"""
Makes a movie of the KH 2D data.

You will need to run your movie with far higher time-resolution than usual to
get a nice movie; around 450 snapshots over 6s is required.

Edit this file near the bottom with the number of snaps you have.

Written by Josh Borrow (joshua.borrow@durham.ac.uk)
"""

import os
import h5py as h5
import numpy as np
import scipy.interpolate as si

from swiftsimio import load
from swiftsimio.visualisation import project_gas_pixel_grid


def load_and_extract(filename):
    """
    Load the data and extract relevant info.
    """

    return load(filename)


def make_plot(filename, array, nx, ny, dx, dy):
    """
    Load the data and plop it on the grid using nearest
    neighbour searching for finding the 'correct' value of
    the density.
    """

    data = load_and_extract(filename)

    mesh = project_gas_pixel_grid(data, nx).T

    array.set_array(mesh)

    return (array,)


def frame(n, *args):
    """
    Make a single frame. Requires the global variables plot and dpi.
    """

    global plot, dpi

    fn = "{}_{:04d}.hdf5".format(filename, n)

    return make_plot(fn, plot, dpi, dpi, (0, 1), (0, 1))


if __name__ == "__main__":
    import matplotlib

    matplotlib.use("Agg")

    from tqdm import tqdm
    from matplotlib.animation import FuncAnimation
    from scipy.stats import gaussian_kde

    import matplotlib.pyplot as plt

    filename = "kelvinHelmholtz"
    dpi = 512

    # Look for the number of files in the directory.
    i = 0
    while True:
        if os.path.isfile("{}_{:04d}.hdf5".format(filename, i)):
            i += 1
        else:
            break

        if i > 10000:
            raise FileNotFoundError("Could not find the snapshots in the directory")

    frames = tqdm(np.arange(0, i))

    # Creation of first frame
    fig, ax = plt.subplots(1, 1, figsize=(1, 1), frameon=False)
    ax.axis("off")  # Remove annoying black frame.

    data = load_and_extract("kelvinHelmholtz_0000.hdf5")

    mesh = project_gas_pixel_grid(data, dpi)

    # Global variable for set_array
    plot = ax.imshow(
        mesh,
        extent=[0, 1, 0, 1],
        animated=True,
        interpolation="none",
        vmin=1,
        vmax=2,
        cmap="RdBu_r",
    )

    anim = FuncAnimation(fig, frame, frames, interval=40, blit=False)

    # Remove all whitespace
    fig.subplots_adjust(left=0, bottom=0, right=1, top=1, wspace=None, hspace=None)

    # Actually make the movie
    anim.save("khmovie.mp4", dpi=dpi)