# This code is part of Qiskit.
#
# (C) Copyright IBM 2017, 2018.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""A module for visualizing device coupling maps"""

import math
from typing import List

import numpy as np
import rustworkx as rx

from qiskit.exceptions import QiskitError
from qiskit.utils import optionals as _optionals
from qiskit.providers.exceptions import BackendPropertyError
from .exceptions import VisualizationError
from .utils import matplotlib_close_if_inline


def _get_backend_interface_version(backend):
    backend_interface_version = getattr(backend, "version", None)
    return backend_interface_version


@_optionals.HAS_MATPLOTLIB.require_in_call
def plot_gate_map(
    backend,
    figsize=None,
    plot_directed=False,
    label_qubits=True,
    qubit_size=None,
    line_width=4,
    font_size=None,
    qubit_color=None,
    qubit_labels=None,
    line_color=None,
    font_color="w",
    ax=None,
    filename=None,
    qubit_coordinates=None,
):
    """Plots the gate map of a device.

    Args:
        backend (Backend): The backend instance that will be used to plot the device
            gate map.
        figsize (tuple): Output figure size (wxh) in inches.
        plot_directed (bool): Plot directed coupling map.
        label_qubits (bool): Label the qubits.
        qubit_size (float): Size of qubit marker.
        line_width (float): Width of lines.
        font_size (int): Font size of qubit labels.
        qubit_color (list): A list of colors for the qubits
        qubit_labels (list): A list of qubit labels
        line_color (list): A list of colors for each line from coupling_map.
        font_color (str): The font color for the qubit labels.
        ax (Axes): A Matplotlib axes instance.
        filename (str): file path to save image to.
        qubit_coordinates (Sequence): An optional sequence input (list or array being the
            most common) of 2d coordinates for each qubit. The length of the
            sequence much match the number of qubits on the backend. The sequence
            should be the planar coordinates in a 0-based square grid where each
            qubit is located.

    Returns:
        Figure: A Matplotlib figure instance.

    Raises:
        QiskitError: if tried to pass a simulator, or if the backend is None,
            but one of num_qubits, mpl_data, or cmap is None.
        MissingOptionalLibraryError: if matplotlib not installed.

    Example:

        .. plot::
           :include-source:

           from qiskit import QuantumCircuit, execute
           from qiskit.providers.fake_provider import FakeVigoV2
           from qiskit.visualization import plot_gate_map

           backend = FakeVigoV2()

           plot_gate_map(backend)
    """
    qubit_coordinates_map = {}

    qubit_coordinates_map[1] = [[0, 0]]

    qubit_coordinates_map[5] = [[1, 0], [0, 1], [1, 1], [1, 2], [2, 1]]

    qubit_coordinates_map[7] = [[0, 0], [0, 1], [0, 2], [1, 1], [2, 0], [2, 1], [2, 2]]

    qubit_coordinates_map[20] = [
        [0, 0],
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [1, 0],
        [1, 1],
        [1, 2],
        [1, 3],
        [1, 4],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [3, 0],
        [3, 1],
        [3, 2],
        [3, 3],
        [3, 4],
    ]

    qubit_coordinates_map[15] = [
        [0, 0],
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [1, 7],
        [1, 6],
        [1, 5],
        [1, 4],
        [1, 3],
        [1, 2],
        [1, 1],
        [1, 0],
    ]

    qubit_coordinates_map[16] = [
        [1, 0],
        [1, 1],
        [2, 1],
        [3, 1],
        [1, 2],
        [3, 2],
        [0, 3],
        [1, 3],
        [3, 3],
        [4, 3],
        [1, 4],
        [3, 4],
        [1, 5],
        [2, 5],
        [3, 5],
        [1, 6],
    ]

    qubit_coordinates_map[27] = [
        [1, 0],
        [1, 1],
        [2, 1],
        [3, 1],
        [1, 2],
        [3, 2],
        [0, 3],
        [1, 3],
        [3, 3],
        [4, 3],
        [1, 4],
        [3, 4],
        [1, 5],
        [2, 5],
        [3, 5],
        [1, 6],
        [3, 6],
        [0, 7],
        [1, 7],
        [3, 7],
        [4, 7],
        [1, 8],
        [3, 8],
        [1, 9],
        [2, 9],
        [3, 9],
        [3, 10],
    ]

    qubit_coordinates_map[28] = [
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [1, 2],
        [1, 6],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [2, 5],
        [2, 6],
        [2, 7],
        [2, 8],
        [3, 0],
        [3, 4],
        [3, 8],
        [4, 0],
        [4, 1],
        [4, 2],
        [4, 3],
        [4, 4],
        [4, 5],
        [4, 6],
        [4, 7],
        [4, 8],
    ]

