/*
 * 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.
 */
#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 A representation of a set of changes in the repository
 * @defgroup git_commit Git commit parsing, formatting routines
 * @ingroup Git
 *
 * A commit represents a set of changes made to the files within a
 * repository, and metadata about who made the changes, and when the
 * changes were made.
 * @{
 */
GIT_BEGIN_DECL

/**
 * Lookup a commit object from a repository.
 *
 * The returned object should be released with `git_commit_free` when no
 * longer needed.
 *
 * @param[out] 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_EXTERN(int) git_commit_lookup(
	git_commit **commit, git_repository *repo, const git_oid *id);

/**
 * Lookup a commit object from a repository, given a prefix of its
 * identifier (short id).
 *
 * The returned object should be released with `git_commit_free` when no
 * longer needed.
 *
 * @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_EXTERN(int) git_commit_lookup_prefix(
	git_commit **commit, git_repository *repo, const git_oid *id, size_t len);

/**
 * 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_EXTERN(void) git_commit_free(git_commit *commit);

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

/**
 * Get the repository that contains the commit.
 *
 * @param commit A previously loaded commit.
 * @return Repository that contains this commit.
 */
GIT_EXTERN(git_repository *) git_commit_owner(const git_commit *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.
 *
 * The returned message will be slightly prettified by removing any
 * potential leading newlines.
 *
 * @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 full raw message of a commit.
 *
 * @param commit a previously loaded commit.
 * @return the raw message of a commit
 */
GIT_EXTERN(const char *) git_commit_message_raw(const git_commit *commit);

/**
 * Get the short "summary" of the git commit message.
 *
 * The returned message is the summary of the commit, comprising the
 * first paragraph of the message with whitespace trimmed and squashed.
 *
 * @param commit a previously loaded commit.
 * @return the summary of a commit or NULL on error
 */
GIT_EXTERN(const char *) git_commit_summary(git_commit *commit);

/**
 * Get the long "body" of the git commit message.
 *
 * The returned message is the body of the commit, comprising
 * everything but the first paragraph of the message. Leading and
 * trailing whitespaces are trimmed.
 *
 * @param commit a previously loaded commit.
 * @return the body of a commit or NULL when no the message only
 * consists of a summary
 */
GIT_EXTERN(const char *) git_commit_body(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 committer of a commit, using the mailmap to map names and email
 * addresses to canonical real names and email addresses.
 *
 * Call `git_signature_free` to free the signature.
 *
 * @param[out] out a pointer to store the resolved signature.
 * @param commit a previously loaded commit.
 * @param mailmap the mailmap to resolve with. (may be NULL)
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_commit_committer_with_mailmap(
	git_signature **out,
	const git_commit *commit,
	const git_mailmap *mailmap);

/**
 * Get the author of a commit, using the mailmap to map names and email
 * addresses to canonical real names and email addresses.
 *
 * Call `git_signature_free` to free the signature.
 *
 * @param[out] out a pointer to store the resolved signature.
 * @param commit a previously loaded commit.
 * @param mailmap the mailmap to resolve with. (may be NULL)
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_commit_author_with_mailmap(
	git_signature **out,
	const git_commit *commit,
	const git_mailmap *mailmap);

/**
 * Get the full raw text of the commit header.
 *
 * @param commit a previously loaded commit
 * @return the header text of the commit
 */
GIT_EXTERN(const char *) git_commit_raw_header(const git_commit *commit);

/**
 * Get the tree pointed to by a commit.
 *
 * @param[out] 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] 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,
	const 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(
	const 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);

/**
 * Get an arbitrary header field
 *
 * @param out the buffer to fill; existing content will be
 * overwritten
 * @param commit the commit to look in
 * @param field the header field to return
 * @return 0 on succeess, GIT_ENOTFOUND if the field does not exist,
 * or an error code
 */
GIT_EXTERN(int) git_commit_header_field(
	git_buf *out, const git_commit *commit, const char *field);

