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#######################################################
# 
# AdbParser.py
# Python implementation of the Class AdbParser
# Created on:      23-Mar-2020 8:00:00 AM
# Original author: talve
# 
#######################################################
import xml.etree.ElementTree as ET


class AdbParser:
    """This class is responsible for loading and parsing the adb file.
    """
    def __init__(self, adb_path):
        try:
            # build a dictionary with all the adb nodes.
            self.adb_dict = ET.parse(adb_path)
            self._build_xml_elements_dict()
            self._build_definitions()
            # build a dictionary with only the adb nodes that contain segment id field.
            self.segment_id_nodes_dict = {}
            self._build_nodes_with_seg_id()
            # fix the offset since subnode should contain the offset with the addition of his parent.
            self._fix_nodes_offset(self.segment_id_nodes_dict)
        except Exception as _:
            raise Exception("Fail to parse the ADB file")

    def _build_xml_elements_dict(self):
        self._node_xml_elements = {}
        for xml_element in self.adb_dict.iter('node'):
            self._node_xml_elements[xml_element.attrib["name"]] = xml_element

    def _build_definitions(self):
        # Create a list for 'inst_ifdef' (C like 'define' feature)
        self.ifdef_list = []
        for xml_element in self.adb_dict.iter('config'):
            if 'define' in xml_element.attrib and "=" not in xml_element.attrib["define"]:
                self.ifdef_list.append(xml_element.attrib["define"])

        # Create a dict for 'inst_if' (C like 'define' feature)
        self.if_dict = {}
        for xml_element in self.adb_dict.iter('config'):
            if 'define' in xml_element.attrib and "=" in xml_element.attrib["define"]:
                define_name, define_value = xml_element.attrib["define"].split("=")
                self.if_dict[define_name] = define_value

    def _check_condition(self, left_operand, right_operand, condition):
        """
        This method do the right logic according the given condition
        """
        if condition == ' EQ ':
            return left_operand == right_operand
        elif condition == ' LESS ':
            return left_operand < right_operand
        elif condition == ' LESS_EQ ':
            return left_operand <= right_operand
        elif condition == ' GREAT_EQ ':
            return left_operand >= right_operand
        elif condition == ' GREAT ':
            return left_operand > right_operand

        raise Exception("unsupported condition {0}".format(condition))

    def _get_condition_str(self, expression):
        """
        This method return the right condition exist in the expression
        """
        if ' EQ ' in expression:
            return ' EQ '
        elif ' LESS ' in expression:
            return ' LESS '
        elif ' LESS_EQ ' in expression:
            return ' LESS_EQ '
        elif ' GREAT_EQ ' in expression:
            return ' GREAT_EQ '
        elif ' GREAT ' in expression:
            return ' GREAT '

        raise Exception("No condition found in expression {0}".format(expression))

    def _check_single_expression(self, expression):
        """
        The method check the condition type and perform the
        logic accordingly.
        """
        condition = self._get_condition_str(expression)
        define_name, define_value = expression.split(condition)
        define_name = define_name.strip()
        define_value = define_value.strip()

        # if operand not exist in the if dictionary its a value that we need to convert from str to int
        left_operand = int(self.if_dict[define_name]) if define_name in self.if_dict else int(define_name)
        right_operand = int(self.if_dict[define_value]) if define_value in self.if_dict else int(define_value)
        return self._check_condition(left_operand, right_operand, condition)

    def _check_expressions(self, inst_if_attrib):
        """
        The method checks an expression and return True/False.
        Note that the method support only OR(s) or AND(s) but not together.
        """
        # assumption using 'OR' or 'AND' but not together
        expressions = []
        if ' OR ' in inst_if_attrib:
            expressions = inst_if_attrib.split(' OR ')
            # check if one of the expressions is True return True
            return any([self._check_single_expression(expression) for expression in expressions])
        elif ' AND ' in inst_if_attrib:
            expressions = inst_if_attrib.split(' AND ')
            # check if all of the expressions is True return True
            return all([self._check_single_expression(expression) for expression in expressions])

