# Source code for canlib.kvadblib.signal

    """Wrapper for Kvaser Database API (kvaDbLib)."""

    import ctypes as ct

    from collections import namedtuple

    from .attribute import Attribute
    from .bound_signal import BoundSignal
    from .enums import SignalByteOrder, SignalMultiplexMode, AttributeOwner, SignalType
    from .exceptions import KvdNoAttribute, KvdWrongOwner
    from .wrapper import dll

    ValueLimits = namedtuple('ValueLimits', 'min max')
    ValueScaling = namedtuple('ValueScaling', 'factor offset')
    ValueSize = namedtuple('ValueSize', 'startbit length')

    class Signal(object):
        """Database signal, holds meta data about a signal"""
        def __init__(self, db, message, sh,
                     name=None, type=None,
                     byte_order=None,
                     mode=None,
                     representation=None,
                     size=None,
                     scaling=None,
                     limits=None, unit=None, comment=None):
            self._db = db  # used to lookup attribute definitions
            self._handle = sh
            self.message = message  # Parent message
            if byte_order is not None:
                self.byte_order = byte_order
            if mode is not None:
                self.mode = mode
            if scaling is not None:
                self.scaling = scaling
            if comment is not None:
                self.comment = comment
            if limits is not None:
                self.limits = limits
            if name is not None:
                self.name = name
            if representation is not None:
                self.representation = representation
            if size is not None:
                self.size = size
            if type is not None:
                self.type = type
            if unit is not None:
                self.unit = unit

        def __eq__(self, other):
            attrs = 'name type byte_order mode size scaling limits unit comment'.split()
            return all(getattr(self, a) == getattr(other, a) for a in attrs)

        def __ne__(self, other):
            return not self == other

        def __repr__(self):
            return ("Signal(name={!r}, type={!r}, byte_order={!r}, mode={!r}, size={!r}, "
                    "scaling={!r}, limits={!r}, unit={!r}, comment={!r})".
                    format(self.name, self.type, self.byte_order, self.mode,
                           self.size, self.scaling, self.limits, self.unit,
                           self.comment))

        def attributes(self):
            """Return a generator over all signal attributes."""
            ah = None
            nah = ct.c_void_p()
            try:
                dll.kvaDbGetFirstSignalAttribute(self._handle, ct.byref(nah))
            except KvdNoAttribute:
                return
            while nah.value is not None:
                ah, nah = nah, ct.c_void_p()
                yield Attribute(self, ah)
                try:
                    dll.kvaDbGetNextAttribute(ah, ct.byref(nah))
                except KvdNoAttribute:
                    return

        def bind(self, frame=None):
            """Bind this signal to a frame

            Creates a new BoundSignal object representing this signal bound to
            the given Frame object, or a new Frame object if `frame` is `None`..

            """
            return BoundSignal(self, frame or self.message.asframe())

        def add_node(self, node):
            """Add receiving node to signal."""
            dll.kvaDbAddReceiveNodeToSignal(self._handle, node._handle)

        def data_from(self, can_data, phys=None, raw=None):
            """Convert a raw or physical value into CAN data bytes."""
            c_buf = (ct.c_char * len(can_data)).from_buffer_copy(can_data)
            if phys is not None:
                c_phys = ct.c_double(phys)
                dll.kvaDbStoreSignalValuePhys(
                    self._handle, c_buf, ct.sizeof(c_buf), c_phys)
            if raw is not None:
                c_raw = ct.c_uint64(raw)
                dll.kvaDbStoreSignalValueRaw64(
                    self._handle, c_buf, ct.sizeof(c_buf), c_raw)
            return bytearray(c_buf)

        def delete_attribute(self, name):
            """Delete attribute from signal."""
            ah = ct.c_void_p()
            dll.kvaDbGetSignalAttributeByName(
                self._handle, name.encode('utf-8'), ct.byref(ah))
            dll.kvaDbDeleteSignalAttribute(self._handle, ah)

        def get_attribute_value(self, name):
            """Return attribute value

            If the attribute is not set on the signal, we return the attribute
            definition default value.