/**
 * Extract the signature from a commit
 *
 * If the id is not for a commit, the error class will be
 * `GIT_ERROR_INVALID`. If the commit does not have a signature, the
 * error class will be `GIT_ERROR_OBJECT`.
 *
 * @param signature the signature block; existing content will be
 * overwritten
 * @param signed_data signed data; this is the commit contents minus the signature block;
 * existing content will be overwritten
 * @param repo the repository in which the commit exists
 * @param commit_id the commit from which to extract the data
 * @param field the name of the header field containing the signature
 * block; pass `NULL` to extract the default 'gpgsig'
 * @return 0 on success, GIT_ENOTFOUND if the id is not for a commit
 * or the commit does not have a signature.
 */
GIT_EXTERN(int) git_commit_extract_signature(git_buf *signature, git_buf *signed_data, git_repository *repo, git_oid *commit_id, const char *field);


/** The field name and value for a custom commit header entry. */
typedef struct {
	const char *field;
	const char *value;
} git_commit_header;

/** An accessor object for setting commit signature data. */
typedef struct git_commitbuilder git_commitbuilder;

/**
 * Add a header on a commit being created.
 *
 * @param builder in-progress commitbuilder object
 * @param field the header field to add
 * @param value the header value to add
 * @return 0 on success or an error code
 */
GIT_EXTERN(int) git_commitbuilder_add_header(
	git_commitbuilder *builder,
	const char *field,
	const char *value);

/**
 * Commit signing callback: used when a function is going to write
 * a commit (for example, in `git_commit_create_ext`) to allow callers
 * to sign the commit.
 *
 * @param builder commit builder object to populate with the signature
 * @param repo the repository being committed in
 * @param commit_content the raw contents of the commit (to be signed)
 * @param payload the caller-specified callback payload
 * @return 0 if this callback has created a signature and populated the
 * field and signature buffers, `GIT_PASSTHROUGH` if the callback
 * does not want to sign the commit, any other value to stop and
 * return a failure
 */
typedef int GIT_CALLBACK(git_commit_signature_cb)(
	git_commitbuilder *builder,
	git_repository *repo,
	const char *commit_content,
	void *payload);

/**
 * Commit creation options for the simple commit creation options.
 *
 * @options[version] GIT_COMMIT_CREATE_OPTIONS_VERSION
 * @options[init_macro] GIT_COMMIT_CREATE_OPTIONS_INIT
 * @options[init_function] git_commit_create_options_init
 */
typedef struct {
	unsigned int version;

	/**
	 * Flags for creating the commit.
	 *
	 * If `allow_empty_commit` is specified, a commit with no changes
	 * from the prior commit (an "empty" commit) is allowed. Otherwise,
	 * commit creation will be stopped.
	 */
	unsigned int allow_empty_commit : 1;

	/** The commit author, or NULL for the default. */
	const git_signature *author;

	/** The committer, or NULL for the default. */
	const git_signature *committer;

	/** Encoding for the commit message; leave NULL for default. */
	const char *message_encoding;

	/**
	 * Extra headers can be specified as an array of field name and
	 * value pairs.
	 */
	const git_commit_header *extra_headers;
	size_t extra_headers_len; /**< Number of extra headers */

	/** Signing callback; leave NULL for no commit signing. */
	git_commit_signature_cb sign;

	/** Callback payload (optional) */
	void *payload;
} git_commit_create_options;

/** Current version for the `git_commit_create_options` structure */
#define GIT_COMMIT_CREATE_OPTIONS_VERSION 1

/** Static constructor for `git_commit_create_options` */
#define GIT_COMMIT_CREATE_OPTIONS_INIT { GIT_COMMIT_CREATE_OPTIONS_VERSION }