    qubit_coordinates_map[53] = [
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [1, 2],
        [1, 6],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [2, 5],
        [2, 6],
        [2, 7],
        [2, 8],
        [3, 0],
        [3, 4],
        [3, 8],
        [4, 0],
        [4, 1],
        [4, 2],
        [4, 3],
        [4, 4],
        [4, 5],
        [4, 6],
        [4, 7],
        [4, 8],
        [5, 2],
        [5, 6],
        [6, 0],
        [6, 1],
        [6, 2],
        [6, 3],
        [6, 4],
        [6, 5],
        [6, 6],
        [6, 7],
        [6, 8],
        [7, 0],
        [7, 4],
        [7, 8],
        [8, 0],
        [8, 1],
        [8, 2],
        [8, 3],
        [8, 4],
        [8, 5],
        [8, 6],
        [8, 7],
        [8, 8],
        [9, 2],
        [9, 6],
    ]

    qubit_coordinates_map[65] = [
        [0, 0],
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [0, 7],
        [0, 8],
        [0, 9],
        [1, 0],
        [1, 4],
        [1, 8],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [2, 5],
        [2, 6],
        [2, 7],
        [2, 8],
        [2, 9],
        [2, 10],
        [3, 2],
        [3, 6],
        [3, 10],
        [4, 0],
        [4, 1],
        [4, 2],
        [4, 3],
        [4, 4],
        [4, 5],
        [4, 6],
        [4, 7],
        [4, 8],
        [4, 9],
        [4, 10],
        [5, 0],
        [5, 4],
        [5, 8],
        [6, 0],
        [6, 1],
        [6, 2],
        [6, 3],
        [6, 4],
        [6, 5],
        [6, 6],
        [6, 7],
        [6, 8],
        [6, 9],
        [6, 10],
        [7, 2],
        [7, 6],
        [7, 10],
        [8, 1],
        [8, 2],
        [8, 3],
        [8, 4],
        [8, 5],
        [8, 6],
        [8, 7],
        [8, 8],
        [8, 9],
        [8, 10],
    ]

    qubit_coordinates_map[127] = [
        [0, 0],
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [0, 7],
        [0, 8],
        [0, 9],
        [0, 10],
        [0, 11],
        [0, 12],
        [0, 13],
        [1, 0],
        [1, 4],
        [1, 8],
        [1, 12],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [2, 5],
        [2, 6],
        [2, 7],
        [2, 8],
        [2, 9],
        [2, 10],
        [2, 11],
        [2, 12],
        [2, 13],
        [2, 14],
        [3, 2],
        [3, 6],
        [3, 10],
        [3, 14],
        [4, 0],
        [4, 1],
        [4, 2],
        [4, 3],
        [4, 4],
        [4, 5],
        [4, 6],
        [4, 7],
        [4, 8],
        [4, 9],
        [4, 10],
        [4, 11],
        [4, 12],
        [4, 13],
        [4, 14],
        [5, 0],
        [5, 4],
        [5, 8],
        [5, 12],
        [6, 0],
        [6, 1],
        [6, 2],
        [6, 3],
        [6, 4],
        [6, 5],
        [6, 6],
        [6, 7],
        [6, 8],
        [6, 9],
        [6, 10],
        [6, 11],
        [6, 12],
        [6, 13],
        [6, 14],
        [7, 2],
        [7, 6],
        [7, 10],
        [7, 14],
        [8, 0],
        [8, 1],
        [8, 2],
        [8, 3],
        [8, 4],
        [8, 5],
        [8, 6],
        [8, 7],
        [8, 8],
        [8, 9],
        [8, 10],
        [8, 11],
        [8, 12],
        [8, 13],
        [8, 14],
        [9, 0],
        [9, 4],
        [9, 8],
        [9, 12],
        [10, 0],
        [10, 1],
        [10, 2],
        [10, 3],
        [10, 4],
        [10, 5],
        [10, 6],
        [10, 7],
        [10, 8],
        [10, 9],
        [10, 10],
        [10, 11],
        [10, 12],
        [10, 13],
        [10, 14],
        [11, 2],
        [11, 6],
        [11, 10],
        [11, 14],
        [12, 1],
        [12, 2],
        [12, 3],
        [12, 4],
        [12, 5],
        [12, 6],
        [12, 7],
        [12, 8],
        [12, 9],
        [12, 10],
        [12, 11],
        [12, 12],
        [12, 13],
        [12, 14],
    ]

