# Copyright (c) 2022-2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
#
# See LICENSE for license information.
"""Test transformer_engine.jax.flax.TransformerLayer"""
import os
from functools import partial
from typing import Dict

import flax
import jax
import jax.numpy as jnp
import pytest

from utils import assert_allclose, assert_tree_like_allclose, sync_params_values
from utils import DecoderLayer as RefDecoderLayer
from utils import EncoderLayer as RefEncoderLayer

from transformer_engine.common.recipe import Format
from transformer_engine.jax.flax import TransformerLayer, TransformerLayerType
from transformer_engine.jax.fp8 import FP8Helper, is_fp8_available

is_fp8_supported, reason = is_fp8_available()


@pytest.fixture(autouse=True, scope='function')
def enable_fused_attn():
    """Enable fused attention"""
    os.environ["NVTE_FUSED_ATTN"] = "1"
    yield
    del os.environ["NVTE_FUSED_ATTN"]


DATA_SHAPE = [    # (batch, seqlen, emb_dim)
    pytest.param((32, 128, 1024), id='32-128-1024'),
    pytest.param((32, 512, 1024), id='32-512-1024'),
]
DTYPE = [jnp.float32, jnp.bfloat16]
FP8_FORMATS = [Format.E4M3, Format.HYBRID]

_KEY_OF_RESIDUAL_POST_LAYERNORM = "apply_residual_connection_post_layernorm"
_KEY_OF_OUTPUT_LAYERNORM = "output_layernorm"
_KEY_OF_DROP_PATH = "drop_path"
_KEY_OF_FUSE_QKV_PARAMS = "fuse_qkv_params"
_KEY_OF_HIDDEN_DROPOUT = "hidden_dropout"
_KEY_OF_ATTENTION_DROPOUT = "attention_dropout"
_KEY_OF_INTERMEDIATE_DROPOUT = "intermediate_dropout"
_KEY_OF_HIDDEN_DROPOUT_DIMS = "hidden_dropout_dims"
_KEY_OF_INTERMEDIATE_DROPOUT_DIMS = "intermediate_dropout_dims"
_KEY_OF_MLP_ACTIVATIONS = "mlp_activations"
_KEY_OF_LAYERNORM_TYPE = "layernorm_type"
_KEY_OF_LAYERNORM_EPS = "layernorm_epsilon"
_KEY_OF_ZERO_CENTERED_GAMMA = "zero_centered_gamma"
_KEY_OF_TRANSPOSE_BS = "transpose_batch_sequence"
_KEY_OF_SCALE_ATTN_LOGITS = "scale_attn_logits"
_KEY_OF_NUM_HEADS = "num_attention_heads"
_KEY_OF_NUM_GQA_GROUPS = "num_gqa_groups"
_KEY_OF_ENABLE_ROPE = "enable_rotary_pos_emb"
_KEY_OF_ROPE_GROUP_METHOD = "rotary_pos_emb_group_method"
_KEY_OF_SELF_ATTN_BIAS_TYPE = "self_attn_bias_type"
_KEY_OF_SELF_ATTN_MASK_TYPE = "self_attn_mask_type"
_KEY_OF_FLOAT32_ATTENTION_LOGITS = "float32_attention_logits"
_KEY_OF_USE_BIAS = "use_bias"
_KEY_OF_RELATIVE_EMBEDDING = "enable_relative_embedding"

BASE_ATTRS = {
    _KEY_OF_TRANSPOSE_BS: True,
    _KEY_OF_NUM_HEADS: 8,
    _KEY_OF_HIDDEN_DROPOUT: 0,
    _KEY_OF_ATTENTION_DROPOUT: 0,
    _KEY_OF_INTERMEDIATE_DROPOUT: 0,
    _KEY_OF_SELF_ATTN_MASK_TYPE: "padding_causal",
    _KEY_OF_LAYERNORM_TYPE: 'layernorm',
}

