from __future__ import annotations

import os

from fastapi import Depends, FastAPI, HTTPException
from mcp_common.auth import Principal, TokenStore, require_principal
from mcp_common.mcp_bridge import mount_mcp_endpoint
from mcp_common.risk_guard import (
    enforce_aggregate,
    enforce_leverage,
    enforce_single_notional,
)
from mcp_common.server import build_app
from pydantic import BaseModel, field_validator, model_validator

from mcp_deribit.client import DeribitClient

# --- Body models ---

class GetTickerReq(BaseModel):
    instrument_name: str | None = None
    instrument: str | None = None

    model_config = {"extra": "allow"}

    @model_validator(mode="after")
    def _normalize(self):
        sym = self.instrument_name or self.instrument
        if not sym:
            raise ValueError("instrument_name (or instrument) is required")
        self.instrument_name = sym
        return self


class GetTickerBatchReq(BaseModel):
    instrument_names: list[str] | None = None
    instruments: list[str] | None = None

    model_config = {"extra": "allow"}

    @model_validator(mode="after")
    def _normalize(self):
        names = self.instrument_names or self.instruments
        if not names:
            raise ValueError("instrument_names (or instruments) is required")
        self.instrument_names = names
        return self


class GetInstrumentsReq(BaseModel):
    currency: str
    kind: str | None = None
    expiry_from: str | None = None
    expiry_to: str | None = None
    strike_min: float | None = None
    strike_max: float | None = None
    min_open_interest: float | None = None
    limit: int = 100
    offset: int = 0


class GetOrderbookReq(BaseModel):
    instrument_name: str
    depth: int = 10


class GetPositionsReq(BaseModel):
    currency: str = "USDC"


class GetAccountSummaryReq(BaseModel):
    currency: str = "USDC"


class GetTradeHistoryReq(BaseModel):
    limit: int = 100
    instrument_name: str | None = None


class GetHistoricalReq(BaseModel):
    instrument: str
    start_date: str
    end_date: str
    resolution: str = "1h"


class GetDvolReq(BaseModel):
    currency: str = "BTC"
    start_date: str
    end_date: str
    resolution: str = "1D"


class GetDvolHistoryReq(BaseModel):
    currency: str = "BTC"
    lookback_days: int = 90


class GetIvRankReq(BaseModel):
    instrument: str


class GetRealizedVolReq(BaseModel):
    currency: str = "BTC"
    windows: list[int] = [14, 30]


class GetGexReq(BaseModel):
    currency: str
    expiry_from: str | None = None
    expiry_to: str | None = None
    top_n_strikes: int = 50


class GetPcRatioReq(BaseModel):
    currency: str


class GetSkew25dReq(BaseModel):
    currency: str
    expiry: str


class GetTermStructureReq(BaseModel):
    currency: str


class CalculateSpreadPayoffReq(BaseModel):
    legs: list[dict]
    quote_currency: str = "USD"


class RunBacktestReq(BaseModel):
    strategy_name: str
    underlying: str = "BTC"
    lookback_days: int = 30
    resolution: str = "4h"
    entry_rules: dict | None = None
    exit_rules: dict | None = None


class FindByDeltaReq(BaseModel):
    currency: str
    expiry: str
    target_delta: float
    option_type: str
    max_results: int = 3
    min_open_interest: float = 100.0
    min_volume_24h: float = 20.0


class GetIndicatorsReq(BaseModel):
    instrument: str
    indicators: list[str]
    start_date: str
    end_date: str
    resolution: str = "1h"