        # if only one expression
        return self._check_single_expression(inst_if_attrib)

    def _fix_nodes_offset(self, nodes_dict):
        """This method go over all the nodes in the dictionary and
        send them to offset fixing.
        """
        for node in nodes_dict.values():
            self._fix_node(node, node.offset)

    def _fix_node(self, node, offset):
        """This method go over all the subnodes and perform offset addition
        to all nodes recursively.
        """
        for sub_node in node.subItems:
            sub_node.offset += offset
            self._fix_node(sub_node, sub_node.offset)

    def _build_nodes_with_seg_id(self):
        """This method go over all the nodes in the adb dictionary and build a dictionary with the nodes
        that contain the "segment_id' field.
        """
        for node in self.adb_dict.iter('node'):
            if "segment_id" in node.attrib:
                adb_layout_item = self._node_to_AdbLayoutItem(node)
                self.segment_id_nodes_dict[node.attrib["segment_id"]] = adb_layout_item

    def _retrieve_node_by_name(self, node_name):
        """This method return the node with the
        wanted name, if not found return None.
        """
        if node_name in self._node_xml_elements:
            return self._node_xml_elements[node_name]
        else:  # Missing-nodes feature
            return None

    def _build_subitems(self, node):
        """This method build the subitems of the specific node
        """
        sub_items = []
        counter = 0
        for item in node:
            # Skip on elements that are excluded in the configuration ('inst_ifdef')
            if 'inst_ifdef' in item.attrib:
                if item.attrib['inst_ifdef'] not in self.ifdef_list:
                    continue
            # Skip on elements that are excluded in the configuration ('inst_if')
            if 'inst_if' in item.attrib:
                if not self._check_expressions(item.attrib['inst_if']):
                    continue
            if "low_bound" in item.attrib and "high_bound" in item.attrib:
                self._extract_array_to_list(counter, item, sub_items)
            else:
                adb_layout_item = self._node_to_AdbLayoutItem(item)
                if adb_layout_item:
                    sub_items.insert(counter, adb_layout_item)
                    counter += 1
        return sub_items

    def _extract_array_to_list(self, index, item, subitems_list):
        """This method build insert array items to a list form a specific index.
        """
        name = item.attrib["name"]
        start_index = int(item.attrib["low_bound"], 10)
        if item.attrib["high_bound"] == "VARIABLE":
            end_index = 1
        else:
            end_index = int(item.attrib["high_bound"], 10) + 1

        offset = self._parse_node_size(item.attrib["offset"])
        size = self._parse_node_size(item.attrib["size"])

        calculated_size = int(size / (end_index - start_index))
        current_offset = offset


        for i in range(start_index, end_index):
            adb_layout_item = AdbLayoutItem()
            adb_layout_item.nodeDesc = self._node_to_node_desc(item)
            adb_layout_item.name = name + "[" + str(i) + "]"
            adb_layout_item.size = calculated_size
            adb_layout_item.offset = current_offset
            if "subnode" in item.attrib:
                sub_node = self._retrieve_node_by_name(item.attrib["subnode"])
                if sub_node:
                    if "attr_is_union" in sub_node.attrib:
                        adb_layout_item.nodeDesc.isUnion = self._parse_union(sub_node.attrib["attr_is_union"])
                    adb_layout_item.subItems = self._build_subitems(sub_node)  # List of the child items (for nodes only)
            subitems_list.insert(index, adb_layout_item)
            current_offset += calculated_size
            index += 1

    def _node_to_AdbLayoutItem(self, node):
        """This method build adb layout field from a given node.
        """
        adb_layout_item = AdbLayoutItem()
        #adb_layout_item.fieldDesc = None  # Reference to "AdbFieldDesc" object, always != None
        #adb_layout_item.parent = None  # Reference to parent "AdbLayoutItem" object, always != None (expect of the root)
        adb_layout_item.name = node.attrib["name"]
        adb_layout_item.nodeDesc = self._node_to_node_desc(node)  # For leafs must be None
        if "subnode" in node.attrib:
            sub_node = self._retrieve_node_by_name(node.attrib["subnode"])
            if "attr_is_union" in sub_node.attrib:
                adb_layout_item.nodeDesc.isUnion = self._parse_union(sub_node.attrib["attr_is_union"])
            adb_layout_item.subItems = self._build_subitems(sub_node)  # List of the child items (for nodes only)
        else:
            adb_layout_item.subItems = self._build_subitems(node)

