import lark

class Selector():
    def parse(self, ifc_file, query):
        self.file = ifc_file
        l = lark.Lark('''start: query (lfunction query)*
                    query: selector | group
                    group: "(" query (lfunction query)* ")"
                    selector: (inverse_relationship)? guid_selector | (inverse_relationship)? class_selector
                    guid_selector: "#" /[0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_$]{22}/
                    class_selector: "." WORD filter ?
                    filter: "[" filter_key (comparison filter_value)? "]"
                    filter_key: WORD | pset_or_qto
                    filter_value: ESCAPED_STRING
                    pset_or_qto: /[A-Za-z0-9_]+/ "." /[A-Za-z0-9_]+/
                    lfunction: and | or
                    inverse_relationship: types | contains_elements
                    types: "*"
                    contains_elements: "@"
                    and: "&"
                    or: "|"
                    comparison: contains | morethanequalto | lessthanequalto | equal | morethan | lessthan
                    contains: "*="
                    morethanequalto: ">="
                    lessthanequalto: "<"
                    equal: "="
                    morethan: ">"
                    lessthan: "<"

                    // Embed common.lark for packaging
                    DIGIT: "0".."9"
                    HEXDIGIT: "a".."f"|"A".."F"|DIGIT
                    INT: DIGIT+
                    SIGNED_INT: ["+"|"-"] INT
                    DECIMAL: INT "." INT? | "." INT
                    _EXP: ("e"|"E") SIGNED_INT
                    FLOAT: INT _EXP | DECIMAL _EXP?
                    SIGNED_FLOAT: ["+"|"-"] FLOAT
                    NUMBER: FLOAT | INT
                    SIGNED_NUMBER: ["+"|"-"] NUMBER
                    _STRING_INNER: /.*?/
                    _STRING_ESC_INNER: _STRING_INNER /(?<!\\\\)(\\\\\\\\)*?/
                    ESCAPED_STRING : "\\"" _STRING_ESC_INNER "\\""
                    LCASE_LETTER: "a".."z"
                    UCASE_LETTER: "A".."Z"
                    LETTER: UCASE_LETTER | LCASE_LETTER
                    WORD: LETTER+
                    CNAME: ("_"|LETTER) ("_"|LETTER|DIGIT)*
                    WS_INLINE: (" "|/\\t/)+
                    WS: /[ \\t\\f\\r\\n]/+
                    CR : /\\r/
                    LF : /\\n/
                    NEWLINE: (CR? LF)+

                    %ignore WS // Disregard spaces in text
                 ''')

        start = l.parse(query)
        return self.get_group(start)

    def get_group(self, group):
        lfunction = None
        for child in group.children:
            if child.data == 'query':
                new_results = self.get_query(child)
                if not lfunction:
                    results = new_results
                elif lfunction == 'or':
                    results.extend(new_results)
                elif lfunction == 'and':
                    results = list(set(results).intersection(new_results))
                results = list(set(results))
            elif child.data == 'lfunction':
                lfunction = child.children[0].data
        return results

    def get_query(self, query):
        for child in query.children:
            if child.data == 'selector':
                return self.get_selector(child)
            elif child.data == 'group':
                return self.get_group(child)

    def get_selector(self, selector):
        if len(selector.children) == 1:
            inverse_relationship = None
            class_or_guid_selector = selector.children[0]
        else:
            inverse_relationship = selector.children[0]
            class_or_guid_selector = selector.children[1]

        if class_or_guid_selector.data == 'class_selector':
            results = self.get_class_selector(class_or_guid_selector)
        elif class_or_guid_selector.data == 'guid_selector':
            results = self.get_guid_selector(class_or_guid_selector)

        if not inverse_relationship:
            return results
        return self.parse_inverse_relationship(results, inverse_relationship.children[0].data)

    def parse_inverse_relationship(self, elements, inverse_relationship):
        results = []
        for element in elements:
            if inverse_relationship == 'types':
                if hasattr(element, 'Types') and element.Types:
                    results.extend(element.Types[0].RelatedObjects)
                elif hasattr(element, 'ObjectTypeOf') and element.ObjectTypeOf:
                    results.extend(element.ObjectTypeOf[0].RelatedObjects)
            elif inverse_relationship == 'contains_elements' \
                    and hasattr(element, 'ContainsElements'):
                for relationship in element.ContainsElements:
                    results.extend(relationship.RelatedElements)
        return results

    def get_class_selector(self, class_selector):
        elements = self.file.by_type(class_selector.children[0])
        if len(class_selector.children) > 1 \
                and class_selector.children[1].data == 'filter':
            return self.filter_elements(elements, class_selector.children[1])
        return elements

    def filter_elements(self, elements, filter_rule):
        results = []
        key = filter_rule.children[0].children[0]
        if not isinstance(key, str):
            key = key.children[0] + '.' + key.children[1]
        comparison = value = None
        if len(filter_rule.children) > 1:
            comparison = filter_rule.children[1].children[0].data
            value = filter_rule.children[2].children[0][1:-1]
        for element in elements:
            element_value = IfcAttributeExtractor.get_element_key(element, key)
            if not element_value:
                continue
            if not comparison \
                    or self.filter_element(element, element_value, comparison, value):
                results.append(element)
        return results

    def filter_element(self, element, element_value, comparison, value):
        if comparison == 'equal':
            return str(element_value) == value
        elif comparison == 'contains':
            return value in str(element_value)
        elif comparison == 'morethan':
            return element_value > float(value)
        elif comparison == 'lessthan':
            return element_value < float(value)
        elif comparison == 'morethanequalto':
            return element_value >= float(value)
        elif comparison == 'lessthanequalto':
            return element_value <= float(value)
        return False

    def get_guid_selector(self, guid_selector):
        return [self.file.by_id(guid_selector.children[0])]