from typing import List, Optional, Union, cast

from httpx import Headers, Response

from litellm.exceptions import InternalServerError
from litellm.llms.base_llm.chat.transformation import BaseLLMException
from litellm.llms.base_llm.embedding.transformation import LiteLLMLoggingObj
from litellm.types.llms.openai import AllEmbeddingInputValues, AllMessageValues
from litellm.types.llms.vertex_ai import (
    Instance,
    InstanceImage,
    InstanceVideo,
    MultimodalPredictions,
    VertexMultimodalEmbeddingRequest,
)
from litellm.types.utils import (
    Embedding,
    EmbeddingResponse,
    PromptTokensDetailsWrapper,
    Usage,
)
from litellm.utils import _count_characters, is_base64_encoded

from ...base_llm.embedding.transformation import BaseEmbeddingConfig
from ..common_utils import VertexAIError


class VertexAIMultimodalEmbeddingConfig(BaseEmbeddingConfig):
    def get_supported_openai_params(self, model: str) -> list:
        return ["dimensions"]

    def map_openai_params(
        self,
        non_default_params: dict,
        optional_params: dict,
        model: str,
        drop_params: bool,
    ) -> dict:
        for param, value in non_default_params.items():
            if param == "dimensions":
                optional_params["outputDimensionality"] = value
        return optional_params

    def validate_environment(
        self,
        headers: dict,
        model: str,
        messages: List[AllMessageValues],
        optional_params: dict,
        litellm_params: dict,
        api_key: Optional[str] = None,
        api_base: Optional[str] = None,
    ) -> dict:
        default_headers = {
            "Content-Type": "application/json; charset=utf-8",
            "Authorization": f"Bearer {api_key}",
        }
        headers.update(default_headers)
        return headers

    def _is_gcs_uri(self, input_str: str) -> bool:
        """Check if the input string is a GCS URI."""
        return "gs://" in input_str

    def _is_video(self, input_str: str) -> bool:
        """Check if the input string represents a video (mp4)."""
        return "mp4" in input_str

    def _is_media_input(self, input_str: str) -> bool:
        """Check if the input string is a media element (GCS URI or base64 image)."""
        return self._is_gcs_uri(input_str) or is_base64_encoded(s=input_str)

    def _create_image_instance(self, input_str: str) -> InstanceImage:
        """Create an InstanceImage from a GCS URI or base64 string."""
        if self._is_gcs_uri(input_str):
            return InstanceImage(gcsUri=input_str)
        else:
            return InstanceImage(
                bytesBase64Encoded=(
                    input_str.split(",")[1] if "," in input_str else input_str
                )
            )

    def _create_video_instance(self, input_str: str) -> InstanceVideo:
        """Create an InstanceVideo from a GCS URI."""
        return InstanceVideo(gcsUri=input_str)

    def _process_input_element(self, input_element: str) -> Instance:
        """
        Process a single input element for multimodal embedding requests.
        Detects if the input is a GCS URI, base64 encoded image, or plain text.

        Args:
            input_element (str): The input element to process.

        Returns:
            Instance: A dictionary representing the processed input element.
        """
        if len(input_element) == 0:
            return Instance(text=input_element)
        elif self._is_gcs_uri(input_element):
            if self._is_video(input_element):
                return Instance(video=self._create_video_instance(input_element))
            else:
                return Instance(image=self._create_image_instance(input_element))
        elif is_base64_encoded(s=input_element):
            return Instance(image=self._create_image_instance(input_element))
        else:
            return Instance(text=input_element)

    def _try_merge_text_with_media(
        self, text_str: str, next_elem: Optional[str]
    ) -> tuple[Instance, bool]:
        """
        Try to merge a text element with a following media element into a single instance.

        Args:
            text_str: The text string to potentially merge.
            next_elem: The next element in the input list (may be media).

        Returns:
            A tuple of (Instance, consumed_next) where consumed_next indicates
            if the next element was merged into this instance.
        """
        instance_args: Instance = {"text": text_str}

        if next_elem and isinstance(next_elem, str) and self._is_media_input(next_elem):
            if self._is_gcs_uri(next_elem) and self._is_video(next_elem):
                instance_args["video"] = self._create_video_instance(next_elem)
            else:
                instance_args["image"] = self._create_image_instance(next_elem)
            return instance_args, True

        return instance_args, False

    def process_openai_embedding_input(
        self, _input: Union[list, str]
    ) -> List[Instance]:
        """
        Process the input for multimodal embedding requests.

        Args:
            _input (Union[list, str]): The input data to process.

