# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from collections.abc import Sequence
from typing import Any, Literal, cast

import torch
from openai.types.chat import (
    ChatCompletionContentPartImageParam,
    ChatCompletionContentPartTextParam,
)
from openai.types.chat.chat_completion_content_part_image_param import ImageURL

from vllm import PoolingParams
from vllm.entrypoints.chat_utils import (
    ChatCompletionContentPartParam,
    ChatCompletionMessageParam,
    CustomChatCompletionMessageParam,
)
from vllm.entrypoints.pooling.base.io_processor import PoolingIOProcessor
from vllm.entrypoints.pooling.embed.protocol import (
    CohereEmbedInput,
    CohereEmbedRequest,
    EmbeddingChatRequest,
    EmbeddingCompletionRequest,
)
from vllm.entrypoints.pooling.typing import PoolingServeContext
from vllm.inputs import EngineInput, tokens_input
from vllm.logger import init_logger
from vllm.outputs import PoolingOutput, PoolingRequestOutput
from vllm.renderers import merge_kwargs
from vllm.utils.collection_utils import chunk_list
from vllm.utils.mistral import is_mistral_tokenizer

logger = init_logger(__name__)


class EmbedIOProcessor(PoolingIOProcessor):
    name = "embedding"

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        assert self.model_config.pooler_config is not None

        self.pooler_config = self.model_config.pooler_config
        self.enable_chunked_processing = self.pooler_config.enable_chunked_processing

        # Load task instructions from HF config or sentence-transformers config
        self.task_instructions: dict[str, str] | None = self._load_task_instructions(
            self.model_config.hf_config
        ) or self._load_st_prompts(self.model_config.model, self.model_config.revision)
        if self.task_instructions:
            logger.info(
                "Loaded prompt prefixes for input_type: %s",
                list(self.task_instructions.keys()),
            )

    def pre_process_online(self, ctx: PoolingServeContext):
        if isinstance(ctx.request, CohereEmbedRequest):
            self._pre_process_cohere_online(ctx)
        else:
            super().pre_process_online(ctx)

        if self.enable_chunked_processing:
            self._pre_process_chunked(ctx)

    def post_process_online(
        self,
        ctx: PoolingServeContext,
    ):
        if ctx.final_res_batch is None:
            raise ValueError("Final response batch not available")

        if not self.enable_chunked_processing:
            self._enforce_cohere_max_tokens(ctx)
            return super().post_process_online(ctx)

        self._post_process_chunked(ctx)
        self._enforce_cohere_max_tokens(ctx)

    #################################################################
    # Long Text Embedding with Chunked Processing
    # PTAL: examples/pooling/embed/openai_embedding_long_text
    #################################################################

    def _pre_process_chunked(self, ctx: PoolingServeContext) -> None:
        if ctx.engine_inputs is None:
            raise ValueError("Engine prompts not available")

        ctx.intermediates = ctx.engine_inputs
        request_id = ctx.request_id
        max_model_len = self.model_config.max_model_len
        chunked_engine_inputs: list[EngineInput] = []
        prompt_request_ids: list[str] = []
        for prompt_idx, engine_input in enumerate(ctx.engine_inputs):
            token_ids = engine_input.get("prompt_token_ids", None)
            if token_ids is None:
                raise NotImplementedError(
                    "Long Text Embedding with Chunked Processing does "
                    "not support EmbedsPrompt and EncoderDecoderInput."
                )

            prompt_token_ids = cast(list[int], token_ids)

            for chunk_idx, chunk_tokens in enumerate(
                chunk_list(prompt_token_ids, max_model_len)
            ):
                chunked_engine_inputs.append(
                    tokens_input(prompt_token_ids=chunk_tokens)
                )
                prompt_request_ids.append(
                    f"{request_id}-prompt-{prompt_idx}-chunk-{chunk_idx}"
                )

        ctx.engine_inputs = chunked_engine_inputs
        ctx.prompt_request_ids = prompt_request_ids

