"""Functions for formatting Theano compute graphs.

Author: Christof Angermueller <cangermueller@gmail.com>
"""
import os
from functools import reduce

import numpy as np

import theano
from theano.compile import Function, builders
from theano.graph.basic import Apply, Constant, Variable, graph_inputs
from theano.graph.fg import FunctionGraph
from theano.printing import pydot_imported, pydot_imported_msg


try:
    from theano.printing import pd
except ImportError:
    pass


class PyDotFormatter:
    """Create `pydot` graph object from Theano function.

    Parameters
    ----------
    compact : bool
        if True, will remove intermediate variables without name.

    Attributes
    ----------
    node_colors : dict
        Color table of node types.
    apply_colors : dict
        Color table of apply nodes.
    shapes : dict
        Shape table of node types.
    """

    def __init__(self, compact=True):
        """Construct PyDotFormatter object."""
        if not pydot_imported:
            raise ImportError("Failed to import pydot. " + pydot_imported_msg)

        self.compact = compact
        self.node_colors = {
            "input": "limegreen",
            "constant_input": "SpringGreen",
            "shared_input": "YellowGreen",
            "output": "dodgerblue",
            "unused": "lightgrey",
        }
        self.apply_colors = {
            "GpuFromHost": "red",
            "HostFromGpu": "red",
            "Scan": "yellow",
            "Shape": "cyan",
            "IfElse": "magenta",
            "Elemwise": "#FFAABB",  # dark pink
            "Subtensor": "#FFAAFF",  # purple
            "Alloc": "#FFAA22",
        }  # orange
        self.shapes = {"input": "box", "output": "box", "apply": "ellipse"}
        self.__node_prefix = "n"

    def __add_node(self, node):
        """Add new node to node list and return unique id.

        Parameters
        ----------
        node : Theano graph node
            Apply node, tensor variable, or shared variable in compute graph.

        Returns
        -------
        str
            Unique node id.
        """
        assert node not in self.__nodes
        _id = f"{self.__node_prefix}{len(self.__nodes) + 1}"
        self.__nodes[node] = _id
        return _id

    def __node_id(self, node):
        """Return unique node id.

        Parameters
        ----------
        node : Theano graph node
            Apply node, tensor variable, or shared variable in compute graph.

        Returns
        -------
        str
            Unique node id.
        """
        if node in self.__nodes:
            return self.__nodes[node]
        else:
            return self.__add_node(node)

    def __call__(self, fct, graph=None):
        """Create pydot graph from function.

        Parameters
        ----------
        fct : theano.compile.function.types.Function
            A compiled Theano function, variable, apply or a list of variables.
        graph: pydot.Dot
            `pydot` graph to which nodes are added. Creates new one if
            undefined.

        Returns
        -------
        pydot.Dot
            Pydot graph of `fct`
        """
        if graph is None:
            graph = pd.Dot()

        self.__nodes = {}

        profile = None

        if isinstance(fct, Function):
            profile = getattr(fct, "profile", None)
            fgraph = fct.maker.fgraph
        elif isinstance(fct, FunctionGraph):
            fgraph = fct
        else:
            if isinstance(fct, Variable):
                fct = [fct]
            elif isinstance(fct, Apply):
                fct = fct.outputs
            assert isinstance(fct, (list, tuple))
            assert all(isinstance(v, Variable) for v in fct)
            fgraph = FunctionGraph(inputs=graph_inputs(fct), outputs=fct)

        outputs = fgraph.outputs
        topo = fgraph.toposort()
        outputs = list(outputs)

        # Loop over apply nodes
        for node in topo:
            nparams = {}
            __node_id = self.__node_id(node)
            nparams["name"] = __node_id
            nparams["label"] = apply_label(node)
            nparams["profile"] = apply_profile(fgraph, node, profile)
            nparams["node_type"] = "apply"
            nparams["apply_op"] = nparams["label"]
            nparams["shape"] = self.shapes["apply"]

            use_color = None
            for opName, color in self.apply_colors.items():
                if opName in node.op.__class__.__name__:
                    use_color = color
            if use_color:
                nparams["style"] = "filled"
                nparams["fillcolor"] = use_color
                nparams["type"] = "colored"

            pd_node = dict_to_pdnode(nparams)
            graph.add_node(pd_node)

            # Loop over input nodes
            for id, var in enumerate(node.inputs):
                var_id = self.__node_id(var.owner if var.owner else var)
                if var.owner is None:
                    vparams = {
                        "name": var_id,
                        "label": var_label(var),
                        "node_type": "input",
                    }
                    if isinstance(var, Constant):
                        vparams["node_type"] = "constant_input"
                    elif isinstance(var, theano.tensor.sharedvar.TensorSharedVariable):
                        vparams["node_type"] = "shared_input"
                    vparams["dtype"] = type_to_str(var.type)
                    vparams["tag"] = var_tag(var)
                    vparams["style"] = "filled"
                    vparams["fillcolor"] = self.node_colors[vparams["node_type"]]
                    vparams["shape"] = self.shapes["input"]
                    pd_var = dict_to_pdnode(vparams)
                    graph.add_node(pd_var)

                edge_params = {}
                if hasattr(node.op, "view_map") and id in reduce(
                    list.__add__, node.op.view_map.values(), []
                ):
                    edge_params["color"] = self.node_colors["output"]
                elif hasattr(node.op, "destroy_map") and id in reduce(
                    list.__add__, node.op.destroy_map.values(), []
                ):
                    edge_params["color"] = "red"

                edge_label = vparams["dtype"]
                if len(node.inputs) > 1:
                    edge_label = str(id) + " " + edge_label
                pdedge = pd.Edge(var_id, __node_id, label=edge_label, **edge_params)
                graph.add_edge(pdedge)

