import pandas as pd
from . import DAILY_DIR


def download_files(count=20):
    from exchange import ExchangeMessage

    em = ExchangeMessage()
    emails = em.get_msgs(
        path=["NYops", "Margin calls"], count=count, subject__contains="Margin"
    )
    DATA_DIR = DAILY_DIR / "GS_reports"
    for msg in emails:
        for attach in msg.attachments:
            fname = attach.name
            if fname.endswith("xls"):
                p = DATA_DIR / fname
                if not p.exists():
                    p.write_bytes(attach.content)


def load_file(d, pattern):
    try:
        fname = next(
            (DAILY_DIR / "GS_reports").glob(f"{pattern}*{d.strftime('%d_%b_%Y')}*")
        )
    except StopIteration:
        raise FileNotFoundError(f"GS {pattern} file not found for date {d}")
    return pd.read_excel(fname, skiprows=9, skipfooter=77)


def collateral(d, dawn_trades, *args):
    df = load_file(d, "Collateral_Detail")
    collateral = float(df.Quantity)
    df = load_file(d, "Trade_Detail")
    df = df[["Trade Id", "Transaction Type", "NPV (USD)", "Initial Margin Required"]]
    df = df.merge(dawn_trades, how="left", left_on="Trade Id", right_on="cpty_id")
    missing_ids = df.loc[df.cpty_id.isnull(), "Trade Id"]
    if not missing_ids.empty:
        raise ValueError(f"{missing_ids.tolist()} not in the database")
    df = df[["folder", "NPV (USD)", "Initial Margin Required"]]
    df = df.groupby("folder").sum()
    df = df.sum(axis=1).to_frame(name="Amount")
    df["Currency"] = "USD"
    df = df.reset_index()
    df.columns = ["Strategy", "Amount", "Currency"]
    df.Amount *= -1
    df = df.append(
        {
            "Strategy": "M_CSH_CASH",
            "Amount": -collateral - df.Amount.sum(),
            "Currency": "USD",
        },
        ignore_index=True,
    )
    df["date"] = d
    return df.set_index("Strategy")