signal_flow_graph.py

"""
B-ASIC Signal Flow Graph Module.

Contains the signal flow graph operation.
"""

import itertools as it
import re
from collections import defaultdict, deque
from io import StringIO
from numbers import Number
from queue import PriorityQueue
from typing import (
    DefaultDict,
    Deque,
    Dict,
    Iterable,
    List,
    MutableSet,
    Optional,
    Sequence,
    Set,
    Tuple,
    Union,
    cast,
)

from graphviz import Digraph

from b_asic.graph_component import (
    GraphComponent,
    GraphID,
    GraphIDNumber,
    Name,
    TypeName,
)
from b_asic.operation import (
    AbstractOperation,
    MutableDelayMap,
    MutableResultMap,
    Operation,
    ResultKey,
)
from b_asic.port import InputPort, OutputPort, SignalSourceProvider
from b_asic.signal import Signal
from b_asic.special_operations import Delay, Input, Output

DelayQueue = List[Tuple[str, ResultKey, OutputPort]]


class GraphIDGenerator:
    """Generates Graph IDs for objects."""

    _next_id_number: DefaultDict[TypeName, GraphIDNumber]

    def __init__(self, id_number_offset: GraphIDNumber = GraphIDNumber(0)):
        """Construct a GraphIDGenerator."""
        self._next_id_number = defaultdict(lambda: id_number_offset)

    def next_id(
        self, type_name: TypeName, used_ids: MutableSet = set()
    ) -> GraphID:
        """Get the next graph id for a certain graph id type."""
        self._next_id_number[type_name] += 1
        new_id = type_name + str(self._next_id_number[type_name])
        while new_id in used_ids:
            self._next_id_number[type_name] += 1
            new_id = type_name + str(self._next_id_number[type_name])
        return GraphID(new_id)

    @property
    def id_number_offset(self) -> GraphIDNumber:
        """Get the graph id number offset of this generator."""
        return GraphIDNumber(
            self._next_id_number.default_factory()
        )  # pylint: disable=not-callable


class SFG(AbstractOperation):
    """
    Construct an SFG given its inputs and outputs.

    Contains a set of connected operations, forming a new operation.
    Used as a base for simulation, scheduling, etc.

    Inputs/outputs may be specified using either Input/Output operations
    directly with the *inputs*/*outputs* parameters, or using signals with the
    *input_signals*/*output_signals parameters*. If signals are used, the
    corresponding Input/Output operations will be created automatically.

    The *id_number_offset* parameter specifies what number graph IDs will be
    offset by for each new graph component type. IDs start at 1 by default,
    so the default offset of 0 will result in IDs like "c1", "c2", etc.
    while an offset of 3 will result in "c4", "c5", etc.

    Parameters
    ----------
    inputs : array of Input, optional

    outputs : array of Output, optional

    input_signals : array of Signal, optional

    output_signals : array of Signal, optional

    id_number_offset : GraphIDNumber, optional

    name : Name, optional

    input_sources :

    """

    _components_by_id: Dict[GraphID, GraphComponent]
    _components_by_name: DefaultDict[Name, List[GraphComponent]]
    _components_dfs_order: List[GraphComponent]
    _operations_dfs_order: List[Operation]
    _operations_topological_order: List[Operation]
    _graph_id_generator: GraphIDGenerator
    _input_operations: List[Input]
    _output_operations: List[Output]
    _original_components_to_new: Dict[GraphComponent, GraphComponent]
    _original_input_signals_to_indices: Dict[Signal, int]
    _original_output_signals_to_indices: Dict[Signal, int]
    _precedence_list: Optional[List[List[OutputPort]]]
    _used_ids: Set[GraphID] = set()

    def __init__(
        self,
        inputs: Optional[Sequence[Input]] = None,
        outputs: Optional[Sequence[Output]] = None,
        input_signals: Optional[Sequence[Signal]] = None,
        output_signals: Optional[Sequence[Signal]] = None,
        id_number_offset: GraphIDNumber = GraphIDNumber(0),
        name: Name = Name(""),
        input_sources: Optional[
            Sequence[Optional[SignalSourceProvider]]
        ] = None,
    ):
        input_signal_count = 0 if input_signals is None else len(input_signals)
        input_operation_count = 0 if inputs is None else len(inputs)
        output_signal_count = (
            0 if output_signals is None else len(output_signals)
        )
        output_operation_count = 0 if outputs is None else len(outputs)
        super().__init__(
            input_count=input_signal_count + input_operation_count,
            output_count=output_signal_count + output_operation_count,
            name=name,
            input_sources=input_sources,
        )

        self._components_by_id = {}
        self._used_ids = set()
        self._components_by_name = defaultdict(list)
        self._components_dfs_order = []
        self._operations_dfs_order = []
        self._operations_topological_order = []
        self._graph_id_generator = GraphIDGenerator(
            GraphIDNumber(id_number_offset)
        )
        self._input_operations = []
        self._output_operations = []
        self._original_components_to_new = {}
        self._original_input_signals_to_indices = {}
        self._original_output_signals_to_indices = {}
        self._precedence_list = None

        # Setup input signals.
        if input_signals is not None:
            for input_index, signal in enumerate(input_signals):
                if signal in self._original_components_to_new:
                    raise ValueError(
                        f"Duplicate input signal {signal!r} in SFG"
                    )
                new_input_op = cast(
                    Input, self._add_component_unconnected_copy(Input())
                )
                new_signal = cast(
                    Signal, self._add_component_unconnected_copy(signal)
                )
                new_signal.set_source(new_input_op.output(0))
                self._input_operations.append(new_input_op)
                self._original_input_signals_to_indices[signal] = input_index

        # Setup input operations, starting from indices after input signals.
        if inputs is not None:
            for input_index, input_op in enumerate(inputs, input_signal_count):
                if input_op in self._original_components_to_new:
                    raise ValueError(
                        f"Duplicate input operation {input_op!r} in SFG"
                    )
                new_input_op = cast(
                    Input, self._add_component_unconnected_copy(input_op)
                )
                for signal in input_op.output(0).signals:
                    if signal in self._original_components_to_new:
                        raise ValueError(
                            "Duplicate input signals connected to input ports"
                            " supplied to SFG constructor."