"""
HmmCarry — conjunction of HmmRegime4Rolling bull-state signal AND
FundingCarry sustained-negative-funding signal.

Hypothesis: each standalone signal had a known failure mode.
  - HmmRegime4Rolling on the 7-coin universe: −5.62% (HMM does not generalise).
  - FundingCarry naive long: −30.16% (negative funding in bear is trend, not contrarian).

A conjunction *might* filter both:
  - The HMM bull-state requirement screens out the "crashing alt" case where
    funding goes negative because shorts are right.
  - The negative-funding requirement screens out HMM false positives where
    the model thinks bull but the venue is actually paying shorts.

If signals are independent, conjunction tightens entries and should improve
win rate and risk-adjusted metrics — at the cost of trade count.
If signals are redundant or anti-correlated, conjunction will produce few
or zero trades.

This is a structural test of *signal independence*, not just a tuning run.

Long-only by repo convention. Walk-forward HMM refit (no look-ahead).
"""
from __future__ import annotations

import os
from pathlib import Path
import numpy as np
import pandas as pd
from pandas import DataFrame
from freqtrade.strategy import IStrategy

try:
    from hmmlearn.hmm import GaussianHMM
    _HMM_AVAILABLE = True
except ImportError:
    _HMM_AVAILABLE = False

# HMM block (matches HmmRegime4Rolling)
RETURN_WINDOW = 24
N_COMPONENTS = 4
BULL_THRESHOLD = 0.65
BULL_EXIT_THRESHOLD = 0.45
FIT_WINDOW = 1000
REFIT_EVERY = 168

# Carry block (matches FundingCarry)
ENTRY_FUNDING = -0.00001
EXIT_FUNDING = 0.00002
ROLLING_WINDOW_HOURS = 24

def _funding_dir() -> Path:
    # Resolve per-call so backtests can switch venues via env without reimporting.
    exchange = os.environ.get("CARRY_FUNDING_EXCHANGE", "hyperliquid")
    return Path(f"data/{exchange}/funding")


def _load_funding(coin: str) -> pd.DataFrame:
    path = _funding_dir() / f"{coin}-funding.parquet"
    if not path.exists():
        return pd.DataFrame()
    df = pd.read_parquet(path)
    df["time"] = pd.to_datetime(df["time"], utc=True)
    return df[["time", "funding_rate"]].sort_values("time").drop_duplicates("time")


class HmmCarry(IStrategy):
    INTERFACE_VERSION = 3
    can_short = False

    timeframe = "1h"
    startup_candle_count = FIT_WINDOW + RETURN_WINDOW

    minimal_roi = {"0": 100}
    stoploss = -0.10
    trailing_stop = False

    process_only_new_candles = True
    use_exit_signal = True
    exit_profit_only = False
    ignore_roi_if_entry_signal = False

    def populate_indicators(self, dataframe: DataFrame, metadata: dict) -> DataFrame:
        if not _HMM_AVAILABLE:
            raise ImportError("hmmlearn required: pip install hmmlearn")

        # ---- HMM block: walk-forward bull_prob (matches HmmRegime4Rolling) ----
        log_return = np.log(
            dataframe["close"] / dataframe["close"].shift(RETURN_WINDOW)
        )
        log_vol = np.log(dataframe["volume"].clip(lower=1e-9))
        log_vol_z = (log_vol - log_vol.mean()) / max(log_vol.std(), 1e-9)

        dataframe["_log_return"] = log_return
        dataframe["_log_vol_z"] = log_vol_z

        valid_mask = dataframe[["_log_return", "_log_vol_z"]].notna().all(axis=1)
        valid_idx = np.where(valid_mask.values)[0]
        bull_prob = np.full(len(dataframe), np.nan)

        if len(valid_idx) >= FIT_WINDOW + REFIT_EVERY:
            X_full = dataframe[["_log_return", "_log_vol_z"]].values
            first_refit = valid_idx[0] + FIT_WINDOW

            for r in range(first_refit, len(dataframe), REFIT_EVERY):
                fit_start = r - FIT_WINDOW
                X_fit = X_full[fit_start:r]
                if np.isnan(X_fit).any():
                    continue
                try:
                    model = GaussianHMM(
                        n_components=N_COMPONENTS,
                        covariance_type="full",
                        n_iter=200,
                        random_state=42,
                    )
                    model.fit(X_fit)
                except Exception:
                    continue

                bull_states = [i for i in range(N_COMPONENTS) if model.means_[i, 0] > 0]
                if not bull_states:
                    bull_states = [int(np.argmax(model.means_[:, 0]))]

                seg_end = min(r + REFIT_EVERY, len(dataframe))
                for t in range(r, seg_end):
                    if np.isnan(X_full[t]).any():
                        continue
                    try:
                        post = model.predict_proba(X_full[fit_start:t + 1])[-1]
                    except Exception:
                        continue
                    bull_prob[t] = post[bull_states].sum()

        dataframe["bull_prob"] = bull_prob

        # ---- Carry block: funding_roll (matches FundingCarry) ----
        coin = metadata["pair"].split("/")[0]
        funding = _load_funding(coin)
        if funding.empty:
            dataframe["funding_roll"] = np.nan
        else:
            hours = pd.to_datetime(dataframe["date"], utc=True).dt.floor("h")
            funding["_hour"] = funding["time"].dt.floor("h")
            by_hour = funding.groupby("_hour")["funding_rate"].mean()
            aligned = hours.map(by_hour).ffill()
            dataframe["funding_roll"] = (
                aligned.rolling(ROLLING_WINDOW_HOURS, min_periods=ROLLING_WINDOW_HOURS)
                .mean()
                .values
            )

        return dataframe

    def populate_entry_trend(self, dataframe: DataFrame, metadata: dict) -> DataFrame:
        # Conjunction: bull regime AND negative carry, on the bar where either
        # condition newly enters the joint regime (i.e. previous bar did not
        # satisfy the conjunction).
        joint = (
            (dataframe["bull_prob"] >= BULL_THRESHOLD)
            & (dataframe["funding_roll"] < ENTRY_FUNDING)
        )
        prev_joint = joint.shift(1).fillna(False)
        dataframe.loc[joint & ~prev_joint, "enter_long"] = 1
        return dataframe

    def populate_exit_trend(self, dataframe: DataFrame, metadata: dict) -> DataFrame:
        # Exit when *either* signal flips: HMM leaves bull state, or funding
        # normalises back above the exit band.
        exit_cond = (
            (dataframe["bull_prob"] < BULL_EXIT_THRESHOLD)
            | (dataframe["funding_roll"] >= EXIT_FUNDING)
        )
        dataframe.loc[exit_cond, "exit_long"] = 1
        return dataframe