    @field_validator("indicators", mode="before")
    @classmethod
    def _coerce_indicators(cls, v):
        if isinstance(v, str):
            import json
            s = v.strip()
            if s.startswith("["):
                try:
                    parsed = json.loads(s)
                    if isinstance(parsed, list):
                        return [str(x).strip() for x in parsed if str(x).strip()]
                except json.JSONDecodeError:
                    pass
            return [x.strip() for x in s.split(",") if x.strip()]
        if isinstance(v, list):
            return v
        raise ValueError(
            "indicators must be a list like ['rsi','atr','macd'] "
            "or a comma-separated string like 'rsi,atr,macd'"
        )


class PlaceOrderReq(BaseModel):
    instrument_name: str
    side: str  # "buy" | "sell"
    amount: float
    type: str = "limit"
    price: float | None = None
    reduce_only: bool = False
    post_only: bool = False
    label: str | None = None
    leverage: int | None = None  # CER-016: None → default cap (3x)


class CancelOrderReq(BaseModel):
    order_id: str


class SetStopLossReq(BaseModel):
    order_id: str
    stop_price: float


class SetTakeProfitReq(BaseModel):
    order_id: str
    tp_price: float


class ClosePositionReq(BaseModel):
    instrument_name: str


# --- CER-016 notional helpers ---

async def _compute_notional_deribit(client: DeribitClient, body: PlaceOrderReq) -> float:
    """Stima notional in USD per un ordine Deribit.

    - Perp USDC: contract size = 1 USD → amount è già notional USD.
    - Options: amount è in base asset (BTC/ETH) → moltiplica per index price.
    - Altri perp BTC/ETH: amount in USD notional.
    """
    name = body.instrument_name.upper()
    if name.endswith("-PERPETUAL"):
        return float(body.amount)
    ref_price: float | None = body.price
    if ref_price is None:
        try:
            tk = await client.get_ticker(body.instrument_name)
            ref_price = tk.get("mark_price") or tk.get("last_price")
        except Exception:
            ref_price = None
    if not ref_price:
        return float(body.amount)
    return float(body.amount) * float(ref_price)


async def _current_aggregate_deribit(client: DeribitClient) -> float:
    """Somma notional posizioni aperte su Deribit (USDC)."""
    try:
        positions = await client.get_positions("USDC")
    except Exception:
        return 0.0
    total = 0.0
    for p in positions or []:
        size = abs(float(p.get("size") or 0))
        name = str(p.get("instrument") or "").upper()
        if name.endswith("-PERPETUAL"):
            total += size
        else:
            mark = float(p.get("mark_price") or 0)
            total += size * mark
    return total


# --- ACL helper ---

def _check(principal: Principal, *, core: bool = False, observer: bool = False) -> None:
    allowed: set[str] = set()
    if core:
        allowed.add("core")
    if observer:
        allowed.add("observer")
    if not (principal.capabilities & allowed):
        raise HTTPException(403, f"capability required: {allowed}")


# --- App factory ---

def create_app(*, client: DeribitClient, token_store: TokenStore) -> FastAPI:
    from contextlib import asynccontextmanager

    # CER-016: pre-set leverage 3x su perp principali al boot (best-effort).
    @asynccontextmanager
    async def _lifespan(_app: FastAPI):
        cap = enforce_leverage(None)
        for inst in ("BTC-PERPETUAL", "ETH-PERPETUAL"):
            try:
                await client.set_leverage(inst, cap)
            except Exception:
                pass
        yield

    app = build_app(
        name="mcp-deribit",
        version="0.1.0",
        token_store=token_store,
        lifespan=_lifespan,
    )

    # --- Read tools: core + observer ---

    @app.post("/tools/is_testnet", tags=["reads"])
    async def t_is_testnet(principal: Principal = Depends(require_principal)):
        _check(principal, core=True, observer=True)
        return client.is_testnet()

    @app.post("/tools/get_ticker", tags=["reads"])
    async def t_get_ticker(
        body: GetTickerReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_ticker(body.instrument_name)

    @app.post("/tools/get_ticker_batch", tags=["reads"])
    async def t_get_ticker_batch(
        body: GetTickerBatchReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_ticker_batch(body.instrument_names)

    @app.post("/tools/get_instruments", tags=["reads"])
    async def t_get_instruments(
        body: GetInstrumentsReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_instruments(
            currency=body.currency,
            kind=body.kind,
            expiry_from=body.expiry_from,
            expiry_to=body.expiry_to,
            strike_min=body.strike_min,
            strike_max=body.strike_max,
            min_open_interest=body.min_open_interest,
            limit=body.limit,
            offset=body.offset,
        )

