import numpy as np
import numpy.linalg as la
import pyopencl as cl
import pyopencl.array  # noqa
import pyopencl.clrandom  # noqa
import loopy as lp
import sys

from pyopencl.tools import (  # noqa
        pytest_generate_tests_for_pyopencl
        as pytest_generate_tests)


_WENO_PRG = []


def get_weno_program():
    if _WENO_PRG:
        return _WENO_PRG[0]

    fn = "WENO.F90"

    with open(fn, "r") as infile:
        infile_content = infile.read()

    prg = lp.parse_transformed_fortran(infile_content, filename=fn)
    _WENO_PRG.append(prg)
    return prg


def with_root_kernel(prg, root_name):
    # FIXME This is a little less beautiful than it could be
    new_prg = prg.copy(name=root_name)
    for name in prg:
        clbl = new_prg[name]
        if isinstance(clbl, lp.LoopKernel) and clbl.is_called_from_host:
            new_prg = new_prg.with_kernel(clbl.copy(is_called_from_host=False))

    new_prg = new_prg.with_kernel(prg[root_name].copy(is_called_from_host=True))
    return new_prg


def test_matvec(ctx_factory):
    ctx = ctx_factory()
    queue = cl.CommandQueue(ctx)

    prg = get_weno_program()
    prg = with_root_kernel(prg, "mult_mat_vec")

    a = np.random.rand(10, 10).astype(np.float32).copy(order="F")
    b = np.random.rand(10).astype(np.float32)

    c_dev = cl.array.empty(queue, 10, dtype=np.float32)

    prg = lp.set_options(prg, write_cl=True)
    prg(queue, a=a, b=b, c=c_dev, alpha=1.0)

    c = c_dev.get()

    assert la.norm(a@b - c, 2)/la.norm(c) < 1e-5


# This lets you run 'python test.py test_case(cl._csc)' without pytest.

if __name__ == "__main__":
    if len(sys.argv) > 1:
        exec(sys.argv[1])
    else:
        from pytest import main
        main([__file__])