# Copyright (c) 2022-2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
#
# See LICENSE for license information.

import pytest

import jax
import jax.numpy as jnp
import numpy as np
from flax.linen import dot_product_attention
from jax import random
from jax.sharding import Mesh, NamedSharding, PartitionSpec

from distributed_test_base import generate_configs, generate_collectives_count
from distributed_test_base import compare_ops
from utils import make_causal_mask, make_self_mask
from transformer_engine.jax import fp8_autocast
from transformer_engine.jax.fused_attn import is_fused_attn_kernel_available
from transformer_engine.jax.fused_attn import self_fused_attn, cross_fused_attn
from transformer_engine.jax.fused_attn import AttnBiasType, AttnMaskType, QKVLayout

DTYPES = [jnp.float16, jnp.bfloat16]


class TestDistributedSelfAttn:

    def generate_collectives_count_ref(self, mesh_shape, mesh_axes, mesh_resource, with_bias, shape,
                                       dtype):
        jax_dtype = jax.dtypes.canonicalize_dtype(dtype)
        _, seqlen, _, heads, _ = shape
        is_dp_enabled = mesh_resource.dp_resource is not None
        tp_size = 1
        if mesh_resource.tp_resource is not None:
            idx = mesh_axes.index(mesh_resource.tp_resource)
            tp_size = mesh_shape[idx]

        all_reduce_loss_bytes = 4    # 1 * FP32
        bias_bytes = int(with_bias) * (heads // tp_size) * seqlen * seqlen * jax_dtype.itemsize
        allreduce_total_bytes = all_reduce_loss_bytes + (bias_bytes * is_dp_enabled)
        # for loss and dbias
        return generate_collectives_count(allreduce=allreduce_total_bytes, allgather=0, other=0)

    def generate_inputs(self, shape, mesh_resource, with_bias, attn_mask_type, dtype):
        batch, seqlen, _, heads, _ = shape

        qkv = random.normal(random.PRNGKey(1124), shape, dtype=dtype)

        bias = random.normal(random.PRNGKey(1125), (1, heads, seqlen, seqlen), dtype) \
                if with_bias else None

        mask = None
        if attn_mask_type == AttnMaskType.PADDING_MASK:
            mask = make_causal_mask(batch, seqlen)
        elif attn_mask_type == AttnMaskType.CAUSAL_MASK:
            mask = make_self_mask(batch, seqlen)

        qkv_pspec = PartitionSpec(mesh_resource.dp_resource, None, None, mesh_resource.tp_resource,
                                  None)
        bias_pspec = PartitionSpec(None, mesh_resource.tp_resource, None, None) \
                     if with_bias else None
        mask_pspec = PartitionSpec(mesh_resource.dp_resource, None, None, None) \
                     if attn_mask_type != AttnMaskType.NO_MASK else None

        return (qkv, bias, mask), (qkv_pspec, bias_pspec, mask_pspec)

    @pytest.mark.parametrize('device_count,mesh_shape,mesh_axes,mesh_resource', generate_configs())
    @pytest.mark.parametrize('data_shape', [[32, 512, 3, 12, 64], [32, 1024, 3, 16, 128]])
    @pytest.mark.parametrize(
        'attn_bias_type',
        [AttnBiasType.NO_BIAS, AttnBiasType.PRE_SCALE_BIAS, AttnBiasType.POST_SCALE_BIAS])
    @pytest.mark.parametrize('attn_mask_type',
                             [AttnMaskType.PADDING_MASK, AttnMaskType.CAUSAL_MASK])
    @pytest.mark.parametrize('dtype', DTYPES)
    def test_self_attn(self, device_count, mesh_shape, mesh_axes, mesh_resource, data_shape,
                       attn_bias_type, attn_mask_type, dtype):
        dropout_prob = 0.0
        is_training = True
        scaling_factor = 1.0

        _, seqlen, _, num_head, hidden = data_shape

        if not is_fused_attn_kernel_available(dtype, dtype, QKVLayout.BS3HD, attn_bias_type,
                                              attn_mask_type, dropout_prob, num_head, num_head,
                                              seqlen, seqlen, hidden):
            pytest.skip(f"No FusedAttn backwend found")

        def target_func(qkv, bias, mask):
            return jnp.mean(
                self_fused_attn(qkv,
                                bias,
                                mask,
                                None,
                                attn_bias_type=attn_bias_type,
                                attn_mask_type=attn_mask_type,
                                scaling_factor=scaling_factor,
                                dropout_probability=dropout_prob,
                                is_training=is_training))

        def ref_func(qkv, bias, mask):
            query, key, value = jnp.split(qkv, [1, 2], axis=-3)
            query = jnp.squeeze(query)
            key = jnp.squeeze(key)
            value = jnp.squeeze(value)

            output = dot_product_attention(query,
                                           key,
                                           value,
                                           bias=bias,
                                           mask=mask,
                                           deterministic=is_training,
                                           dropout_rate=dropout_prob,
                                           dropout_rng=None,
                                           dtype=jnp.float32)

            return jnp.mean(output).astype(dtype)

