from typing import BinaryIO, Any, Dict, Iterator, List, Optional, Tuple
from openpyxl import Workbook, load_workbook
from collections import defaultdict

from backend.condition.parsing.parser import Parser
from backend.condition.parsing.records.lbwf.lbwf_asset_condition import (
    LbwfAssetCondition,
)
from backend.condition.parsing.records.lbwf.lbwf_house import LbwfHouse
from backend.condition.utils.date_utils import normalise_date
from utils.logger import setup_logger

logger = setup_logger()


class LbwfParser(Parser):

    def parse(
        self,
        file_stream: BinaryIO,
    ) -> Any:
        wb: Workbook = load_workbook(file_stream)
        address_to_uprn_map: Dict[str, int] = LbwfParser._generate_address_to_uprn_dict(
            wb
        )

        assets = self._parse_assets(wb)
        houses = self._parse_houses(wb, address_to_uprn_map)

        self._merge_assets_into_houses(assets, houses)

        return houses

    @staticmethod
    def _parse_assets(wb: Workbook) -> List[LbwfAssetCondition]:
        assets_sheet = wb["Houses Asset Data"]
        asset_rows = assets_sheet.iter_rows(values_only=True)

        asset_headers = next(asset_rows)
        asset_header_indexes = LbwfParser._get_column_indexes_by_name(asset_headers)

        assets: List[LbwfAssetCondition] = []
        for row in asset_rows:
            try:
                assets.append(
                    LbwfParser._map_row_to_asset_record(row, asset_header_indexes)
                )
            except Exception as e:
                logger.error(f"Error mapping LBWF row to asset record: {e}")
                continue

        return assets

    @staticmethod
    def _parse_houses(
        wb: Workbook,
        address_to_uprn_map: Dict[str, int],
    ) -> List[LbwfHouse]:
        houses_sheet = wb["Houses"]
        house_rows = houses_sheet.iter_rows(values_only=True)

        house_headers = next(house_rows)
        house_header_indexes = LbwfParser._get_column_indexes_by_name(house_headers)

        houses: List[LbwfHouse] = []
        for row in house_rows:
            try:
                houses.append(
                    LbwfParser._map_row_to_house_record(
                        row,
                        house_header_indexes,
                        address_to_uprn_map,
                    )
                )
            except Exception as e:
                logger.error(f"Error mapping LBWF row to house record: {e}")
                continue

        return houses

    @staticmethod
    def _merge_assets_into_houses(
        assets: List[LbwfAssetCondition],
        houses: List[LbwfHouse],
    ) -> None:
        assets_by_ref: Dict[int, List[LbwfAssetCondition]] = defaultdict(list)
        for asset in assets:
            assets_by_ref[asset.prop_ref].append(asset)

        for house in houses:
            house.assets = assets_by_ref.get(house.reference, [])

    @staticmethod
    def _map_row_to_house_record(
        row: Any | Tuple[object | None, ...],
        header_indexes: Dict[str, int],
        address_to_uprn_map: Dict[str, int],
    ) -> LbwfHouse:
        address: str = row[header_indexes["Address"]]

        return LbwfHouse(
            uprn=LbwfParser._get_uprn_from_address(address, address_to_uprn_map),
            reference=row[header_indexes["Reference"]],
            address=address,
            epc=row[header_indexes["EPC "]],
            shdf=row[header_indexes["SHDF"]],
            house=row[header_indexes["HOSUE"]],
            fail_decency=row[header_indexes["Fail Decency"]],
            assets=[],
        )

    @staticmethod
    def _map_row_to_asset_record(
        row: Any | Tuple[object | None, ...],
        header_indexes: Dict[str, int],
    ) -> LbwfAssetCondition:
        return LbwfAssetCondition(
            prop_ref=row[header_indexes["PROP REF"]],
            domna=row[header_indexes["Domna"]],
            address=row[header_indexes["ADDRESS"]],
            ownership=row[header_indexes["OWNERSHIP"]],
            prop_status=row[header_indexes["PROP STATUS"]],
            prop_type=row[header_indexes["PROP TYPE"]],
            prop_sub_type=row[header_indexes["PROP SUB TYPE"]],
            element_group=row[header_indexes["ELEMENT GROUP"]],
            element_code=row[header_indexes["ELEMENT CODE"]],
            element_code_description=row[header_indexes["ELEMENT CODE DESCRIPTION"]],
            attribute_code=row[header_indexes["ATTRIBUTE CODE"]],
            attribute_code_description=row[
                header_indexes["ATTRIBUTE CODE DESCRIPTION"]
            ],
            element_date_value=row[header_indexes["ELEMENT DATE VALUE"]],
            element_numerical_value=row[header_indexes["ELEMENT NUMERIC VALUE"]],
            element_text_value=row[header_indexes["ELEMENT TEXT VALUE"]],
            quantity=row[header_indexes["QUANTITY"]],
            install_date=normalise_date(row[header_indexes["INSTALL DATE"]]),
            remaining_life=row[header_indexes["REMAINING LIFE"]],
            element_comments=row[header_indexes["ELEMENT COMMENTS"]],
        )

    @staticmethod
    def _generate_address_to_uprn_dict(wb: Workbook) -> Dict[str, int | None]:
        sheet = wb["All Energy Breakdown "]

        rows: Iterator[Tuple[object | None, ...]] = sheet.iter_rows(values_only=True)

        headers = next(rows)
        header_indexes: Dict[str, int] = LbwfParser._get_column_indexes_by_name(headers)

        address_idx = header_indexes["Address"]
        uprn_idx = header_indexes["UPRN"]

        mapping: Dict[str, int | None] = {}

        for row in rows:
            address = row[address_idx]
            uprn = row[uprn_idx]

            if not isinstance(address, str):
                continue

            if uprn is not None and not isinstance(uprn, int):
                raise ValueError(f"Unexpected UPRN value: {uprn!r}")

            mapping[address] = uprn

        return mapping

    @staticmethod
    def _get_column_indexes_by_name(
        headers: Tuple[object | None, ...],
    ) -> Dict[str, int]:
        index: Dict[str, int] = {}

        for i, header in enumerate(headers):
            if isinstance(header, str):
                index[header] = i

        return index

    @staticmethod
    def _get_uprn_from_address(
        address: str, address_to_uprn_map: Dict[str, int]
    ) -> int | None:
        pseudo_name = address.split(",")[0]

        if pseudo_name.lower() in (k.lower() for k in address_to_uprn_map.keys()):
            return address_to_uprn_map[pseudo_name.upper()]

        return None