    qubit_coordinates_map[433] = [
        [0, 0],
        [0, 1],
        [0, 2],
        [0, 3],
        [0, 4],
        [0, 5],
        [0, 6],
        [0, 7],
        [0, 8],
        [0, 9],
        [0, 10],
        [0, 11],
        [0, 12],
        [0, 13],
        [0, 14],
        [0, 15],
        [0, 16],
        [0, 17],
        [0, 18],
        [0, 19],
        [0, 20],
        [0, 21],
        [0, 22],
        [0, 23],
        [0, 24],
        [0, 25],
        [1, 0],
        [1, 4],
        [1, 8],
        [1, 12],
        [1, 16],
        [1, 20],
        [1, 24],
        [2, 0],
        [2, 1],
        [2, 2],
        [2, 3],
        [2, 4],
        [2, 5],
        [2, 6],
        [2, 7],
        [2, 8],
        [2, 9],
        [2, 10],
        [2, 11],
        [2, 12],
        [2, 13],
        [2, 14],
        [2, 15],
        [2, 16],
        [2, 17],
        [2, 18],
        [2, 19],
        [2, 20],
        [2, 21],
        [2, 22],
        [2, 23],
        [2, 24],
        [2, 25],
        [2, 26],
        [3, 2],
        [3, 6],
        [3, 10],
        [3, 14],
        [3, 18],
        [3, 22],
        [3, 26],
        [4, 0],
        [4, 1],
        [4, 2],
        [4, 3],
        [4, 4],
        [4, 5],
        [4, 6],
        [4, 7],
        [4, 8],
        [4, 9],
        [4, 10],
        [4, 11],
        [4, 12],
        [4, 13],
        [4, 14],
        [4, 15],
        [4, 16],
        [4, 17],
        [4, 18],
        [4, 19],
        [4, 20],
        [4, 21],
        [4, 22],
        [4, 23],
        [4, 24],
        [4, 25],
        [4, 26],
        [5, 0],
        [5, 4],
        [5, 8],
        [5, 12],
        [5, 16],
        [5, 20],
        [5, 24],
        [6, 0],
        [6, 1],
        [6, 2],
        [6, 3],
        [6, 4],
        [6, 5],
        [6, 6],
        [6, 7],
        [6, 8],
        [6, 9],
        [6, 10],
        [6, 11],
        [6, 12],
        [6, 13],
        [6, 14],
        [6, 15],
        [6, 16],
        [6, 17],
        [6, 18],
        [6, 19],
        [6, 20],
        [6, 21],
        [6, 22],
        [6, 23],
        [6, 24],
        [6, 25],
        [6, 26],
        [7, 2],
        [7, 6],
        [7, 10],
        [7, 14],
        [7, 18],
        [7, 22],
        [7, 26],
        [8, 0],
        [8, 1],
        [8, 2],
        [8, 3],
        [8, 4],
        [8, 5],
        [8, 6],
        [8, 7],
        [8, 8],
        [8, 9],
        [8, 10],
        [8, 11],
        [8, 12],
        [8, 13],
        [8, 14],
        [8, 15],
        [8, 16],
        [8, 17],
        [8, 18],
        [8, 19],
        [8, 20],
        [8, 21],
        [8, 22],
        [8, 23],
        [8, 24],
        [8, 25],
        [8, 26],
        [9, 0],
        [9, 4],
        [9, 8],
        [9, 12],
        [9, 16],
        [9, 20],
        [9, 24],
        [10, 0],
        [10, 1],
        [10, 2],
        [10, 3],
        [10, 4],
        [10, 5],
        [10, 6],
        [10, 7],
        [10, 8],
        [10, 9],
        [10, 10],
        [10, 11],
        [10, 12],
        [10, 13],
        [10, 14],
        [10, 15],
        [10, 16],
        [10, 17],
        [10, 18],
        [10, 19],
        [10, 20],
        [10, 21],
        [10, 22],
        [10, 23],
        [10, 24],
        [10, 25],
        [10, 26],
        [11, 2],
        [11, 6],
        [11, 10],
        [11, 14],
        [11, 18],
        [11, 22],
        [11, 26],
        [12, 0],
        [12, 1],
        [12, 2],
        [12, 3],
        [12, 4],
        [12, 5],
        [12, 6],
        [12, 7],
        [12, 8],
        [12, 9],
        [12, 10],
        [12, 11],
        [12, 12],
        [12, 13],
        [12, 14],
        [12, 15],
        [12, 16],
        [12, 17],
        [12, 18],
        [12, 19],
        [12, 20],
        [12, 21],
        [12, 22],
        [12, 23],
        [12, 24],
        [12, 25],
        [12, 26],
        [13, 0],
        [13, 4],
        [13, 8],
        [13, 12],
        [13, 16],
        [13, 20],
        [13, 24],
        [14, 0],
        [14, 1],
        [14, 2],
        [14, 3],
        [14, 4],
        [14, 5],
        [14, 6],
        [14, 7],
        [14, 8],
        [14, 9],
        [14, 10],
        [14, 11],
        [14, 12],
        [14, 13],
        [14, 14],
        [14, 15],
        [14, 16],
        [14, 17],
        [14, 18],
        [14, 19],
        [14, 20],
        [14, 21],
        [14, 22],
        [14, 23],
        [14, 24],
        [14, 25],
        [14, 26],
        [15, 2],
        [15, 6],
        [15, 10],
        [15, 14],
        [15, 18],
        [15, 22],
        [15, 26],
        [16, 0],
        [16, 1],
        [16, 2],
        [16, 3],
        [16, 4],
        [16, 5],
        [16, 6],
        [16, 7],
        [16, 8],
        [16, 9],
        [16, 10],
        [16, 11],
        [16, 12],
        [16, 13],
        [16, 14],
        [16, 15],
        [16, 16],
        [16, 17],
        [16, 18],
        [16, 19],
        [16, 20],
        [16, 21],
        [16, 22],
        [16, 23],
        [16, 24],
        [16, 25],
        [16, 26],
        [17, 0],
        [17, 4],
        [17, 8],
        [17, 12],
        [17, 16],
        [17, 20],
        [17, 24],
        [18, 0],
        [18, 1],
        [18, 2],
        [18, 3],
        [18, 4],
        [18, 5],
        [18, 6],
        [18, 7],
        [18, 8],
        [18, 9],
        [18, 10],
        [18, 11],
        [18, 12],
        [18, 13],
        [18, 14],
        [18, 15],
        [18, 16],
        [18, 17],
        [18, 18],
        [18, 19],
        [18, 20],
        [18, 21],
        [18, 22],
        [18, 23],
        [18, 24],
        [18, 25],
        [18, 26],
        [19, 2],
        [19, 6],
        [19, 10],
        [19, 14],
        [19, 18],
        [19, 22],
        [19, 26],
        [20, 0],
        [20, 1],
        [20, 2],
        [20, 3],
        [20, 4],
        [20, 5],
        [20, 6],
        [20, 7],
        [20, 8],
        [20, 9],
        [20, 10],
        [20, 11],
        [20, 12],
        [20, 13],
        [20, 14],
        [20, 15],
        [20, 16],
        [20, 17],
        [20, 18],
        [20, 19],
        [20, 20],
        [20, 21],
        [20, 22],
        [20, 23],
        [20, 24],
        [20, 25],
        [20, 26],
        [21, 0],
        [21, 4],
        [21, 8],
        [21, 12],
        [21, 16],
        [21, 20],
        [21, 24],
        [22, 0],
        [22, 1],
        [22, 2],
        [22, 3],
        [22, 4],
        [22, 5],
        [22, 6],
        [22, 7],
        [22, 8],
        [22, 9],
        [22, 10],
        [22, 11],
        [22, 12],
        [22, 13],
        [22, 14],
        [22, 15],
        [22, 16],
        [22, 17],
        [22, 18],
        [22, 19],
        [22, 20],
        [22, 21],
        [22, 22],
        [22, 23],
        [22, 24],
        [22, 25],
        [22, 26],
        [23, 2],
        [23, 6],
        [23, 10],
        [23, 14],
        [23, 18],
        [23, 22],
        [23, 26],
        [24, 1],
        [24, 2],
        [24, 3],
        [24, 4],
        [24, 5],
        [24, 6],
        [24, 7],
        [24, 8],
        [24, 9],
        [24, 10],
        [24, 11],
        [24, 12],
        [24, 13],
        [24, 14],
        [24, 15],
        [24, 16],
        [24, 17],
        [24, 18],
        [24, 19],
        [24, 20],
        [24, 21],
        [24, 22],
        [24, 23],
        [24, 24],
        [24, 25],
        [24, 26],
    ]

