package funkin.util;

import Type.ValueType;
import polymod.hscript._internal.PolymodScriptClass;

/**
 * Provides sanitized and blacklisted access to haxe's Reflection functions.
 * Used for sandboxing in scripts.
 */
@:nullSafety @SuppressWarnings(['checkstyle:VarTypeHint', 'checkstyle:FieldDocComment'])
class ReflectUtil
{
  /**
   * Calls a method value of a specific field on an object.
   * Accounts for property blacklist for security.
   * @param obj The object to modify.
   * @param name The field to modify.
   * @param value The new value to apply.
   * @throws error When trying to call a blacklisted method.
   */
  public static function callMethod(obj:Any, name:String, args:Array<Any>):Any
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to call blacklisted method "${name}"';
    }
    return Reflect.callMethod(getReflectionParent(obj), Reflect.field(getReflectionParent(obj), name), args);
  }

  /**
   * Compares two objects by value.
   *
   * @param valueA First value to compare
   * @param valueB Second value to compare
   * @return Int indicating relative order of values
   */
  public static function compare(valueA:Any, valueB:Any):Int
  {
    return compareValues(valueA, valueB);
  }

  /**
   * Compares two values and returns an integer indicating their relative order.
   * Returns:
   * - -1 if valueA < valueB
   * - 0 if valueA == valueB
   * - 1 if valueA > valueB
   *
   * @param valueA First value to compare
   * @param valueB Second value to compare
   * @return An integer indicating relative order of values
   */
  public static function compareValues(valueA:Any, valueB:Any):Int
  {
    return Reflect.compare(valueA, valueB);
  }

  /**
   * Compare the two Function objects to determine whether they are the same.
   * @param functionA A method closure to compare.
   * @param functionB A method closure to compare.
   * @return Whether functionA and functionB are equal.
   */
  public static function compareMethods(functionA:Any, functionB:Any):Bool
  {
    return Reflect.compareMethods(functionA, functionB);
  }

  /**
   * Copies the given object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to copy.
   * @return An independent clone of that object.
   */
  public static function copy(obj:Any):Null<Any>
  {
    return copyAnonymousFieldsOf(obj);
  }

  /**
   * Copies the anonymous structure to a new object.
   * @param obj The object to copy.
   * @return An independent clone of the structure.
   */
  public static function copyAnonymousFieldsOf(obj:Any):Null<Any>
  {
    return Reflect.copy(obj);
  }

  /**
   * Delete the field of a given name from an object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to delete the field from.
   * @param name The name of the field to delete.
   * @return Whether the operation was successful.
   */
  public static function delete(obj:Any, name:String):Bool
  {
    return deleteAnonymousField(obj, name);
  }

  /**
   * Delete the field of a given name from an anonymous structure.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to delete the field from.
   * @param name The name of the field to delete.
   * @return Whether the operation was successful.
   */
  public static function deleteAnonymousField(obj:Any, name:String):Bool
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to delete blacklisted field "${name}"';
    };
    return Reflect.deleteField(obj, name);
  }

  /**
   * Retrive the value of a given field (by name) from an object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to delete the field from.
   * @param name The name of the field to delete.
   * @return Whether the operation was successful.
   */
  public static function field(obj:Any, name:String):Any
  {
    return getAnonymousField(obj, name);
  }

  /**
   * Retrive the value of a given field (by name) from an object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to delete the field from.
   * @param name The name of the field to delete.
   * @return Whether the operation was successful.
   */
  public static function getField(obj:Any, name:String):Any
  {
    return getAnonymousField(obj, name);
  }

  /**
   * Retrieve the value of the field of the given name from an anonymous structure.
   * @param obj The object to query.
   * @param name The name of the field to retrieve.
   * @return The resulting field value.
   * @throws error If the field is blacklisted.
   */
  public static function getAnonymousField(obj:Any, name:String):Any
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to retrieve blacklisted field "${name}"';
    };

    return Reflect.field(getReflectionParent(obj), name);
  }

  /**
   * Get a list of fields available on the given object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to query.
   * @return A list of fields on that object.
   */
  public static function fields(obj:Any):Array<String>
  {
    return getAnonymousFieldsOf(obj);
  }

  /**
   * Get a list of fields available on the given object.
   * Only guaranteed to work on anonymous structures.
   * @param obj The object to query.
   * @return A list of fields on that object.
   */
  public static function getFieldsOf(obj:Any):Array<String>
  {
    return getAnonymousFieldsOf(obj);
  }

  /**
   * Get a list of fields available on the given anonymous structure.
   * @param obj The object to query.
   * @return A list of fields on that object.
   */
  public static function getAnonymousFieldsOf(obj:Any):Array<String>
  {
    return Reflect.fields(obj);
  }

