import os
import glob
import json
import numpy as np
import pandas as pd
from dataclasses import dataclass
from typing import List, Tuple

from config import config


@dataclass
class AssetSeries:
    symbol: str
    asset_type: str  # "stock" or "crypto"
    df: pd.DataFrame  # columns: date, open, high, low, close, volume


def _parse_mixed_date(series: pd.Series) -> pd.Series:
    s = series.astype(str).str.strip()
    iso_mask = s.str.match(r"^\d{4}-\d{2}-\d{2}$", na=False)
    out = pd.Series(pd.NaT, index=series.index)
    out.loc[iso_mask] = pd.to_datetime(s.loc[iso_mask], errors="coerce", dayfirst=False)
    out.loc[~iso_mask] = pd.to_datetime(s.loc[~iso_mask], errors="coerce", dayfirst=True)
    return out


def _read_any_ohlcv_csv(path: str) -> pd.DataFrame:
    df = pd.read_csv(path, sep=None, engine="python")
    cols = [str(c).strip().lower() for c in df.columns]

    # Binance format (timestamp_ms)
    if "timestamp_ms" in cols:
        df.columns = cols
        df["date"] = pd.to_datetime(df["timestamp_ms"], unit="ms", errors="coerce", utc=True).dt.tz_convert(None)
        out = df[["date", "open", "high", "low", "close", "volume"]].copy()
        for c in ["open", "high", "low", "close", "volume"]:
            out[c] = pd.to_numeric(out[c], errors="coerce")
        out = out.dropna().sort_values("date").reset_index(drop=True)
        return out

    # Stooq / generic OHLCV
    if "date" in cols and "open" in cols and "close" in cols:
        df.columns = cols
        out = df[["date", "open", "high", "low", "close", "volume"]].copy()
    else:
        out = df.iloc[:, :6].copy()
        out.columns = ["date", "open", "high", "low", "close", "volume"]

    out["date"] = _parse_mixed_date(out["date"])
    out = out.dropna(subset=["date"]).copy()

    for c in ["open", "high", "low", "close", "volume"]:
        out[c] = pd.to_numeric(out[c], errors="coerce")

    out = out.dropna().sort_values("date").reset_index(drop=True)
    return out


def discover_assets(data_dir: str) -> List[Tuple[str, str, str]]:
    assets = []

    stock_glob = os.path.join(data_dir, "stocks", "stooq", "*", f"{config.INTERVAL}.csv")
    for p in glob.glob(stock_glob):
        sym = os.path.basename(os.path.dirname(p))
        assets.append((sym, "stock", p))

    crypto_glob = os.path.join(data_dir, "crypto", "binance", "*", f"{config.INTERVAL}.csv")
    for p in glob.glob(crypto_glob):
        sym = os.path.basename(os.path.dirname(p))
        assets.append((sym, "crypto", p))

    assets = sorted(assets, key=lambda x: (x[1], x[0]))
    return assets[: config.MAX_ASSETS]


def load_asset_series() -> List[AssetSeries]:
    assets = discover_assets(config.DATA_DIR)
    series = []
    for sym, a_type, path in assets:
        df = _read_any_ohlcv_csv(path)
        if len(df) >= config.WINDOW + config.HORIZON_DAYS + 5:
            series.append(AssetSeries(symbol=sym, asset_type=a_type, df=df))
    return series


def make_features(df: pd.DataFrame) -> pd.DataFrame:
    out = df.copy()
    out["log_return"] = np.log(out["close"] / out["close"].shift(1))
    out["hl_range"] = (out["high"] - out["low"]) / (out["close"] + 1e-12)
    out["oc_return"] = (out["close"] - out["open"]) / (out["open"] + 1e-12)
    out["vol_log"] = np.log10(out["volume"].clip(lower=0) + 1.0)
    out = out.dropna().reset_index(drop=True)
    return out


def build_windows(feats: pd.DataFrame, window: int, horizon: int):
    values = feats[["log_return", "hl_range", "oc_return", "vol_log"]].values.astype(np.float32)
    dates = feats["date"].values

    X_list, y_list, ts_list = [], [], []
    for i in range(window, len(values) - horizon):
        X_list.append(values[i - window:i])
        y_list.append(values[i + horizon, 0])
        ts_list.append(pd.Timestamp(dates[i + horizon]))

    return np.stack(X_list), np.array(y_list, dtype=np.float32), ts_list


def save_manifest(series: List[AssetSeries]):
    os.makedirs(config.ARTIFACT_DIR, exist_ok=True)
    path = os.path.join(config.ARTIFACT_DIR, "manifest.json")
    payload = [{"symbol": s.symbol, "asset_type": s.asset_type, "rows": int(len(s.df))} for s in series]
    with open(path, "w", encoding="utf-8") as f:
        json.dump(payload, f, indent=2)
    return path