    backend_version = _get_backend_interface_version(backend)
    if backend_version <= 1:
        from qiskit.transpiler.coupling import CouplingMap

        if backend.configuration().simulator:
            raise QiskitError("Requires a device backend, not simulator.")
        config = backend.configuration()
        num_qubits = config.n_qubits
        coupling_map = CouplingMap(config.coupling_map)
        name = backend.name()
    else:
        num_qubits = backend.num_qubits
        coupling_map = backend.coupling_map
        name = backend.name
    if qubit_coordinates is None and ("ibm" in name or "fake" in name):
        qubit_coordinates = qubit_coordinates_map.get(num_qubits, None)

    if qubit_coordinates is None:
        # Replace with planar_layout() when rustworkx offers it
        qubit_coordinates_rx = rx.spring_layout(coupling_map.graph, seed=1234)
        scaling_factor = 10 ** int(math.log10(num_qubits) + 1)
        qubit_coordinates = [
            (
                int(scaling_factor * qubit_coordinates_rx[i][0]),
                int(scaling_factor * qubit_coordinates_rx[i][1]),
            )
            for i in range(num_qubits)
        ]

    if any(x[0] < 0 or x[1] < 0 for x in qubit_coordinates):
        min_entry = min(qubit_coordinates, key=lambda x: min(x[0], x[1]))
        negative_offset = 0 - min(min_entry)
        qubit_coordinates = [
            (x[0] + negative_offset, x[1] + negative_offset) for x in qubit_coordinates
        ]

    if len(qubit_coordinates) != num_qubits:
        raise QiskitError(
            f"The number of specified qubit coordinates {len(qubit_coordinates)} "
            f"does not match the device number of qubits: {num_qubits}"
        )

    return plot_coupling_map(
        num_qubits,
        qubit_coordinates,
        coupling_map.get_edges(),
        figsize,
        plot_directed,
        label_qubits,
        qubit_size,
        line_width,
        font_size,
        qubit_color,
        qubit_labels,
        line_color,
        font_color,
        ax,
        filename,
    )