ATTRS = [{}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
}, {
    _KEY_OF_ZERO_CENTERED_GAMMA: True,
    _KEY_OF_LAYERNORM_EPS: 1e-2,
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_RESIDUAL_POST_LAYERNORM: True
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_OUTPUT_LAYERNORM: True
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_RESIDUAL_POST_LAYERNORM: True,
    _KEY_OF_OUTPUT_LAYERNORM: True
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_DROP_PATH: 0.1
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_FUSE_QKV_PARAMS: False
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_MLP_ACTIVATIONS: ('gelu', 'linear'),
}, {
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_HIDDEN_DROPOUT: 0.8,
    _KEY_OF_INTERMEDIATE_DROPOUT: 0.5,
    _KEY_OF_MLP_ACTIVATIONS: ('gelu', 'linear'),
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_MLP_ACTIVATIONS: ('gelu', 'linear'),
}, {
    _KEY_OF_NUM_HEADS: 8,
    _KEY_OF_NUM_GQA_GROUPS: 4,
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_MLP_ACTIVATIONS: ('gelu',),
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_MLP_ACTIVATIONS: (('silu', 'linear')),
}, {
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_HIDDEN_DROPOUT: 0.8,
    _KEY_OF_INTERMEDIATE_DROPOUT: 0.5,
    _KEY_OF_MLP_ACTIVATIONS: (('silu', 'linear')),
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_MLP_ACTIVATIONS: (('silu', 'linear')),
}, {
    _KEY_OF_NUM_HEADS: 8,
    _KEY_OF_NUM_GQA_GROUPS: 4,
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_SCALE_ATTN_LOGITS: True,
    _KEY_OF_LAYERNORM_TYPE: 'layernorm',
    _KEY_OF_MLP_ACTIVATIONS: (('silu',)),
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_NUM_GQA_GROUPS: 1,
    _KEY_OF_ENABLE_ROPE: True,
    _KEY_OF_ROPE_GROUP_METHOD: "consecutive",
    _KEY_OF_FLOAT32_ATTENTION_LOGITS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: True,
    _KEY_OF_ENABLE_ROPE: True,
    _KEY_OF_ROPE_GROUP_METHOD: "consecutive",
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: False,
    _KEY_OF_LAYERNORM_TYPE: 'layernorm',
    _KEY_OF_NUM_GQA_GROUPS: 2,
    _KEY_OF_ENABLE_ROPE: True,
    _KEY_OF_ROPE_GROUP_METHOD: "alternate",
    _KEY_OF_USE_BIAS: True,
    _KEY_OF_FLOAT32_ATTENTION_LOGITS: True,
}, {
    _KEY_OF_TRANSPOSE_BS: True,
    _KEY_OF_LAYERNORM_TYPE: 'rmsnorm',
    _KEY_OF_ENABLE_ROPE: True,
    _KEY_OF_ROPE_GROUP_METHOD: "alternate",
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_HIDDEN_DROPOUT: 0.3,
    _KEY_OF_HIDDEN_DROPOUT_DIMS: (0,),
    _KEY_OF_INTERMEDIATE_DROPOUT: 0.5,
    _KEY_OF_INTERMEDIATE_DROPOUT_DIMS: (1,),
}, {
    _KEY_OF_SELF_ATTN_MASK_TYPE: "padding",
    _KEY_OF_USE_BIAS: True,
}, {
    _KEY_OF_RELATIVE_EMBEDDING: False,
    _KEY_OF_SELF_ATTN_BIAS_TYPE: "no_bias",
}, {
    _KEY_OF_ATTENTION_DROPOUT: 0.3,
}, {
    _KEY_OF_MLP_ACTIVATIONS: (('relu', 'relu')),
}]