    @app.post("/tools/get_orderbook", tags=["reads"])
    async def t_get_orderbook(
        body: GetOrderbookReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_orderbook(body.instrument_name, body.depth)

    @app.post("/tools/get_positions", tags=["reads"])
    async def t_get_positions(
        body: GetPositionsReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_positions(body.currency)

    @app.post("/tools/get_account_summary", tags=["reads"])
    async def t_get_account_summary(
        body: GetAccountSummaryReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_account_summary(body.currency)

    @app.post("/tools/get_trade_history", tags=["reads"])
    async def t_get_trade_history(
        body: GetTradeHistoryReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_trade_history(body.limit, body.instrument_name)

    @app.post("/tools/get_historical", tags=["reads"])
    async def t_get_historical(
        body: GetHistoricalReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_historical(
            body.instrument, body.start_date, body.end_date, body.resolution
        )

    @app.post("/tools/get_dvol", tags=["reads"])
    async def t_get_dvol(
        body: GetDvolReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_dvol(
            body.currency, body.start_date, body.end_date, body.resolution
        )

    @app.post("/tools/get_gex", tags=["reads"])
    async def t_get_gex(
        body: GetGexReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_gex(
            body.currency, body.expiry_from, body.expiry_to, body.top_n_strikes
        )

    @app.post("/tools/get_pc_ratio", tags=["reads"])
    async def t_get_pc_ratio(
        body: GetPcRatioReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_pc_ratio(body.currency)

    @app.post("/tools/get_skew_25d", tags=["reads"])
    async def t_get_skew_25d(
        body: GetSkew25dReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_skew_25d(body.currency, body.expiry)

    @app.post("/tools/get_term_structure", tags=["reads"])
    async def t_get_term_structure(
        body: GetTermStructureReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_term_structure(body.currency)

    @app.post("/tools/run_backtest", tags=["writes"])
    async def t_run_backtest(
        body: RunBacktestReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.run_backtest(
            strategy_name=body.strategy_name,
            underlying=body.underlying,
            lookback_days=body.lookback_days,
            resolution=body.resolution,
            entry_rules=body.entry_rules,
            exit_rules=body.exit_rules,
        )

    @app.post("/tools/calculate_spread_payoff", tags=["writes"])
    async def t_calculate_spread_payoff(
        body: CalculateSpreadPayoffReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.calculate_spread_payoff(body.legs, body.quote_currency)

    @app.post("/tools/find_by_delta", tags=["writes"])
    async def t_find_by_delta(
        body: FindByDeltaReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.find_by_delta(
            currency=body.currency,
            expiry=body.expiry,
            target_delta=body.target_delta,
            option_type=body.option_type,
            max_results=body.max_results,
            min_open_interest=body.min_open_interest,
            min_volume_24h=body.min_volume_24h,
        )

    @app.post("/tools/get_iv_rank", tags=["reads"])
    async def t_get_iv_rank(
        body: GetIvRankReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_iv_rank(body.instrument)

    @app.post("/tools/get_dvol_history", tags=["reads"])
    async def t_get_dvol_history(
        body: GetDvolHistoryReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_dvol_history(body.currency, body.lookback_days)

    @app.post("/tools/get_realized_vol", tags=["reads"])
    async def t_get_realized_vol(
        body: GetRealizedVolReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_realized_vol(body.currency, body.windows)

    @app.post("/tools/get_technical_indicators", tags=["reads"])
    async def t_get_indicators(
        body: GetIndicatorsReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True, observer=True)
        return await client.get_technical_indicators(
            body.instrument,
            body.indicators,
            body.start_date,
            body.end_date,
            body.resolution,
        )

    # --- Write tools: core only ---

    @app.post("/tools/place_order", tags=["writes"])
    async def t_place_order(
        body: PlaceOrderReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True)
        lev = enforce_leverage(body.leverage)
        if not body.reduce_only:
            notional = await _compute_notional_deribit(client, body)
            enforce_single_notional(
                notional, exchange="deribit", instrument=body.instrument_name
            )
            agg = await _current_aggregate_deribit(client)
            enforce_aggregate(agg, notional)
        if lev != enforce_leverage(None):
            try:
                await client.set_leverage(body.instrument_name, lev)
            except Exception:
                pass
        return await client.place_order(
            instrument_name=body.instrument_name,
            side=body.side,
            amount=body.amount,
            type=body.type,
            price=body.price,
            reduce_only=body.reduce_only,
            post_only=body.post_only,
            label=body.label,
        )

