/*
 * 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_rebase_h__
#define INCLUDE_git_rebase_h__

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

/**
 * @file git2/rebase.h
 * @brief Git rebase routines
 * @defgroup git_rebase Git merge routines
 * @ingroup Git
 * @{
 */
GIT_BEGIN_DECL

/**
 * Rebase options
 *
 * Use to tell the rebase machinery how to operate.
 */
typedef struct {
	unsigned int version;

	/**
	 * Used by `git_rebase_init`, this will instruct other clients working
	 * on this rebase that you want a quiet rebase experience, which they
	 * may choose to provide in an application-specific manner.  This has no
	 * effect upon libgit2 directly, but is provided for interoperability
	 * between Git tools.
	 */
	int quiet;

	/**
	 * Used by `git_rebase_init`, this will begin an in-memory rebase,
	 * which will allow callers to step through the rebase operations and
	 * commit the rebased changes, but will not rewind HEAD or update the
	 * repository to be in a rebasing state.  This will not interfere with
	 * the working directory (if there is one).
	 */
	int inmemory;

	/**
	 * Used by `git_rebase_finish`, this is the name of the notes reference
	 * used to rewrite notes for rebased commits when finishing the rebase;
	 * if NULL, the contents of the configuration option `notes.rewriteRef`
	 * is examined, unless the configuration option `notes.rewrite.rebase`
	 * is set to false.  If `notes.rewriteRef` is also NULL, notes will
	 * not be rewritten.
	 */
	const char *rewrite_notes_ref;

	/**
	 * Options to control how trees are merged during `git_rebase_next`.
	 */
	git_merge_options merge_options;

	/**
	 * Options to control how files are written during `git_rebase_init`,
	 * `git_rebase_next` and `git_rebase_abort`.  Note that a minimum
	 * strategy of `GIT_CHECKOUT_SAFE` is defaulted in `init` and `next`,
	 * and a minimum strategy of `GIT_CHECKOUT_FORCE` is defaulted in
	 * `abort` to match git semantics.
	 */
	git_checkout_options checkout_options;
} git_rebase_options;

/**
 * Type of rebase operation in-progress after calling `git_rebase_next`.
 */
typedef enum {
	/**
	 * The given commit is to be cherry-picked.  The client should commit
	 * the changes and continue if there are no conflicts.
	 */
	GIT_REBASE_OPERATION_PICK = 0,

	/**
	 * The given commit is to be cherry-picked, but the client should prompt
	 * the user to provide an updated commit message.
	 */
	GIT_REBASE_OPERATION_REWORD,

	/**
	 * The given commit is to be cherry-picked, but the client should stop
	 * to allow the user to edit the changes before committing them.
	 */
	GIT_REBASE_OPERATION_EDIT,

	/**
	 * The given commit is to be squashed into the previous commit.  The
	 * commit message will be merged with the previous message.
	 */
	GIT_REBASE_OPERATION_SQUASH,

	/**
	 * The given commit is to be squashed into the previous commit.  The
	 * commit message from this commit will be discarded.
	 */
	GIT_REBASE_OPERATION_FIXUP,

	/**
	 * No commit will be cherry-picked.  The client should run the given
	 * command and (if successful) continue.
	 */
	GIT_REBASE_OPERATION_EXEC,
} git_rebase_operation_t;

#define GIT_REBASE_OPTIONS_VERSION 1
#define GIT_REBASE_OPTIONS_INIT \
	{ GIT_REBASE_OPTIONS_VERSION, 0, 0, NULL, GIT_MERGE_OPTIONS_INIT, \
	  GIT_CHECKOUT_OPTIONS_INIT}

/** Indicates that a rebase operation is not (yet) in progress. */
#define GIT_REBASE_NO_OPERATION SIZE_MAX

/**
 * A rebase operation
 *
 * Describes a single instruction/operation to be performed during the
 * rebase.
 */
typedef struct {
	/** The type of rebase operation. */
	git_rebase_operation_t type;

	/**
	 * The commit ID being cherry-picked.  This will be populated for
	 * all operations except those of type `GIT_REBASE_OPERATION_EXEC`.
	 */
	const git_oid id;

	/**
	 * The executable the user has requested be run.  This will only
	 * be populated for operations of type `GIT_REBASE_OPERATION_EXEC`.
	 */
	const char *exec;
} git_rebase_operation;

/**
 * Initializes a `git_rebase_options` with default values. Equivalent to
 * creating an instance with GIT_REBASE_OPTIONS_INIT.
 *
 * @param opts the `git_rebase_options` instance to initialize.
 * @param version the version of the struct; you should pass
 *        `GIT_REBASE_OPTIONS_VERSION` here.
 * @return Zero on success; -1 on failure.
 */
GIT_EXTERN(int) git_rebase_init_options(
	git_rebase_options *opts,
	unsigned int version);

