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

class TreeBuilder {
  /// Initializes a new instance of [TreeBuilder] class from provided
  /// [repo]sitory and optional [tree] objects.
  ///
  /// Throws a [LibGit2Error] if error occured.
  TreeBuilder({required Repository repo, Tree? tree}) {
    _treeBuilderPointer = bindings.create(
      repoPointer: repo.pointer,
      sourcePointer: tree?.pointer ?? nullptr,
    );
    _finalizer.attach(this, _treeBuilderPointer, detach: this);
  }

  /// Pointer to memory address for allocated tree builder object.
  late final Pointer<git_treebuilder> _treeBuilderPointer;

  /// Number of entries listed in a tree builder.
  int get length => bindings.entryCount(_treeBuilderPointer);

  /// Writes the contents of the tree builder as a tree object.
  Oid write() => Oid(bindings.write(_treeBuilderPointer));

  /// Clears all the entires in the tree builder.
  void clear() => bindings.clear(_treeBuilderPointer);

  /// Returns an entry from the tree builder with provided [filename].
  ///
  /// Throws [ArgumentError] if nothing found for provided [filename].
  TreeEntry operator [](String filename) {
    return TreeEntry(
      bindings.getByFilename(
        builderPointer: _treeBuilderPointer,
        filename: filename,
      ),
    );
  }

  /// Adds or updates an entry to the tree builder with the given attributes.
  ///
  /// If an entry with [filename] already exists, its attributes will be
  /// updated with the given ones.
  ///
  /// By default the entry that you are inserting will be checked for validity;
  /// that it exists in the object database and is of the correct type.
  ///
  /// [filename] is the filename of the entry.
  ///
  /// [oid] is [Oid] of the entry.
  ///
  /// [filemode] is one of the [GitFilemode] folder attributes of the entry.
  ///
  /// Throws a [LibGit2Error] if error occured.
  void add({
    required String filename,
    required Oid oid,
    required GitFilemode filemode,
  }) {
    bindings.add(
      builderPointer: _treeBuilderPointer,
      filename: filename,
      oidPointer: oid.pointer,
      filemode: filemode.value,
    );
  }

  /// Removes an entry from the tree builder by its [filename].
  ///
  /// Throws a [LibGit2Error] if error occured.
  void remove(String filename) {
    bindings.remove(
      builderPointer: _treeBuilderPointer,
      filename: filename,
    );
  }

  /// Releases memory allocated for tree builder object and all the entries.
  void free() {
    bindings.free(_treeBuilderPointer);
    _finalizer.detach(this);
  }

  @override
  String toString() {
    return 'TreeBuilder{length: $length}';
  }
}

// coverage:ignore-start
final _finalizer = Finalizer<Pointer<git_treebuilder>>(
  (pointer) => bindings.free(pointer),
);
// coverage:ignore-end