router_gen/lib/generator/model_import_generator.dart

import 'package:analyzer/dart/element/element.dart';
import 'package:router_gen/model/router.dart';
import 'package:router_gen/util/utils.dart';
import 'package:source_gen/source_gen.dart';

/// find class path from argument
class ModelImportGenerator extends Generator {
  static List<String> modelImports = [];

  const ModelImportGenerator();

  @override
  Future<String> generate(LibraryReader library, _) async {
    if (library.classes.isNotEmpty) {
      Map routerMap = router.routerMap;
      for (String key in routerMap.keys) {
        Page page = routerMap[key];
        for (Argument argument in page.arguments) {
          if (argument.isImported) continue;
          if (_isSpeciousType(argument.type)) {
            // 处理type
            List<String> type = getType(argument.type);
            type.removeWhere((element) => _isSpeciousType(element) == false);
            if (type.length == 0) {
              continue;
            }
            // 比较class name
            bool isInThisClass = false;
            for (ClassElement element in library.classes) {
              if (type.contains(element.displayName)) {
                isInThisClass = true;
                break;
              }
            }
            // 添加import
            if (isInThisClass) {
              argument.isImported = true;
              router.imports.add(getImportStr(_));
            }
          } else {
            argument.isImported = true;
          }
        }
      }
    }

    return null;
  }

  bool _isSpeciousType(String type) {
    if (type == "int" ||
        type == "double" ||
        type == "num" ||
        type == "Runes" ||
        type == "String" ||
        type == "bool" ||
        type == "dynamic") {
      return false;
    }
    return true;
  }

  /// Notice: not contain all situation
  /// 递归获取type
  List<String> getType(String type) {
    if (type.startsWith("List<") == false && type.startsWith("Map<") == false) {
      return [type];
    }

    List<String> results = [];
    if(type.startsWith("List<")) {
      String result = type.substring(type.indexOf("List<") + 5, type.lastIndexOf(">"));
      results.addAll(getType(result.trim()));
    }

    if (type.startsWith("Map<")) {
      List<String> splits = type.substring(type.indexOf("Map<") + 4, type.lastIndexOf(">")).split(",");
      results.addAll(getType(splits[0].trim()));
      results.addAll(getType(splits[1].trim()));
    }

    return results;
  }
}