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

import sys
import logging

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

from utilities import *


@pytest.mark.xfail
@pytest.mark.parametrize("states_str,fluxes_str,direction", [
    ("2 1,4 1,4 1,4 1,20 5.5", "4 1,11.2 2.6,8 1,8 1,46.4 7.1", "x"),
    ("2 1,4 1,4 1,4 1,20 5.5", "4 1,8 1,11.2 2.6,8 1,46.4 7.1", "y"),
    ("2 1,4 1,4 1,4 1,20 5.5", "4 1,8 1,8 1,11.2 2.6,46.4 7.1", "z"),
    ("1 2,-1 -4,-1 -4,-1 -4,5.5 20", "-1 -4,2.6 11.2,1 8,1 8,-7.1 -46.4", "x"),
    ("1 2,-1 -4,-1 -4,-1 -4,5.5 20", "-1 -4,1 8,2.6 11.2,1 8,-7.1 -46.4", "y"),
    ("1 2,-1 -4,-1 -4,-1 -4,5.5 20", "-1 -4,1 8,1 8,2.6 11.2,-7.1 -46.4", "z"),
    ("2 1,4 1,8 2,12 3,64 11", "4 1,11.2 2.6,16 2,24 3,134.4 12.6", "x"),
    ("2 1,4 1,8 2,12 3,64 11", "8 2,16 2,35.2 5.6,48 6,268.8 25.2", "y"),
    ("2 1,4 1,8 2,12 3,64 11", "12 3,24 3,48 6,75.2 10.6,403.2 37.8", "z")
    ])
def test_roe_uniform_grid(ctx_factory, states_str, fluxes_str, direction):
    class RoeParams:
        def __init__(self, nvars, ndim, d):
            self.nvars = nvars
            self.ndim = ndim
            self.d = d

        def mat_bounds(self):
            return self.nvars, self.nvars

        def vec_bound(self):
            return self.nvars

    def setup_roe_params(nvars, ndim, direction):
        dirs = {"x" : 1, "y" : 2, "z" : 3}
        return RoeParams(nvars, ndim, dirs[direction])

    def identity_matrix(n):
        return np.identity(n).astype(np.float32).copy(order="F")

    def kernel_roe_eigensystem(queue, prg, params, states, metrics_frozen):
        R_dev = empty_array_on_device(queue, *params.mat_bounds())
        Rinv_dev = empty_array_on_device(queue, *params.mat_bounds())
        lam_dev = empty_array_on_device(queue, params.vec_bound())

        prg = with_root_kernel(prg, "roe_eigensystem")
        prg(queue, nvars=params.nvars, ndim=params.ndim, d=params.d,
                states=states, metrics_frozen=metrics_frozen,
                R=R_dev, R_inv=Rinv_dev, lambda_roe=lam_dev)

        return R_dev.get(), Rinv_dev.get(), lam_dev.get()

    def check_roe_identity(states, R, Rinv):
        dState = states[:,1] - states[:,0]
        compare_arrays(R@(Rinv@dState), dState)

    def check_roe_property(states, fluxes, R, Rinv, lam):
        dState = states[:,1] - states[:,0]
        dFlux = fluxes[:,1] - fluxes[:,0]

        temp = Rinv@dState
        temp = np.multiply(lam, temp)
        compare_arrays(R@temp, dFlux)

    queue = get_queue(ctx_factory)
    prg = get_weno_program()

    params = setup_roe_params(nvars=5, ndim=3, direction=direction)
    states = array_from_string(states_str)
    metrics_frozen = identity_matrix(params.ndim)
    R, Rinv, lam = kernel_roe_eigensystem(queue, prg, params, states, metrics_frozen)

    check_roe_identity(states, R, Rinv)

    fluxes = array_from_string(fluxes_str)
    check_roe_property(states, fluxes, R, Rinv, lam)


def test_matvec(ctx_factory):
    prg = get_weno_program()
    queue = get_queue(ctx_factory)

    a = random_array_on_device(queue, 10, 10)
    b = random_array_on_device(queue, 10)

    c = empty_array_on_device(queue, 10)

    prg = with_root_kernel(prg, "mult_mat_vec")
    prg(queue, alpha=1.0, a=a, b=b, c=c)

    compare_arrays(a.get()@b.get(), c.get())


@pytest.mark.slow
def test_compute_flux_derivatives(ctx_factory):
    prg = get_weno_program()

    queue = get_queue(ctx_factory)
    prg = prg.copy(target=lp.PyOpenCLTarget(queue.device))

    lp.auto_test_vs_ref(prg, ctx_factory(), warmup_rounds=1,
            parameters=dict(ndim=3, nvars=5, nx=16, ny=16, nz=16))


@pytest.mark.slow
def test_compute_flux_derivatives_gpu(ctx_factory, write_code=False):
    prg = get_weno_program()
    prg = transform_weno_for_gpu(prg)

    queue = get_queue(ctx_factory)
    prg = prg.copy(target=lp.PyOpenCLTarget(queue.device))
    prg = lp.set_options(prg, no_numpy=True)

    if write_code:
        write_target_device_code(prg)

    lp.auto_test_vs_ref(prg, ctx_factory(), warmup_rounds=1,
            parameters=dict(ndim=3, nvars=5, nx=16, ny=16, nz=16))


# This lets you run 'python test.py test_case(cl._csc)' without pytest.
if __name__ == "__main__":
    if len(sys.argv) > 1:
        logging.basicConfig(level="INFO")
        exec(sys.argv[1])
    else:
        pytest.main([__file__])