        return None

    def _post_process_chunked(self, ctx: PoolingServeContext) -> None:
        # Online aggregation for chunked requests to
        # minimize memory usage
        # Track aggregation state for each prompt
        prompt_aggregators: dict[int, dict[str, Any]] = {}
        short_prompts_results: dict[int, PoolingRequestOutput] = {}
        for result_idx, result in enumerate(ctx.final_res_batch):
            if "-chunk-" not in result.request_id:
                # Non-chunked result - extract prompt_idx from request_id
                parts = result.request_id.split("-")
                try:
                    # Last part should be prompt index
                    prompt_idx = int(parts[-1])
                except (ValueError, IndexError):
                    prompt_idx = result_idx  # Fallback to result_idx

                short_prompts_results[prompt_idx] = result
            else:
                # Extract prompt_idx from chunked request_id
                parts = result.request_id.split("-")
                try:
                    prompt_idx = int(parts[parts.index("prompt") + 1])
                except (ValueError, IndexError):
                    # Fallback: extract from result_idx if parsing fails
                    prompt_idx = result_idx

                # Initialize aggregator for this prompt if needed
                if prompt_idx not in prompt_aggregators:
                    prompt_aggregators[prompt_idx] = {
                        "weighted_sum": None,
                        "total_weight": 0,
                        "chunk_count": 0,
                        "request_id": result.request_id.split("-chunk-")[0],
                    }

                aggregator = prompt_aggregators[prompt_idx]

                # MEAN pooling with online weighted averaging
                # Ensure result is PoolingRequestOutput
                # for embedding processing
                if not isinstance(result, PoolingRequestOutput):
                    raise ValueError(
                        f"Expected PoolingRequestOutput for "
                        f"chunked embedding, got "
                        f"{type(result).__name__}"
                    )
                if result.prompt_token_ids is None:
                    raise ValueError(
                        "prompt_token_ids cannot be None for chunked processing"
                    )

                weight = len(result.prompt_token_ids)
                embedding_data = result.outputs.data
                weighted_embedding = embedding_data.to(dtype=torch.float32) * weight

                if aggregator["weighted_sum"] is None:
                    # First chunk
                    aggregator["weighted_sum"] = weighted_embedding
                else:
                    # Accumulate
                    aggregator["weighted_sum"] += weighted_embedding

                aggregator["total_weight"] += weight
                aggregator["chunk_count"] += 1

        if ctx.intermediates is None:
            raise ValueError("Original prompts inputs not available")

        original_engine_inputs = cast(list[EngineInput], ctx.intermediates)
        num_prompts = len(original_engine_inputs)

        # Finalize aggregated results
        final_res_batch: list[PoolingRequestOutput] = []
        for prompt_idx in range(num_prompts):
            if prompt_idx in prompt_aggregators:
                # Finalize MEAN aggregation for this chunked prompt
                aggregator = prompt_aggregators[prompt_idx]

                weighted_sum = aggregator["weighted_sum"]
                total_weight = aggregator["total_weight"]

                if (
                    weighted_sum is not None
                    and isinstance(weighted_sum, torch.Tensor)
                    and isinstance(total_weight, (int, float))
                    and total_weight > 0
                ):
                    # Compute final mean embedding
                    final_embedding = weighted_sum / total_weight

                    # Create a PoolingRequestOutput
                    # for the aggregated result
                    pooling_output_data = PoolingOutput(data=final_embedding)

                    # Get original prompt token IDs for this prompt
                    original_prompt = original_engine_inputs[prompt_idx]
                    token_ids = original_prompt.get("prompt_token_ids", None)
                    if token_ids is None:
                        raise NotImplementedError(
                            "Long Text Embedding with Chunked Processing does "
                            "not support EmbedsPrompt and EncoderDecoderInput."
                        )

                    original_token_ids = cast(list[int], token_ids)
                    pooling_request_output = PoolingRequestOutput(
                        request_id=aggregator["request_id"],
                        prompt_token_ids=original_token_ids,
                        outputs=pooling_output_data,
                        num_cached_tokens=0,
                        finished=True,
                    )

                    final_res_batch.append(pooling_request_output)
                else:
                    raise ValueError(
                        f"Failed to aggregate chunks for prompt {prompt_idx}"
                    )
            elif prompt_idx in short_prompts_results:
                final_res_batch.append(short_prompts_results[prompt_idx])
            else:
                raise ValueError(f"Result not found for prompt {prompt_idx}")

        ctx.final_res_batch = final_res_batch

        return None

    #################################################################
    # Cohere Request Preprocessing & Postprocessing
    #################################################################

