from __future__ import annotations

from functools import lru_cache
from pathlib import Path

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env", extra="ignore")

    app_name: str = "vsf-duoc-thu-ai-service"
    qdrant_url: str = "http://localhost:6333"
    qdrant_collection: str = "duocthu_v1"
    qdrant_api_key: str | None = None
    postgres_dsn: str = Field(
        default="postgresql://duoc_thu:duoc_thu@localhost:5432/duoc_thu",
        repr=False,
    )
    # `cohere-v4` = semantic query embedding in the corpus's own space (requires
    # live Bedrock). `disabled` skips retrieval entirely. The old local-hash /
    # section-only stub embedders were removed in the 2026-08-06 rebuild.
    embedding_provider: str = "cohere-v4"
    embedding_dimensions: int = 1024
    evidence_minimum_score: float = 0.12
    aws_region: str = "us-east-1"
    # Generation is off unless asked for. `stub` runs the whole answer path —
    # prompt, schema parsing, grounding check, fallback — with no cloud call.
    # Live options: `bedrock-converse` (DeepSeek/Qwen/GLM/Nova via the Converse
    # API) or `bedrock-claude` (Anthropic via the Messages path).
    answer_provider: str = "disabled"
    answer_model_id: str = "deepseek.v3.2"
    # Optional cross-encoder rerank on the similarity fallback (needs live
    # Bedrock invoke on the rerank model). Off by default; the section route
    # never uses it.
    rerank_enabled: bool = False
    metrics_enabled: bool = True
    entities_path: Path = (
        Path(__file__).resolve().parents[2]
        / "ingestion/data/verified/drug_entities.json"
    )


@lru_cache
def get_settings() -> Settings:
    return Settings()