@_optionals.HAS_MATPLOTLIB.require_in_call
def plot_coupling_map(
    num_qubits: int,
    qubit_coordinates: List[List[int]],
    coupling_map: List[List[int]],
    figsize=None,
    plot_directed=False,
    label_qubits=True,
    qubit_size=None,
    line_width=4,
    font_size=None,
    qubit_color=None,
    qubit_labels=None,
    line_color=None,
    font_color="w",
    ax=None,
    filename=None,
):
    """Plots an arbitrary coupling map of qubits (embedded in a plane).

    Args:
        num_qubits (int): The number of qubits defined and plotted.
        qubit_coordinates (List[List[int]]): A list of two-element lists, with entries of each nested
            list being the planar coordinates in a 0-based square grid where each qubit is located.
        coupling_map (List[List[int]]): A list of two-element lists, with entries of each nested
            list being the qubit numbers of the bonds to be plotted.
        figsize (tuple): Output figure size (wxh) in inches.
        plot_directed (bool): Plot directed coupling map.
        label_qubits (bool): Label the qubits.
        qubit_size (float): Size of qubit marker.
        line_width (float): Width of lines.
        font_size (int): Font size of qubit labels.
        qubit_color (list): A list of colors for the qubits
        qubit_labels (list): A list of qubit labels
        line_color (list): A list of colors for each line from coupling_map.
        font_color (str): The font color for the qubit labels.
        ax (Axes): A Matplotlib axes instance.
        filename (str): file path to save image to.

    Returns:
        Figure: A Matplotlib figure instance.

    Raises:
        MissingOptionalLibraryError: if matplotlib not installed.
        QiskitError: If length of qubit labels does not match number of qubits.

    Example:

        .. plot::
           :include-source:

            from qiskit.visualization import plot_coupling_map

            num_qubits = 8
            qubit_coordinates = [[0, 1], [1, 1], [1, 0], [1, 2], [2, 0], [2, 2], [2, 1], [3, 1]]
            coupling_map = [[0, 1], [1, 2], [2, 3], [3, 5], [4, 5], [5, 6], [2, 4], [6, 7]]
            plot_coupling_map(num_qubits, qubit_coordinates, coupling_map)
    """
    import matplotlib.pyplot as plt
    import matplotlib.patches as mpatches

    input_axes = False
    if ax:
        input_axes = True

    if font_size is None:
        font_size = 12

    if qubit_size is None:
        qubit_size = 24
    if num_qubits > 20:
        qubit_size = 28
        font_size = 10

    if qubit_labels is None:
        qubit_labels = list(range(num_qubits))
    else:
        if len(qubit_labels) != num_qubits:
            raise QiskitError("Length of qubit labels does not equal number of qubits.")

    if qubit_coordinates is not None:
        grid_data = qubit_coordinates
    else:
        if not input_axes:
            fig, ax = plt.subplots(figsize=(5, 5))
            ax.axis("off")
            if filename:
                fig.savefig(filename)
            return fig

    x_max = max(d[1] for d in grid_data)
    y_max = max(d[0] for d in grid_data)
    max_dim = max(x_max, y_max)

    if figsize is None:
        if num_qubits == 1 or (x_max / max_dim > 0.33 and y_max / max_dim > 0.33):
            figsize = (5, 5)
        else:
            figsize = (9, 3)

    if ax is None:
        fig, ax = plt.subplots(figsize=figsize)
        ax.axis("off")

    # set coloring
    if qubit_color is None:
        qubit_color = ["#648fff"] * num_qubits
    if line_color is None:
        line_color = ["#648fff"] * len(coupling_map) if coupling_map else []