            """
            ah = ct.c_void_p()

            # Try and find attribute on signal
            try:
                dll.kvaDbGetSignalAttributeByName(
                    self._handle, name.encode('utf-8'), ct.byref(ah))
            except KvdNoAttribute:
                # Lookup the attribute definition
                atr_def = self._db.get_attribute_definition_by_name(name)

                # only attributes with signal as owner are valid, name is also unique
                # accross all attributes so it is enough to check this one for owner
                if atr_def.owner != AttributeOwner.SIGNAL:
                    raise KvdWrongOwner()
                value = atr_def.definition.default
            else:
                attribute = Attribute(self._db, ah)
                value = attribute.value
            return value

        def nodes(self):
            """Return a generator over all receiving nodes of the signal."""
            for node in self._db.nodes():
                if self._db.node_in_signal(node, self):
                    yield node

        def remove_node(self, node):
            """Remove receiving node from signal."""
            dll.kvaDbRemoveReceiveNodeFromSignal(self._handle, node._handle)

        def set_attribute_value(self, name, value):
            """Set value of attribute 'name' on signal.

            If no attribute called 'name' is set on signal, attach a signal
            attribute from the database attribute definition first.

            """
            ah = ct.c_void_p()

            # Try and find attribute on signal
            try:
                dll.kvaDbGetSignalAttributeByName(
                    self._handle, name.encode('utf-8'), ct.byref(ah))
            except KvdNoAttribute:
                # If no attribute was found, lookup the attribute definition and
                # add a new attribute to the message
                attrib_def = self._db.get_attribute_definition_by_name(name)
                dll.kvaDbAddSignalAttribute(
                    self._handle, attrib_def._handle, ct.byref(ah))
            # Set the value in the signal attribute
            attribute = Attribute(self._db, ah)
            attribute.value = value

        @property
        def comment(self):
            """`str`: Get the signal comment."""
            buf = ct.create_string_buffer(255)
            dll.kvaDbGetSignalComment(self._handle, buf, ct.sizeof(buf))
            return buf.value.decode('utf-8')

        @comment.setter
        def comment(self, value):
            """`str`: Set the signal comment."""
            dll.kvaDbSetSignalComment(self._handle, value.encode('utf-8'))

        @property
        def byte_order(self):
            """`SignalByteOrder`: Get the signal byte order encoding."""
            t = ct.c_uint(0)
            dll.kvaDbGetSignalEncoding(self._handle, ct.byref(t))
            try:
                # There is no guarantee the flags from the dbc file will be valid
                # MessageFlags
                return SignalByteOrder(t.value)
            except ValueError:
                return t.value

        @byte_order.setter
        def byte_order(self, value):
            """Set the signal byte order encoding."""
            dll.kvaDbSetSignalEncoding(self._handle, value)

        @property
        def name(self):
            """`str`: Get the signal name."""
            buf = ct.create_string_buffer(255)
            dll.kvaDbGetSignalName(self._handle, buf, ct.sizeof(buf))
            return (buf.value).decode('utf-8')

        @name.setter
        def name(self, value):
            """Set the signal name."""
            dll.kvaDbSetSignalName(self._handle, value.encode('utf-8'))

        @property
        def qualified_name(self):
            """`str`: Get the qualified signal name.

            Returns database, message and signal names separated by dots.
            """
            buf = ct.create_string_buffer(255)
            dll.kvaDbGetSignalQualifiedName(
                self._handle, buf, ct.sizeof(buf))
            return buf.value.decode('utf-8')

        def phys_from(self, can_data):
            """Return signals physical value from data"""
            c_phys = ct.c_double()
            c_buf = (ct.c_char * len(can_data)).from_buffer_copy(can_data)
            dll.kvaDbRetrieveSignalValuePhys(
                self._handle, ct.byref(c_phys), c_buf, ct.sizeof(c_buf))
            return c_phys.value

        def raw_from(self, can_data):
            """Return signals raw value from data"""
            raw = ct.c_uint64()
            c_buf = (ct.c_char * len(can_data)).from_buffer_copy(can_data)
            dll.kvaDbRetrieveSignalValueRaw64(
                self._handle, ct.byref(raw), c_buf, ct.sizeof(c_buf))
            return raw.value

        @property
        def scaling(self):
            """`ValueScaling`: Get the signals factor and offset"""
            c_factor = ct.c_double(0)
            c_offset = ct.c_double(0)
            dll.kvaDbGetSignalValueScaling(
                self._handle, ct.byref(c_factor), ct.byref(c_offset))
            return ValueScaling(factor=c_factor.value, offset=c_offset.value)

        @scaling.setter
        def scaling(self, value):
            """`ValueScaling`: Set the signals factor and offset"""
            dll.kvaDbSetSignalValueScaling(
                self._handle, value.factor, value.offset)

        @property
        def size(self):
            """`ValueSize`: Get the signals startbit and length"""
            c_startbit = ct.c_int(0)
            c_length = ct.c_int(0)
            dll.kvaDbGetSignalValueSize(
                self._handle, ct.byref(c_startbit), ct.byref(c_length))
            return ValueSize(startbit=c_startbit.value, length=c_length.value)

        @size.setter
        def size(self, value):
            """Set the signals startbit and length.