        if "offset" in node.attrib:
            adb_layout_item.offset = self._parse_node_size(node.attrib["offset"])

        adb_layout_item.size = self._parse_node_size(node.attrib["size"])
        adb_layout_item.attrs = {}  # Attributes after evaluations and array expanding
        adb_layout_item.arrayIdx = -1  # in case of being part of an array this will hold the array index, -1 means not part of array
        #adb_layout_item.vars = {}  # all variable relevant to this item after evaluation
        return adb_layout_item

    def _node_to_node_desc(self, node):
        """This method build adb desc field from a given node.
        """
        node_description = AdbNodeDesc()
        #node_description.name = ""
        #node_description.size = 0  # Size in bits
        if "attr_is_union" in node.attrib:
            node_description.isUnion = self._parse_union(node.attrib["attr_is_union"])
        #node_description.desc = ""
        #node_description.fields = []  # List of "AdbFieldDesc" objects
        #node_description.attrs = {}  # Dictionary of attributes: key, value
        # defined in
        #node_description.fileName = ""
        #node_description.lineNumber = -1
        return node_description

    def _parse_union(self, union_str):
        """This method parse the 'is union' attribute.
        """
        if union_str == "1":
            return True
        return False

    def _parse_node_size(self, size_str):
        """This method return the size of the 'size' attribute in bits.
        """
        hex_size = 0
        bit_size = 0

        if "." in size_str:
            # hex size is in bytes, multiply by 8 to convert to bits
            hex_size = size_str[:size_str.index(".")]
            bit_size = size_str[size_str.index(".")+1:]

            hex_size = 0 if len(hex_size) == 0 else int(hex_size, 16) * 8
            bit_size = 0 if len(size_str[size_str.index("."):]) == 0 else int(bit_size, 10)
        else:
            bit_size = int(size_str, 10)

        return hex_size+bit_size

####################################################################


class AdbLayoutItem(object):
    """ Represents a Layout node/leaf instance """

    ##########################
    def __init__(self):
        self.fieldDesc   = None        # Reference to "AdbFieldDesc" object, always != None
        self.nodeDesc    = None        # For leafs must be None
        self.parent      = None        # Reference to parent "AdbLayoutItem" object, always != None (expect of the root)
        self.name        = ""          # The instance name
        self.subItems    = []          # List of the child items (for nodes only)
        self.offset      = 0           # Global offset (relative to the 0 address)
        self.size        = 0           # Element size in bits
        self.attrs       = {}          # Attributes after evaluations and array expanding
        self.arrayIdx    = -1          # in case of being part of an array this will hold the array index, -1 means not part of array
        self.vars        = {}          # all variable relevant to this item after evaluation


####################################################################
class AdbFieldDesc(object):
    """ Represents an ADABE field descriptor, objects of this type are immutable """

    ##########################
    def __init__(self):
        self.name       = ""
        self.size       = 0                    # Size in bits (the whole array size)
        self.offset     = None                 # Offset in bits (relative to the node start addr)
        self.desc       = ""
        self.lowBound   = 0
        self.highBound  = 0
        self.unlimitedArr = False
        self.definedAsArr = False
        self.subNode    = None                # Subnode name as string
        self.attrs      = {}                  # Dictionary of attributes: key, value
        self.reserved   = False
        self.condition  = ""


####################################################################
class AdbNodeDesc(object):
    """ Represents an ADABE node descriptor, objects of this type are immutable """

    ##########################
    def __init__(self):
        self.name       = ""
        self.size       = 0                 # Size in bits
        self.isUnion    = False
        self.desc       = ""
        self.fields     = []                # List of "AdbFieldDesc" objects
        self.attrs      = {}                # Dictionary of attributes: key, value

        # defined in
        self.fileName = ""
        self.lineNumber = -1