import 'runtime_command.dart';
import 'runtime_node.dart';

import '../protocol/runtime_protocol.dart';

class NodeUpdate {
  const NodeUpdate({required this.id, required this.props});

  final String id;
  final Map<String, Object?> props;

  static NodeUpdate fromMap(Map<String, Object?> map) {
    RuntimeProtocolSchema.ensureKnownKeys(
      map,
      allowed: RuntimeProtocolSchema.nodeUpdateFields,
      context: 'NodeUpdate',
    );
    final id = map[RuntimeProtocolField.id];
    if (id is! String || id.isEmpty) {
      throw const FormatException('NodeUpdate.id must be a string');
    }

    final props = map[RuntimeProtocolField.props];
    if (props is! Map) {
      throw const FormatException('NodeUpdate.props must be a map');
    }

    final typedProps = Map<String, Object?>.from(props);
    RuntimeProtocolSchema.ensureKnownKeys(
      typedProps,
      allowed: RuntimeProtocolSchema.nodePropsFields,
      context: 'RuntimeNode.props',
    );

    return NodeUpdate(id: id, props: typedProps);
  }
}

class NodeRemove {
  const NodeRemove({required this.id});

  final String id;

  static NodeRemove fromValue(Object? value) {
    if (value is String && value.isNotEmpty) {
      return NodeRemove(id: value);
    }
    if (value is Map) {
      RuntimeProtocolSchema.ensureKnownKeys(
        value,
        allowed: RuntimeProtocolSchema.nodeRemoveFields,
        context: 'NodeRemove',
      );
      final id = value[RuntimeProtocolField.id];
      if (id is String && id.isNotEmpty) {
        return NodeRemove(id: id);
      }
    }
    throw const FormatException('NodeRemove must be an id string or {id}');
  }
}

class NodeDiff {
  const NodeDiff({
    this.creates = const [],
    this.updates = const [],
    this.removes = const [],
  });

  final List<RuntimeNode> creates;
  final List<NodeUpdate> updates;
  final List<NodeRemove> removes;

  static NodeDiff empty = const NodeDiff();

  static NodeDiff fromMap(Object? value) {
    if (value == null) {
      return NodeDiff.empty;
    }
    if (value is! Map) {
      throw const FormatException('NodeDiff must be a map');
    }
    RuntimeProtocolSchema.ensureKnownKeys(
      value,
      allowed: RuntimeProtocolSchema.nodeDiffFields,
      context: 'NodeDiff',
    );

    return NodeDiff(
      creates: _readList(
        value[RuntimeProtocolField.creates],
        (item) => RuntimeNode.fromMap(Map<String, Object?>.from(item as Map)),
      ),
      updates: _readList(
        value[RuntimeProtocolField.updates],
        (item) => NodeUpdate.fromMap(Map<String, Object?>.from(item as Map)),
      ),
      removes: _readList(
        value[RuntimeProtocolField.removes],
        NodeRemove.fromValue,
      ),
    );
  }

  static List<T> _readList<T>(Object? value, T Function(Object? value) mapper) {
    if (value == null) {
      return const [];
    }
    if (value is List) {
      return value.map(mapper).toList(growable: false);
    }
    if (value is Map && value.isEmpty) {
      return const [];
    }
    if (value is Map && value.keys.every(_isPositiveIntegerKey)) {
      final entries = value.entries.toList()
        ..sort(
          (a, b) => int.parse(
            a.key.toString(),
          ).compareTo(int.parse(b.key.toString())),
        );
      return entries
          .map((entry) => mapper(entry.value))
          .toList(growable: false);
    }
    throw const FormatException('Diff field must be a list');
  }

  static bool _isPositiveIntegerKey(Object? key) {
    final value = int.tryParse(key.toString());
    return value != null && value > 0;
  }
}

class GameDiff {
  const GameDiff({
    required this.render,
    required this.ui,
    required this.commands,
  });

  final NodeDiff render;
  final NodeDiff ui;
  final List<RuntimeCommand> commands;

  static const empty = GameDiff(
    render: NodeDiff(),
    ui: NodeDiff(),
    commands: [],
  );

  static GameDiff fromMap(Map<String, Object?> map) {
    RuntimeProtocolSchema.ensureKnownKeys(
      map,
      allowed: RuntimeProtocolSchema.gameDiffFields,
      context: 'GameDiff',
    );
    final commandsValue = map[RuntimeProtocolField.commands];
    final commands = commandsValue == null
        ? const <RuntimeCommand>[]
        : NodeDiff._readList(
            commandsValue,
            (item) =>
                RuntimeCommand.fromMap(Map<String, Object?>.from(item as Map)),
          );

    return GameDiff(
      render: NodeDiff.fromMap(map[RuntimeProtocolField.render]),
      ui: NodeDiff.fromMap(map[RuntimeProtocolField.ui]),
      commands: commands,
    );
  }
}