crypto_trading/backend/app/api/routes.py

from __future__ import annotations

import asyncio
from typing import Annotated

import httpx
from fastapi import APIRouter, Depends, HTTPException, Request, WebSocket, WebSocketDisconnect

from app.config import Settings
from app.engine.strategies import get_strategy, list_strategies, strategy_spec
from app.models import OrderSide, Position, PositionStatus
from app.runtime import Runtime
from app.schemas import (
    BacktestRequest,
    BacktestResult,
    ClosePositionRequest,
    EquityPointOut,
    EventOut,
    KillRequest,
    ManualOrderRequest,
    OrderOut,
    PositionOut,
    StartRequest,
    StatusOut,
    StrategyConfigIn,
    StrategyConfigOut,
    StrategyOut,
    SweepRequest,
    SweepResult,
)

router = APIRouter(prefix="/api")


def get_runtime(request: Request) -> Runtime:
    return request.app.state.runtime


def get_settings(request: Request) -> Settings:
    return request.app.state.runtime.settings


def get_guarded_runtime(request: Request) -> Runtime:
    """Return the runtime, rejecting requests without the configured API token.

    The check is a no-op when ``API_TOKEN`` is unset, so local dev and the
    Basic-auth-only deployment keep working unchanged.
    """
    runtime: Runtime = request.app.state.runtime
    settings: Settings = runtime.settings
    if settings.api_token:
        provided = request.headers.get(settings.api_token_header, "")
        if provided != settings.api_token:
            raise HTTPException(status_code=401, detail="invalid or missing API token")
    return runtime


GuardedRuntimeDep = Annotated[Runtime, Depends(get_guarded_runtime)]


@router.get("/health")
def health() -> dict[str, str]:
    return {"status": "ok"}


@router.get("/version")
def version(request: Request) -> dict[str, str]:
    """Build version of the running backend, used by the client to self-heal
    from a stale cached bundle after a deploy."""
    return {"version": getattr(request.app.state, "build_version", "unknown")}


@router.get("/strategies", response_model=list[StrategyOut])
def strategies() -> list[StrategyOut]:
    return [strategy_spec(cls) for cls in list_strategies()]


@router.get("/status", response_model=StatusOut)
def status(runtime: GuardedRuntimeDep) -> StatusOut:
    return runtime.status()


@router.post("/bot/start", response_model=StatusOut)
async def start_bot(payload: StartRequest, runtime: GuardedRuntimeDep) -> StatusOut:
    try:
        return await runtime.start(
            payload.strategy_key,
            payload.params,
            symbol=payload.symbol,
            timeframe=payload.timeframe,
            starting_balance=payload.starting_balance,
        )
    except KeyError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc
    except (ValueError, RuntimeError) as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@router.post("/bot/stop", response_model=StatusOut)
async def stop_bot(runtime: GuardedRuntimeDep) -> StatusOut:
    return await runtime.stop()


@router.post("/bot/kill", response_model=StatusOut)
async def kill_bot(payload: KillRequest, runtime: GuardedRuntimeDep) -> StatusOut:
    return await runtime.kill(payload.reason)


@router.post("/backtest", response_model=BacktestResult)
async def run_backtest(payload: BacktestRequest, runtime: GuardedRuntimeDep) -> BacktestResult:
    try:
        return await runtime.run_backtest(payload)
    except KeyError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except httpx.HTTPError as exc:
        raise HTTPException(status_code=502, detail=f"market data error: {exc}") from exc


@router.get("/presets", response_model=list[StrategyConfigOut])
def list_presets(runtime: GuardedRuntimeDep) -> list[StrategyConfigOut]:
    return [
        StrategyConfigOut.model_validate(config) for config in runtime.store.list_strategy_configs()
    ]


@router.post("/presets", response_model=StrategyConfigOut)
def create_preset(payload: StrategyConfigIn, runtime: GuardedRuntimeDep) -> StrategyConfigOut:
    try:
        get_strategy(payload.strategy_key)
    except KeyError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc
    config = runtime.store.save_strategy_config(
        name=payload.name,
        strategy_key=payload.strategy_key,
        symbol=payload.symbol,
        timeframe=payload.timeframe,
        params=payload.params,
    )
    return StrategyConfigOut.model_validate(config)