  /**
   * Get the value of the given property on a given object.
   * Unlike `getField()`, this will check if the field is a property with a getter function,
   * and use that if appropriate.
   * @param obj The object to query.
   * @param name The name of the field to query.
   * @return The value of the field.
   * @throws error If the field is blacklisted.
   */
  public static function getProperty(obj:Any, name:String):Any
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to retrieve blacklisted field "${name}"';
    };

    return Reflect.getProperty(getReflectionParent(obj), name);
  }

  /**
   * Determine whether the given object has the given field.
   * Only guaranteed to work for anonymous structures.
   * @param obj The object to query.
   * @param name The field name to query.
   * @return Whether the field exists.
   */
  public static function hasField(obj:Any, name:String):Bool
  {
    return hasAnonymousField(obj, name);
  }

  /**
   * Determine whether the given anonymous structure has the given field.
   * @param obj The structure to query.
   * @param name The field name to query.
   * @return Whether the field exists and isnt blacklisted.
   */
  public static function hasAnonymousField(obj:Any, name:String):Bool
  {
    if (!isAccessAllowed(obj, name))
    {
      return false;
    }

    return Reflect.hasField(getReflectionParent(obj), name);
  }

  /**
   * Determine whether the given input is an enum value.
   * @param value The input to evaluate.
   * @return Whether `value` is an enum value.
   */
  public static function isEnumValue(value:Any):Bool
  {
    return Reflect.isEnumValue(value);
  }

  /**
   * Determine whether the given input is a callable function.
   * @param value The input to evaluate.
   * @return Whether `value` is a function.
   */
  public static function isFunction(value:Any):Bool
  {
    return Reflect.isFunction(value);
  }

  /**
   * Determine whether the given input is an object.
   * @param value The input to evaluate.
   * @return Whether `value` is an object.
   */
  public static function isObject(value:Any):Bool
  {
    return Reflect.isObject(value);
  }

  /**
   * Set the value of a specific field on an object.
   * Only guaranteed to work for anonymous structures.
   * @param obj The object to modify.
   * @param name The field to modify.
   * @param value The new value to apply.
   */
  public static function setField(obj:Any, name:String, value:Any):Void
  {
    return setAnonymousField(obj, name, value);
  }

  /**
   * Set the value of a specific field on an anonymous structure.
   * @param obj The object to modify.
   * @param name The field to modify.
   * @param value The new value to apply.
   * @throws error When trying to set a blacklisted field.
   */
  public static function setAnonymousField(obj:Any, name:String, value:Any):Void
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to set blacklisted field "${name}"';
    };
    return Reflect.setField(getReflectionParent(obj), name, value);
  }

  /**
   * Set the value of a specific field on an object.
   * Accounts for property fields with getters and setters.
   *
   * @param obj The object to modify.
   * @param name The field to modify.
   * @param value The new value to apply.
   * @throws error When trying to set a blacklisted field.
   */
  public static function setProperty(obj:Any, name:String, value:Any):Void
  {
    if (!isAccessAllowed(obj, name))
    {
      throw 'Attempted to set blacklisted field "${name}"';
    };
    return Reflect.setProperty(getReflectionParent(obj), name, value);
  }

  /**
   * Creats a empty instance of specified class
   * Accounts for property blacklist for security.
   * @param cls The class to create.
   * @throws error When trying to create a blacklisted class.
   */
  public static function createEmptyInstance(cls:Class<Any>):Any
  {
    if (!isAccessAllowed(cls))
    {
      throw 'Attempted to call createInstance onto a blacklisted class "${getClassNameOf(cls)}"';
    }
    return Type.createEmptyInstance(getReflectionParent(cls));
  }

  /**
   * Creats a instance of specified class
   * Accounts for property blacklist for security.
   * @param cls The class to create.
   * @param args Parameters to give to the constructor
   * @throws error When trying to create a blacklisted class.
   */
  public static function createInstance(cls:Class<Any>, args:Array<Any>):Any
  {
    if (!isAccessAllowed(cls))
    {
      throw 'Attempted to call createInstance onto a blacklisted class "${getClassNameOf(cls)}"';
    }
    return Type.createInstance(getReflectionParent(cls), args);
  }

  /**
   * This function is not allowed to be used by scripts.
   * @throws error When called by a script.
   */
  public static function resolveClass(name:String):Null<Class<Any>>
  {
    var resolved = getReflectionParent(getClassOrEnumFromName(name));
    if (resolved == null) return null;
    if (!Std.isOfType(resolved, Class)) return null;
    if (!isAccessAllowed(resolved))
    {
      throw 'Attempted to resolve a blacklisted class "${getClassNameOf(getClassOrEnumFromName(name))}"';
    }
    return resolved;
  }

  /**
   * This function is not allowed to be used by scripts.
   * @throws error When called by a script.
   */
  @SuppressWarnings('checkstyle:FieldDocComment')
  public static function resolveEnum(name:String):Null<Enum<Any>>
  {
    var resolved = getReflectionParent(getClassOrEnumFromName(name));
    if (resolved == null) return null;
    if (!Std.isOfType(resolved, Enum)) return null;
    if (!isAccessAllowed(resolved))
    {
      throw 'Attempted to resolve a blacklisted enum "${getClassNameOf(getClassOrEnumFromName(name))}"';
    }
    return resolved;
  }

