import contextlib
import gc
import os
import sys
from collections import UserList
from typing import Any, Dict, List, Optional, Tuple, TypedDict, TypeVar

import pytest
import torch
import torch.nn as nn
import torch.nn.functional as F
from PIL import Image
from transformers import (AutoModelForCausalLM, AutoModelForVision2Seq,
                          AutoTokenizer, BatchEncoding)

from vllm import LLM, SamplingParams
from vllm.assets.image import ImageAsset
from vllm.config import TokenizerPoolConfig
from vllm.distributed import (destroy_distributed_environment,
                              destroy_model_parallel)
from vllm.inputs import TextPrompt
from vllm.logger import init_logger
from vllm.sequence import SampleLogprobs
from vllm.utils import cuda_device_count_stateless, is_cpu

logger = init_logger(__name__)

_TEST_DIR = os.path.dirname(__file__)
_TEST_PROMPTS = [os.path.join(_TEST_DIR, "prompts", "example.txt")]
_LONG_PROMPTS = [os.path.join(_TEST_DIR, "prompts", "summary.txt")]


def _read_prompts(filename: str) -> List[str]:
    with open(filename, "r") as f:
        prompts = f.readlines()
        return prompts


class _ImageAssetPrompts(TypedDict):
    stop_sign: str
    cherry_blossom: str


if sys.version_info < (3, 9):
    # UserList cannot be subscripted
    class _ImageAssetsBase(UserList):
        pass
else:

    class _ImageAssetsBase(UserList[ImageAsset]):
        pass


class _ImageAssets(_ImageAssetsBase):

    def __init__(self) -> None:
        super().__init__([
            ImageAsset("stop_sign"),
            ImageAsset("cherry_blossom"),
        ])

    def prompts(self, prompts: _ImageAssetPrompts) -> List[str]:
        """
        Convenience method to define the prompt for each test image.

        The order of the returned prompts matches the order of the
        assets when iterating through this object.
        """
        return [prompts["stop_sign"], prompts["cherry_blossom"]]


IMAGE_ASSETS = _ImageAssets()
"""Singleton instance of :class:`_ImageAssets`."""


def cleanup():
    destroy_model_parallel()
    destroy_distributed_environment()
    with contextlib.suppress(AssertionError):
        torch.distributed.destroy_process_group()
    gc.collect()
    if not is_cpu():
        torch.cuda.empty_cache()


@pytest.fixture()
def should_do_global_cleanup_after_test(request) -> bool:
    """Allow subdirectories to skip global cleanup by overriding this fixture.
    This can provide a ~10x speedup for non-GPU unit tests since they don't need
    to initialize torch.
    """

    if request.node.get_closest_marker("skip_global_cleanup"):
        return False

    return True


@pytest.fixture(autouse=True)
def cleanup_fixture(should_do_global_cleanup_after_test: bool):
    yield
    if should_do_global_cleanup_after_test:
        cleanup()


@pytest.fixture
def example_prompts() -> List[str]:
    prompts = []
    for filename in _TEST_PROMPTS:
        prompts += _read_prompts(filename)
    return prompts


@pytest.fixture
def example_long_prompts() -> List[str]:
    prompts = []
    for filename in _LONG_PROMPTS:
        prompts += _read_prompts(filename)
    return prompts


@pytest.fixture(scope="session")
def image_assets() -> _ImageAssets:
    return IMAGE_ASSETS


_STR_DTYPE_TO_TORCH_DTYPE = {
    "half": torch.half,
    "bfloat16": torch.bfloat16,
    "float": torch.float,
}

_T = TypeVar("_T", nn.Module, torch.Tensor, BatchEncoding)


class HfRunner:

    def wrap_device(self, input: _T) -> _T:
        if not is_cpu():
            return input.to("cuda")
        else:
            return input.to("cpu")

    def __init__(
        self,
        model_name: str,
        dtype: str = "half",
        *,
        model_kwargs: Optional[Dict[str, Any]] = None,
        is_embedding_model: bool = False,
        is_vision_model: bool = False,
        is_sparseml_model: bool = False,
    ) -> None:
        assert dtype in _STR_DTYPE_TO_TORCH_DTYPE
        torch_dtype = _STR_DTYPE_TO_TORCH_DTYPE[dtype]

