from __future__ import annotations

import argparse
import hashlib
import json
import logging
from datetime import UTC, datetime
from pathlib import Path
from typing import Any, Iterable

import pandas as pd


DEFAULT_DATA_ROOT = Path("/Users/zach/Desktop/quant-strategy-training-data")
DEFAULT_RAW_ROOT = DEFAULT_DATA_ROOT / "crypto-lake" / "raw"


def setup_logging() -> None:
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s %(levelname)s event=%(message)s",
    )


def add_common_args(parser: argparse.ArgumentParser) -> None:
    parser.add_argument("--data-root", type=Path, default=DEFAULT_DATA_ROOT)
    parser.add_argument("--run-id", required=True)
    parser.add_argument("--config", type=Path)
    parser.add_argument("--workspace", type=Path)
    parser.add_argument("--fail-fast", action="store_true")


def run_root(args: argparse.Namespace) -> Path:
    return args.data_root / "trader-v4" / "runs" / args.run_id


def ensure_dir(path: Path) -> Path:
    path.mkdir(parents=True, exist_ok=True)
    return path


def canonical_json_bytes(value: Any) -> bytes:
    return json.dumps(value, ensure_ascii=False, sort_keys=False, separators=(",", ":")).encode("utf-8")


def sha256_bytes(data: bytes) -> str:
    return hashlib.sha256(data).hexdigest()


def sha256_json(value: Any) -> str:
    return sha256_bytes(canonical_json_bytes(value))


def sha256_file(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as fh:
        for chunk in iter(lambda: fh.read(1024 * 1024), b""):
            digest.update(chunk)
    return digest.hexdigest()


def write_json(path: Path, value: Any) -> str:
    ensure_dir(path.parent)
    data = canonical_json_bytes(value)
    path.write_bytes(data + b"\n")
    return sha256_bytes(data)


def read_json(path: Path) -> Any:
    with path.open("r", encoding="utf-8") as fh:
        return json.load(fh)


def write_parquet(path: Path, frame: pd.DataFrame) -> str:
    ensure_dir(path.parent)
    frame.to_parquet(path, index=False)
    return sha256_file(path)


def read_parquet(path: Path) -> pd.DataFrame:
    if not path.is_file():
        raise FileNotFoundError(f"required parquet is missing: {path}")
    return pd.read_parquet(path)


def write_text(path: Path, text: str) -> None:
    ensure_dir(path.parent)
    path.write_text(text, encoding="utf-8")


def utc_now_text() -> str:
    return datetime.now(UTC).replace(microsecond=0).isoformat().replace("+00:00", "Z")


def to_utc_series(values: pd.Series) -> pd.Series:
    if pd.api.types.is_datetime64_any_dtype(values):
        return pd.to_datetime(values, utc=True)
    numeric = pd.to_numeric(values, errors="coerce")
    if numeric.notna().any():
        max_value = numeric.dropna().abs().max()
        unit = "ms" if max_value > 10_000_000_000 else "s"
        return pd.to_datetime(numeric, unit=unit, utc=True)
    return pd.to_datetime(values, utc=True, errors="coerce")


def open_time_ms(values: pd.Series) -> pd.Series:
    dt = to_utc_series(values)
    return (dt.astype("int64") // 1_000_000).astype("Int64")


def date_texts(start_date: str | None, end_date: str | None) -> tuple[str | None, str | None]:
    return start_date, end_date


def partition_files(raw_root: Path, table: str, symbol: str, start_date: str | None, end_date: str | None) -> list[Path]:
    base = raw_root / f"table={table}"
    if not base.is_dir():
        return []
    files = sorted(base.glob(f"exchange=*/symbol={symbol}/dt=*/data.parquet"))
    selected: list[Path] = []
    for file in files:
        dt_part = next((part.split("=", 1)[1] for part in file.parts if part.startswith("dt=")), "")
        if start_date and dt_part < start_date:
            continue
        if end_date and dt_part > end_date:
            continue
        selected.append(file)
    return selected


def read_partitioned_table(
    raw_root: Path,
    table: str,
    symbol: str,
    start_date: str | None,
    end_date: str | None,
    columns: Iterable[str] | None = None,
) -> pd.DataFrame:
    files = partition_files(raw_root, table, symbol, start_date, end_date)
    if not files:
        return pd.DataFrame()
    logging.info("trader.training.raw_read_started table=%s symbol=%s fileCount=%s", table, symbol, len(files))
    frames = [pd.read_parquet(file, columns=list(columns) if columns else None) for file in files]
    frame = pd.concat(frames, ignore_index=True)
    logging.info("trader.training.raw_read_finished table=%s rowCount=%s", table, len(frame))
    return frame


def require_columns(frame: pd.DataFrame, columns: Iterable[str], name: str) -> None:
    missing = [column for column in columns if column not in frame.columns]
    if missing:
        raise ValueError(f"{name} is missing required columns: {missing}")


def manifest(path: Path, extra: dict[str, Any]) -> dict[str, Any]:
    payload = {
        "path": str(path),
        "hash_sha256": sha256_file(path) if path.is_file() else None,
        "created_at": utc_now_text(),
    }
    payload.update(extra)
    return payload