"""Runtime-configurable sentiment provider.

Lets an admin switch the sentiment LLM (provider, model, API key) at runtime
via SystemSetting, without a redeploy. Precedence for each value:
    DB setting  >  environment variable  >  hardcoded default.

The API key is write-only: it is persisted but never returned through any
read path. Reads report only whether a key is configured and its source.
"""

from __future__ import annotations

import logging

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.config import settings
from app.exceptions import ProviderError, ValidationError
from app.models.settings import SystemSetting
from app.services.admin_service import update_setting

logger = logging.getLogger(__name__)

VALID_PROVIDERS = {"openai", "gemini"}

PROVIDER_DEFAULT_MODELS: dict[str, str] = {
    "openai": "gpt-4o-mini",
    "gemini": "gemini-2.0-flash",
}

# SystemSetting keys
KEY_PROVIDER = "sentiment_provider"
KEY_MODEL = "sentiment_model"
KEY_API_KEY = "sentiment_api_key"


async def _get_settings_map(db: AsyncSession) -> dict[str, str]:
    result = await db.execute(
        select(SystemSetting).where(
            SystemSetting.key.in_([KEY_PROVIDER, KEY_MODEL, KEY_API_KEY])
        )
    )
    return {s.key: s.value for s in result.scalars().all()}


def _env_key_for(provider: str) -> str:
    if provider == "openai":
        return settings.openai_api_key or ""
    if provider == "gemini":
        return settings.gemini_api_key or ""
    return ""


def _env_model_for(provider: str) -> str:
    if provider == "openai":
        return settings.openai_model or PROVIDER_DEFAULT_MODELS["openai"]
    if provider == "gemini":
        return settings.gemini_model or PROVIDER_DEFAULT_MODELS["gemini"]
    return PROVIDER_DEFAULT_MODELS.get(provider, "")


async def _resolve(db: AsyncSession) -> tuple[str, str, str, str]:
    """Resolve (provider, model, api_key, api_key_source) from DB > env > default."""
    stored = await _get_settings_map(db)

    provider = (stored.get(KEY_PROVIDER) or "").strip().lower()
    if provider not in VALID_PROVIDERS:
        # Default to whichever env key is present, else openai
        provider = "openai" if settings.openai_api_key or not settings.gemini_api_key else "gemini"

    model = (stored.get(KEY_MODEL) or "").strip() or _env_model_for(provider)

    db_key = (stored.get(KEY_API_KEY) or "").strip()
    if db_key:
        return provider, model, db_key, "database"
    env_key = _env_key_for(provider)
    if env_key:
        return provider, model, env_key, "environment"
    return provider, model, "", "none"


async def get_sentiment_config(db: AsyncSession) -> dict:
    """Public config — never includes the raw API key."""
    provider, model, api_key, source = await _resolve(db)
    return {
        "provider": provider,
        "model": model,
        "api_key_configured": bool(api_key),
        "api_key_source": source,
        "valid_providers": sorted(VALID_PROVIDERS),
        "default_models": PROVIDER_DEFAULT_MODELS,
    }


async def update_sentiment_config(
    db: AsyncSession,
    provider: str | None = None,
    model: str | None = None,
    api_key: str | None = None,
) -> dict:
    """Persist provider/model/key. An empty/omitted api_key leaves the stored
    key untouched (so saving other fields does not wipe credentials)."""
    if provider is not None:
        provider = provider.strip().lower()
        if provider not in VALID_PROVIDERS:
            raise ValidationError(
                f"Unknown sentiment provider '{provider}'. Valid: {', '.join(sorted(VALID_PROVIDERS))}"
            )
        await update_setting(db, KEY_PROVIDER, provider)

    if model is not None:
        model = model.strip()
        if model:
            await update_setting(db, KEY_MODEL, model)

    if api_key:  # only overwrite when a non-empty key is supplied
        await update_setting(db, KEY_API_KEY, api_key.strip())

    return await get_sentiment_config(db)


async def build_sentiment_provider(db: AsyncSession):
    """Construct the active sentiment provider from current config.

    Raises ProviderError if no API key is available for the chosen provider.
    """
    provider, model, api_key, _source = await _resolve(db)
    if not api_key:
        raise ProviderError(f"No API key configured for sentiment provider '{provider}'")

    if provider == "openai":
        from app.providers.openai_sentiment import OpenAISentimentProvider
        return OpenAISentimentProvider(api_key, model)
    if provider == "gemini":
        from app.providers.gemini_sentiment import GeminiSentimentProvider
        return GeminiSentimentProvider(api_key, model)

    raise ProviderError(f"Unsupported sentiment provider '{provider}'")


async def test_sentiment_provider(db: AsyncSession, ticker: str = "AAPL") -> dict:
    """Build the active provider and fetch one ticker as a live credentials check."""
    provider, model, _key, _source = await _resolve(db)
    try:
        prov = await build_sentiment_provider(db)
        data = await prov.fetch_sentiment(ticker.strip().upper())
        return {
            "ok": True,
            "provider": provider,
            "model": model,
            "ticker": ticker.strip().upper(),
            "classification": data.classification,
            "confidence": data.confidence,
            "reasoning": data.reasoning or None,
        }
    except Exception as exc:
        logger.warning("Sentiment provider test failed: %s", exc)
        return {
            "ok": False,
            "provider": provider,
            "model": model,
            "error": str(exc),
        }