        self.model_name = model_name

        if is_embedding_model:
            # Lazy init required for AMD CI
            from sentence_transformers import SentenceTransformer
            self.model = self.wrap_device(
                SentenceTransformer(
                    model_name,
                    device="cpu",
                ).to(dtype=torch_dtype))
        else:
            if is_vision_model:
                auto_cls = AutoModelForVision2Seq
            elif is_sparseml_model:
                from sparseml.transformers import SparseAutoModelForCausalLM
                auto_cls = SparseAutoModelForCausalLM
            else:
                auto_cls = AutoModelForCausalLM

            model_kwargs = model_kwargs if model_kwargs is not None else {}
            self.model = self.wrap_device(
                auto_cls.from_pretrained(
                    model_name,
                    torch_dtype=torch_dtype,
                    trust_remote_code=True,
                    **model_kwargs,
                ))

        self.tokenizer = AutoTokenizer.from_pretrained(
            model_name,
            torch_dtype=torch_dtype,
            trust_remote_code=True,
        )

        try:
            # don't put this import at the top level
            # it will call torch.cuda.device_count()
            from transformers import AutoProcessor  # noqa: F401
            self.processor = AutoProcessor.from_pretrained(
                model_name,
                torch_dtype=torch_dtype,
                trust_remote_code=True,
            )
        except Exception:
            logger.warning(
                "Unable to auto-load processor from HuggingFace for "
                "model %s. Using tokenizer instead.", model_name)
            self.processor = self.tokenizer

    def generate(
        self,
        prompts: List[str],
        images: Optional[List[Image.Image]] = None,
        **kwargs: Any,
    ) -> List[Tuple[List[List[int]], List[str]]]:
        if images:
            assert len(prompts) == len(images)

        outputs: List[Tuple[List[List[int]], List[str]]] = []
        for i, prompt in enumerate(prompts):
            processor_kwargs: Dict[str, Any] = {
                "text": prompt,
                "return_tensors": "pt",
            }
            if images is not None and images[i] is not None:
                processor_kwargs["images"] = images[i]

            inputs = self.processor(**processor_kwargs)

            output_ids = self.model.generate(
                **self.wrap_device(inputs),
                use_cache=True,
                **kwargs,
            )
            output_str = self.processor.batch_decode(
                output_ids,
                skip_special_tokens=True,
                clean_up_tokenization_spaces=False,
            )
            output_ids = output_ids.cpu().tolist()
            outputs.append((output_ids, output_str))
        return outputs

    def generate_greedy(
        self,
        prompts: List[str],
        max_tokens: int,
        images: Optional[List[Image.Image]] = None,
        **kwargs: Any,
    ) -> List[Tuple[List[int], str]]:
        outputs = self.generate(prompts,
                                do_sample=False,
                                max_new_tokens=max_tokens,
                                images=images,
                                **kwargs)

        return [(output_ids[0], output_str[0])
                for output_ids, output_str in outputs]

    def generate_beam_search(
        self,
        prompts: List[str],
        beam_width: int,
        max_tokens: int,
    ) -> List[Tuple[List[List[int]], List[str]]]:
        outputs = self.generate(prompts,
                                do_sample=False,
                                max_new_tokens=max_tokens,
                                num_beams=beam_width,
                                num_return_sequences=beam_width)
        for i in range(len(outputs)):
            output_ids, output_str = outputs[i]
            for j in range(len(output_ids)):
                output_ids[j] = [
                    x for x in output_ids[j]
                    if x != self.tokenizer.pad_token_id
                ]
            outputs[i] = (output_ids, output_str)
        return outputs

    def generate_greedy_logprobs(
        self,
        prompts: List[str],
        max_tokens: int,
        images: Optional[List[Image.Image]] = None,
        **kwargs: Any,
    ) -> List[List[torch.Tensor]]:
        all_logprobs: List[List[torch.Tensor]] = []
        for i, prompt in enumerate(prompts):
            processor_kwargs: Dict[str, Any] = {
                "text": prompt,
                "return_tensors": "pt",
            }
            if images is not None and images[i] is not None:
                processor_kwargs["images"] = images[i]

            inputs = self.processor(**processor_kwargs)

            output = self.model.generate(
                **self.wrap_device(inputs),
                use_cache=True,
                do_sample=False,
                max_new_tokens=max_tokens,
                output_hidden_states=True,
                return_dict_in_generate=True,
                **kwargs,
            )
            seq_logprobs: List[torch.Tensor] = []
            for hidden_states in output.hidden_states:
                last_hidden_states = hidden_states[-1][0]
                logits = torch.matmul(
                    last_hidden_states,
                    self.model.get_output_embeddings().weight.t(),
                )
                if self.model.get_output_embeddings().bias is not None:
                    logits += self.model.get_output_embeddings(
                    ).bias.unsqueeze(0)
                logprobs = F.log_softmax(logits, dim=-1, dtype=torch.float32)
                seq_logprobs.append(logprobs)
            all_logprobs.append(seq_logprobs)
        return all_logprobs