ATTRS = [{**BASE_ATTRS, **attr} for attr in ATTRS]


class BaseRunner:
    """Base runner to define forward and backward tests"""
    layer_type: TransformerLayerType = None
    reference_layer: flax.linen.Module = None
    transformations: Dict[str, str] = None

    def __init__(self, attrs):
        self.attrs = attrs
        self._generate_test_rngs()
        # Disable fused attention for attention dropout because the different dropout impl
        if attrs.get(_KEY_OF_ATTENTION_DROPOUT, False) and os.getenv('NVTE_FUSED_ATTN'):
            os.environ['NVTE_FUSED_ATTN'] = "0"

    def _generate_test_rngs(self):
        root_rng = jax.random.PRNGKey(0)
        params_rng, init_dropout_rng, apply_dropout_rng = jax.random.split(root_rng, 3)
        self.init_rng = {'params': params_rng, 'dropout': init_dropout_rng}
        self.apply_rng = {'dropout': apply_dropout_rng}

    def _generate_layer(self, layer_cls, diff_inputs, no_diff_inputs):
        layer = layer_cls()
        variables = layer.init(self.init_rng, *diff_inputs, *no_diff_inputs)
        others, params = flax.core.pop(variables, 'params')
        del variables
        return layer, params, others

    def _loss_fn(self, diff_xs, no_diff_xs, params, others, model):
        variables = {'params': params, **others}
        output = model.apply(variables, *diff_xs, *no_diff_xs, rngs=self.apply_rng)
        return jnp.mean(output, dtype=jnp.float32).astype(output.dtype)

    def _sync_params(self, ref, target):
        """Copy the reference params to target"""
        target = sync_params_values(target, ref, self.transformations)
        return ref, target

    def test_forward(self, data_shape, dtype, rtol=1e-05, atol=1e-08):
        """Test only the forward"""
        inputs, (ref_masks, test_masks) = self.generate_inputs(data_shape, dtype)

        ref_layer_cls = partial(self.reference_layer, dtype=dtype, **self.attrs)
        layer_cls = partial(TransformerLayer, layer_type=self.layer_type, dtype=dtype, **self.attrs)

        ref_layer, ref_params, ref_others = self._generate_layer(ref_layer_cls, inputs, ref_masks)
        test_layer, test_params, test_others = self._generate_layer(layer_cls, inputs, test_masks)
        ref_params, test_params = self._sync_params(ref_params, test_params)

        ref_out = self._loss_fn(inputs, ref_masks, ref_params, ref_others, ref_layer)
        test_out = self._loss_fn(inputs, test_masks, test_params, test_others, test_layer)

        assert_allclose(ref_out, test_out, rtol=rtol, atol=atol)

    def test_backward(self, data_shape, dtype, rtol=1e-05, atol=1e-08):
        """Test forward and backward through value_and_grad()"""
        inputs, (ref_masks, test_masks) = self.generate_inputs(data_shape, dtype)

        ref_layer_cls = partial(self.reference_layer, dtype=dtype, **self.attrs)
        layer_cls = partial(TransformerLayer, layer_type=self.layer_type, dtype=dtype, **self.attrs)

        ref_layer, ref_params, ref_others = self._generate_layer(ref_layer_cls, inputs, ref_masks)
        test_layer, test_params, test_others = self._generate_layer(layer_cls, inputs, test_masks)

        ref_params, test_params = self._sync_params(ref_params, test_params)

        if FP8Helper.is_fp8_enabled():
            for _ in range(4):
                _, tmp_grad = jax.value_and_grad(self._loss_fn, argnums=(3,), has_aux=False)(
                    inputs,
                    test_masks,
                    test_params,
                    test_others,
                    test_layer,
                )
                _, fp8_meta_grad = flax.core.pop(tmp_grad[0], FP8Helper.FP8_COLLECTION_NAME)
                test_others = FP8Helper.update_collections(
                    {FP8Helper.FP8_COLLECTION_NAME: fp8_meta_grad}, test_others)
                test_others = FP8Helper.update_fp8_metas(test_others)
                del tmp_grad, fp8_meta_grad

