/*
 * Copyright (C) 2009-2012 the libgit2 contributors
 *
 * 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 "git2.h"
#include "fileops.h"
#include "hash.h"
#include "vector.h"
#include "tree.h"
#include "git2/status.h"
#include "repository.h"
#include "ignore.h"

#include "git2/diff.h"
#include "diff.h"

static int resolve_head_to_tree(git_tree **tree, git_repository *repo)
{
	git_oid head_oid;
	git_object *obj = NULL;

	if (git_reference_name_to_oid(&head_oid, repo, GIT_HEAD_FILE) < 0) {
		/* cannot resolve HEAD - probably brand new repo */
		giterr_clear();
		*tree = NULL;
		return 0;
	}

	if (git_object_lookup(&obj, repo, &head_oid, GIT_OBJ_ANY) < 0)
		goto fail;

	switch (git_object_type(obj)) {
	case GIT_OBJ_TREE:
		*tree = (git_tree *)obj;
		break;
	case GIT_OBJ_COMMIT:
		if (git_commit_tree(tree, (git_commit *)obj) < 0)
			goto fail;
		git_object_free(obj);
		break;
	default:
		goto fail;
	}

	return 0;

fail:
	git_object_free(obj);
	return -1;
}

static unsigned int index_delta2status(git_delta_t index_status)
{
	unsigned int st = GIT_STATUS_CURRENT;

	switch (index_status) {
	case GIT_DELTA_ADDED:
	case GIT_DELTA_COPIED:
	case GIT_DELTA_RENAMED:
		st = GIT_STATUS_INDEX_NEW;
		break;
	case GIT_DELTA_DELETED:
		st = GIT_STATUS_INDEX_DELETED;
		break;
	case GIT_DELTA_MODIFIED:
		st = GIT_STATUS_INDEX_MODIFIED;
		break;
	default:
		break;
	}

	return st;
}

static unsigned int workdir_delta2status(git_delta_t workdir_status)
{
	unsigned int st = GIT_STATUS_CURRENT;

	switch (workdir_status) {
	case GIT_DELTA_ADDED:
	case GIT_DELTA_COPIED:
	case GIT_DELTA_RENAMED:
	case GIT_DELTA_UNTRACKED:
		st = GIT_STATUS_WT_NEW;
		break;
	case GIT_DELTA_DELETED:
		st = GIT_STATUS_WT_DELETED;
		break;
	case GIT_DELTA_MODIFIED:
		st = GIT_STATUS_WT_MODIFIED;
		break;
	case GIT_DELTA_IGNORED:
		st = GIT_STATUS_IGNORED;
		break;
	default:
		break;
	}

	return st;
}

int git_status_foreach_ext(
	git_repository *repo,
	git_status_options *opts,
	int (*cb)(const char *, unsigned int, void *),
	void *cbdata)
{
	int err = 0, cmp;
	git_diff_options diffopt;
	git_diff_list *idx2head = NULL, *wd2idx = NULL;
	git_tree *head = NULL;
	git_status_show_t show =
		opts ? opts->show : GIT_STATUS_SHOW_INDEX_AND_WORKDIR;
	git_diff_delta *i2h, *w2i;
	unsigned int i, j, i_max, j_max;

	assert(show <= GIT_STATUS_SHOW_INDEX_THEN_WORKDIR);

	switch (resolve_head_to_tree(&head, repo)) {
	case 0: break;
	case GIT_ENOTFOUND: return 0;
	default: return -1;
	}

	memset(&diffopt, 0, sizeof(diffopt));
	memcpy(&diffopt.pathspec, &opts->pathspec, sizeof(diffopt.pathspec));

	if ((opts->flags & GIT_STATUS_OPT_INCLUDE_UNTRACKED) != 0)
		diffopt.flags = diffopt.flags | GIT_DIFF_INCLUDE_UNTRACKED;
	if ((opts->flags & GIT_STATUS_OPT_INCLUDE_IGNORED) != 0)
		diffopt.flags = diffopt.flags | GIT_DIFF_INCLUDE_IGNORED;
	if ((opts->flags & GIT_STATUS_OPT_INCLUDE_UNMODIFIED) != 0)
		diffopt.flags = diffopt.flags | GIT_DIFF_INCLUDE_UNMODIFIED;
	if ((opts->flags & GIT_STATUS_OPT_RECURSE_UNTRACKED_DIRS) != 0)
		diffopt.flags = diffopt.flags | GIT_DIFF_RECURSE_UNTRACKED_DIRS;
	/* TODO: support EXCLUDE_SUBMODULES flag */

	if (show != GIT_STATUS_SHOW_WORKDIR_ONLY && head != NULL &&
		(err = git_diff_index_to_tree(repo, &diffopt, head, &idx2head)) < 0)
		goto cleanup;

	if (show != GIT_STATUS_SHOW_INDEX_ONLY &&
		(err = git_diff_workdir_to_index(repo, &diffopt, &wd2idx)) < 0)
		goto cleanup;

