# SPDX-License-Identifier: Apache-2.0
import asyncio
import time
from collections.abc import AsyncGenerator, Mapping
from typing import Any, Optional, Union

from fastapi import Request

from vllm.config import ModelConfig
from vllm.engine.protocol import EngineClient
from vllm.entrypoints.logger import RequestLogger
from vllm.entrypoints.openai.protocol import (ErrorResponse, RerankDocument,
                                              RerankRequest, RerankResponse,
                                              RerankResult, RerankUsage,
                                              ScoreRequest, ScoreResponse,
                                              ScoreResponseData, UsageInfo)
from vllm.entrypoints.openai.serving_engine import OpenAIServing
from vllm.entrypoints.openai.serving_models import OpenAIServingModels
from vllm.entrypoints.score_utils import (_cosine_similarity,
                                          _validate_score_input_lens)
from vllm.inputs.data import TokensPrompt
from vllm.logger import init_logger
from vllm.lora.request import LoRARequest
from vllm.outputs import PoolingRequestOutput, ScoringRequestOutput
from vllm.prompt_adapter.request import PromptAdapterRequest
from vllm.transformers_utils.tokenizer import (AnyTokenizer, MistralTokenizer,
                                               PreTrainedTokenizer,
                                               PreTrainedTokenizerFast)
from vllm.utils import make_async, merge_async_iterators

logger = init_logger(__name__)


class ServingScores(OpenAIServing):

    def __init__(
        self,
        engine_client: EngineClient,
        model_config: ModelConfig,
        models: OpenAIServingModels,
        *,
        request_logger: Optional[RequestLogger],
    ) -> None:
        super().__init__(engine_client=engine_client,
                         model_config=model_config,
                         models=models,
                         request_logger=request_logger)

    async def _embedding_score(
        self,
        tokenizer: Union[PreTrainedTokenizer, PreTrainedTokenizerFast],
        texts_1: list[str],
        texts_2: list[str],
        request: Union[RerankRequest, ScoreRequest],
        request_id=str,
        tokenization_kwargs: Optional[dict[str, Any]] = None,
        lora_request: Optional[Union[LoRARequest, None]] = None,
        prompt_adapter_request: Optional[Union[PromptAdapterRequest,
                                               None]] = None,
        trace_headers: Optional[Mapping[str, str]] = None,
    ) -> list[PoolingRequestOutput]:

        input_texts = texts_1 + texts_2

        engine_prompts: list[TokensPrompt] = []
        tokenize_async = make_async(tokenizer.__call__,
                                    executor=self._tokenizer_executor)

        tokenization_kwargs = tokenization_kwargs or {}
        tokenized_prompts = await asyncio.gather(
            *(tokenize_async(t, **tokenization_kwargs) for t in input_texts))

        for tok_result, input_text in zip(tokenized_prompts, input_texts):

            text_token_prompt = \
                self._validate_input(
                    request,
                    tok_result["input_ids"],
                    input_text)

            engine_prompts.append(
                TokensPrompt(
                    prompt_token_ids=text_token_prompt["prompt_token_ids"]))

        # Schedule the request and get the result generator.
        generators: list[AsyncGenerator[PoolingRequestOutput, None]] = []
        pooling_params = request.to_pooling_params()

        for i, engine_prompt in enumerate(engine_prompts):

            request_id_item = f"{request_id}-{i}"

            self._log_inputs(request_id_item,
                             input_texts[i],
                             params=pooling_params,
                             lora_request=lora_request,
                             prompt_adapter_request=prompt_adapter_request)

            generators.append(
                self.engine_client.encode(
                    engine_prompt,
                    pooling_params,
                    request_id_item,
                    lora_request=lora_request,
                    trace_headers=trace_headers,
                    priority=request.priority,
                ))

        result_generator = merge_async_iterators(*generators)

        # Non-streaming response
        final_res_batch: list[PoolingRequestOutput] = []

        embeddings: list[Optional[PoolingRequestOutput]] =\
              [None] * len(engine_prompts)

        async for i, res in result_generator:
            embeddings[i] = res

        emb_texts_1: list[PoolingRequestOutput] = []
        emb_texts_2: list[PoolingRequestOutput] = []

        for i in range(0, len(texts_1)):
            assert (emb := embeddings[i]) is not None
            emb_texts_1.append(emb)

        for i in range(len(texts_1), len(embeddings)):
            assert (emb := embeddings[i]) is not None
            emb_texts_2.append(emb)

        if len(emb_texts_1) == 1:
            emb_texts_1 = emb_texts_1 * len(emb_texts_2)

        final_res_batch = _cosine_similarity(tokenizer=tokenizer,
                                             embed_1=emb_texts_1,
                                             embed_2=emb_texts_2)