/**
 * Initialize git_commit_create_options structure
 *
 * Initialize a `git_commit_create_options` with default values.
 * Equivalent to creating an instance with GIT_COMMIT_CREATE_OPTIONS_INIT.
 *
 * @param opts The `git_commit_create_options` struct to initialize.
 * @param version The struct version; pass
 * `GIT_COMMIT_CREATE_OPTIONS_VERSION`
 * @return 0 on success or -1 on failure.
 */
GIT_EXTERN(int) git_commit_create_options_init(
	git_commit_create_options *opts,
	unsigned int version);

/**
 * Commits the staged changes in the repository; this is a near analog to
 * `git commit -m message`.
 *
 * By default, empty commits are not allowed.
 *
 * @param id pointer to store the new commit's object id
 * @param repo repository to commit changes in
 * @param message the commit message
 * @param opts options for creating the commit
 * @return 0 on success, GIT_EUNCHANGED if there were no changes to commit, or an error code
 */
GIT_EXTERN(int) git_commit_create_from_stage(
	git_oid *id,
	git_repository *repo,
	const char *message,
	const git_commit_create_options *opts);

/**
 * Commit creation options for the extended commit creation options.
 *
 * @options[version] GIT_COMMIT_CREATE_EXT_OPTIONS_VERSION
 * @options[init_macro] GIT_COMMIT_CREATE_EXT_OPTIONS_INIT
 * @options[init_function] git_commit_create_ext_options_init
 */
typedef struct {
	unsigned int version;

	/**
	 * If not NULL, the 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.
	 * If it does exist, the first parent must be the tip of this
	 * branch.
	 */
	const char *update_ref;

	/** Encoding for the commit message; leave NULL for default. */
	const char *message_encoding;

	/**
	 * Extra headers can be specified as an array of field name and
	 * value pairs.
	 */
	const git_commit_header *extra_headers;
	size_t extra_headers_len; /**< Number of extra headers */

	/** Signing callback; leave NULL for no commit signing. */
	git_commit_signature_cb sign;

	/** Callback payload (optional) */
	void *payload;
} git_commit_create_ext_options;

/** Current version for the `git_commit_create_ext_options` structure */
#define GIT_COMMIT_CREATE_EXT_OPTIONS_VERSION 1

/** Static constructor for `git_commit_create_ext_options` */
#define GIT_COMMIT_CREATE_EXT_OPTIONS_INIT { GIT_COMMIT_CREATE_EXT_OPTIONS_VERSION }

/**
 * Initialize git_commit_create_ext_options structure
 *
 * Initialize a `git_commit_create_ext_options` with default values.
 * Equivalent to creating an instance with
 * GIT_COMMIT_CREATE_EXT_OPTIONS_INIT.
 *
 * @param opts The `git_commit_create_ext_options` struct to initialize.
 * @param version The struct version; pass
 * `GIT_COMMIT_CREATE_EXT_OPTIONS_VERSION`
 * @return 0 on success or -1 on failure.
 */
GIT_EXTERN(int) git_commit_create_ext_options_init(
	git_commit_create_ext_options *opts,
	unsigned int version);

/**
 * Create a new commit object and write it to the object database.
 *
 * Note that the message will _not_ be cleaned up automatically. You
 * may wish to use the `git_message_prettify` API to clean it up.
 *
 * This API provides the most control for generating commit objects;
 * this is useful if (for example) you have a tree object already.
 * If you have staged changes, and just want to emulate `git commit`
 * on the command line, then `git_commit_create_from_stage` may be a
 * simpler option.
 *
 * @param id_out pointer to store the new commit's object id
 * @param repo repository to store the commit in
 * @param author The name of the author and time of authorship
 * @param committer The name of the committer and time of commit
 * @param message Full message for this commit
 * @param tree The `git_tree` that will be used as the tree for this commit
 * @param parent_count Number of parents for this commit
 * @param parents Array pointers to `git_commit` objects that will be used
 * as parents for this commit.
 * @param opts Additional options for creating this commit,
 * or `NULL` for defaults
 * @return 0 on success or an error code
 */
GIT_EXTERN(int) git_commit_create_ext(
	git_oid *id_out,
	git_repository *repo,
	const git_signature *author,
	const git_signature *committer,
	const char *message,
	const git_tree *tree,
	size_t parent_count,
	git_commit * const parents[],
	const git_commit_create_ext_options *opts);


