import contextlib
import gc
import os
from typing import List, Optional, Tuple

import pytest
import torch
from PIL import Image
from transformers import (AutoModelForCausalLM, AutoProcessor,
                          LlavaForConditionalGeneration)

from vllm import LLM, SamplingParams
from vllm.config import TokenizerPoolConfig, VisionLanguageConfig
from vllm.model_executor.parallel_utils.parallel_state import (
    destroy_model_parallel)
from vllm.sequence import MultiModalData
from vllm.transformers_utils.tokenizer import get_tokenizer

_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")]

# Multi modal related
_PIXEL_VALUES_FILES = [
    os.path.join(_TEST_DIR, "images", filename) for filename in
    ["stop_sign_pixel_values.pt", "cherry_blossom_pixel_values.pt"]
]
_IMAGE_FEATURES_FILES = [
    os.path.join(_TEST_DIR, "images", filename) for filename in
    ["stop_sign_image_features.pt", "cherry_blossom_image_features.pt"]
]
_IMAGE_FILES = [
    os.path.join(_TEST_DIR, "images", filename)
    for filename in ["stop_sign.jpg", "cherry_blossom.jpg"]
]
_IMAGE_PROMPTS = [
    "<image>\nUSER: What's the content of the image?\nASSISTANT:",
    "<image>\nUSER: What is the season?\nASSISTANT:"
]
assert len(_PIXEL_VALUES_FILES) == len(_IMAGE_FEATURES_FILES) == len(
    _IMAGE_FILES) == len(_IMAGE_PROMPTS)


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


def cleanup():
    destroy_model_parallel()
    with contextlib.suppress(AssertionError):
        torch.distributed.destroy_process_group()
    gc.collect()
    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(scope="session")
def hf_image_prompts() -> List[str]:
    return _IMAGE_PROMPTS


@pytest.fixture(scope="session")
def hf_images() -> List[Image.Image]:
    return [Image.open(filename) for filename in _IMAGE_FILES]


@pytest.fixture()
def vllm_images(request) -> "torch.Tensor":
    vision_language_config = request.getfixturevalue("model_and_config")[1]
    all_images = []
    if vision_language_config.image_input_type == (
            VisionLanguageConfig.ImageInputType.IMAGE_FEATURES):
        filenames = _IMAGE_FEATURES_FILES
    else:
        filenames = _PIXEL_VALUES_FILES
    for filename in filenames:
        all_images.append(torch.load(filename))
    return torch.concat(all_images, dim=0)


@pytest.fixture()
def vllm_image_prompts(request) -> List[str]:
    vision_language_config = request.getfixturevalue("model_and_config")[1]
    return [
        "<image>" * (vision_language_config.image_feature_size - 1) + p
        for p in _IMAGE_PROMPTS
    ]


@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


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

_VISION_LANGUAGE_MODELS = {
    "llava-hf/llava-1.5-7b-hf": LlavaForConditionalGeneration,
}


class HfRunner:

    def __init__(
        self,
        model_name: str,
        tokenizer_name: Optional[str] = None,
        dtype: str = "half",
    ) -> None:
        assert dtype in _STR_DTYPE_TO_TORCH_DTYPE
        torch_dtype = _STR_DTYPE_TO_TORCH_DTYPE[dtype]
        self.model_name = model_name
        if model_name not in _VISION_LANGUAGE_MODELS:
            self.model = AutoModelForCausalLM.from_pretrained(
                model_name,
                torch_dtype=torch_dtype,
                trust_remote_code=True,
            ).cuda()
            self.processor = None
        else:
            self.model = _VISION_LANGUAGE_MODELS[model_name].from_pretrained(
                model_name,
                torch_dtype=torch_dtype,
                trust_remote_code=True,
            ).cuda()
            self.processor = AutoProcessor.from_pretrained(
                model_name,
                torch_dtype=torch_dtype,
            )
        if tokenizer_name is None:
            tokenizer_name = model_name
        self.tokenizer = get_tokenizer(tokenizer_name, trust_remote_code=True)

