import torch
import numpy as np
import pytest

import deepspeed
from deepspeed.ops.adagrad import DeepSpeedCPUAdagrad
from deepspeed.ops.op_builder import CPUAdagradBuilder

if not deepspeed.ops.__compatible_ops__[CPUAdagradBuilder.NAME]:
    pytest.skip("cpu-adagrad is not compatible", allow_module_level=True)


def check_equal(first, second, atol=1e-2, verbose=False):
    x = first.detach().numpy()
    y = second.detach().numpy()
    if verbose:
        print("x = {}".format(x.flatten()))
        print("y = {}".format(y.flatten()))
        print('-' * 80)
    np.testing.assert_allclose(x, y, err_msg="param-update mismatch!", atol=atol)


@pytest.mark.parametrize('model_size',
                         [
                             (64),
                             (22),
                             (55),
                             (127),
                             (1024),
                             (1048576),
                             (30000000),
                         ]) # yapf: disable
def test_cpu_adagrad_opt(model_size):
    device = 'cpu'
    rng_state = torch.get_rng_state()
    param = torch.nn.Parameter(torch.randn(model_size, device=device))
    torch.set_rng_state(rng_state)
    param1 = torch.nn.Parameter(torch.randn(model_size, device=device))
    torch.set_rng_state(rng_state)

    optimizer = DeepSpeedCPUAdagrad([param])
    optimizer1 = torch.optim.Adagrad([param1])

    for i in range(10):
        rng_state = torch.get_rng_state()
        param.grad = torch.randn(model_size, device=device)
        torch.set_rng_state(rng_state)
        param1.grad = torch.randn(model_size, device=device)
        optimizer.step()
        optimizer1.step()

    check_equal(param, param1, atol=1e-2, verbose=True)


@pytest.mark.parametrize('model_size,vocabulary_size,dim',
                         [
                             (16 * 2, 16 * 4, 16),
                             (16 * 32, 16 * 256, 16),
                             (16 * 256, 16 * 16384, 16),
                         ]) # yapf: disable
def test_cpu_adagrad_opt_sparse_embedding(model_size, vocabulary_size, dim):
    device = 'cpu'
    rng_state = torch.get_rng_state()

    def gen_sparse_grad(vocabulary_size, dim, num_indices, dtype, device):
        i = torch.randint(vocabulary_size,
                          size=(1,
                                num_indices),
                          dtype=torch.int64,
                          device=device)
        v = torch.randn(num_indices, dim, dtype=dtype, device=device)
        t = torch.sparse_coo_tensor(i, v, (vocabulary_size, dim), device=device)
        t = t.coalesce()
        new_i = (t.indices().view(-1,
                                  1).repeat(1,
                                            dim) * dim +
                 torch.tensor(range(dim))).flatten().unsqueeze(0)
        new_v = t.values().flatten()
        new_t = torch.sparse_coo_tensor(new_i,
                                        new_v,
                                        (vocabulary_size * dim,
                                         ),
                                        device=device)
        new_t = new_t.coalesce()
        new_t.requires_grad = False
        return new_t

    voc_size = vocabulary_size
    dim = dim
    num_indices = int(model_size // dim)
    dtype = torch.float32

    param = torch.nn.Parameter(torch.randn((voc_size * dim,
                                            ),
                                           dtype=dtype,
                                           device=device),
                               requires_grad=True)
    torch.set_rng_state(rng_state)
    param1 = torch.nn.Parameter(torch.randn((voc_size * dim,
                                             ),
                                            dtype=dtype,
                                            device=device),
                                requires_grad=True)
    torch.set_rng_state(rng_state)

    optimizer = DeepSpeedCPUAdagrad([param])
    optimizer1 = torch.optim.Adagrad([param1])

    for i in range(10):
        torch.set_rng_state(rng_state)
        param.grad = gen_sparse_grad(voc_size,
                                     dim,
                                     num_indices,
                                     dtype=dtype,
                                     device=device)
        torch.set_rng_state(rng_state)
        param1.grad = gen_sparse_grad(voc_size,
                                      dim,
                                      num_indices,
                                      dtype=dtype,
                                      device=device)
        optimizer.step()
        optimizer1.step()

    check_equal(param, param1, atol=1e-2, verbose=True)


def test_cpu_adam_gpu_error():
    model_size = 64
    device = 'cuda:0'
    param = torch.nn.Parameter(torch.randn(model_size, device=device))
    optimizer = DeepSpeedCPUAdagrad([param])

    param.grad = torch.randn(model_size, device=device)
    with pytest.raises(AssertionError):
        optimizer.step()
