/*
 * 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.
 */
#ifndef INCLUDE_git_commit_h__
#define INCLUDE_git_commit_h__

#include "common.h"
#include "types.h"
#include "oid.h"
#include "object.h"

/**
 * @file git2/commit.h
 * @brief Git commit parsing, formatting routines
 * @defgroup git_commit Git commit parsing, formatting routines
 * @ingroup Git
 * @{
 */
GIT_BEGIN_DECL

/**
 * Lookup a commit object from a repository.
 *
 * @param commit pointer to the looked up commit
 * @param repo the repo to use when locating the commit.
 * @param id identity of the commit to locate. If the object is
 *		an annotated tag it will be peeled back to the commit.
 * @return 0 or an error code
 */
GIT_INLINE(int) git_commit_lookup(git_commit **commit, git_repository *repo, const git_oid *id)
{
	return git_object_lookup((git_object **)commit, repo, id, GIT_OBJ_COMMIT);
}

/**
 * Lookup a commit object from a repository,
 * given a prefix of its identifier (short id).
 *
 * @see git_object_lookup_prefix
 *
 * @param commit pointer to the looked up commit
 * @param repo the repo to use when locating the commit.
 * @param id identity of the commit to locate. If the object is
 *		an annotated tag it will be peeled back to the commit.
 * @param len the length of the short identifier
 * @return 0 or an error code
 */
GIT_INLINE(int) git_commit_lookup_prefix(git_commit **commit, git_repository *repo, const git_oid *id, size_t len)
{
	return git_object_lookup_prefix((git_object **)commit, repo, id, len, GIT_OBJ_COMMIT);
}

/**
 * Close an open commit
 *
 * This is a wrapper around git_object_free()
 *
 * IMPORTANT:
 * It *is* necessary to call this method when you stop
 * using a commit. Failure to do so will cause a memory leak.
 *
 * @param commit the commit to close
 */

GIT_INLINE(void) git_commit_free(git_commit *commit)
{
	git_object_free((git_object *) commit);
}

/**
 * Get the id of a commit.
 *
 * @param commit a previously loaded commit.
 * @return object identity for the commit.
 */
GIT_INLINE(const git_oid *) git_commit_id(const git_commit *commit)
{
	return git_object_id((const git_object *)commit);
}

/**
 * Get the encoding for the message of a commit,
 * as a string representing a standard encoding name.
 *
 * The encoding may be NULL if the `encoding` header
 * in the commit is missing; in that case UTF-8 is assumed.
 *
 * @param commit a previously loaded commit.
 * @return NULL, or the encoding
 */
GIT_EXTERN(const char *) git_commit_message_encoding(const git_commit *commit);

/**
 * Get the full message of a commit.
 *
 * @param commit a previously loaded commit.
 * @return the message of a commit
 */
GIT_EXTERN(const char *) git_commit_message(const git_commit *commit);

/**
 * Get the commit time (i.e. committer time) of a commit.
 *
 * @param commit a previously loaded commit.
 * @return the time of a commit
 */
GIT_EXTERN(git_time_t) git_commit_time(const git_commit *commit);

/**
 * Get the commit timezone offset (i.e. committer's preferred timezone) of a commit.
 *
 * @param commit a previously loaded commit.
 * @return positive or negative timezone offset, in minutes from UTC
 */
GIT_EXTERN(int) git_commit_time_offset(const git_commit *commit);

/**
 * Get the committer of a commit.
 *
 * @param commit a previously loaded commit.
 * @return the committer of a commit
 */
GIT_EXTERN(const git_signature *) git_commit_committer(const git_commit *commit);

/**
 * Get the author of a commit.
 *
 * @param commit a previously loaded commit.
 * @return the author of a commit
 */
GIT_EXTERN(const git_signature *) git_commit_author(const git_commit *commit);

/**
 * Get the tree pointed to by a commit.
 *
 * @param tree_out pointer where to store the tree object
 * @param commit a previously loaded commit.
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_commit_tree(git_tree **tree_out, const git_commit *commit);

/**
 * Get the id of the tree pointed to by a commit. This differs from
 * `git_commit_tree` in that no attempts are made to fetch an object
 * from the ODB.
 *
 * @param commit a previously loaded commit.
 * @return the id of tree pointed to by commit.
 */
GIT_EXTERN(const git_oid *) git_commit_tree_id(const git_commit *commit);