    def generate_greedy_logprobs_limit(
        self,
        prompts: List[str],
        max_tokens: int,
        num_logprobs: int,
        images: Optional[List[Image.Image]] = None,
        **kwargs: Any,
    ) -> List[Tuple[List[int], str, List[Dict[int, float]]]]:
        all_logprobs: List[List[Dict[int, float]]] = []
        all_output_ids: List[List[int]] = []
        all_output_strs: List[str] = []

        for i, prompt in enumerate(prompts):
            processor_kwargs: Dict[str, Any] = {
                "text": prompt,
                "return_tensors": "pt",
            }
            if images is not None and images[i] is not None:
                processor_kwargs["images"] = images[i]

            inputs = self.processor(**processor_kwargs)
            input_ids = inputs.input_ids

            output = self.model.generate(
                **self.wrap_device(inputs),
                use_cache=True,
                do_sample=False,
                max_new_tokens=max_tokens,
                output_hidden_states=True,
                return_dict_in_generate=True,
                **kwargs,
            )

            seq_logprobs: List[torch.Tensor] = []
            for _, hidden_states in enumerate(output.hidden_states):
                last_hidden_states = hidden_states[-1][0]
                logits = torch.matmul(
                    last_hidden_states,
                    self.model.get_output_embeddings().weight.t(),
                )
                if getattr(self.model.get_output_embeddings(), "bias",
                           None) is not None:
                    logits += self.model.get_output_embeddings(
                    ).bias.unsqueeze(0)
                logprobs = F.log_softmax(logits, dim=-1, dtype=torch.float32)
                seq_logprobs.append(logprobs)

            # convert to dict
            seq_logprobs_lst: List[Dict[int, float]] = []
            for tok_idx, tok_logprobs in enumerate(seq_logprobs):
                # drop prompt logprobs
                if tok_idx == 0:
                    tok_logprobs = tok_logprobs[-1, :].reshape(1, -1)
                topk = tok_logprobs.topk(num_logprobs)

                tok_logprobs_dct = {}
                for token_id, logprob in zip(topk.indices[0], topk.values[0]):
                    tok_logprobs_dct[token_id.item()] = logprob.item()

                seq_logprobs_lst.append(tok_logprobs_dct)

            all_logprobs.append(seq_logprobs_lst)
            seq_ids = output.sequences[0]
            output_len = seq_ids.shape[0] - input_ids.shape[1]
            output_ids = seq_ids[-output_len:]
            all_output_ids.append(output_ids.tolist())
            all_output_strs.append(self.tokenizer.decode(output_ids))

        outputs = zip(all_output_ids, all_output_strs, all_logprobs)
        return [(output_ids, output_str, output_logprobs)
                for output_ids, output_str, output_logprobs in outputs]

    def encode(self, prompts: List[str]) -> List[List[torch.Tensor]]:
        return self.model.encode(prompts)

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        del self.model
        cleanup()


@pytest.fixture(scope="session")
def hf_runner():
    return HfRunner


class VllmRunner:

    def __init__(
        self,
        model_name: str,
        tokenizer_name: Optional[str] = None,
        # Use smaller max model length, otherwise bigger model cannot run due
        # to kv cache size limit.
        max_model_len: int = 1024,
        dtype: str = "half",
        disable_log_stats: bool = True,
        tensor_parallel_size: int = 1,
        block_size: int = 16,
        enable_chunked_prefill: bool = False,
        swap_space: int = 4,
        enforce_eager: bool = False,
        **kwargs,
    ) -> None:
        self.model = LLM(
            model=model_name,
            tokenizer=tokenizer_name,
            trust_remote_code=True,
            dtype=dtype,
            swap_space=swap_space,
            enforce_eager=enforce_eager,
            disable_log_stats=disable_log_stats,
            tensor_parallel_size=tensor_parallel_size,
            max_model_len=max_model_len,
            block_size=block_size,
            enable_chunked_prefill=enable_chunked_prefill,
            **kwargs,
        )

    def generate(
        self,
        prompts: List[str],
        sampling_params: SamplingParams,
        images: Optional[List[Image.Image]] = None,
    ) -> List[Tuple[List[List[int]], List[str]]]:
        if images is not None:
            assert len(prompts) == len(images)

