include "primitives.alh"
include "library.alh"
include "object_operations.alh"
include "constructors.alh"
include "modelling.alh"

Boolean function is_direct_instance(model : Element, instance : Element, type : Element):
	// Just check whether or not the type mapping specifies the type as the type of the instance
	return element_eq(dict_read_node(model["type_mapping"], instance), type)

Boolean function is_nominal_instance(model : Element, instance : Element, type : Element):
	return is_nominal_subtype(model["metamodel"], dict_read_node(model["type_mapping"], instance), type)

Boolean function is_nominal_subtype(metamodel : Element, subclass : Element, superclass : Element):
	if (element_eq(subclass, superclass)):
		return True

	Element superclasses
	Element new_superclass
	Element result

	superclasses = get_superclasses(metamodel, subclass)

	while (0 < list_len(superclasses)):
		new_superclass = set_pop(superclasses)
		result = is_nominal_subtype(metamodel, new_superclass, superclass)
		if (result):
			return True
	
	return False

Boolean function is_structural_instance(model : Element, instance : Element, type : Element):
	return is_structural_subtype(dict_read_node(model["type_mapping"], instance), type)
	
Boolean function is_structural_subtype(subtype : Element, supertype : Element):
	// Determine whether it is just the exact type or not
	if (element_eq(subtype, supertype)):
		return True

	// Find all links that are required (name and type) from the specified type
	Element required_keys
	required_keys = dict_keys(supertype)
	Integer required_keys_len
	required_keys_len = dict_len(required_keys)

	String key
	Element equivalent
	Integer i
	i = 0

	// Go over all keys that we require
	while (i < required_keys_len):
		key = set_pop(required_keys)
		// Check whether they exist in the instance
		if (dict_in(subtype, key)):
			// Normally, we should still check whether they don't violate the constraints imposed on the class (i.e., are actually present)
			// For now, we ignore this and simply require that it is always there in the metamodel (not necessarily in the instance)
			// TODO

			// Still check whether the types match
			if (bool_not(is_structural_subtype(subtype[key], supertype[key]))):
				return False

			// All clear, so pass on to the next attribute
			i = i + 1
		else:
			return False

	// No violations found, so OK
	return True

String function conformance_scd(model : Element):
	// Initialization
	Element keys
	Element metamodel
	Element typing
	String model_name
	Element src_model
	Element dst_model
	Element src_metamodel
	Element dst_metamodel
	Element element

	// Load in variables
	keys = dict_keys(model["model"])
	metamodel = model["metamodel"]
	typing = model["type_mapping"]

	// Iterate over each element of the model, finding out whether everything is fine
	while (0 < list_len(keys)):
		model_name = set_pop(keys)
		element = model["model"][model_name]

		if (bool_not(dict_in_node(typing, element))):
			return "Model has no type specified: " + model_name

		if (bool_not(set_in_node(metamodel["model"], dict_read_node(typing, element)))):
			return "Type of element not in specified metamodel: " + model_name

		if (bool_not(is_nominal_instance(model, element, dict_read_node(typing, element)))):
			return "Element is not an instance of its specified type: " + model_name

		if (is_edge(element)):
			src_model = read_edge_src(element)
			dst_model = read_edge_dst(element)
			src_metamodel = read_edge_src(dict_read_node(typing, element))
			dst_metamodel = read_edge_dst(dict_read_node(typing, element))

			if (bool_not(is_nominal_instance(model, src_model, src_metamodel))):
				return "Source of model edge not typed by source of type: " + model_name

			if (bool_not(is_nominal_instance(model, dst_model, dst_metamodel))):
				return "Destination of model edge not typed by source of type: " + model_name

	// Structure seems fine, now do static semantics
	if (dict_in(metamodel, "constraints")):
		Element constraint_function
		constraint_function = metamodel["constraints"]
		return constraint_function(model)
	else:
		return "OK"

Element function set_model_constraints(model : Element, func : Element):
	if (dict_in(model, "constraints")):
		dict_delete(model, "constraints")
	dict_add(model, "constraints", func)
	return model

Element function generate_bottom_type_mapping(model : Element):
	Element mm
	mm = model["metamodel"]["model"]
	dict_delete(model, "type_mapping")
	Element tm
	tm = create_node()
	dict_add(model, "type_mapping", tm)
	
	// Iterate over every element
	Element elem_keys
	Element elem
	elem_keys = dict_keys(model["model"])
	while (0 < read_nr_out(elem_keys)):
		elem = model["model"][set_pop(elem_keys)]
		if (is_edge(elem)):
			dict_add(tm, elem, mm["Edge"])
		else:
			dict_add(tm, elem, mm["Node"])

	return model