Extending BrokerBridge with plugins

class DataSourcePlugin(ABC):
    name: str                    # Unique plugin identifier
    display_name: str            # Human-readable name
    auth_type: AuthType          # "api_key" | "oauth" | "connection"
    required: bool = False       # System won't start without it if True

    async def validate_credentials(self) -> bool: ...
    async def fetch_signals(self, symbols: list[str]) -> list[Signal]: ...
    async def health_check(self) -> PluginStatus: ...

from datetime import datetime, timezone
import httpx
from brokerbridge.plugins.base import DataSourcePlugin
from brokerbridge.plugins.types import AuthType, PluginStatus, Signal


class MyScannerPlugin(DataSourcePlugin):
    name = "my_scanner"
    display_name = "My Custom Scanner"
    auth_type: AuthType = "api_key"

    def __init__(self, api_key: str):
        self._api_key = api_key

    async def validate_credentials(self) -> bool:
        async with httpx.AsyncClient() as client:
            resp = await client.get(
                "https://api.example.com/ping",
                headers={"Authorization": f"Bearer {self._api_key}"},
            )
            return resp.status_code == 200

    async def fetch_signals(self, symbols: list[str]) -> list[Signal]:
        async with httpx.AsyncClient() as client:
            resp = await client.post(
                "https://api.example.com/scan",
                headers={"Authorization": f"Bearer {self._api_key}"},
                json={"symbols": symbols},
            )
            resp.raise_for_status()
            data = resp.json()

        signals = []
        for item in data.get("signals", []):
            signals.append(Signal(
                symbol=item["symbol"],
                direction=item["direction"],
                score=item["score"],
                timestamp=datetime.now(timezone.utc),
                source=self.name,
            ))
        return sorted(signals, key=lambda s: s.score, reverse=True)

    async def health_check(self) -> PluginStatus:
        try:
            valid = await self.validate_credentials()
            return PluginStatus(connected=valid)
        except Exception as e:
            return PluginStatus(connected=False, message=str(e))