            Args:
                value (:obj:`ValueSize`

            """
            dll.kvaDbSetSignalValueSize(
                self._handle, value.startbit, value.length)

        @property
        def type(self):
            """`SignalType`: Get the signal representation type."""
            t = ct.c_uint(-1)
            dll.kvaDbGetSignalRepresentationType(self._handle, ct.byref(t))
            try:
                # There is no guarantee the flags from the dbc file will be valid
                # MessageFlags
                return SignalType(t.value)
            except ValueError:
                return t.value

        @type.setter
        def type(self, value):
            """Set the signal representation type."""
            dll.kvaDbSetSignalRepresentationType(self._handle, value)

        @property
        def unit(self):
            """`str`: Get the signal unit"""
            buf = ct.create_string_buffer(255)
            dll.kvaDbGetSignalUnit(self._handle, buf, ct.sizeof(buf))
            return buf.value.decode('utf-8')

        @unit.setter
        def unit(self, value):
            """Set the signal unit (str)."""
            dll.kvaDbSetSignalUnit(self._handle, value.encode('utf-8'))

        @property
        def limits(self):
            """`ValueLimits`: Get message min and max values"""
            c_min = ct.c_double(0)
            c_max = ct.c_double(0)
            dll.kvaDbGetSignalValueLimits(
                self._handle, ct.byref(c_min), ct.byref(c_max))
            return ValueLimits(min=c_min.value, max=c_max.value)

        @limits.setter
        def limits(self, value):
            """Get message min and max values.

            Args:
                value (:obj:`ValueLimits`)

            """
            dll.kvaDbSetSignalValueLimits(
                self._handle, value.min, value.max)

        @property
        def mode(self):
            c_mux = ct.c_int()
            dll.kvaDbGetSignalMode(self._handle, ct.byref(c_mux))
            return c_mux.value

        @mode.setter
        def mode(self, value):
            c_mux = ct.c_int(value)
            dll.kvaDbSetSignalMode(self._handle, c_mux)

    class EnumSignal(Signal):
        """Database signal of type enum, holds meta data about a signal."""
        def __init__(self, db, message, sh,
                     name=None, type=None,
                     byte_order=SignalByteOrder.INTEL,
                     mode=SignalMultiplexMode.SIGNAL,
                     size=None,
                     scaling=ValueScaling(factor=1, offset=0),
                     limits=None, unit=None, comment=None, enums={}):
            super(EnumSignal, self).__init__(db, message=message,
                                             sh=sh, name=name, type=type,
                                             byte_order=byte_order, mode=mode,
                                             size=size, scaling=scaling,
                                             limits=limits, unit=unit,
                                             comment=comment)
            self.add_enum_definition(enums)

        def _enum_handles(self):
            """Return enum generator"""
            eh = ct.c_void_p(None)
            try:
                dll.kvaDbGetFirstEnumValue(self._handle, ct.byref(eh))
            except KvdNoAttribute:
                return
            while eh.value is not None:
                yield eh.value
                try:
                    dll.kvaDbGetNextEnumValue(self._handle, ct.byref(eh))
                except KvdNoAttribute:
                    return

        def _delete_enum(self, eh):
            """Delete enum assosiated with handle eh."""
            c_eh = ct.c_void_p(eh)
            dll.kvaDbDeleteEnumValue(self._handle, c_eh)

        def add_enum_definition(self, enums):
            """Add enums dictionary to definition."""
            for key, value in enums.items():
                c_key = ct.create_string_buffer(key.encode('utf-8'))
                c_value = ct.c_int(value)
                dll.kvaDbAddEnumValue(
                    self._handle, c_value, c_key)

        @property
        def enums(self):
            """`dict`: Signal enum definition dictionary"""
            enums = {}
            c_val = ct.c_int()
            buf = ct.create_string_buffer(255)

            for eh in self._enum_handles():
                c_eh = ct.c_void_p(eh)
                dll.kvaDbGetEnumValue(c_eh, ct.byref(c_val), buf, ct.sizeof(buf))
                enums[buf.value.decode('utf-8')] = c_val.value
            return enums

        @enums.setter
        def enums(self, enums):
            # Deleting affects the generator, so get the whole list here
            for eh in list(self._enum_handles()):
                self._delete_enum(eh)
            self.add_enum_definition(enums)

        def __eq__(self, other):
            sup = super(EnumSignal, self).__eq__(other)
            if sup is NotImplemented:
                return sup
            else:
                return sup and self.enums == other.enums