        return final_res_batch

    async def _cross_encoding_score(
        self,
        tokenizer: Union[AnyTokenizer],
        texts_1: list[str],
        texts_2: list[str],
        request: Union[RerankRequest, ScoreRequest],
        request_id=str,
        tokenization_kwargs: Optional[dict[str, Any]] = None,
        lora_request: Optional[Union[LoRARequest, None]] = None,
        prompt_adapter_request: Optional[Union[PromptAdapterRequest,
                                               None]] = None,
        trace_headers: Optional[Mapping[str, str]] = None,
    ) -> list[PoolingRequestOutput]:

        request_prompts: list[str] = []
        engine_prompts: list[TokensPrompt] = []

        if len(texts_1) == 1:
            texts_1 = texts_1 * len(texts_2)

        input_pairs = [(t1, t2) for t1, t2 in zip(texts_1, texts_2)]

        if isinstance(tokenizer, MistralTokenizer):
            raise ValueError(
                "MistralTokenizer not supported for cross-encoding")

        tokenize_async = make_async(tokenizer.__call__,
                                    executor=self._tokenizer_executor)

        tokenization_kwargs = tokenization_kwargs or {}
        tokenized_prompts = await asyncio.gather(
            *(tokenize_async(text=t1, text_pair=t2, **tokenization_kwargs)
              for t1, t2 in input_pairs))

        for prompt_inputs, (t1, t2) in zip(tokenized_prompts, input_pairs):

            request_prompt = f"{t1}{tokenizer.sep_token}{t2}"

            input_ids = prompt_inputs["input_ids"]
            text_token_prompt = \
                self._validate_input(request, input_ids, request_prompt)
            engine_prompt = TokensPrompt(
                prompt_token_ids=text_token_prompt["prompt_token_ids"],
                token_type_ids=prompt_inputs.get("token_type_ids"))

            request_prompts.append(request_prompt)
            engine_prompts.append(engine_prompt)

        # Schedule the request and get the result generator.
        generators: list[AsyncGenerator[PoolingRequestOutput, None]] = []

        pooling_params = request.to_pooling_params()

        for i, engine_prompt in enumerate(engine_prompts):
            request_id_item = f"{request_id}-{i}"

            self._log_inputs(request_id_item,
                             request_prompts[i],
                             params=pooling_params,
                             lora_request=lora_request,
                             prompt_adapter_request=prompt_adapter_request)

            generator = self.engine_client.encode(
                engine_prompt,
                pooling_params,
                request_id_item,
                lora_request=lora_request,
                trace_headers=trace_headers,
                priority=request.priority,
            )

            generators.append(generator)

        result_generator = merge_async_iterators(*generators)

        # Non-streaming response
        final_res_batch: list[
            Optional[PoolingRequestOutput]] = [None] * len(engine_prompts)

        async for i, res in result_generator:
            final_res_batch[i] = res

        return [out for out in final_res_batch if out is not None]

    async def _run_scoring(
        self,
        texts_1: Union[str, list[str]],
        texts_2: Union[str, list[str]],
        request: Union[ScoreRequest, RerankRequest],
        request_id: str,
        raw_request: Optional[Request] = None,
        truncate_prompt_tokens: Optional[int] = None,
    ) -> list[PoolingRequestOutput]:

        tokenization_kwargs: dict[str, Any] = {}
        if truncate_prompt_tokens is not None:
            tokenization_kwargs["truncation"] = True
            tokenization_kwargs["max_length"] = truncate_prompt_tokens

        (
            lora_request,
            prompt_adapter_request,
        ) = self._maybe_get_adapters(request)

        if prompt_adapter_request is not None:
            raise NotImplementedError("Prompt adapter is not supported "
                                      "for scoring models")

        tokenizer = await self.engine_client.get_tokenizer(lora_request)

        if truncate_prompt_tokens is not None and \
                truncate_prompt_tokens > self.max_model_len:
            raise ValueError(
                f"truncate_prompt_tokens value ({truncate_prompt_tokens}) "
                f"is greater than max_model_len ({self.max_model_len})."
                f" Please, select a smaller truncation size.")

        trace_headers = (None if raw_request is None else await
                         self._get_trace_headers(raw_request.headers))

        if isinstance(texts_1, str):
            texts_1 = [texts_1]
        if isinstance(texts_2, str):
            texts_2 = [texts_2]