/**
 * Create new commit in the repository from a list of `git_object` pointers
 *
 * The message will **not** be cleaned up automatically. You can do that
 * with the `git_message_prettify()` function.
 *
 * @param id Pointer in which 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. If it does exist, the first
 *	parent must be the tip of this branch.
 *
 * @param author Signature with author and author time of commit
 *
 * @param committer Signature with committer and * commit time of 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,
	size_t parent_count,
	const git_commit *parents[]);

/**
 * Create new commit in the repository using a variable argument list.
 *
 * The message will **not** be cleaned up automatically. You can do that
 * with the `git_message_prettify()` function.
 *
 * 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 as `git_commit_create()`.
 *
 * @param id Pointer in which 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. If it does exist, the first
 *	parent must be the tip of this branch.
 *
 * @param author Signature with author and author time of commit
 *
 * @param committer Signature with committer and * commit time of 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
 *
 * @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_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,
	size_t parent_count,
	...);

/**
 * A "batteries included" commit creation from a tree using defaults.
 *
 * By default, empty commits are not allowed.
 *
 * @param id pointer to store the new commit's object id
 * @param repo repository to commit changes in
 * @param tree tree to point the commit to
 * @param message the commit message
 * @param opts options for creating the commit
 * @return 0 on success, GIT_EUNCHANGED if there were no changes to commit, or an error code
 */
GIT_EXTERN(int) git_commit_create_from_tree(
	git_oid *id,
	git_repository *repo,
	const git_tree *tree,
	const char *message,
	const git_commit_create_options *opts);

/**
 * Amends the HEAD commit in the repository using the staged changes;
 * this is a near analog to `git commit --amend -m message`.
 *
 * @param id pointer to store the new commit's object id
 * @param repo repository to commit changes in
 * @param message the commit message
 * @param opts options for creating the commit
 * @return 0 on success or an error code
 */
GIT_EXTERN(int) git_commit_amend_from_stage(
	git_oid *id,
	git_repository *repo,
	const char *message,
	const git_commit_create_options *opts);

/**
 * Amends the HEAD commit in the repository using the given tree.
 *
 * @param id pointer to store the new commit's object id
 * @param repo repository to commit changes in
 * @param tree tree to point the commit to
 * @param message the commit message
 * @param opts options for creating the commit
 * @return 0 on success or an error code
 */
GIT_EXTERN(int) git_commit_amend_from_tree(
	git_oid *id,
	git_repository *repo,
	const git_tree *tree,
	const char *message,
	const git_commit_create_options *opts);

/**
 * Amend an existing commit by replacing only non-NULL values.
 *
 * This creates a new commit that is exactly the same as the old commit,
 * except that any non-NULL values will be updated. The new commit has
 * the same parents as the old commit.
 *
 * The `update_ref` value works as in the regular `git_commit_create()`,
 * updating the ref to point to the newly rewritten commit. If you want
 * to amend a commit that is not currently the tip of the branch and then
 * rewrite the following commits to reach a ref, pass this as NULL and
 * update the rest of the commit chain and ref separately.
 *
 * Unlike `git_commit_create()`, the `author`, `committer`, `message`,
 * `message_encoding`, and `tree` parameters can be NULL in which case this
 * will use the values from the original `commit_to_amend`.
 *
 * All parameters have the same meanings as in `git_commit_create()`.
 *
 * @param id Pointer in which to store the OID of the newly created commit
 *
 * @param commit_to_amend The commit to amend
 *
 * @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. If it does exist, the first
 *	parent must be the tip of this branch.
 *
 * @param author Signature with author and author time of commit
 *
 * @param committer Signature with committer and commit time of 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`.
 *
 * @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_amend(
	git_oid *id,
	const git_commit *commit_to_amend,
	const char *update_ref,
	const git_signature *author,
	const git_signature *committer,
	const char *message_encoding,
	const char *message,
	const git_tree *tree);