    # Add lines for couplings
    if num_qubits != 1:
        for ind, edge in enumerate(coupling_map):
            is_symmetric = False
            if edge[::-1] in coupling_map:
                is_symmetric = True
            y_start = grid_data[edge[0]][0]
            x_start = grid_data[edge[0]][1]
            y_end = grid_data[edge[1]][0]
            x_end = grid_data[edge[1]][1]

            if is_symmetric:
                if y_start == y_end:
                    x_end = (x_end - x_start) / 2 + x_start

                elif x_start == x_end:
                    y_end = (y_end - y_start) / 2 + y_start

                else:
                    x_end = (x_end - x_start) / 2 + x_start
                    y_end = (y_end - y_start) / 2 + y_start
            ax.add_artist(
                plt.Line2D(
                    [x_start, x_end],
                    [-y_start, -y_end],
                    color=line_color[ind],
                    linewidth=line_width,
                    zorder=0,
                )
            )
            if plot_directed:
                dx = x_end - x_start
                dy = y_end - y_start
                if is_symmetric:
                    x_arrow = x_start + dx * 0.95
                    y_arrow = -y_start - dy * 0.95
                    dx_arrow = dx * 0.01
                    dy_arrow = -dy * 0.01
                    head_width = 0.15
                else:
                    x_arrow = x_start + dx * 0.5
                    y_arrow = -y_start - dy * 0.5
                    dx_arrow = dx * 0.2
                    dy_arrow = -dy * 0.2
                    head_width = 0.2
                ax.add_patch(
                    mpatches.FancyArrow(
                        x_arrow,
                        y_arrow,
                        dx_arrow,
                        dy_arrow,
                        head_width=head_width,
                        length_includes_head=True,
                        edgecolor=None,
                        linewidth=0,
                        facecolor=line_color[ind],
                        zorder=1,
                    )
                )

    # Add circles for qubits
    for var, idx in enumerate(grid_data):
        _idx = [idx[1], -idx[0]]
        ax.add_artist(
            mpatches.Ellipse(
                _idx,
                qubit_size / 48,
                qubit_size / 48,  # This is here so that the changes
                color=qubit_color[var],
                zorder=1,
            )
        )  # to how qubits are plotted does
        if label_qubits:  # not affect qubit size kwarg.
            ax.text(
                *_idx,
                s=qubit_labels[var],
                horizontalalignment="center",
                verticalalignment="center",
                color=font_color,
                size=font_size,
                weight="bold",
            )
    ax.set_xlim([-1, x_max + 1])
    ax.set_ylim([-(y_max + 1), 1])
    ax.set_aspect("equal")

    if not input_axes:
        matplotlib_close_if_inline(fig)
        if filename:
            fig.savefig(filename)
        return fig
    return None


def plot_circuit_layout(circuit, backend, view="virtual", qubit_coordinates=None):
    """Plot the layout of a circuit transpiled for a given
    target backend.

    Args:
        circuit (QuantumCircuit): Input quantum circuit.
        backend (Backend): Target backend.
        view (str): Layout view: either 'virtual' or 'physical'.
        qubit_coordinates (Sequence): An optional sequence input (list or array being the
            most common) of 2d coordinates for each qubit. The length of the
            sequence must match the number of qubits on the backend. The sequence
            should be the planar coordinates in a 0-based square grid where each
            qubit is located.

    Returns:
        Figure: A matplotlib figure showing layout.

    Raises:
        QiskitError: Invalid view type given.
        VisualizationError: Circuit has no layout attribute.

    Example:
        .. plot::
           :include-source:

            import numpy as np
            from qiskit import QuantumCircuit, transpile
            from qiskit.providers.fake_provider import FakeVigoV2
            from qiskit.visualization import plot_circuit_layout
            from qiskit.tools.monitor import job_monitor
            from qiskit.providers.fake_provider import FakeVigoV2
            import matplotlib.pyplot as plt

            ghz = QuantumCircuit(3, 3)
            ghz.h(0)
            for idx in range(1,3):
                ghz.cx(0,idx)
            ghz.measure(range(3), range(3))

            backend = FakeVigoV2()
            new_circ_lv3 = transpile(ghz, backend=backend, optimization_level=3)
            plot_circuit_layout(new_circ_lv3, backend)
    """
    if circuit._layout is None:
        raise QiskitError("Circuit has no layout. Perhaps it has not been transpiled.")

    backend_version = _get_backend_interface_version(backend)
    if backend_version <= 1:
        num_qubits = backend.configuration().n_qubits
        cmap = backend.configuration().coupling_map
        cmap_len = len(cmap)
    else:
        num_qubits = backend.num_qubits
        cmap = backend.coupling_map
        cmap_len = cmap.graph.num_edges()

    qubits = []
    qubit_labels = [None] * num_qubits

    bit_locations = {
        bit: {"register": register, "index": index}
        for register in circuit._layout.initial_layout.get_registers()
        for index, bit in enumerate(register)
    }
    for index, qubit in enumerate(circuit._layout.initial_layout.get_virtual_bits()):
        if qubit not in bit_locations:
            bit_locations[qubit] = {"register": None, "index": index}

    if view == "virtual":
        for key, val in circuit._layout.initial_layout.get_virtual_bits().items():
            bit_register = bit_locations[key]["register"]
            if bit_register is None or bit_register.name != "ancilla":
                qubits.append(val)
                qubit_labels[val] = bit_locations[key]["index"]

    elif view == "physical":
        for key, val in circuit._layout.initial_layout.get_physical_bits().items():
            bit_register = bit_locations[val]["register"]
            if bit_register is None or bit_register.name != "ancilla":
                qubits.append(key)
                qubit_labels[key] = key

    else:
        raise VisualizationError("Layout view must be 'virtual' or 'physical'.")