    @staticmethod
    def _load_task_instructions(hf_config: Any) -> dict[str, str] | None:
        """Extract ``task_instructions`` from the HF model config."""
        ti = getattr(hf_config, "task_instructions", None)
        if not isinstance(ti, dict) or not ti:
            return None
        return {k: v for k, v in ti.items() if isinstance(v, str)}

    @staticmethod
    def _load_st_prompts(
        model: str | Any,
        revision: str | None,
    ) -> dict[str, str] | None:
        """Load ``task_instructions`` from ``config_sentence_transformers.json``."""
        from vllm.transformers_utils.repo_utils import get_hf_file_to_dict

        try:
            cfg = get_hf_file_to_dict(
                "config_sentence_transformers.json", str(model), revision
            )
        except (ValueError, OSError):
            return None

        if cfg is None:
            return None
        prompts = cfg.get("prompts")
        if not isinstance(prompts, dict) or not prompts:
            return None
        return {k: v for k, v in prompts.items() if isinstance(v, str)}

    @staticmethod
    def _mixed_input_to_messages(
        inp: CohereEmbedInput,
        *,
        task_prefix: str | None = None,
    ) -> list[ChatCompletionMessageParam]:
        """Build chat messages from a mixed text+image input.

        When *task_prefix* is given, it is prepended to each text part.
        """
        parts: list[ChatCompletionContentPartParam] = []
        for item in inp.content:
            if item.type == "text" and item.text is not None:
                text = task_prefix + item.text if task_prefix else item.text
                parts.append(ChatCompletionContentPartTextParam(type="text", text=text))
            elif item.type == "image_url" and item.image_url is not None:
                parts.append(
                    ChatCompletionContentPartImageParam(
                        type="image_url",
                        image_url=ImageURL(url=item.image_url["url"]),
                    )
                )
        return [CustomChatCompletionMessageParam(role="user", content=parts)]

    @staticmethod
    def _check_cohere_max_tokens(
        outputs: list[PoolingRequestOutput],
        max_tokens_check: int | None,
    ) -> None:
        """Raise if any output exceeds *max_tokens_check* tokens.

        Used to enforce ``truncate=NONE`` with an explicit ``max_tokens``:
        the pipeline runs without truncation and we reject afterwards.
        """
        if max_tokens_check is None:
            return
        for out in outputs:
            n = len(out.prompt_token_ids)
            if n > max_tokens_check:
                raise ValueError(
                    f"Input of {n} tokens exceeds max_tokens={max_tokens_check} "
                    "with truncate=NONE. Set truncate to END or START to "
                    "allow truncation."
                )

    @staticmethod
    def _resolve_cohere_truncation(
        request: CohereEmbedRequest,
    ) -> tuple[int | None, Literal["left", "right"] | None]:
        """Return ``(truncate_prompt_tokens, truncation_side)``."""
        if request.truncate == "NONE":
            return None, None
        if request.truncate == "START":
            tokens = request.max_tokens if request.max_tokens is not None else -1
            return tokens, "left"
        if request.max_tokens is not None:
            return request.max_tokens, None
        return -1, None

    def create_pooling_params(self, request):
        if isinstance(request, CohereEmbedRequest):
            return PoolingParams(
                task="embed",
                dimensions=request.output_dimension,
            )
        return super().create_pooling_params(request)

    def _pre_process_cohere_online(self, ctx: PoolingServeContext) -> None:
        """Convert a ``CohereEmbedRequest`` into engine prompts.