    @app.post("/tools/cancel_order", tags=["writes"])
    async def t_cancel_order(
        body: CancelOrderReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True)
        return await client.cancel_order(body.order_id)

    @app.post("/tools/set_stop_loss", tags=["writes"])
    async def t_set_sl(
        body: SetStopLossReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True)
        return await client.set_stop_loss(body.order_id, body.stop_price)

    @app.post("/tools/set_take_profit", tags=["writes"])
    async def t_set_tp(
        body: SetTakeProfitReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True)
        return await client.set_take_profit(body.order_id, body.tp_price)

    @app.post("/tools/close_position", tags=["writes"])
    async def t_close_position(
        body: ClosePositionReq, principal: Principal = Depends(require_principal)
    ):
        _check(principal, core=True)
        return await client.close_position(body.instrument_name)

    # ───── MCP endpoint (/mcp) — bridge verso /tools/* ─────
    port = int(os.environ.get("PORT", "9011"))
    mount_mcp_endpoint(
        app,
        name="cerbero-deribit",
        version="0.1.0",
        token_store=token_store,
        internal_base_url=f"http://localhost:{port}",
        tools=[
            {"name": "is_testnet", "description": "True se client Deribit è in modalità testnet."},
            {"name": "get_ticker", "description": "Ticker di un instrument Deribit."},
            {"name": "get_ticker_batch", "description": "Ticker per N instruments in parallelo (max 20)."},
            {"name": "get_instruments", "description": "Lista instruments per currency."},
            {"name": "get_orderbook", "description": "Orderbook L1/L2 per instrument."},
            {"name": "get_positions", "description": "Posizioni aperte."},
            {"name": "get_account_summary", "description": "Summary account (equity, balance)."},
            {"name": "get_trade_history", "description": "Storia trade recenti."},
            {"name": "get_historical", "description": "OHLCV storico."},
            {"name": "get_dvol", "description": "Deribit Volatility Index (DVOL) OHLC per currency (BTC/ETH)."},
            {"name": "get_dvol_history", "description": "DVOL time series + percentili su lookback_days."},
            {"name": "get_iv_rank", "description": "IV rank 30/90/365d di un instrument vs DVOL storico della currency."},
            {"name": "find_by_delta", "description": "Trova strike con delta più vicino a target, filtrato per liquidità (OI/vol)."},
            {"name": "calculate_spread_payoff", "description": "Payoff/greci/max P-L/break-even/fee per struttura multi-leg."},
            {"name": "run_backtest", "description": "Heuristic backtest RSI-based su storia OHLCV per threshold accept/marginal/reject."},
            {"name": "get_term_structure", "description": "IV ATM per ogni expiry disponibile, detect contango/backwardation."},
            {"name": "get_skew_25d", "description": "Skew 25-delta put/call IV + risk reversal + butterfly per expiry."},
            {"name": "get_pc_ratio", "description": "Put/Call ratio aggregato su OI e volume 24h."},
            {"name": "get_gex", "description": "Gamma exposure per strike + zero gamma level (top N strikes per OI)."},
            {"name": "get_technical_indicators", "description": "Indicatori tecnici (RSI, MACD, ATR, ADX)."},
            {"name": "get_realized_vol", "description": "Volatilità realizzata annualizzata (log-return std) BTC/ETH + spread IV−RV."},
            {"name": "place_order", "description": "Invia ordine (CORE only, testnet)."},
            {"name": "cancel_order", "description": "Cancella ordine."},
            {"name": "set_stop_loss", "description": "Setta stop loss su posizione."},
            {"name": "set_take_profit", "description": "Setta take profit su posizione."},
            {"name": "close_position", "description": "Chiude posizione aperta."},
        ],
    )

    return app