from __future__ import annotations

from typing import Any, Dict, List


def map_procurement_to_documents(
    tables: Dict[str, Any],
    task_prefix: str,
    max_docs: int,
    column_mapping: Dict[str, str] | None = None,
) -> List[Dict[str, str]]:
    invoices = tables["invoices"]

    column_mapping = column_mapping or {}
    doc_id_col = _resolve_column(
        invoices.columns,
        column_mapping.get("invoice_id"),
        ["invoice_id", "id", "InvoiceID", "invoice_number"],
    )
    amount_col = _resolve_column(
        invoices.columns,
        column_mapping.get("amount"),
        ["amount", "invoice_amount", "Amount"],
    )
    vendor_col = _resolve_column(
        invoices.columns,
        column_mapping.get("vendor_id"),
        ["supplier_id", "vendor_id", "SupplierID"],
    )
    dept_col = _resolve_column(
        invoices.columns,
        column_mapping.get("department_id"),
        ["department_id", "DepartmentID"],
    )
    date_col = _resolve_column(
        invoices.columns,
        column_mapping.get("invoice_date"),
        ["invoice_date", "date", "InvoiceDate"],
    )

    docs: List[Dict[str, str]] = []
    for idx, row in invoices.head(max_docs).iterrows():
        source_id = str(row.get(doc_id_col, f"SRC-{idx:05d}")) if doc_id_col else f"SRC-{idx:05d}"
        amount = str(row.get(amount_col, "")) if amount_col else ""
        vendor = str(row.get(vendor_col, "")) if vendor_col else ""
        dept = str(row.get(dept_col, "")) if dept_col else ""
        date = str(row.get(date_col, "")) if date_col else ""
        dup_flag = str(row.get("is_duplicate_invoice_id", ""))
        dup_group_size = str(row.get("duplicate_invoice_group_size", ""))

        doc_id = f"{task_prefix}-DOC-{idx:04d}"
        text = (
            f"invoice_id={source_id}; amount={amount}; vendor={vendor}; department={dept}; "
            f"invoice_date={date}; is_duplicate_invoice_id={dup_flag}; "
            f"duplicate_invoice_group_size={dup_group_size}"
        )
        docs.append({"id": doc_id, "type": "invoice", "text": text})

    return docs


def map_hf_fraud_rows_to_signals(rows: list[dict[str, Any]], max_rows: int) -> list[str]:
    signals: list[str] = []
    for row in rows[:max_rows]:
        pieces = []
        for key in ["Company", "Label", "Fillings", "Filing", "text"]:
            if key in row and row[key] is not None:
                pieces.append(f"{key}={str(row[key])[:120]}")
        if pieces:
            signals.append(" | ".join(pieces))
    return signals


def _first_existing_column(columns: Any, candidates: list[str]) -> str | None:
    lower_map = {str(c).lower(): str(c) for c in columns}
    for cand in candidates:
        if cand.lower() in lower_map:
            return lower_map[cand.lower()]
    return None


def _resolve_column(columns: Any, preferred: str | None, fallbacks: list[str]) -> str | None:
    if preferred:
        lower_map = {str(c).lower(): str(c) for c in columns}
        hit = lower_map.get(preferred.lower())
        if hit:
            return hit
    return _first_existing_column(columns, fallbacks)