        grad_fn = jax.value_and_grad(self._loss_fn, argnums=(0, 2), has_aux=False)

        ref_out, (ref_dgrads, ref_wgrads) = grad_fn(inputs, ref_masks, ref_params, ref_others,
                                                    ref_layer)
        test_out, (test_dgrads, test_wgrads) = grad_fn(inputs, test_masks, test_params, test_others,
                                                       test_layer)

        assert_allclose(ref_out, test_out, rtol=rtol, atol=atol)
        assert_tree_like_allclose(ref_dgrads, test_dgrads, rtol=rtol, atol=atol)

        _, restructed_ref_wgrads = self._sync_params(ref_wgrads, test_wgrads)
        assert_tree_like_allclose(restructed_ref_wgrads, test_wgrads, rtol=rtol, atol=atol)


class EncoderRunner(BaseRunner):
    """Encoder runner implementations"""
    layer_type = TransformerLayerType.ENCODER
    reference_layer = RefEncoderLayer
    transformations = {
        'attention/qkv/scale': 'pre_attention_layer_norm/scale',
        'attention/qkv/ln_bias': 'pre_attention_layer_norm/ln_bias',
        'attention/query/scale': 'pre_attention_layer_norm/scale',
        'attention/query/ln_bias': 'pre_attention_layer_norm/ln_bias',
        'mlp/wi_kernel': 'mlp/wi/kernel',
        'mlp/wi_bias': 'mlp/wi/bias',
        'mlp/wo_kernel': 'mlp/wo/kernel',
        'mlp/wo_bias': 'mlp/wo/bias',
        'mlp/scale': 'pre_mlp_layer_norm/scale',
        'mlp/ln_bias': 'pre_mlp_layer_norm/ln_bias',
    }

    def generate_inputs(self, data_shape, dtype):
        """
        Return inputs, (ref_masks, test_masks)
        """
        transpose_batch_sequence = self.attrs[_KEY_OF_TRANSPOSE_BS]
        batch, seqlen = data_shape[:2]
        if transpose_batch_sequence:
            data_shape = (data_shape[1], data_shape[0], *data_shape[2:])

        data_rng = jax.random.PRNGKey(2024)
        inputs = (jax.random.normal(data_rng, data_shape, dtype),)

        padded_mask = jnp.zeros((batch, 1, seqlen, seqlen), dtype=jnp.uint8)
        causal_mask = jnp.triu(jnp.ones((batch, 1, seqlen, seqlen), dtype=jnp.uint8), k=1)
        if self.attrs[_KEY_OF_SELF_ATTN_MASK_TYPE] in ['casual', 'padding_causal']:
            mask = causal_mask
        else:
            mask = padded_mask

        ref_masks = (1 - mask,)
        test_masks = (None, mask)    # The second arg of Transformer is encoded tokens.

        return inputs, (ref_masks, test_masks)


class DecoderRunner(BaseRunner):
    """
    Decoder runner implementations
    """
    layer_type = TransformerLayerType.DECODER
    reference_layer = RefDecoderLayer
    transformations = {
        'encoder_decoder_attention/qkv/scale': 'pre_cross_attention_layer_norm/scale',
        'encoder_decoder_attention/qkv/ln_bias': 'pre_cross_attention_layer_norm/ln_bias',
        'encoder_decoder_attention/query/scale': 'pre_cross_attention_layer_norm/scale',
        'encoder_decoder_attention/query/ln_bias': 'pre_cross_attention_layer_norm/ln_bias',
        'self_attention/qkv/scale': 'pre_self_attention_layer_norm/scale',
        'self_attention/qkv/ln_bias': 'pre_self_attention_layer_norm/ln_bias',
        'self_attention/query/scale': 'pre_self_attention_layer_norm/scale',
        'self_attention/query/ln_bias': 'pre_self_attention_layer_norm/ln_bias',
        'mlp/wi_kernel': 'mlp/wi/kernel',
        'mlp/wi_bias': 'mlp/wi/bias',
        'mlp/wo_kernel': 'mlp/wo/kernel',
        'mlp/wo_bias': 'mlp/wo/bias',
        'mlp/scale': 'pre_mlp_layer_norm/scale',
        'mlp/ln_bias': 'pre_mlp_layer_norm/ln_bias',
    }