        inputs = [TextPrompt(prompt=prompt) for prompt in prompts]
        if images is not None:
            for i, image in enumerate(images):
                inputs[i]["multi_modal_data"] = {"image": image}

        req_outputs = self.model.generate(inputs,
                                          sampling_params=sampling_params)

        outputs: List[Tuple[List[List[int]], List[str]]] = []
        for req_output in req_outputs:
            prompt_str = req_output.prompt
            prompt_ids = req_output.prompt_token_ids
            req_sample_output_ids: List[List[int]] = []
            req_sample_output_strs: List[str] = []
            for sample in req_output.outputs:
                output_str = sample.text
                output_ids = list(sample.token_ids)
                req_sample_output_ids.append(prompt_ids + output_ids)
                req_sample_output_strs.append(prompt_str + output_str)
            outputs.append((req_sample_output_ids, req_sample_output_strs))
        return outputs

    def generate_w_logprobs(
        self,
        prompts: List[str],
        sampling_params: SamplingParams,
        images: Optional[List[Image.Image]] = None,
    ) -> List[Tuple[List[int], str, Optional[SampleLogprobs]]]:
        assert sampling_params.logprobs is not None

        if images is not None:
            assert len(prompts) == len(images)

        inputs = [TextPrompt(prompt=prompt) for prompt in prompts]
        if images is not None:
            for i, image in enumerate(images):
                inputs[i]["multi_modal_data"] = {"image": image}

        req_outputs = self.model.generate(inputs,
                                          sampling_params=sampling_params)
        outputs: List[Tuple[List[int], str, Optional[SampleLogprobs]]] = []
        for req_output in req_outputs:
            for sample in req_output.outputs:
                output_str = sample.text
                output_ids = sample.token_ids
                output_logprobs = sample.logprobs
            outputs.append((output_ids, output_str, output_logprobs))
        return outputs

    def generate_greedy(
        self,
        prompts: List[str],
        max_tokens: int,
        images: Optional[List[Image.Image]] = None,
    ) -> List[Tuple[List[int], str]]:
        greedy_params = SamplingParams(temperature=0.0, max_tokens=max_tokens)
        outputs = self.generate(prompts, greedy_params, images=images)
        return [(output_ids[0], output_str[0])
                for output_ids, output_str in outputs]

    def generate_greedy_logprobs(
        self,
        prompts: List[str],
        max_tokens: int,
        num_logprobs: int,
        images: Optional[List[Image.Image]] = None,
    ) -> List[Tuple[List[int], str, Optional[SampleLogprobs]]]:
        greedy_logprobs_params = SamplingParams(temperature=0.0,
                                                max_tokens=max_tokens,
                                                logprobs=num_logprobs)
        outputs = self.generate_w_logprobs(prompts,
                                           greedy_logprobs_params,
                                           images=images)

        return [(output_ids, output_str, output_logprobs)
                for output_ids, output_str, output_logprobs in outputs]

    def generate_beam_search(
        self,
        prompts: List[str],
        beam_width: int,
        max_tokens: int,
    ) -> List[Tuple[List[List[int]], List[str]]]:
        beam_search_params = SamplingParams(n=beam_width,
                                            use_beam_search=True,
                                            temperature=0.0,
                                            max_tokens=max_tokens)
        outputs = self.generate(prompts, beam_search_params)
        return outputs

    def encode(self, prompts: List[str]) -> List[List[float]]:
        req_outputs = self.model.encode(prompts)
        outputs = []
        for req_output in req_outputs:
            embedding = req_output.outputs.embedding
            outputs.append(embedding)
        return outputs

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        del self.model
        cleanup()


@pytest.fixture(scope="session")
def vllm_runner():
    return VllmRunner


def get_tokenizer_pool_config(tokenizer_group_type):
    if tokenizer_group_type is None:
        return None
    if tokenizer_group_type == "ray":
        return TokenizerPoolConfig(pool_size=1,
                                   pool_type="ray",
                                   extra_config={})
    raise ValueError(f"Unknown tokenizer_group_type: {tokenizer_group_type}")


@pytest.fixture()
def temporary_enable_log_propagate():
    import logging
    logger = logging.getLogger("vllm")
    logger.propagate = True
    yield
    logger.propagate = False


@pytest.fixture()
def caplog_vllm(temporary_enable_log_propagate, caplog):
    # To capture vllm log, we should enable propagate=True temporarily
    # because caplog depends on logs propagated to the root logger.
    yield caplog


@pytest.fixture(scope="session")
def num_gpus_available():
    """Get number of GPUs without initializing the CUDA context
    in current process."""

    return cuda_device_count_stateless()