    qcolors = ["#648fff"] * num_qubits
    for k in qubits:
        qcolors[k] = "k"

    lcolors = ["#648fff"] * cmap_len

    for idx, edge in enumerate(cmap):
        if edge[0] in qubits and edge[1] in qubits:
            lcolors[idx] = "k"

    fig = plot_gate_map(
        backend,
        qubit_color=qcolors,
        qubit_labels=qubit_labels,
        line_color=lcolors,
        qubit_coordinates=qubit_coordinates,
    )
    return fig


@_optionals.HAS_MATPLOTLIB.require_in_call
@_optionals.HAS_SEABORN.require_in_call
def plot_error_map(backend, figsize=(12, 9), show_title=True, qubit_coordinates=None):
    """Plots the error map of a given backend.

    Args:
        backend (Backend): Given backend.
        figsize (tuple): Figure size in inches.
        show_title (bool): Show the title or not.
        qubit_coordinates (Sequence): An optional sequence input (list or array being the
            most common) of 2d coordinates for each qubit. The length of the
            sequence much mast the number of qubits on the backend. The sequence
            should be the planar coordinates in a 0-based square grid where each
            qubit is located.

    Returns:
        Figure: A matplotlib figure showing error map.

    Raises:
        VisualizationError: The backend does not provide gate errors for the 'sx' gate.
        MissingOptionalLibraryError: If seaborn is not installed

    Example:
        .. plot::
           :include-source:

            from qiskit import QuantumCircuit, execute
            from qiskit.visualization import plot_error_map
            from qiskit.providers.fake_provider import FakeVigoV2

            backend = FakeVigoV2()
            plot_error_map(backend)
    """
    import seaborn as sns
    import matplotlib
    import matplotlib.pyplot as plt
    from matplotlib import gridspec, ticker

    color_map = sns.cubehelix_palette(reverse=True, as_cmap=True)

    backend_version = _get_backend_interface_version(backend)
    if backend_version <= 1:
        backend_name = backend.name()
        num_qubits = backend.configuration().n_qubits
        cmap = backend.configuration().coupling_map
        props = backend.properties()
        props_dict = props.to_dict()
        single_gate_errors = [0] * num_qubits
        read_err = [0] * num_qubits
        cx_errors = []
        # sx error rates
        for gate in props_dict["gates"]:
            if gate["gate"] == "sx":
                _qubit = gate["qubits"][0]
                for param in gate["parameters"]:
                    if param["name"] == "gate_error":
                        single_gate_errors[_qubit] = param["value"]
                        break
                else:
                    raise VisualizationError(
                        f"Backend '{backend}' did not supply an error for the 'sx' gate."
                    )
        if cmap:
            directed = False
            if num_qubits < 20:
                for edge in cmap:
                    if not [edge[1], edge[0]] in cmap:
                        directed = True
                        break

            for line in cmap:
                for item in props_dict["gates"]:
                    if item["qubits"] == line:
                        cx_errors.append(item["parameters"][0]["value"])
                        break
        for qubit in range(num_qubits):
            try:
                read_err[qubit] = props.readout_error(qubit)
            except BackendPropertyError:
                pass

    else:
        backend_name = backend.name
        num_qubits = backend.num_qubits
        cmap = backend.coupling_map
        two_q_error_map = {}
        single_gate_errors = [0] * num_qubits
        read_err = [0] * num_qubits
        cx_errors = []
        for gate, prop_dict in backend.target.items():
            if prop_dict is None or None in prop_dict:
                continue
            for qargs, inst_props in prop_dict.items():
                if inst_props is None:
                    continue
                if gate == "measure":
                    if inst_props.error is not None:
                        read_err[qargs[0]] = inst_props.error
                elif len(qargs) == 1:
                    if inst_props.error is not None:
                        single_gate_errors[qargs[0]] = max(
                            single_gate_errors[qargs[0]], inst_props.error
                        )
                elif len(qargs) == 2:
                    if inst_props.error is not None:
                        two_q_error_map[qargs] = max(
                            two_q_error_map.get(qargs, 0), inst_props.error
                        )
        if cmap:
            directed = False
            if num_qubits < 20:
                for edge in cmap:
                    if not [edge[1], edge[0]] in cmap:
                        directed = True
                        break
            for line in cmap.get_edges():
                err = two_q_error_map.get(tuple(line), 0)
                cx_errors.append(err)

