# Python program that can be executed to report whether particular
# python packages are available on the system.

import datetime
import math
import os
import sys
import time


def test_is_python_35():
    major = sys.version_info.major
    minor = sys.version_info.minor
    micro = sys.version_info.micro
    if major == 3:
        pass
    else:
        print("You are running Python {}, but we need Python {}.".format(major, 3))
        print("Download and install the Anaconda distribution for Python 3.")
        print("Stopping here.")

        # Let's stop here
        sys.exit(1)
        return None
        # assert major == 3, "Stopping here - we need Python 3."

    if minor >= 5:
        print(
            "Testing Python version-> Python     OK {}.{}.{}".format(
                major, minor, micro
            )
        )
    else:
        print(
            "Warning: You should be running Python 3.5 or newer, "
            + "you have Python {}.{}.".format(major, minor)
        )


def test_numpy():
    try:
        import numpy as np
    except ImportError:
        print("Could not import numpy -> numpy failed")
        return None
    # Simple test
    a = np.arange(0, 100, 1)
    assert np.sum(a) == sum(a)
    print(f"Testing numpy...      -> numpy      OK {np.__version__}")


def test_scipy():
    try:
        import scipy
    except ImportError:
        print("Could not import 'scipy' -> scipy failed")
        return None
    # Simple test
    import scipy.integrate

    assert abs(scipy.integrate.quad(lambda x: x * x, 0, 6)[0] - 72.0) < 1e-6
    print(f"Testing scipy...      -> scipy      OK {scipy.__version__}")


def test_pandas():
    try:
        import pandas as pd
    except ImportError:
        print("Could not import pandas -> pandas failed")
        return None
    # Simple test for Series
    a = pd.Series(range(10))
    assert a.size == 10

    # Simple test for Dataframe
    b = pd.DataFrame()
    b["day"] = ["Mon", "Tue", "Wed"]
    assert b.shape == (3, 1)
    print(f"Testing pandas...     -> pandas     OK {pd.__version__}")


def test_pylab():
    """Actually testing matplotlib, as pylab is part of matplotlib."""
    try:
        import pylab
        import matplotlib
    except ImportError:
        print("Could not import 'matplotlib/pylab' -> failed")
        return None
    # Creata plot for testing purposes
    xvalues = [i * 0.1 for i in range(100)]
    yvalues = [math.sin(x) for x in xvalues]
    pylab.plot(xvalues, yvalues, "-o", label="sin(x)")
    pylab.legend()
    pylab.xlabel("x")
    testfilename = "pylab-testfigure.png"

    # check that file does not exist yet:
    if os.path.exists(testfilename):
        os.remove(testfilename)
    # Write plot to file
    pylab.savefig(testfilename)
    # Then check that file exists
    assert os.path.exists(testfilename)
    os.remove(testfilename)

    print(f"Testing matplotlib... -> matplotlib OK {matplotlib.__version__}")


def test_sympy():
    try:
        import sympy
    except ImportError:
        print("Could not import 'sympy' -> fail")
        return None
    # simple test
    x = sympy.Symbol("x")
    my_f = x**2
    assert sympy.diff(my_f, x) == 2 * x
    print(f"Testing sympy...      -> sympy      OK {sympy.__version__}")


def test_pytest():
    try:
        import pytest
    except ImportError:
        print("Could not import 'pytest' -> fail")
        return None
    print(f"Testing pytest...     -> pytest     OK {pytest.__version__}")


if __name__ == "__main__":

    starttime = time.time()
    print("Running using Python {}".format(sys.version))
    test_is_python_35()
    test_numpy()
    test_scipy()
    test_pandas()
    test_pylab()
    test_sympy()
    test_pytest()
    print(
        f"Completed {str(datetime.datetime.now())} in {time.time()-starttime:.1f} seconds."
    )