import os
from typing import Literal, Optional

from vertexai.language_models import TextEmbeddingInput, TextEmbeddingModel

from dejavu.configs.embeddings.base import BaseEmbedderConfig
from dejavu.embeddings.base import EmbeddingBase
from dejavu.utils.gcp_auth import GCPAuthenticator


class VertexAIEmbedding(EmbeddingBase):
    def __init__(self, config: Optional[BaseEmbedderConfig] = None):
        super().__init__(config)

        self.config.model = self.config.model or "gemini-embedding-001"
        self.config.embedding_dims = self.config.embedding_dims or 256

        self.embedding_types = {
            "add": self.config.memory_add_embedding_type or "RETRIEVAL_DOCUMENT",
            "update": self.config.memory_update_embedding_type or "RETRIEVAL_DOCUMENT",
            "search": self.config.memory_search_embedding_type or "RETRIEVAL_QUERY",
        }

        # Set up authentication using centralized GCP authenticator
        # This supports multiple authentication methods while preserving environment variable support
        try:
            GCPAuthenticator.setup_vertex_ai(
                service_account_json=getattr(self.config, 'google_service_account_json', None),
                credentials_path=self.config.vertex_credentials_json,
                project_id=getattr(self.config, 'google_project_id', None)
            )
        except Exception:
            # Fall back to original behavior for backward compatibility
            credentials_path = self.config.vertex_credentials_json
            if credentials_path:
                os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = credentials_path
            elif not os.getenv("GOOGLE_APPLICATION_CREDENTIALS"):
                raise ValueError(
                    "Google application credentials JSON is not provided. Please provide a valid JSON path or set the 'GOOGLE_APPLICATION_CREDENTIALS' environment variable."
                )

        self.model = TextEmbeddingModel.from_pretrained(self.config.model)

    def embed(self, text, memory_action: Optional[Literal["add", "search", "update"]] = None):
        """
        Get the embedding for the given text using Vertex AI.

        Args:
            text (str): The text to embed.
            memory_action (optional): The type of embedding to use. Must be one of "add", "search", or "update". Defaults to None.
        Returns:
            list: The embedding vector.
        """
        embedding_type = "SEMANTIC_SIMILARITY"
        if memory_action is not None:
            if memory_action not in self.embedding_types:
                raise ValueError(f"Invalid memory action: {memory_action}")

            embedding_type = self.embedding_types[memory_action]

        text_input = TextEmbeddingInput(text=text, task_type=embedding_type)
        embeddings = self.model.get_embeddings(texts=[text_input], output_dimensionality=self.config.embedding_dims)

        return embeddings[0].values