  /**
   * This function is not allowed to be used by scripts.
   * @throws error When called by a script.
   */
  public static function typeof(value:Any):ValueType
  {
    throw 'Function Type.typeof is blacklisted.';
  }

  /**
   * Get a list of the static class fields on the given class.
   * @param cls The class object to query.
   * @return A list of class field names.
   */
  public static function getClassFields(cls:Class<Any>):Array<String>
  {
    return Type.getClassFields(cls);
  }

  /**
   * Get a list of the static class fields on the class of the given object.
   * @param obj The object whose class should be queried.
   * @return A list of class field names.
   */
  public static function getClassFieldsOf(obj:Any):Array<String>
  {
    if (obj == null) return [];
    @:nullSafety(Off)
    var cls = Type.getClass(obj);
    if (cls == null) return [];
    return Type.getClassFields(cls);
  }

  /**
   * Get a list of all the fields on instances of the given class.
   * @param cls The class object to query.
   * @return A list of object field names.
   */
  public static function getInstanceFields(cls:Class<Any>):Array<String>
  {
    if (cls == null) return [];
    return Type.getInstanceFields(cls);
  }

  /**
   * Get a list of all the fields on instances of the class of the given object.
   * @param obj The object whose class should be query.
   * @return A list of object field names.
   */
  public static function getInstanceFieldsOf(obj:Any):Array<String>
  {
    if (obj == null) return [];
    @:nullSafety(Off)
    var cls = Type.getClass(obj);
    if (cls == null) return [];
    return Type.getInstanceFields(cls);
  }

  /**
   * Get the string name of the given class.
   * @param cls The class to query.
   * @return The name of the given class.
   */
  public static function getClassName(cls:Class<Any>):String
  {
    return Type.getClassName(cls);
  }

  /**
   * Get the string name of the class of the given object.
   * @param obj The object to query.
   * @return The name of the given class, or `Unknown` if the class couldn't be determined.
   */
  public static function getClassNameOf(obj:Any):String
  {
    if (obj == null) return 'Unknown';
    if (obj is String && Type.resolveClass(obj) != null) return obj;
    @:nullSafety(Off)
    var cls = Type.getClass(obj);
    if (cls == null) return 'Unknown';
    return Type.getClassName(cls);
  }

  /**
   * Transform a function taking an array of arguments into a function that can
   * be called with any number of arguments.
   *
   * @param f A function which takes an array of arguments.
   * @return A new function that takes any number of arguments and passes them as an array to `f`.
   */
  public static function makeVarArgs(f:Array<Dynamic>->Dynamic):Dynamic
  {
    return Reflect.makeVarArgs(f);
  }

  @:unreflective
  static var pathResolveCache:Map<String, Any> = new Map();
  @:unreflective
  static var blacklistedFieldsCache:Map<String, Any> = new Map();

  @:unreflective @:nullSafety(Off)
  static function getClassOrEnumFromName(path:String):Any
  {
    if (pathResolveCache.exists(path)) return pathResolveCache.get(path);
    var resultCls:Class<Dynamic> = Type.resolveClass(path);
    if (resultCls != null)
    {
      pathResolveCache.set(path, resultCls);
      return resultCls;
    }
    else
    {
      var resultEnm:Enum<Dynamic> = Type.resolveEnum(path);
      if (resultEnm != null) pathResolveCache.set(path, resultEnm);
      return resultEnm;
    }
  }

  @:unreflective @:nullSafety(Off)
  static function getReflectionParent(obj:Dynamic):Dynamic
  {
    var clsName = getClassNameOf(obj);
    if (clsName == 'Unknown') clsName = null;
    var objName = obj is String ? obj : (clsName ?? obj);
    return PolymodScriptClass.importOverrides.exists(objName) ? PolymodScriptClass.importOverrides.get(objName) : obj;
  }

  @:unreflective @:nullSafety(Off)
  static function isAccessAllowed(obj:Dynamic, ?varName:String):Bool
  {
    var reflectedObj = getReflectionParent(obj);
    var isClassReflect = Std.isOfType(reflectedObj, Class);

    var key:String;
    if (isClassReflect)
    {
      key = Type.getClassName(cast reflectedObj);
    }
    else
    {
      key = getClassNameOf(reflectedObj);
    }

    if (varName != null)
    {
      var cacheKey = '${isClassReflect ? "C_" : "I_"}$key';
      var blacklistedFields:Array<String> = blacklistedFieldsCache.get(cacheKey);
      if (blacklistedFields == null)
      {
        if (isClassReflect)
        {
          blacklistedFields = PolymodScriptClass.blacklistedStaticFields.get(cast reflectedObj);
        }
        else
        {
          blacklistedFields = PolymodScriptClass.blacklistedInstanceFields.get(key);
        }

        if (blacklistedFields == null) blacklistedFields = [];
        blacklistedFieldsCache.set(cacheKey, blacklistedFields);
      }

      if (blacklistedFields.contains(varName)) return false;
    }

    if (PolymodScriptClass.importOverrides.exists(key) && PolymodScriptClass.importOverrides.get(key) == null) return false;

    return true;
  }
}