"""Optionale REST-API + HTML-Dashboard (Befehl `trademind serve`).

Endpoints:
    GET /                  → HTML-Dashboard
    GET /api/health        → Liveness
    GET /api/status        → Strategie-Konfiguration, zuletzt berechnetes Signal, letztes Paper-Ergebnis
    GET /api/signals       → Signals der letzten Candles
    GET /api/equity        → Equity-Kurve des letzten Paper-Laufs
    POST /api/paper        → neuer Paper-Lauf (nutzt konfigurierte Datenquelle)

Der Server ist read-only gegenüber dem Live-Handel: es werden hier nie
echte Orders platziert.
"""

from __future__ import annotations

import asyncio
import html
import json
import logging
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, Optional

import pandas as pd

from . import __version__
from .config import Config, load as load_config
from .engine import save_state
from .exchange import MockBroker
from .strategy import Strategy
from .trader import Trader

log = logging.getLogger("trademind.server")

DASHBOARD_DIR = Path(__file__).parent / "static"


def _safe_int(value: Any, default: int) -> int:
    try:
        return int(value)
    except (TypeError, ValueError):
        return default


def _candles_to_signals(strategy: Strategy, candles: pd.DataFrame, limit: int = 50):
    prep = strategy.prepare(candles)
    signals = strategy.decide(prep)
    out = []
    for i, sig in enumerate(signals[-limit:]):
        idx = len(signals) - len(signals[-limit:]) + i
        ts = None
        if "time" in candles.columns and len(candles) > idx:
            ts = str(pd.Timestamp(candles["time"].iloc[idx]))
        out.append(
            {
                "time": ts,
                "action": int(sig.action),
                "price": round(float(sig.price), 8),
                "score": round(float(sig.score), 4),
                "reason": sig.reason,
            }
        )
    return out


def make_app(
    cfg_path: str,
    data: str = "auto",
    exchange: Optional[str] = None,
) -> "FastAPI":
    """Erzeugt die FastAPI-App für eine Konfigurationsdatei."""
    from fastapi import FastAPI
    from fastapi.responses import HTMLResponse, JSONResponse

    def _cfg() -> Config:
        return load_config(cfg_path)

    app = FastAPI(title="TradeMind", version=__version__)
    state: Dict[str, Any] = {}

    def _broker(cfg: Config):
        import os

        from .cli import _data_broker

        ex = exchange or (cfg.active_exchange().name if cfg.active_exchange() else "binance")
        return _data_broker(cfg, data, ex, int(os.environ.get("TM_SEED", "7")))

    def _symbol(cfg: Config) -> str:
        return f"{cfg.trading.base_currency}/{cfg.trading.quote_currency}"

    @app.get("/api/health")
    def health() -> Dict[str, Any]:
        return {"status": "ok", "version": __version__}

    @app.get("/api/status")
    def status() -> Dict[str, Any]:
        cfg = _cfg()
        ex_names = [
            {
                "name": name,
                "sandbox": entry.sandbox,
                "has_keys": bool(entry.api_key and entry.api_secret),
            }
            for name, entry in cfg.exchanges.items()
        ]
        last = state.get("last_run")
        return {
            "version": __version__,
            "symbol": _symbol(cfg),
            "trading": cfg.trading.__dict__,
            "strategy": cfg.strategy.__dict__,
            "exchanges": ex_names,
            "state_file": cfg.training.state_file,
            "last_run": last,
        }

    @app.get("/api/signals")
    def signals(limit: int = 50) -> Dict[str, Any]:
        cfg = _cfg()
        broker = _broker(cfg)
        candles = broker.fetch_ohlcv(_symbol(cfg), cfg.trading.timeframe, cfg.trading.candles)
        strat = Strategy(cfg.strategy)
        out = _candles_to_signals(strat, candles, limit)
        return {
            "broker": broker.name,
            "generated_at": datetime.now(timezone.utc).isoformat(),
            "signals": out,
        }

    @app.get("/api/equity")
    def equity() -> Dict[str, Any]:
        last = state.get("last_run")
        if last is None:
            return {"summary": None, "equity_curve": [], "hint": "POST /api/paper ausführen"}
        return {
            "summary": last["summary"],
            "equity_curve": last.get("equity_curve", []),
        }

    @app.post("/api/paper")
    async def paper() -> Dict[str, Any]:
        def _run() -> Dict[str, Any]:
            cfg = _cfg()
            broker = _broker(cfg)
            strat = Strategy(cfg.strategy)
            trader = Trader(cfg, broker, strat)
            res = trader.simulate()
            summary = res.summary()
            payload = {
                "summary": summary,
                "equity_curve": res.equity_curve,
                "broker": broker.name,
                "finished_at": datetime.now(timezone.utc).isoformat(),
            }
            save_state("state/paper.json", res, strat.parameters())
            return payload

        payload = await asyncio.to_thread(_run)
        state["last_run"] = payload
        return payload

    @app.get("/", response_class=HTMLResponse)
    async def index() -> str:
        path = DASHBOARD_DIR / "dashboard.html"
        return path.read_text(encoding="utf-8")

    # Fehler-Fallback, damit auch unklare Requests JSON liefern
    @app.exception_handler(Exception)
    async def _exc(request, exc: Exception):  # pragma: no cover
        log.exception("Fehler bei %s", request.url.path)
        return JSONResponse({"error": str(exc)}, status_code=500)

    app.state.cfg_path = cfg_path
    return app


def run_server(
    cfg_path: str,
    host: str,
    port: int,
    data: str = "auto",
    exchange: Optional[str] = None,
) -> None:
    import uvicorn

    app = make_app(cfg_path, data=data, exchange=exchange)
    log.info("TradeMind-API läuft auf http://%s:%d (Dashboard: /)", host, port)
    uvicorn.run(app, host=host, port=port, log_level="info")