;

	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;

	size_t i, max_i;

	git_index_entry entry;

	int error;

	git_index *index = NULL;

	assert(pathspecs != NULL && pathspecs->count > 0);

	memset(&entry, 0, sizeof(git_index_entry));

	if ((error = git_repository_index(&index, repo)) < 0)

		goto cleanup;

	if (target) {

		if (git_object_owner(target) != repo) {

			giterr_set(GITERR_OBJECT,

				"%s_default - The given target does not belong to this repository.", ERROR_MSG);

			return -1;

		}

		if ((error = git_object_peel(&commit, target, GIT_OBJ_COMMIT)) < 0 ||

			(error = git_commit_tree(&tree, (git_commit *)commit)) < 0)

			goto cleanup;

	}

	opts.pathspec = *pathspecs;

	opts.flags = GIT_DIFF_REVERSE;

	if ((error = git_diff_tree_to_index(

		&diff, repo, tree, index, &opts)) < 0)

			goto cleanup;

	for (i = 0, max_i = git_diff_num_deltas(diff); i < max_i; ++i) {

		const git_diff_delta *delta = git_diff_get_delta(diff, i);

		assert(delta->status == GIT_DELTA_ADDED ||

			delta->status == GIT_DELTA_MODIFIED ||

			delta->status == GIT_DELTA_CONFLICTED ||

			delta->status == GIT_DELTA_DELETED);

		error = git_index_conflict_remove(index, delta->old_file.path);

		if (error < 0) {

			if (delta->status == GIT_DELTA_ADDED && error == GIT_ENOTFOUND)

				giterr_clear();

			else

				goto cleanup;

		}

		if (delta->status == GIT_DELTA_DELETED) {

			if ((error = git_index_remove(index, delta->old_file.path, 0)) < 0)

				goto cleanup;

		} else {

			entry.mode = delta->new_file.mode;

			git_oid_cpy(&entry.id, &delta->new_file.id);

			entry.path = (char *)delta->new_file.path;

			if ((error = git_index_add(index, &entry)) < 0)

				goto cleanup;

		}

	}

	error = git_index_write(index);

cleanup:

	git_object_free(commit);

	git_tree_free(tree);

	git_index_free(index);

	git_diff_free(diff);

	return error;

}

static int reset(

	git_repository *repo,

	git_object *target,

	const char *to,

	git_reset_t reset_type,

	const git_checkout_options *checkout_opts)

{

	git_object *commit = NULL;

	git_index *index = NULL;

	git_tree *tree = NULL;

	int error = 0;

	git_checkout_options opts = GIT_CHECKOUT_OPTIONS_INIT;

	git_buf log_message = GIT_BUF_INIT;

	assert(repo && target);

	if (checkout_opts)

		opts = *checkout_opts;

	if (git_object_owner(target) != repo) {

		giterr_set(GITERR_OBJECT,

			"%s - The given target does not belong to this repository.", ERROR_MSG);

		return -1;

	}

	if (reset_type != GIT_RESET_SOFT &&

		(error = git_repository__ensure_not_bare(repo,

			reset_type == GIT_RESET_MIXED ? "reset mixed" : "reset hard")) < 0)

		return error;

	if ((error = git_object_peel(&commit, target, GIT_OBJ_COMMIT)) < 0 ||

		(error = git_repository_index(&index, repo)) < 0 ||

		(error = git_commit_tree(&tree, (git_commit *)commit)) < 0)

		goto cleanup;

	if (reset_type == GIT_RESET_SOFT &&

		(git_repository_state(repo) == GIT_REPOSITORY_STATE_MERGE ||

		 git_index_has_conflicts(index)))

	{

		giterr_set(GITERR_OBJECT, "%s (soft) in the middle of a merge", ERROR_MSG);

		error = GIT_EUNMERGED;

		goto cleanup;

	}

	if ((error = git_buf_printf(&log_message, "reset: moving to %s", to)) < 0)

		return error;

	if (reset_type == GIT_RESET_HARD) {

		/* overwrite working directory with the new tree */

		opts.checkout_strategy = GIT_CHECKOUT_FORCE;

		if ((error = git_checkout_tree(repo, (git_object *)tree, &opts)) < 0)

			goto cleanup;

	}

	/* move HEAD to the new target */

	if ((error = git_reference__update_terminal(repo, GIT_HEAD_FILE,

		git_object_id(commit), NULL, git_buf_cstr(&log_message))) < 0)

		goto cleanup;

	if (reset_type > GIT_RESET_SOFT) {

		/* reset index to the target content */

		if ((error = git_index_read_tree(index, tree)) < 0 ||

			(error = git_index_write(index)) < 0)

			goto cleanup;

		if ((error = git_repository_state_cleanup(repo)) < 0) {

			giterr_set(GITERR_INDEX, "%s - failed to clean up merge data", ERROR_MSG);

			goto cleanup;

		}

	}

cleanup:

	git_object_free(commit);

	git_index_free(index);

	git_tree_free(tree);

	git_buf_free(&log_message);

	return error;

}

int git_reset(

	git_repository *repo,

	git_object *target,

	git_reset_t reset_type,

	const git_checkout_options *checkout_opts)

{

	return reset(repo, target, git_oid_tostr_s(git_object_id(target)), reset_type, checkout_opts);

}

int git_reset_from_annotated(

	git_repository *repo,

	git_annotated_commit *commit,

	git_reset_t reset_type,

	const git_checkout_options *checkout_opts)

{

	return reset(repo, (git_object *) commit->commit, commit->description, reset_type, checkout_opts);

}