    # Convert to percent
    single_gate_errors = 100 * np.asarray(single_gate_errors)
    avg_1q_err = np.mean(single_gate_errors)

    single_norm = matplotlib.colors.Normalize(
        vmin=min(single_gate_errors), vmax=max(single_gate_errors)
    )
    q_colors = [color_map(single_norm(err)) for err in single_gate_errors]

    directed = False
    line_colors = []
    if cmap:

        # Convert to percent
        cx_errors = 100 * np.asarray(cx_errors)
        avg_cx_err = np.mean(cx_errors)

        cx_norm = matplotlib.colors.Normalize(vmin=min(cx_errors), vmax=max(cx_errors))
        line_colors = [color_map(cx_norm(err)) for err in cx_errors]

    read_err = 100 * np.asarray(read_err)
    avg_read_err = np.mean(read_err)
    max_read_err = np.max(read_err)

    fig = plt.figure(figsize=figsize)
    gridspec.GridSpec(nrows=2, ncols=3)

    grid_spec = gridspec.GridSpec(
        12, 12, height_ratios=[1] * 11 + [0.5], width_ratios=[2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2]
    )

    left_ax = plt.subplot(grid_spec[2:10, :1])
    main_ax = plt.subplot(grid_spec[:11, 1:11])
    right_ax = plt.subplot(grid_spec[2:10, 11:])
    bleft_ax = plt.subplot(grid_spec[-1, :5])
    if cmap:
        bright_ax = plt.subplot(grid_spec[-1, 7:])

    qubit_size = 28
    if num_qubits <= 5:
        qubit_size = 20
    plot_gate_map(
        backend,
        qubit_color=q_colors,
        line_color=line_colors,
        qubit_size=qubit_size,
        line_width=5,
        plot_directed=directed,
        ax=main_ax,
        qubit_coordinates=qubit_coordinates,
    )
    main_ax.axis("off")
    main_ax.set_aspect(1)
    if cmap:
        single_cb = matplotlib.colorbar.ColorbarBase(
            bleft_ax, cmap=color_map, norm=single_norm, orientation="horizontal"
        )
        tick_locator = ticker.MaxNLocator(nbins=5)
        single_cb.locator = tick_locator
        single_cb.update_ticks()
        single_cb.update_ticks()
        bleft_ax.set_title(f"H error rate (%) [Avg. = {round(avg_1q_err, 3)}]")

    if cmap is None:
        bleft_ax.axis("off")
        bleft_ax.set_title(f"H error rate (%) = {round(avg_1q_err, 3)}")

    if cmap:
        cx_cb = matplotlib.colorbar.ColorbarBase(
            bright_ax, cmap=color_map, norm=cx_norm, orientation="horizontal"
        )
        tick_locator = ticker.MaxNLocator(nbins=5)
        cx_cb.locator = tick_locator
        cx_cb.update_ticks()
        bright_ax.set_title(f"CNOT error rate (%) [Avg. = {round(avg_cx_err, 3)}]")

    if num_qubits < 10:
        num_left = num_qubits
        num_right = 0
    else:
        num_left = math.ceil(num_qubits / 2)
        num_right = num_qubits - num_left

    left_ax.barh(range(num_left), read_err[:num_left], align="center", color="#DDBBBA")
    left_ax.axvline(avg_read_err, linestyle="--", color="#212121")
    left_ax.set_yticks(range(num_left))
    left_ax.set_xticks([0, round(avg_read_err, 2), round(max_read_err, 2)])
    left_ax.set_yticklabels([str(kk) for kk in range(num_left)], fontsize=12)
    left_ax.invert_yaxis()
    left_ax.set_title("Readout Error (%)", fontsize=12)

    for spine in left_ax.spines.values():
        spine.set_visible(False)

    if num_right:
        right_ax.barh(
            range(num_left, num_qubits), read_err[num_left:], align="center", color="#DDBBBA"
        )
        right_ax.axvline(avg_read_err, linestyle="--", color="#212121")
        right_ax.set_yticks(range(num_left, num_qubits))
        right_ax.set_xticks([0, round(avg_read_err, 2), round(max_read_err, 2)])
        right_ax.set_yticklabels([str(kk) for kk in range(num_left, num_qubits)], fontsize=12)
        right_ax.invert_yaxis()
        right_ax.invert_xaxis()
        right_ax.yaxis.set_label_position("right")
        right_ax.yaxis.tick_right()
        right_ax.set_title("Readout Error (%)", fontsize=12)
    else:
        right_ax.axis("off")

    for spine in right_ax.spines.values():
        spine.set_visible(False)

    if show_title:
        fig.suptitle(f"{backend_name} Error Map", fontsize=24, y=0.9)
    matplotlib_close_if_inline(fig)
    return fig