import datetime
from typing import ClassVar
from functools import partial
from dataclasses import dataclass
import pandas as pd

from serenitas.utils.env import DAILY_DIR
from serenitas.utils.db2 import dbconn
from serenitas.analytics.dates import prev_business_day

from .misc import get_dir, dt_from_fname, Custodian


@dataclass
class CashReport:
    custodian: ClassVar[Custodian]
    date: datetime.date
    dtkey: ClassVar
    _conn: ClassVar = dbconn("dawndb")
    _staging_queue: ClassVar[set] = set()
    _insert_sql = "INSERT INTO cash_balances VALUES (%s, %s, %s, %s, %s, %s) ON CONFLICT DO NOTHING"
    _registry = {}

    def __init_subclass__(cls, custodian, dtkey):
        cls.custodian = custodian
        cls.dtkey = dtkey
        cls._registry[custodian] = cls

    def __class_getitem__(cls, key):
        return cls._registry[key]

    @classmethod
    def get_report(cls, date, fund, prefix=None):
        report_dir = get_dir(date)
        report_dir.mkdir(exist_ok=True, parents=True)
        prefix = prefix if prefix else f"{cls.custodian}_CASH_{fund}"
        p = max(
            [f for f in get_dir(date).iterdir() if f.name.startswith(prefix)],
            key=partial(dt_from_fname, dt_format=cls.dtkey),
            default=None,
        )
        if not p:
            raise ValueError(
                f"No reports found for fund: {prefix.split('_')[-1]} date: {date}"
            )
        return p

    @classmethod
    def commit(cls):
        with cls._conn.cursor() as c:
            c.executemany(cls._insert_sql, cls._staging_queue)
        cls._conn.commit()

    @classmethod
    def clear(cls):
        cls._staging_queue.clear()

    @classmethod
    def stage_from_row(cls, row, date, fund):
        (account, currency), amount = row
        cls._staging_queue.add(
            (
                prev_business_day(date),
                fund,
                f"{cls.custodian} Custody Account {fund}",
                account,
                currency,
                amount,
            )
        )

    @classmethod
    def to_db(cls, date, fund):
        for row in cls.yield_rows(date, fund):
            cls.stage_from_row(row, date, fund)
        cls.commit()
        cls.clear()


class NTCashReport(CashReport, custodian="NT", dtkey="%Y%m%d%H%M"):
    @classmethod
    def yield_rows(cls, date, fund):
        p = cls.get_report(date, fund)
        df = pd.read_csv(p, on_bad_lines="warn")
        df = df[df["T-NARR-LONG"] == "CLOSING BALANCE"]
        df = df[["Consolidation", "Currency code", "A-TRAN-AMT"]]
        df.columns = df.columns.str.replace(" |-|_", "", regex=True).str.lower()
        df = df.set_index(["consolidation", "currencycode"])
        yield from df.itertuples()


class UMBCashReport(CashReport, custodian="UMB", dtkey="%Y%m%d%H%M"):
    @classmethod
    def yield_rows(cls, date, fund):
        p = cls.get_report(date, fund)
        df = pd.read_excel(p, skiprows=3)
        yield from df.groupby(["Portfolio #", "Currency"]).sum(numeric_only=True)[
            "Current Balance"
        ].items()


class BNYCashReport(CashReport, custodian="BNY", dtkey="%Y%m%d%H%M%S"):
    @classmethod
    def yield_rows(cls, date, fund):
        p = cls.get_report(date, fund)
        df = pd.read_csv(p)
        df["Beginning Balance Local"] = df["Beginning Balance Local"].apply(
            lambda s: "-" + s[1:-1] if s.startswith("(") else s
        )
        df["Beginning Balance Local"] = pd.to_numeric(
            df["Beginning Balance Local"].str.replace(",", "")
        )
        yield from df.groupby(["Account Number", "Local Currency Code"]).sum(
            numeric_only=True
        )["Beginning Balance Local"].items()


class ScotiaCashReport(CashReport, custodian="SCOTIA", dtkey="%Y%m%d%H%M%S"):
    @classmethod
    def yield_rows(cls, date, fund):
        p = cls.get_report(date, fund)
        df = pd.read_excel(p, skipfooter=1)
        if df.empty:
            # No wires, so we can't skip the footer
            df = pd.read_excel(p)
        yield (
            (int(df.loc[0]["Account"]), df.loc[0]["Curr."]),
            df.loc[0]["Closing Bal."],
        )

    @classmethod
    def get_report(cls, date, fund):
        REPORT_DIR = DAILY_DIR / "Selene" / "Scotia_reports"
        try:
            return next(
                REPORT_DIR.glob(
                    f"IsoSelene_{prev_business_day(date):%d-%b-%Y}_*_xlsx.JOAAPKO3.JOAAPKO1"
                )
            )
        except StopIteration as e:
            raise ValueError(f"No file available for Scotia on {date}") from e