    def generate_inputs(self, data_shape, dtype):
        """
        Return inputs, (ref_masks, test_masks)
        """
        transpose_batch_sequence = self.attrs[_KEY_OF_TRANSPOSE_BS]
        batch, seqlen = data_shape[:2]
        if transpose_batch_sequence:
            data_shape = (data_shape[1], data_shape[0], *data_shape[2:])

        data_rng = jax.random.PRNGKey(0)
        data_rng_0, data_rng_1 = jax.random.split(data_rng, 2)
        inputs = (jax.random.normal(data_rng_0, data_shape,
                                    dtype), jax.random.normal(data_rng_1, data_shape, dtype))

        padded_mask = jnp.zeros((batch, 1, seqlen, seqlen), dtype=jnp.uint8)
        causal_mask = jnp.triu(jnp.ones((batch, 1, seqlen, seqlen), dtype=jnp.uint8), k=1)
        if self.attrs[_KEY_OF_SELF_ATTN_MASK_TYPE] in ['casual', 'padding_causal']:
            self_mask = causal_mask
        else:
            self_mask = padded_mask

        ref_masks = (1 - self_mask, 1 - padded_mask)
        test_masks = (self_mask, padded_mask)

        return inputs, (ref_masks, test_masks)


@pytest.mark.parametrize('data_shape', DATA_SHAPE)
@pytest.mark.parametrize('dtype', DTYPE)
@pytest.mark.parametrize('attrs', ATTRS)
class BaseTester():
    """
    Pytest interface to invoke the runner
    """
    runner = BaseRunner

    def test_forward(self, data_shape, dtype, attrs):
        """Test normal datatype forward"""
        FP8Helper.finalize()    # Ensure FP8 disabled.
        self.runner(attrs).test_forward(data_shape, dtype, rtol=1e-5, atol=7e-5)

    def test_backward(self, data_shape, dtype, attrs):
        """Test normal datatype backward"""
        FP8Helper.finalize()    # Ensure FP8 disabled.
        self.runner(attrs).test_backward(data_shape, dtype, rtol=1e-5, atol=7e-5)

    @pytest.mark.skipif(not is_fp8_supported, reason=reason)
    @pytest.mark.parametrize('fp8_format', FP8_FORMATS)
    def test_forward_with_fp8(self, data_shape, dtype, attrs, fp8_format):
        """Test forward with fp8 enabled"""
        FP8Helper.initialize(fp8_format=fp8_format)
        self.runner(attrs).test_forward(data_shape, dtype, rtol=1e-4, atol=1e-3)
        FP8Helper.finalize()

    @pytest.mark.skipif(not is_fp8_supported, reason=reason)
    @pytest.mark.parametrize('fp8_format', FP8_FORMATS)
    def test_backward_with_fp8(self, data_shape, dtype, attrs, fp8_format):
        """Test backward with fp8 enabled"""
        FP8Helper.initialize(fp8_format=fp8_format)
        self.runner(attrs).test_backward(data_shape, dtype, rtol=1e-4, atol=1e-3)
        FP8Helper.finalize()


class TestEncoderLayer(BaseTester):
    """
    Test transformer_engine.jax.flax.TransformerLayer(layer_type=Encoder)
    """
    runner = EncoderRunner


class TestDecoderLayer(BaseTester):
    """
    Test transformer_engine.jax.flax.TransformerLayer(layer_type=Decoder)
    """
    runner = DecoderRunner