        with_bias = attn_bias_type != AttnBiasType.NO_BIAS
        (qkv, bias, mask), (qkv_pspec, bias_pspec, mask_pspec) = \
                self.generate_inputs(data_shape, mesh_resource, with_bias,
                                     attn_mask_type, dtype)
        collective_count_ref = self.generate_collectives_count_ref(mesh_shape, mesh_axes,
                                                                   mesh_resource, with_bias,
                                                                   data_shape, dtype)
        devices = np.asarray(jax.devices()[:device_count]).reshape(*mesh_shape)
        mesh = Mesh(devices, mesh_axes)
        with mesh, fp8_autocast(mesh_resource=mesh_resource):
            qkv_ = jax.device_put(qkv, NamedSharding(mesh, qkv_pspec))
            bias_ = jax.device_put(bias, NamedSharding(mesh, bias_pspec)) \
                    if bias is not None else bias
            mask_ = jax.device_put(mask, NamedSharding(mesh, mask_pspec)) \
                    if mask is not None else mask

            grad_args = (0, 1) if with_bias else (0,)
            out_grad_shardings = (qkv_pspec, bias_pspec) if with_bias else (qkv_pspec,)

            compare_ops(target_func,
                        ref_func, [qkv_, bias_, mask_],
                        collective_count_ref,
                        grad_args=grad_args,
                        metric_fwd_dtype=dtype,
                        metric_bwd_dtype=dtype,
                        in_shardings=(qkv_pspec, bias_pspec, mask_pspec),
                        out_shardings=(None, out_grad_shardings))


class TestDistributedCrossAttn:

    def generate_collectives_count_ref(self):
        # for loss
        all_reduce_loss_bytes = 4    # 1 * FP32
        return generate_collectives_count(allreduce=all_reduce_loss_bytes, allgather=0, other=0)

    def generate_inputs(self, shape, mesh_resource, attn_mask_type, dtype):
        batch, seqlen, heads, hidden = shape

        q = random.normal(random.PRNGKey(1124), shape, dtype=dtype)
        kv = random.normal(random.PRNGKey(1125), (batch, seqlen, 2, heads, hidden), dtype=dtype)

        mask = None
        if attn_mask_type == AttnMaskType.PADDING_MASK:
            mask = make_causal_mask(batch, seqlen)
        elif attn_mask_type == AttnMaskType.CAUSAL_MASK:
            mask = make_self_mask(batch, seqlen)

        q_pspec = PartitionSpec(mesh_resource.dp_resource, None, mesh_resource.tp_resource, None)

        kv_pspec = PartitionSpec(mesh_resource.dp_resource, None, None, mesh_resource.tp_resource,
                                 None)
        mask_pspec = PartitionSpec(mesh_resource.dp_resource, None, None, None) \
                     if attn_mask_type != AttnMaskType.NO_MASK else None

        return (q, kv, mask), (q_pspec, kv_pspec, mask_pspec)

    @pytest.mark.parametrize('device_count,mesh_shape,mesh_axes,mesh_resource', generate_configs())
    @pytest.mark.parametrize('data_shape', [[32, 128, 12, 64], [32, 512, 16, 64]])
    @pytest.mark.parametrize('attn_mask_type',
                             [AttnMaskType.PADDING_MASK, AttnMaskType.CAUSAL_MASK])
    @pytest.mark.parametrize('dtype', DTYPES)
    def test_cross_attn(self, device_count, mesh_shape, mesh_axes, mesh_resource, data_shape,
                        attn_mask_type, dtype):
        attn_bias_type = AttnBiasType.NO_BIAS
        dropout_prob = 0.0
        is_training = True
        scaling_factor = 1.0

        _, seqlen, num_head, hidden = data_shape

        if not is_fused_attn_kernel_available(dtype, dtype, QKVLayout.BSHD_BS2HD, attn_bias_type,
                                              attn_mask_type, dropout_prob, num_head, num_head,
                                              seqlen, seqlen, hidden):
            pytest.skip(f"No FusedAttn backwend found")

        def target_func(q, kv, mask):
            return jnp.mean(
                cross_fused_attn(q,
                                 kv,
                                 None,
                                 mask,
                                 None,
                                 attn_bias_type=attn_bias_type,
                                 attn_mask_type=attn_mask_type,
                                 scaling_factor=scaling_factor,
                                 dropout_probability=dropout_prob,
                                 is_training=is_training))

        def ref_func(query, kv, mask):
            key, value = jnp.split(kv, [1], axis=-3)
            query = jnp.squeeze(query)
            key = jnp.squeeze(key)
            value = jnp.squeeze(value)

            output = dot_product_attention(query,
                                           key,
                                           value,
                                           bias=None,
                                           mask=mask,
                                           deterministic=is_training,
                                           dropout_rate=dropout_prob,
                                           dropout_rng=None,
                                           dtype=jnp.float32)

            return jnp.mean(output).astype(dtype)

        (q, kv, mask), (q_pspec, kv_pspec,  mask_pspec) = \
                self.generate_inputs(data_shape, mesh_resource, attn_mask_type, dtype)
        collective_count_ref = self.generate_collectives_count_ref()
        devices = np.asarray(jax.devices()[:device_count]).reshape(*mesh_shape)
        mesh = Mesh(devices, mesh_axes)
        with mesh, fp8_autocast(mesh_resource=mesh_resource):
            q_ = jax.device_put(q, NamedSharding(mesh, q_pspec))
            kv_ = jax.device_put(kv, NamedSharding(mesh, kv_pspec))
            mask_ = jax.device_put(mask, NamedSharding(mesh, mask_pspec)) \
                    if mask is not None else mask

            compare_ops(target_func,
                        ref_func, [q_, kv_, mask_],
                        collective_count_ref,
                        grad_args=(0, 1),
                        metric_fwd_dtype=dtype,
                        metric_bwd_dtype=dtype,
                        in_shardings=(q_pspec, kv_pspec, mask_pspec),
                        out_shardings=(None, (q_pspec, kv_pspec)))