	if (show == GIT_STATUS_SHOW_INDEX_THEN_WORKDIR) {
		for (i = 0; !err && i < idx2head->deltas.length; i++) {
			i2h = GIT_VECTOR_GET(&idx2head->deltas, i);
			err = cb(i2h->old.path, index_delta2status(i2h->status), cbdata);
		}
		git_diff_list_free(idx2head);
		idx2head = NULL;
	}

	i_max = idx2head ? idx2head->deltas.length : 0;
	j_max = wd2idx   ? wd2idx->deltas.length   : 0;

	for (i = 0, j = 0; !err && (i < i_max || j < j_max); ) {
		i2h = idx2head ? GIT_VECTOR_GET(&idx2head->deltas,i) : NULL;
		w2i = wd2idx   ? GIT_VECTOR_GET(&wd2idx->deltas,j)   : NULL;

		cmp = !w2i ? -1 : !i2h ? 1 : strcmp(i2h->old.path, w2i->old.path);

		if (cmp < 0) {
			err = cb(i2h->old.path, index_delta2status(i2h->status), cbdata);
			i++;
		} else if (cmp > 0) {
			err = cb(w2i->old.path, workdir_delta2status(w2i->status), cbdata);
			j++;
		} else {
			err = cb(i2h->old.path, index_delta2status(i2h->status) |
					 workdir_delta2status(w2i->status), cbdata);
			i++; j++;
		}
	}

cleanup:
	git_tree_free(head);
	git_diff_list_free(idx2head);
	git_diff_list_free(wd2idx);
	return err;
}

int git_status_foreach(
	git_repository *repo,
	int (*callback)(const char *, unsigned int, void *),
	void *payload)
{
	git_status_options opts;

	memset(&opts, 0, sizeof(opts));
	opts.show  = GIT_STATUS_SHOW_INDEX_AND_WORKDIR;
	opts.flags = GIT_STATUS_OPT_INCLUDE_IGNORED |
		GIT_STATUS_OPT_INCLUDE_UNTRACKED |
		GIT_STATUS_OPT_RECURSE_UNTRACKED_DIRS;

	return git_status_foreach_ext(repo, &opts, callback, payload);
}


/*
 * the old stuff
 */

struct status_entry {
	git_index_time mtime;

	git_oid head_oid;
	git_oid index_oid;
	git_oid wt_oid;

	unsigned int status_flags;

	char path[GIT_FLEX_ARRAY]; /* more */
};

static struct status_entry *status_entry_new(git_vector *entries, const char *path)
{
	struct status_entry *e = git__calloc(sizeof(*e) + strlen(path) + 1, 1);
	if (e == NULL)
		return NULL;

	if (entries != NULL)
		git_vector_insert(entries, e);

	strcpy(e->path, path);

	return e;
}

GIT_INLINE(void) status_entry_update_from_tree_entry(struct status_entry *e, const git_tree_entry *tree_entry)
{
	assert(e && tree_entry);

	git_oid_cpy(&e->head_oid, &tree_entry->oid);
}

GIT_INLINE(void) status_entry_update_from_index_entry(struct status_entry *e, const git_index_entry *index_entry)
{
	assert(e && index_entry);

	git_oid_cpy(&e->index_oid, &index_entry->oid);
	e->mtime = index_entry->mtime;
}

static void status_entry_update_from_index(struct status_entry *e, git_index *index)
{
	int idx;
	git_index_entry *index_entry;

	assert(e && index);

	idx = git_index_find(index, e->path);
	if (idx < 0)
		return;

	index_entry = git_index_get(index, idx);

	status_entry_update_from_index_entry(e, index_entry);
}

static int status_entry_update_from_workdir(struct status_entry *e, const char* full_path)
{
	struct stat filest;

	if (p_stat(full_path, &filest) < 0) {
		giterr_set(GITERR_OS, "Cannot access file '%s'", full_path);
		return GIT_ENOTFOUND;
	}

	if (e->mtime.seconds == (git_time_t)filest.st_mtime)
		git_oid_cpy(&e->wt_oid, &e->index_oid);
	else
		git_odb_hashfile(&e->wt_oid, full_path, GIT_OBJ_BLOB);

	return 0;
}

static int status_entry_update_flags(struct status_entry *e)
{
	git_oid zero;
	int head_zero, index_zero, wt_zero;

	memset(&zero, 0x0, sizeof(git_oid));

	head_zero = git_oid_cmp(&zero, &e->head_oid);
	index_zero = git_oid_cmp(&zero, &e->index_oid);
	wt_zero = git_oid_cmp(&zero, &e->wt_oid);

	if (head_zero == 0 && index_zero == 0 && wt_zero == 0)
		return GIT_ENOTFOUND;