        Returns:
            List[Instance]: List of Instance objects for the embedding request.
        """
        _input_list = [_input] if not isinstance(_input, list) else _input
        processed_instances: List[Instance] = []

        i = 0
        while i < len(_input_list):
            current = _input_list[i]
            next_elem = _input_list[i + 1] if i + 1 < len(_input_list) else None

            if isinstance(current, str):
                if self._is_media_input(current):
                    # Current element is media - process it standalone
                    processed_instances.append(self._process_input_element(current))
                    i += 1
                else:
                    # Current element is text - try to merge with next media element
                    instance, consumed_next = self._try_merge_text_with_media(
                        text_str=current, next_elem=next_elem
                    )
                    processed_instances.append(instance)
                    i += 2 if consumed_next else 1
            elif isinstance(current, dict):
                processed_instances.append(Instance(**current))
                i += 1
            else:
                raise ValueError(f"Unsupported input type: {type(current)}")

        return processed_instances

    def transform_embedding_request(
        self,
        model: str,
        input: AllEmbeddingInputValues,
        optional_params: dict,
        headers: dict,
    ) -> dict:
        optional_params = optional_params or {}

        request_data = VertexMultimodalEmbeddingRequest(instances=[])

        if "instances" in optional_params:
            request_data["instances"] = optional_params["instances"]
        elif isinstance(input, list):
            vertex_instances: List[Instance] = self.process_openai_embedding_input(
                _input=input
            )
            request_data["instances"] = vertex_instances

        else:
            # construct instances
            vertex_request_instance = Instance(**optional_params)

            if isinstance(input, str):
                vertex_request_instance = self._process_input_element(input)

            request_data["instances"] = [vertex_request_instance]

        if "outputDimensionality" in optional_params:
            request_data["parameters"] = {
                "dimension": optional_params["outputDimensionality"]
            }

        return cast(dict, request_data)

    def transform_embedding_response(
        self,
        model: str,
        raw_response: Response,
        model_response: EmbeddingResponse,
        logging_obj: LiteLLMLoggingObj,
        api_key: Optional[str],
        request_data: dict,
        optional_params: dict,
        litellm_params: dict,
    ) -> EmbeddingResponse:
        if raw_response.status_code != 200:
            raise Exception(f"Error: {raw_response.status_code} {raw_response.text}")

        _json_response = raw_response.json()
        if "predictions" not in _json_response:
            raise InternalServerError(
                message=f"embedding response does not contain 'predictions', got {_json_response}",
                llm_provider="vertex_ai",
                model=model,
            )
        _predictions = _json_response["predictions"]
        vertex_predictions = MultimodalPredictions(predictions=_predictions)
        model_response.data = self.transform_embedding_response_to_openai(
            predictions=vertex_predictions
        )
        model_response.model = model

        model_response.usage = self.calculate_usage(
            request_data=cast(VertexMultimodalEmbeddingRequest, request_data),
            vertex_predictions=vertex_predictions,
        )

        return model_response

    def calculate_usage(
        self,
        request_data: VertexMultimodalEmbeddingRequest,
        vertex_predictions: MultimodalPredictions,
    ) -> Usage:
        ## Calculate text embeddings usage
        prompt: Optional[str] = None
        character_count: Optional[int] = None

        for instance in request_data["instances"]:
            text = instance.get("text")
            if text:
                if prompt is None:
                    prompt = text
                else:
                    prompt += text

        if prompt is not None:
            character_count = _count_characters(prompt)

        ## Calculate image embeddings usage
        image_count = 0
        for instance in request_data["instances"]:
            if instance.get("image"):
                image_count += 1

        ## Calculate video embeddings usage
        video_length_seconds = 0.0
        for prediction in vertex_predictions["predictions"]:
            video_embeddings = prediction.get("videoEmbeddings")
            if video_embeddings:
                for embedding in video_embeddings:
                    duration = embedding["endOffsetSec"] - embedding["startOffsetSec"]
                    video_length_seconds += duration

        prompt_tokens_details = PromptTokensDetailsWrapper(
            character_count=character_count,
            image_count=image_count,
            video_length_seconds=video_length_seconds,
        )

        return Usage(
            prompt_tokens=0,
            completion_tokens=0,
            total_tokens=0,
            prompt_tokens_details=prompt_tokens_details,
        )

    def transform_embedding_response_to_openai(
        self, predictions: MultimodalPredictions
    ) -> List[Embedding]:
        openai_embeddings: List[Embedding] = []
        if "predictions" in predictions:
            for idx, _prediction in enumerate(predictions["predictions"]):
                if _prediction:
                    if "textEmbedding" in _prediction:
                        openai_embedding_object = Embedding(
                            embedding=_prediction["textEmbedding"],
                            index=idx,
                            object="embedding",
                        )
                        openai_embeddings.append(openai_embedding_object)
                    elif "imageEmbedding" in _prediction:
                        openai_embedding_object = Embedding(
                            embedding=_prediction["imageEmbedding"],
                            index=idx,
                            object="embedding",
                        )
                        openai_embeddings.append(openai_embedding_object)
                    elif "videoEmbeddings" in _prediction:
                        for video_embedding in _prediction["videoEmbeddings"]:
                            openai_embedding_object = Embedding(
                                embedding=video_embedding["embedding"],
                                index=idx,
                                object="embedding",
                            )
                            openai_embeddings.append(openai_embedding_object)
        return openai_embeddings

    def get_error_class(
        self, error_message: str, status_code: int, headers: Union[dict, Headers]
    ) -> BaseLLMException:
        return VertexAIError(
            status_code=status_code, message=error_message, headers=headers
        )