/**
 * Initializes a rebase operation to rebase the changes in `branch`
 * relative to `upstream` onto another branch.  To begin the rebase
 * process, call `git_rebase_next`.  When you have finished with this
 * object, call `git_rebase_free`.
 *
 * @param out Pointer to store the rebase object
 * @param repo The repository to perform the rebase
 * @param branch The terminal commit to rebase, or NULL to rebase the
 *               current branch
 * @param upstream The commit to begin rebasing from, or NULL to rebase all
 *                 reachable commits
 * @param onto The branch to rebase onto, or NULL to rebase onto the given
 *             upstream
 * @param opts Options to specify how rebase is performed, or NULL
 * @return Zero on success; -1 on failure.
 */
GIT_EXTERN(int) git_rebase_init(
	git_rebase **out,
	git_repository *repo,
	const git_annotated_commit *branch,
	const git_annotated_commit *upstream,
	const git_annotated_commit *onto,
	const git_rebase_options *opts);

/**
 * Opens an existing rebase that was previously started by either an
 * invocation of `git_rebase_init` or by another client.
 *
 * @param out Pointer to store the rebase object
 * @param repo The repository that has a rebase in-progress
 * @param opts Options to specify how rebase is performed
 * @return Zero on success; -1 on failure.
 */
GIT_EXTERN(int) git_rebase_open(
	git_rebase **out,
	git_repository *repo,
	const git_rebase_options *opts);

/**
 * Gets the count of rebase operations that are to be applied.
 *
 * @param rebase The in-progress rebase
 * @return The number of rebase operations in total
 */
GIT_EXTERN(size_t) git_rebase_operation_entrycount(git_rebase *rebase);

/**
 * Gets the index of the rebase operation that is currently being applied.
 * If the first operation has not yet been applied (because you have
 * called `init` but not yet `next`) then this returns
 * `GIT_REBASE_NO_OPERATION`.
 *
 * @param rebase The in-progress rebase
 * @return The index of the rebase operation currently being applied.
 */
GIT_EXTERN(size_t) git_rebase_operation_current(git_rebase *rebase);

/**
 * Gets the rebase operation specified by the given index.
 *
 * @param rebase The in-progress rebase
 * @param idx The index of the rebase operation to retrieve
 * @return The rebase operation or NULL if `idx` was out of bounds
 */
GIT_EXTERN(git_rebase_operation *) git_rebase_operation_byindex(
	git_rebase *rebase,
	size_t idx);

/**
 * Performs the next rebase operation and returns the information about it.
 * If the operation is one that applies a patch (which is any operation except
 * GIT_REBASE_OPERATION_EXEC) then the patch will be applied and the index and
 * working directory will be updated with the changes.  If there are conflicts,
 * you will need to address those before committing the changes.
 *
 * @param operation Pointer to store the rebase operation that is to be performed next
 * @param rebase The rebase in progress
 * @return Zero on success; -1 on failure.
 */
GIT_EXTERN(int) git_rebase_next(
	git_rebase_operation **operation,
	git_rebase *rebase);

/**
 * Gets the index produced by the last operation, which is the result
 * of `git_rebase_next` and which will be committed by the next
 * invocation of `git_rebase_commit`.  This is useful for resolving
 * conflicts in an in-memory rebase before committing them.  You must
 * call `git_index_free` when you are finished with this.
 *
 * This is only applicable for in-memory rebases; for rebases within
 * a working directory, the changes were applied to the repository's
 * index.
 */
GIT_EXTERN(int) git_rebase_inmemory_index(
	git_index **index,
	git_rebase *rebase);

/**
 * Commits the current patch.  You must have resolved any conflicts that
 * were introduced during the patch application from the `git_rebase_next`
 * invocation.
 *
 * @param id Pointer in which to store the OID of the newly created commit
 * @param rebase The rebase that is in-progress
 * @param author The author of the updated commit, or NULL to keep the
 *        author from the original commit
 * @param committer The committer of the rebase
 * @param message_encoding The encoding for the message in the commit,
 *        represented with a standard encoding name.  If message is NULL,
 *        this should also be NULL, and the encoding from the original
 *        commit will be maintained.  If message is specified, this may be
 *        NULL to indicate that "UTF-8" is to be used.
 * @param message The message for this commit, or NULL to use the message
 *        from the original commit.
 * @return Zero on success, GIT_EUNMERGED if there are unmerged changes in
 *        the index, GIT_EAPPLIED if the current commit has already
 *        been applied to the upstream and there is nothing to commit,
 *        -1 on failure.
 */
GIT_EXTERN(int) git_rebase_commit(
	git_oid *id,
	git_rebase *rebase,
	const git_signature *author,
	const git_signature *committer,
	const char *message_encoding,
	const char *message);

/**
 * Aborts a rebase that is currently in progress, resetting the repository
 * and working directory to their state before rebase began.
 *
 * @param rebase The rebase that is in-progress
 * @return Zero on success; GIT_ENOTFOUND if a rebase is not in progress,
 *         -1 on other errors.
 */
GIT_EXTERN(int) git_rebase_abort(git_rebase *rebase);

/**
 * Finishes a rebase that is currently in progress once all patches have
 * been applied.
 *
 * @param rebase The rebase that is in-progress
 * @param signature The identity that is finishing the rebase (optional)
 * @return Zero on success; -1 on error
 */
GIT_EXTERN(int) git_rebase_finish(
	git_rebase *rebase,
	const git_signature *signature);

/**
 * Frees the `git_rebase` object.
 *
 * @param rebase The rebase object
 */
GIT_EXTERN(void) git_rebase_free(git_rebase *rebase);

/** @} */
GIT_END_DECL
#endif