import 'dart:ffi';

import 'package:libgit2dart/libgit2dart.dart';
import 'package:libgit2dart/src/bindings/annotated.dart' as bindings;
import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';

/// An annotated commit contains information about how it was looked up, which
/// may be useful for functions like merge or rebase to provide context to the
/// operation. For example, conflict files will include the name of the source
/// or target branches being merged.
class AnnotatedCommit {
  /// Lookups an annotated commit from the given commit [oid].
  ///
  /// It is preferable to use [AnnotatedCommit.fromReference] instead of this
  /// one, for commit to contain more information about how it was looked up.
  ///
  /// **IMPORTANT**: Should be freed to release allocated memory.
  ///
  /// Throws a [LibGit2Error] if error occured.
  AnnotatedCommit.lookup({required Repository repo, required Oid oid}) {
    _annotatedCommitPointer = bindings.lookup(
      repoPointer: repo.pointer,
      oidPointer: oid.pointer,
    );
  }

  /// Creates an annotated commit from the given [reference].
  ///
  /// **IMPORTANT**: Should be freed to release allocated memory.
  ///
  /// Throws a [LibGit2Error] if error occured.
  AnnotatedCommit.fromReference({
    required Repository repo,
    required Reference reference,
  }) {
    _annotatedCommitPointer = bindings.fromRef(
      repoPointer: repo.pointer,
      referencePointer: reference.pointer,
    );
  }

  /// Creates an annotated commit from a revision string.
  ///
  /// See `man gitrevisions`, or http://git-scm.com/docs/git-rev-parse.html#_specifying_revisions
  /// for information on the syntax accepted.
  ///
  /// **IMPORTANT**: Should be freed to release allocated memory.
  ///
  /// Throws a [LibGit2Error] if error occured.
  AnnotatedCommit.fromRevSpec({
    required Repository repo,
    required String spec,
  }) {
    _annotatedCommitPointer = bindings.fromRevSpec(
      repoPointer: repo.pointer,
      revspec: spec,
    );
  }

  /// Creates an annotated commit from the given fetch head data.
  ///
  /// [repo] is repository that contains the given commit.
  ///
  /// [branchName] is name of the (remote) branch.
  ///
  /// [remoteUrl] is url of the remote.
  ///
  /// [oid] is the commit object id of the remote branch.
  ///
  /// **IMPORTANT**: Should be freed to release allocated memory.
  ///
  /// Throws a [LibGit2Error] if error occured.
  AnnotatedCommit.fromFetchHead({
    required Repository repo,
    required String branchName,
    required String remoteUrl,
    required Oid oid,
  }) {
    _annotatedCommitPointer = bindings.fromFetchHead(
      repoPointer: repo.pointer,
      branchName: branchName,
      remoteUrl: remoteUrl,
      oid: oid.pointer,
    );
  }

  late final Pointer<git_annotated_commit> _annotatedCommitPointer;

  /// Pointer to pointer to memory address for allocated commit object.
  Pointer<git_annotated_commit> get pointer => _annotatedCommitPointer;

  /// Commit oid that the given annotated commit refers to.
  Oid get oid => Oid.fromRaw(bindings.oid(_annotatedCommitPointer).ref);

  /// Reference name that the annotated commit refers to.
  ///
  /// Returns empty string if no information found.
  String get refName => bindings.refName(_annotatedCommitPointer);

  /// Releases memory allocated for commit object.
  void free() => bindings.free(_annotatedCommitPointer);
}