            # Loop over output nodes
            for id, var in enumerate(node.outputs):
                var_id = self.__node_id(var)

                if var in outputs or len(fgraph.clients[var]) == 0:
                    vparams = {
                        "name": var_id,
                        "label": var_label(var),
                        "node_type": "output",
                        "dtype": type_to_str(var.type),
                        "tag": var_tag(var),
                        "style": "filled",
                    }
                    if len(fgraph.clients[var]) == 0:
                        vparams["fillcolor"] = self.node_colors["unused"]
                    else:
                        vparams["fillcolor"] = self.node_colors["output"]
                    vparams["shape"] = self.shapes["output"]
                    pd_var = dict_to_pdnode(vparams)
                    graph.add_node(pd_var)

                    graph.add_edge(pd.Edge(__node_id, var_id, label=vparams["dtype"]))
                elif var.name or not self.compact:
                    graph.add_edge(pd.Edge(__node_id, var_id, label=vparams["dtype"]))

            # Create sub-graph for OpFromGraph nodes
            if isinstance(node.op, builders.OpFromGraph):
                subgraph = pd.Cluster(__node_id)
                gf = PyDotFormatter()
                # Use different node prefix for sub-graphs
                gf.__node_prefix = __node_id
                node.op.prepare_node(node, None, None, "py")
                gf(node.op.fn, subgraph)
                graph.add_subgraph(subgraph)
                pd_node.get_attributes()["subg"] = subgraph.get_name()

                def format_map(m):
                    return str([list(x) for x in m])

                # Inputs mapping
                ext_inputs = [self.__node_id(x) for x in node.inputs]
                int_inputs = [gf.__node_id(x) for x in node.op.local_inputs]
                assert len(ext_inputs) == len(int_inputs)
                h = format_map(zip(ext_inputs, int_inputs))
                pd_node.get_attributes()["subg_map_inputs"] = h

                # Outputs mapping
                ext_outputs = [self.__node_id(x) for x in node.outputs]
                int_outputs = [gf.__node_id(x) for x in node.op.local_outputs]
                assert len(ext_outputs) == len(int_outputs)
                h = format_map(zip(int_outputs, ext_outputs))
                pd_node.get_attributes()["subg_map_outputs"] = h

        return graph


def var_label(var, precision=3):
    """Return label of variable node."""
    if var.name is not None:
        return var.name
    elif isinstance(var, Constant):
        h = np.asarray(var.data)
        is_const = False
        if h.ndim == 0:
            is_const = True
            h = np.array([h])
        dstr = np.array2string(h, precision=precision)
        if "\n" in dstr:
            dstr = dstr[: dstr.index("\n")]
        if is_const:
            dstr = dstr.replace("[", "").replace("]", "")
        return dstr
    else:
        return type_to_str(var.type)


def var_tag(var):
    """Parse tag attribute of variable node."""
    tag = var.tag
    if hasattr(tag, "trace") and len(tag.trace) and len(tag.trace[0]) == 4:
        if isinstance(tag.trace[0][0], (tuple, list)):
            path, line, _, src = tag.trace[0][-1]
        else:
            path, line, _, src = tag.trace[0]
        path = os.path.basename(path)
        path = path.replace("<", "")
        path = path.replace(">", "")
        src = src.encode()
        return [path, line, src]
    else:
        return None


def apply_label(node):
    """Return label of apply node."""
    return node.op.__class__.__name__


def apply_profile(fgraph, node, profile):
    """Return apply profiling informaton."""
    if not profile or profile.fct_call_time == 0:
        return None
    time = profile.apply_time.get((fgraph, node), 0)
    call_time = profile.fct_call_time
    return [time, call_time]


def broadcastable_to_str(b):
    """Return string representation of broadcastable."""
    named_broadcastable = {
        (): "scalar",
        (False,): "vector",
        (False, True): "col",
        (True, False): "row",
        (False, False): "matrix",
    }
    if b in named_broadcastable:
        bcast = named_broadcastable[b]
    else:
        bcast = ""
    return bcast


def dtype_to_char(dtype):
    """Return character that represents data type."""
    dtype_char = {
        "complex64": "c",
        "complex128": "z",
        "float32": "f",
        "float64": "d",
        "int8": "b",
        "int16": "w",
        "int32": "i",
        "int64": "l",
    }
    if dtype in dtype_char:
        return dtype_char[dtype]
    else:
        return "X"


def type_to_str(t):
    """Return str of variable type."""
    if not hasattr(t, "broadcastable"):
        return str(t)
    s = broadcastable_to_str(t.broadcastable)
    if s == "":
        s = str(t.dtype)
    else:
        s = dtype_to_char(t.dtype) + s
    return s


def dict_to_pdnode(d):
    """Create pydot node from dict."""
    e = dict()
    for k, v in d.items():
        if v is not None:
            if isinstance(v, list):
                v = "\t".join([str(x) for x in v])
            else:
                v = str(v)
            v = str(v)
            v = v.replace('"', "'")
            e[k] = v
    pynode = pd.Node(**e)
    return pynode