        _validate_score_input_lens(texts_1, texts_2)

        if self.model_config.is_cross_encoder:
            return await self._cross_encoding_score(
                tokenizer=tokenizer,
                texts_1=texts_1,
                texts_2=texts_2,
                request=request,
                request_id=request_id,
                tokenization_kwargs=tokenization_kwargs,
                lora_request=lora_request,
                prompt_adapter_request=prompt_adapter_request,
                trace_headers=trace_headers)

        else:
            return await self._embedding_score(
                tokenizer=tokenizer,
                texts_1=texts_1,
                texts_2=texts_2,
                request=request,
                request_id=request_id,
                tokenization_kwargs=tokenization_kwargs,
                lora_request=lora_request,
                prompt_adapter_request=prompt_adapter_request,
                trace_headers=trace_headers)

    async def create_score(
        self,
        request: ScoreRequest,
        raw_request: Optional[Request] = None,
    ) -> Union[ScoreResponse, ErrorResponse]:
        """
        Score API similar to Sentence Transformers cross encoder

        See https://sbert.net/docs/package_reference/cross_encoder
        """
        error_check_ret = await self._check_model(request)
        if error_check_ret is not None:
            return error_check_ret

        request_id = f"score-{self._base_request_id(raw_request)}"
        created_time = int(time.time())

        try:
            final_res_batch = await self._run_scoring(
                request.text_1,
                request.text_2,
                request,
                request_id,
                raw_request,
                request.truncate_prompt_tokens,
            )

            return self.request_output_to_score_response(
                final_res_batch,
                request_id,
                created_time,
                self._get_model_name(request.model),
            )
        except asyncio.CancelledError:
            return self.create_error_response("Client disconnected")
        except ValueError as e:
            # TODO: Use a vllm-specific Validation Error
            return self.create_error_response(str(e))

    async def do_rerank(
        self,
        request: RerankRequest,
        raw_request: Optional[Request] = None
    ) -> Union[RerankResponse, ErrorResponse]:
        """
        Rerank API based on JinaAI's rerank API; implements the same
        API interface. Designed for compatibility with off-the-shelf
        tooling, since this is a common standard for reranking APIs

        See example client implementations at
        https://github.com/infiniflow/ragflow/blob/main/rag/llm/rerank_model.py
        numerous clients use this standard.
        """
        error_check_ret = await self._check_model(request)
        if error_check_ret is not None:
            return error_check_ret

        request_id = f"rerank-{self._base_request_id(raw_request)}"
        documents = request.documents
        top_n = request.top_n if request.top_n > 0 else len(documents)

        try:
            final_res_batch = await self._run_scoring(
                request.query,
                documents,
                request,
                request_id,
                raw_request,
                request.truncate_prompt_tokens,
            )
            return self.request_output_to_rerank_response(
                final_res_batch,
                request_id,
                self._get_model_name(request.model),
                documents,
                top_n,
            )
        except asyncio.CancelledError:
            return self.create_error_response("Client disconnected")
        except ValueError as e:
            # TODO: Use a vllm-specific Validation Error
            return self.create_error_response(str(e))

    def request_output_to_score_response(
        self,
        final_res_batch: list[PoolingRequestOutput],
        request_id: str,
        created_time: int,
        model_name: str,
    ) -> ScoreResponse:
        items: list[ScoreResponseData] = []
        num_prompt_tokens = 0

        for idx, final_res in enumerate(final_res_batch):
            classify_res = ScoringRequestOutput.from_base(final_res)

            item = ScoreResponseData(
                index=idx,
                score=classify_res.outputs.score,
            )
            prompt_token_ids = final_res.prompt_token_ids

            items.append(item)
            num_prompt_tokens += len(prompt_token_ids)

        usage = UsageInfo(
            prompt_tokens=num_prompt_tokens,
            total_tokens=num_prompt_tokens,
        )

        return ScoreResponse(
            id=request_id,
            created=created_time,
            model=model_name,
            data=items,
            usage=usage,
        )

    def request_output_to_rerank_response(
            self, final_res_batch: list[PoolingRequestOutput], request_id: str,
            model_name: str, documents: list[str],
            top_n: int) -> RerankResponse:
        """
        Convert the output of do_rank to a RerankResponse
        """
        results: list[RerankResult] = []
        num_prompt_tokens = 0
        for idx, final_res in enumerate(final_res_batch):
            classify_res = ScoringRequestOutput.from_base(final_res)

            result = RerankResult(
                index=idx,
                document=RerankDocument(text=documents[idx]),
                relevance_score=classify_res.outputs.score,
            )
            results.append(result)
            prompt_token_ids = final_res.prompt_token_ids
            num_prompt_tokens += len(prompt_token_ids)

        # sort by relevance, then return the top n if set
        results.sort(key=lambda x: x.relevance_score, reverse=True)
        if top_n < len(documents):
            results = results[:top_n]

        return RerankResponse(
            id=request_id,
            model=model_name,
            results=results,
            usage=RerankUsage(total_tokens=num_prompt_tokens))