/**
 * Create a commit and write it into a buffer
 *
 * Create a commit as with `git_commit_create()` but instead of
 * writing it to the objectdb, write the contents of the object into a
 * buffer.
 *
 * @param out the buffer into which to write the commit object content
 *
 * @param repo Repository where the referenced tree and parents live
 *
 * @param author Signature with author and author time of commit
 *
 * @param committer Signature with committer and * commit time of 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
 */
GIT_EXTERN(int) git_commit_create_buffer(
	git_buf *out,
	git_repository *repo,
	const git_signature *author,
	const git_signature *committer,
	const char *message_encoding,
	const char *message,
	const git_tree *tree,
	size_t parent_count,
	const git_commit *parents[]);

/**
 * Create a commit object from the given buffer and signature
 *
 * Given the unsigned commit object's contents, its signature and the
 * header field in which to store the signature, attach the signature
 * to the commit and write it into the given repository.
 *
 * @param out the resulting commit id
 * @param repo the repository to create the commit in.
 * @param commit_content the content of the unsigned commit object
 * @param signature the signature to add to the commit. Leave `NULL`
 * to create a commit without adding a signature field.
 * @param signature_field which header field should contain this
 * signature. Leave `NULL` for the default of "gpgsig"
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_commit_create_with_signature(
	git_oid *out,
	git_repository *repo,
	const char *commit_content,
	const char *signature,
	const char *signature_field);

/**
 * Create an in-memory copy of a commit. The copy must be explicitly
 * free'd or it will leak.
 *
 * @param[out] out Pointer to store the copy of the commit
 * @param source Original commit to copy
 * @return 0
 */
GIT_EXTERN(int) git_commit_dup(git_commit **out, git_commit *source);

/**
 * Commit creation callback: used when a function is going to create
 * commits (for example, in `git_rebase_commit`) to allow callers to
 * override the commit creation behavior. For example, users may
 * wish to sign commits by providing this information to
 * `git_commit_create_buffer`, signing that buffer, then calling
 * `git_commit_create_with_signature`. The resultant commit id
 * should be set in the `out` object id parameter.
 *
 * @param out pointer that this callback will populate with the object
 * id of the commit that is created
 * @param author the author name and time of the commit
 * @param committer the committer name and time of the commit
 * @param message_encoding the encoding of the given message, or NULL
 * to assume UTF8
 * @param message the commit message
 * @param tree the tree to be committed
 * @param parent_count the number of parents for this commit
 * @param parents the commit parents
 * @param payload the payload pointer in the rebase options
 * @return 0 if this callback has created the commit and populated the out
 * parameter, GIT_PASSTHROUGH if the callback has not created a
 * commit and wants the calling function to create the commit as
 * if no callback had been specified, any other value to stop
 * and return a failure
 */
typedef int (*git_commit_create_cb)(
	git_oid *out,
	const git_signature *author,
	const git_signature *committer,
	const char *message_encoding,
	const char *message,
	const git_tree *tree,
	size_t parent_count,
	const git_commit *parents[],
	void *payload);

/** An array of commits returned from the library */
typedef struct git_commitarray {
	git_commit *const *commits;
	size_t count;
} git_commitarray;

/**
 * Free the commits contained in a commit array. This method should
 * be called on `git_commitarray` objects that were provided by the
 * library. Not doing so will result in a memory leak.
 *
 * This does not free the `git_commitarray` itself, since the library
 * will never allocate that object directly itself.
 *
 * @param array The git_commitarray that contains commits to free
 */
GIT_EXTERN(void) git_commitarray_dispose(git_commitarray *array);

/** @} */
GIT_END_DECL

#endif