"""
Base embedding provider interface.
[AC-AISVC-29] Abstract interface for embedding providers.

Design reference: progress.md Section 7.1 - EmbeddingProvider interface
- embed(text) -> list[float]
- embed_batch(texts) -> list[list[float]]
- get_dimension() -> int
- get_provider_name() -> str
"""

from abc import ABC, abstractmethod
from dataclasses import dataclass, field
from typing import Any


@dataclass
class EmbeddingConfig:
    """
    Configuration for embedding provider.
    [AC-AISVC-31] Supports configurable embedding parameters.
    """
    dimension: int = 768
    batch_size: int = 32
    timeout_seconds: int = 60
    extra_params: dict[str, Any] = field(default_factory=dict)


@dataclass
class EmbeddingResult:
    """
    Result from embedding generation.
    [AC-AISVC-29] Contains embedding vector and metadata.
    """
    embedding: list[float]
    dimension: int
    model: str
    latency_ms: float = 0.0
    metadata: dict[str, Any] = field(default_factory=dict)


class EmbeddingProvider(ABC):
    """
    Abstract base class for embedding providers.
    [AC-AISVC-29] Provides unified interface for different embedding providers.

    Design reference: progress.md Section 7.1 - Architecture
    - OllamaEmbeddingProvider / OpenAIEmbeddingProvider can be swapped
    - Factory pattern for dynamic loading
    """

    @abstractmethod
    async def embed(self, text: str) -> list[float]:
        """
        Generate embedding vector for a single text.
        [AC-AISVC-29] Returns embedding vector.

        Args:
            text: Input text to embed.

        Returns:
            List of floats representing the embedding vector.

        Raises:
            EmbeddingException: If embedding generation fails.
        """
        pass

    @abstractmethod
    async def embed_batch(self, texts: list[str]) -> list[list[float]]:
        """
        Generate embedding vectors for multiple texts.
        [AC-AISVC-29] Returns list of embedding vectors.

        Args:
            texts: List of input texts to embed.

        Returns:
            List of embedding vectors.

        Raises:
            EmbeddingException: If embedding generation fails.
        """
        pass

    @abstractmethod
    def get_dimension(self) -> int:
        """
        Get the dimension of embedding vectors.
        [AC-AISVC-29] Returns vector dimension.

        Returns:
            Integer dimension of embedding vectors.
        """
        pass

    @abstractmethod
    def get_provider_name(self) -> str:
        """
        Get the name of this embedding provider.
        [AC-AISVC-29] Returns provider identifier.

        Returns:
            String identifier for this provider.
        """
        pass

    @abstractmethod
    def get_config_schema(self) -> dict[str, Any]:
        """
        Get the configuration schema for this provider.
        [AC-AISVC-38] Returns JSON Schema for configuration parameters.

        Returns:
            Dict describing configuration parameters.
        """
        pass

    async def close(self) -> None:
        """Close the provider and release resources. Default no-op."""
        pass


class EmbeddingException(Exception):
    """Exception raised when embedding generation fails."""
    
    def __init__(self, message: str, provider: str = "", details: dict[str, Any] | None = None):
        self.provider = provider
        self.details = details or {}
        super().__init__(f"[{provider}] {message}" if provider else message)