    def generate(
        self,
        prompts: List[str],
        images: Optional[List[Image.Image]] = None,
        **kwargs,
    ) -> List[Tuple[List[int], str]]:
        outputs: List[Tuple[List[int], str]] = []
        if images:
            assert len(prompts) == len(images)
        for i, prompt in enumerate(prompts):
            if self.model_name not in _VISION_LANGUAGE_MODELS:
                input_ids = self.tokenizer(prompt,
                                           return_tensors="pt").input_ids
                inputs = {"input_ids": input_ids.cuda()}
            else:
                image = images[i] if images else None
                inputs = self.processor(text=prompt,
                                        images=image,
                                        return_tensors="pt")
                inputs = {
                    key: value.cuda() if value is not None else None
                    for key, value in inputs.items()
                }
            output_ids = self.model.generate(
                **inputs,
                use_cache=True,
                **kwargs,
            )
            output_str = self.tokenizer.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["torch.Tensor"] = None,
    ) -> List[Tuple[List[int], str]]:
        outputs = self.generate(prompts,
                                do_sample=False,
                                max_new_tokens=max_tokens,
                                images=images)
        for i in range(len(outputs)):
            output_ids, output_str = outputs[i]
            outputs[i] = (output_ids[0], output_str[0])
        return outputs

    def generate_beam_search(
        self,
        prompts: List[str],
        beam_width: int,
        max_tokens: int,
    ) -> List[Tuple[List[int], 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,
    ) -> List[List[torch.Tensor]]:
        all_logprobs = []
        for prompt in prompts:
            input_ids = self.tokenizer(prompt, return_tensors="pt").input_ids
            output = self.model.generate(
                input_ids.cuda(),
                use_cache=True,
                do_sample=False,
                max_new_tokens=max_tokens,
                output_hidden_states=True,
                return_dict_in_generate=True,
            )
            seq_logprobs = []
            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 = torch.nn.functional.log_softmax(logits,
                                                           dim=-1,
                                                           dtype=torch.float32)
                seq_logprobs.append(logprobs)
            all_logprobs.append(seq_logprobs)
        return all_logprobs

    def __del__(self):
        del self.model
        cleanup()


@pytest.fixture
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=1024,
        dtype: str = "half",
        disable_log_stats: bool = True,
        tensor_parallel_size: int = 1,
        block_size: int = 16,
        enable_chunked_prefill: bool = False,
        **kwargs,
    ) -> None:
        self.model = LLM(
            model=model_name,
            tokenizer=tokenizer_name,
            trust_remote_code=True,
            dtype=dtype,
            swap_space=0,
            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["torch.Tensor"] = None,
    ) -> List[Tuple[List[int], str]]:
        if images is not None:
            assert len(prompts) == images.shape[0]
        req_outputs = self.model.generate(
            prompts,
            sampling_params=sampling_params,
            multi_modal_data=MultiModalData(type=MultiModalData.Type.IMAGE,
                                            data=images)
            if images is not None else None)
        outputs = []
        for req_output in req_outputs:
            prompt_str = req_output.prompt
            prompt_ids = req_output.prompt_token_ids
            req_sample_output_ids = []
            req_sample_output_strs = []
            for sample in req_output.outputs:
                output_str = sample.text
                output_ids = 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,
    ) -> List[Tuple[List[int], str]]:
        assert sampling_params.logprobs is not None

        req_outputs = self.model.generate(prompts,
                                          sampling_params=sampling_params)
        outputs = []
        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[torch.Tensor] = 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,
    ) -> List[Tuple[List[int], str]]:
        greedy_logprobs_params = SamplingParams(temperature=0.0,
                                                max_tokens=max_tokens,
                                                logprobs=num_logprobs)
        outputs = self.generate_w_logprobs(prompts, greedy_logprobs_params)

        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[int], 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 __del__(self):
        del self.model
        cleanup()


@pytest.fixture
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}")