@router.delete("/presets/{config_id}")
def delete_preset(config_id: int, runtime: GuardedRuntimeDep) -> dict[str, bool]:
    if not runtime.store.delete_strategy_config(config_id):
        raise HTTPException(status_code=404, detail="preset not found")
    return {"deleted": True}


@router.post("/sweep", response_model=SweepResult)
async def run_sweep_endpoint(payload: SweepRequest, runtime: GuardedRuntimeDep) -> SweepResult:
    try:
        return await runtime.run_sweep(payload)
    except KeyError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except httpx.HTTPError as exc:
        raise HTTPException(status_code=502, detail=f"market data error: {exc}") from exc


def _position_out(position: Position, price: float | None) -> PositionOut:
    out = PositionOut.model_validate(position)
    if position.status == PositionStatus.OPEN and price is not None:
        sign = 1 if position.side.value == "long" else -1
        out.unrealized_pnl = sign * (price - position.entry_price) * position.qty
    return out


@router.get("/positions", response_model=list[PositionOut])
def positions(runtime: GuardedRuntimeDep, limit: int = 50) -> list[PositionOut]:
    price = runtime.engine.last_price if runtime.engine else None
    return [_position_out(position, price) for position in runtime.store.list_positions(limit)]


@router.get("/orders", response_model=list[OrderOut])
def orders(runtime: GuardedRuntimeDep, limit: int = 50) -> list[OrderOut]:
    return [OrderOut.model_validate(order) for order in runtime.store.list_orders(limit)]


@router.get("/events", response_model=list[EventOut])
def events(runtime: GuardedRuntimeDep, limit: int = 50) -> list[EventOut]:
    return [EventOut.model_validate(event) for event in runtime.store.list_events(limit)]


@router.get("/equity", response_model=list[EquityPointOut])
def equity(runtime: GuardedRuntimeDep, limit: int = 500) -> list[EquityPointOut]:
    return [EquityPointOut.model_validate(point) for point in runtime.store.list_equity(limit)]


@router.post("/orders", response_model=StatusOut)
async def manual_order(payload: ManualOrderRequest, runtime: GuardedRuntimeDep) -> StatusOut:
    engine = runtime.engine
    if engine is None or not engine.running:
        raise HTTPException(status_code=409, detail="engine is not running")
    side = OrderSide.BUY if payload.side == "buy" else OrderSide.SELL
    await engine.manual_order(side, payload.qty, payload.quote_amount, payload.reason)
    return engine.status()


@router.post("/positions/{position_id}/close", response_model=StatusOut)
async def close_position(
    position_id: int, payload: ClosePositionRequest, runtime: GuardedRuntimeDep
) -> StatusOut:
    engine = runtime.engine
    if engine is None or not engine.running:
        raise HTTPException(status_code=409, detail="engine is not running")
    if engine.position is None or engine.position.id != position_id:
        raise HTTPException(status_code=404, detail="no open position with that id")
    await engine.close_current_position(payload.reason)
    return engine.status()


@router.get("/ws")
def websocket_info() -> dict[str, str]:
    """A plain browser hit on the socket URL gets a clear hint, not a 404/426."""
    return {
        "detail": "This endpoint is a WebSocket. Connect with a WebSocket client.",
        "path": "/api/ws",
    }


@router.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket) -> None:
    runtime: Runtime = websocket.app.state.runtime
    settings: Settings = runtime.settings
    if settings.api_token:
        # The frontend nginx injects the token as a header on the upgrade request
        # (browsers can't set WebSocket headers themselves); accept a query param
        # too for direct/manual clients.
        provided = websocket.headers.get(settings.api_token_header) or websocket.query_params.get(
            "token", ""
        )
        if provided != settings.api_token:
            await websocket.close(code=1008)
            return
    await websocket.accept()
    queue = runtime.subscribe()
    try:
        await websocket.send_json(
            {"type": "status", "data": runtime.status().model_dump(mode="json")}
        )
        while True:
            try:
                payload = await asyncio.wait_for(queue.get(), timeout=15.0)
            except TimeoutError:
                await websocket.send_json({"type": "ping"})
                continue
            await websocket.send_json(payload)
    except WebSocketDisconnect:
        pass
    finally:
        runtime.unsubscribe(queue)