"""Shared helpers for reading GCP account metadata."""

from __future__ import annotations

import csv
from pathlib import Path
from typing import Optional, Set


GCP_DIR = Path(__file__).resolve().parent

_TRUTHY_MARKERS = {
    "true",
    "1",
    "yes",
    "y",
    "on",
    "active",
    "enabled",
}

_TRUTHY_NATIVE = {"是", "启用"}


def _normalize_flag(value: Optional[str]) -> bool:
    """Return True when the provided CSV field represents an enabled flag."""

    if value is None:
        return False

    raw = str(value).strip()
    if not raw:
        return False

    lowered = raw.lower()
    if lowered in _TRUTHY_MARKERS:
        return True

    return raw in _TRUTHY_NATIVE


def resolve_account_details_path(account_details_file: Optional[str] = None) -> Optional[Path]:
    """Resolve the preferred account details CSV path if one exists."""

    candidates = []

    if account_details_file:
        path = Path(account_details_file)
        if not path.is_absolute():
            path = GCP_DIR / path
        candidates.append(path)

    # Fall back to the canonical filename, but also honour the legacy typo.
    candidates.extend(
        [
            GCP_DIR / "gcp_account_details.csv",
            GCP_DIR / "gcp_accout_details.csv",
        ]
    )

    for path in candidates:
        if path.exists():
            return path

    return None


def load_active_accounts(account_details_file: Optional[str] = None) -> Optional[Set[str]]:
    """Load the set of active GCP account identifiers from the CSV file.

    Returns ``None`` when the account metadata file is missing or malformed,
    signalling that callers should not filter the input data.
    """

    details_path = resolve_account_details_path(account_details_file)
    if details_path is None:
        print("Warning: GCP account details file not found. Skipping account filtering.")
        return None

    active_accounts: Set[str] = set()

    try:
        with details_path.open("r", encoding="utf-8-sig") as handle:
            reader = csv.DictReader(handle)
            if not reader.fieldnames or "account_id" not in reader.fieldnames:
                print(
                    "Warning: account details file missing 'account_id' column: "
                    f"{details_path}"
                )
                return None

            for row in reader:
                account_id = (row.get("account_id") or "").strip()
                if not account_id:
                    continue

                flag_value = row.get("is_active")
                if flag_value is None:
                    # Accept camelCase should future templates adopt it.
                    flag_value = row.get("isActive")

                if _normalize_flag(flag_value):
                    active_accounts.add(account_id)

    except Exception as exc:  # pylint: disable=broad-except
        print(f"Warning: Failed to load GCP account details from {details_path}: {exc}")
        return None

    if not active_accounts:
        print(f"Warning: No active GCP accounts marked in {details_path}")

    print(f"Loaded {len(active_accounts)} active GCP accounts from {details_path.name}")
    return active_accounts