	if (head_zero == 0 && index_zero != 0)
		e->status_flags |= GIT_STATUS_INDEX_NEW;
	else if (index_zero == 0 && head_zero != 0)
		e->status_flags |= GIT_STATUS_INDEX_DELETED;
	else if (git_oid_cmp(&e->head_oid, &e->index_oid) != 0)
		e->status_flags |= GIT_STATUS_INDEX_MODIFIED;

	if (index_zero == 0 && wt_zero != 0)
		e->status_flags |= GIT_STATUS_WT_NEW;
	else if (wt_zero == 0 && index_zero != 0)
		e->status_flags |= GIT_STATUS_WT_DELETED;
	else if (git_oid_cmp(&e->index_oid, &e->wt_oid) != 0)
		e->status_flags |= GIT_STATUS_WT_MODIFIED;

	return 0;
}

static int status_entry_is_ignorable(struct status_entry *e)
{
	/* don't ignore files that exist in head or index already */
	return (e->status_flags == GIT_STATUS_WT_NEW);
}

static int status_entry_update_ignore(struct status_entry *e, git_ignores *ignores, const char *path)
{
	int ignored;

	if (git_ignore__lookup(ignores, path, &ignored) < 0)
		return -1;

	if (ignored)
		/* toggle off WT_NEW and on IGNORED */
		e->status_flags =
			(e->status_flags & ~GIT_STATUS_WT_NEW) | GIT_STATUS_IGNORED;

	return 0;
}

static int recurse_tree_entry(git_tree *tree, struct status_entry *e, const char *path)
{
	char *dir_sep;
	const git_tree_entry *tree_entry;
	git_tree *subtree;
	int error;

	dir_sep = strchr(path, '/');
	if (!dir_sep) {
		if ((tree_entry = git_tree_entry_byname(tree, path)) != NULL)
			/* The leaf exists in the tree*/
			status_entry_update_from_tree_entry(e, tree_entry);
		return 0;
	}

	/* Retrieve subtree name */
	*dir_sep = '\0';

	if ((tree_entry = git_tree_entry_byname(tree, path)) == NULL)
		return 0; /* The subtree doesn't exist in the tree*/

	*dir_sep = '/';

	/* Retreive subtree */
	error = git_tree_lookup(&subtree, tree->object.repo, &tree_entry->oid);
	if (!error) {
		error = recurse_tree_entry(subtree, e, dir_sep+1);
		git_tree_free(subtree);
	}

	return error;
}

int git_status_file(
	unsigned int *status_flags, git_repository *repo, const char *path)
{
	struct status_entry *e;
	git_index *index = NULL;
	git_buf temp_path = GIT_BUF_INIT;
	int error = 0;
	git_tree *tree = NULL;
	const char *workdir;

	assert(status_flags && repo && path);

	if ((workdir = git_repository_workdir(repo)) == NULL) {
		giterr_set(GITERR_OS, "Cannot get file status from bare repo");
		return GIT_ENOTFOUND;
	}

	if (git_buf_joinpath(&temp_path, workdir, path) < 0)
		return -1;

	if (git_path_isdir(temp_path.ptr)) {
		giterr_set(GITERR_OS, "Cannot get file status for directory '%s'", temp_path.ptr);
		git_buf_free(&temp_path);
		return GIT_ENOTFOUND;
	}

	e = status_entry_new(NULL, path);
	GITERR_CHECK_ALLOC(e);

	/* Find file in Workdir */
	if (git_path_exists(temp_path.ptr) == true &&
		(error = status_entry_update_from_workdir(e, temp_path.ptr)) < 0)
		goto cleanup;

	/* Find file in Index */
	if ((error = git_repository_index__weakptr(&index, repo)) < 0)
		goto cleanup;
	status_entry_update_from_index(e, index);

	/* Try to find file in HEAD */
	if ((error = resolve_head_to_tree(&tree, repo)) < 0)
		goto cleanup;

	if (tree != NULL) {
		if ((error = git_buf_sets(&temp_path, path)) < 0 ||
			(error = recurse_tree_entry(tree, e, temp_path.ptr)) < 0)
			goto cleanup;
	}

	/* Determine status */
	if ((error = status_entry_update_flags(e)) < 0)
		giterr_set(GITERR_OS, "Cannot find file '%s' to determine status", path);

	if (!error && status_entry_is_ignorable(e)) {
		git_ignores ignores;

		if ((error = git_ignore__for_path(repo, path, &ignores)) == 0)
			error = status_entry_update_ignore(e, &ignores, path);

		git_ignore__free(&ignores);
	}

	if (!error)
		*status_flags = e->status_flags;

cleanup:
	git_buf_free(&temp_path);
	git_tree_free(tree);
	git__free(e);

	return error;
}

int git_status_should_ignore(git_repository *repo, const char *path, int *ignored)
{
	int error;
	git_ignores ignores;

	if (git_ignore__for_path(repo, path, &ignores) < 0)
		return -1;

	error = git_ignore__lookup(&ignores, path, ignored);
	git_ignore__free(&ignores);
	return error;
}

