# This code is part of Qiskit.
#
# (C) Copyright IBM 2021.
#
# 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.

"""An interactive backend error map."""

from typing import List, Union

import numpy as np
import seaborn as sns
from matplotlib.colors import ListedColormap

HELIX_LIGHT_CMAP = sns.cubehelix_palette(
    start=3.1, hue=1.5, light=0.9, dark=0.1, reverse=True, as_cmap=True
)
"""Color map with a white background."""

HELIX_DARK_CMAP = sns.cubehelix_palette(
    start=3.1, hue=1.5, light=0.97, dark=0.25, reverse=True, as_cmap=True
)
"""Color map in dark mode, with a black background."""


def _sns_to_plotly(
    cmap: ListedColormap, pl_entries: int = 255
) -> List[List[Union[float, str]]]:
    """Convert a color map to a plotly color scale.

    Args:
        cmap: Color map to be converted.
        pl_entries: Number of entries in the color scale.

    Returns:
        Color scale.
    """
    hgt = 1.0 / (pl_entries - 1)
    pl_colorscale = []

    for k in range(pl_entries):
        clr = list(map(np.uint8, np.array(cmap(k * hgt)[:3]) * 255))
        pl_colorscale.append([k * hgt, "rgb" + str((clr[0], clr[1], clr[2]))])

    return pl_colorscale


HELIX_LIGHT = _sns_to_plotly(HELIX_LIGHT_CMAP)
HELIX_DARK = _sns_to_plotly(HELIX_DARK_CMAP)