from __future__ import annotations

from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, Field

from ..config import get_settings
from ..exchange.runtime import (
    load_runtime_settings,
    normalize_exchange_name,
    persist_exchange_choice,
    reload_market_session,
)
from ..models.db import get_db
from ..sim.ledger import Ledger
from ..sim.matcher import Matcher
from .auth import require_user

router = APIRouter(prefix="/api/settings", tags=["settings"])

KEYS = (
    "fee_rate",
    "exit_move_pct",
    "exit_mode",
    "net_profit_target",
    "premium_exit_multiple",
    "rest_seconds",
    "skip_weekends",
    "initial_equity",
    "leverage",
    "min_option_hours",
    "min_option_leverage",
    "close_bid_mark_max_pct",
    "perp_qty_eth",
    "option_qty_eth",
)


class StrategySettingsBody(BaseModel):
    fee_rate: float | None = Field(default=None, ge=0, le=0.05)
    exit_move_pct: float | None = Field(default=None, ge=0.1, le=50)
    exit_mode: str | None = Field(default=None, pattern="^(fixed_usdt|premium_multiple)$")
    net_profit_target: float | None = Field(default=None, ge=0.1, le=1_000_000)
    premium_exit_multiple: float | None = Field(default=None, ge=0.1, le=100)
    rest_seconds: int | None = Field(default=None, ge=0, le=3600)
    skip_weekends: bool | None = None
    initial_equity: float | None = Field(default=None, ge=1000, le=10_000_000)
    leverage: float | None = Field(default=None, ge=1, le=125)
    min_option_hours: float | None = Field(default=None, ge=1, le=720)
    min_option_leverage: float | None = Field(default=None, ge=1, le=10000)
    close_bid_mark_max_pct: float | None = Field(default=None, ge=1, le=100)
    perp_qty_eth: float | None = Field(default=None, ge=0.01, le=100)
    option_qty_eth: float | None = Field(default=None, ge=0.01, le=100)
    exchange: str | None = Field(default=None, pattern="^(okx|binance|bn)$")


def _as_bool(raw: str | None, default: bool) -> bool:
    if raw is None or raw == "":
        return default
    return str(raw).strip().lower() in ("1", "true", "yes", "on")


def _read_settings() -> dict:
    db = get_db()
    s = get_settings()
    rt = load_runtime_settings()
    mode = str(db.get_setting("exit_mode", s.exit_mode) or s.exit_mode)
    if mode not in ("fixed_usdt", "premium_multiple"):
        mode = "fixed_usdt"
    return {
        "fee_rate": float(db.get_setting("fee_rate", str(s.fee_rate)) or s.fee_rate),
        "exit_move_pct": float(
            db.get_setting("exit_move_pct", str(s.exit_move_pct)) or s.exit_move_pct
        ),
        "exit_mode": mode,
        "net_profit_target": float(
            db.get_setting("net_profit_target", str(s.net_profit_target))
            or s.net_profit_target
        ),
        "premium_exit_multiple": float(
            db.get_setting("premium_exit_multiple", str(s.premium_exit_multiple))
            or s.premium_exit_multiple
        ),
        "rest_seconds": int(
            float(db.get_setting("rest_seconds", str(s.rest_seconds)) or s.rest_seconds)
        ),
        "skip_weekends": _as_bool(
            db.get_setting("skip_weekends", str(s.skip_weekends)), s.skip_weekends
        ),
        "initial_equity": float(
            db.get_setting("initial_equity", str(s.initial_equity)) or s.initial_equity
        ),
        "leverage": float(db.get_setting("leverage", str(s.leverage)) or s.leverage),
        "min_option_hours": float(
            db.get_setting("min_option_hours", str(s.min_option_hours))
            or s.min_option_hours
        ),
        "min_option_leverage": float(
            db.get_setting("min_option_leverage", str(s.min_option_leverage))
            or s.min_option_leverage
        ),
        "close_bid_mark_max_pct": float(
            db.get_setting("close_bid_mark_max_pct", str(s.close_bid_mark_max_pct))
            or s.close_bid_mark_max_pct
        ),
        "perp_qty_eth": float(
            db.get_setting("perp_qty_eth", str(s.perp_qty_eth)) or s.perp_qty_eth
        ),
        "option_qty_eth": float(
            db.get_setting("option_qty_eth", str(s.option_qty_eth)) or s.option_qty_eth
        ),
        "exchange": rt.exchange,
        "perp_inst_id": rt.perp_inst_id,
        "option_inst_family": rt.option_inst_family,
        "index_inst_id": rt.index_inst_id,
        "ledger": Ledger(db).snapshot(),
    }


@router.get("/strategy")
async def get_strategy_settings(_user: Annotated[str, Depends(require_user)]) -> dict:
    return _read_settings()


@router.put("/strategy")
async def put_strategy_settings(
    body: StrategySettingsBody,
    _user: Annotated[str, Depends(require_user)],
) -> dict:
    db = get_db()
    s = get_settings()
    data = body.model_dump(exclude_none=True)
    equity_to_apply: float | None = None
    switch_to: str | None = None

    if "exchange" in data:
        new_ex = normalize_exchange_name(str(data.pop("exchange")))
        old_ex = normalize_exchange_name(
            db.get_setting("exchange", s.exchange) or s.exchange
        )
        if new_ex != old_ex:
            if Matcher(db).has_open_position():
                raise HTTPException(
                    status_code=409,
                    detail="有未平仓，无法切换交易所；请先平仓后再改",
                )
            switch_to = new_ex

    if "initial_equity" in data:
        new_eq = float(data["initial_equity"])
        old_eq = float(
            db.get_setting("initial_equity", str(s.initial_equity)) or s.initial_equity
        )
        if abs(new_eq - old_eq) > 1e-9:
            if Matcher(db).has_open_position():
                raise HTTPException(
                    status_code=409,
                    detail="有未平仓，无法重置模拟资金；请先平仓后再改",
                )
            equity_to_apply = new_eq

    for k, v in data.items():
        if k in KEYS:
            db.set_setting(k, str(v))

    if equity_to_apply is not None:
        Ledger(db).reset_equity(
            equity_to_apply,
            note=f"设置模拟资金={equity_to_apply:.2f}",
        )

    if switch_to is not None:
        rt = persist_exchange_choice(switch_to)
        try:
            await reload_market_session(rt)
        except Exception as e:
            raise HTTPException(
                status_code=502,
                detail=f"交易所已切换为 {switch_to}，但行情重连失败: {e}",
            ) from e

    return _read_settings()