/**
 * Get the number of parents of this commit
 *
 * @param commit a previously loaded commit.
 * @return integer of count of parents
 */
GIT_EXTERN(unsigned int) git_commit_parentcount(const git_commit *commit);

/**
 * Get the specified parent of the commit.
 *
 * @param out Pointer where to store the parent commit
 * @param commit a previously loaded commit.
 * @param n the position of the parent (from 0 to `parentcount`)
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_commit_parent(git_commit **out, git_commit *commit, unsigned int n);

/**
 * Get the oid of a specified parent for a commit. This is different from
 * `git_commit_parent`, which will attempt to load the parent commit from
 * the ODB.
 *
 * @param commit a previously loaded commit.
 * @param n the position of the parent (from 0 to `parentcount`)
 * @return the id of the parent, NULL on error.
 */
GIT_EXTERN(const git_oid *) git_commit_parent_id(git_commit *commit, unsigned int n);

/**
 * Get the commit object that is the <n>th generation ancestor
 * of the named commit object, following only the first parents.
 * The returned commit has to be freed by the caller.
 *
 * Passing `0` as the generation number returns another instance of the
 * base commit itself.
 *
 * @param ancestor Pointer where to store the ancestor commit
 * @param commit a previously loaded commit.
 * @param n the requested generation
 * @return 0 on success; GIT_ENOTFOUND if no matching ancestor exists
 * or an error code
 */
GIT_EXTERN(int) git_commit_nth_gen_ancestor(
	git_commit **ancestor,
	const git_commit *commit,
	unsigned int n);

/**
 * Create a new commit in the repository using `git_object`
 * instances as parameters.
 *
 * The message will not be cleaned up. This can be achieved
 * through `git_message_prettify()`.
 *
 * @param id Pointer where to store the OID of the
 *	newly created commit
 *
 * @param repo Repository where to store the commit
 *
 * @param update_ref If not NULL, name of the reference that
 *	will be updated to point to this commit. If the reference
 *	is not direct, it will be resolved to a direct reference.
 *	Use "HEAD" to update the HEAD of the current branch and
 *	make it point to this commit. If the reference doesn't
 *	exist yet, it will be created.
 *
 * @param author Signature representing the author and the authory
 *	time of this commit
 *
 * @param committer Signature representing the committer and the
 * commit time of this commit
 *
 * @param message_encoding The encoding for the message in the
 * commit, represented with a standard encoding name.
 * E.g. "UTF-8". If NULL, no encoding header is written and
 * UTF-8 is assumed.
 *
 * @param message Full message for this commit
 *
 * @param tree An instance of a `git_tree` object that will
 * be used as the tree for the commit. This tree object must
 * also be owned by the given `repo`.
 *
 * @param parent_count Number of parents for this commit
 *
 * @param parents[] Array of `parent_count` pointers to `git_commit`
 * objects that will be used as the parents for this commit. This
 * array may be NULL if `parent_count` is 0 (root commit). All the
 * given commits must be owned by the `repo`.
 *
 * @return 0 or an error code
 *	The created commit will be written to the Object Database and
 *	the given reference will be updated to point to it
 */
GIT_EXTERN(int) git_commit_create(
		git_oid *id,
		git_repository *repo,
		const char *update_ref,
		const git_signature *author,
		const git_signature *committer,
		const char *message_encoding,
		const char *message,
		const git_tree *tree,
		int parent_count,
		const git_commit *parents[]);

/**
 * Create a new commit in the repository using a variable
 * argument list.
 *
 * The message will be cleaned up from excess whitespace
 * it will be made sure that the last line ends with a '\n'.
 *
 * The parents for the commit are specified as a variable
 * list of pointers to `const git_commit *`. Note that this
 * is a convenience method which may not be safe to export
 * for certain languages or compilers
 *
 * All other parameters remain the same
 *
 * @see git_commit_create
 */
GIT_EXTERN(int) git_commit_create_v(
		git_oid *id,
		git_repository *repo,
		const char *update_ref,
		const git_signature *author,
		const git_signature *committer,
		const char *message_encoding,
		const char *message,
		const git_tree *tree,
		int parent_count,
		...);

/** @} */
GIT_END_DECL
#endif