        For texts, a single batched completion request path is used.
        For images and mixed inputs, conversations are batch-rendered
        through the chat template in one ``render_chat`` call.
        """
        request = ctx.request
        assert isinstance(request, CohereEmbedRequest)

        if request.texts is None and request.images is None and request.inputs is None:
            raise ValueError("One of texts, images, or inputs must be provided")

        truncate_prompt_tokens, truncation_side = self._resolve_cohere_truncation(
            request
        )
        input_type = request.input_type
        self._validate_input_type(input_type)

        if request.images is not None:
            all_messages: list[list[ChatCompletionMessageParam]] = [
                [
                    CustomChatCompletionMessageParam(
                        role="user",
                        content=[{"type": "image_url", "image_url": {"url": uri}}],
                    )
                ]
                for uri in request.images
            ]
            ctx.engine_inputs = self._batch_render_chat(
                request, all_messages, truncate_prompt_tokens, truncation_side
            )

        elif request.inputs is not None:
            task_prefix = self._get_task_instruction_prefix(input_type)
            all_messages = [
                self._mixed_input_to_messages(inp, task_prefix=task_prefix)
                for inp in request.inputs
            ]
            ctx.engine_inputs = self._batch_render_chat(
                request, all_messages, truncate_prompt_tokens, truncation_side
            )

        else:
            prefixed = self._apply_task_instruction(request.texts or [], input_type)
            proxy = EmbeddingCompletionRequest(
                model=request.model,
                input=prefixed,
                dimensions=request.output_dimension,
                encoding_format="float",
                truncate_prompt_tokens=truncate_prompt_tokens,
                truncation_side=truncation_side,
            )
            ctx.engine_inputs = self._preprocess_completion_online(
                proxy, prompt_input=proxy.input, prompt_embeds=None
            )

    def _batch_render_chat(
        self,
        request: CohereEmbedRequest,
        all_messages: Sequence[list[ChatCompletionMessageParam]],
        truncate_prompt_tokens: int | None,
        truncation_side: Literal["left", "right"] | None,
    ) -> list[EngineInput]:
        """Batch-render multiple conversations through the chat template."""
        if not all_messages:
            return []

        proxy = EmbeddingChatRequest(
            model=request.model,
            messages=list(all_messages[0]),
            dimensions=request.output_dimension,
            encoding_format="float",
            truncate_prompt_tokens=truncate_prompt_tokens,
            truncation_side=truncation_side,
        )

        renderer = self.renderer
        mm_config = self.model_config.multimodal_config

        tok_params = proxy.build_tok_params(self.model_config)
        chat_params = proxy.build_chat_params(
            self.chat_template,
            self.chat_template_content_format,
        ).with_defaults(
            merge_kwargs(
                None,
                dict(
                    tools=None,
                    tokenize=is_mistral_tokenizer(renderer.tokenizer),
                ),
            ),
            default_media_io_kwargs=(mm_config.media_io_kwargs if mm_config else None),
        )

        _, engine_inputs = renderer.render_chat(all_messages, chat_params, tok_params)
        return engine_inputs

    def _validate_input_type(self, input_type: str | None) -> None:
        """Raise if *input_type* is not supported by this model."""
        if input_type is None:
            return
        if self.task_instructions is None:
            raise ValueError(
                f"Unsupported input_type {input_type!r}. "
                "This model does not define any input_type task instructions."
            )
        if input_type not in self.task_instructions:
            supported = ", ".join(sorted(self.task_instructions))
            raise ValueError(
                f"Unsupported input_type {input_type!r}. Supported values: {supported}"
            )

    def _apply_task_instruction(
        self,
        texts: list[str],
        input_type: str | None,
    ) -> list[str]:
        """Prepend the task-instruction prefix for *input_type*.

        Returns *texts* unchanged when no matching prefix is configured.
        """
        prefix = self._get_task_instruction_prefix(input_type)
        if not prefix:
            return texts
        return [prefix + t for t in texts]

    def _get_task_instruction_prefix(self, input_type: str | None) -> str | None:
        """Return the task-instruction prefix for *input_type*, or ``None``."""
        if not self.task_instructions or input_type is None:
            return None
        return self.task_instructions.get(input_type) or None

    def _enforce_cohere_max_tokens(self, ctx: PoolingServeContext) -> None:
        if isinstance(ctx.request, CohereEmbedRequest):
            request = ctx.request
            if request.truncate == "NONE" and request.max_tokens is not None:
                self._check_cohere_max_tokens(ctx.final_res_batch, request.max_tokens)
