import openpyxl
from typing import List, Dict, Any, BinaryIO
from datetime import datetime
from .base_parser import BaseBankStatementParser

class VCBExcelParser(BaseBankStatementParser):
    """
    Parser for Vietcombank Excel statements.
    This is a mock implementation that expects standard columns.
    """
    def parse(self, file_content: BinaryIO, filename: str) -> List[Dict[str, Any]]:
        wb = openpyxl.load_workbook(file_content, data_only=True)
        sheet = wb.active
        
        transactions = []
        # Find header row (mock logic: assuming header is at row 1 for simplicity)
        # Real VCB statements usually have headers around row 13 or 14.
        header_row = 1
        for i, row in enumerate(sheet.iter_rows(values_only=True)):
            if i < header_row:
                continue
                
            # Expected columns: Date, Ref, Description, Debit, Credit, Balance
            if len(row) >= 6 and row[0] is not None:
                try:
                    tx_date = row[0] if isinstance(row[0], datetime) else datetime.strptime(str(row[0]).strip(), "%d/%m/%Y")
                    
                    tx = {
                        "transaction_date": tx_date,
                        "transaction_reference": str(row[1]) if row[1] else None,
                        "description": str(row[2]) if row[2] else "",
                        "debit_amount_vnd": float(row[3]) if row[3] else 0.0,
                        "credit_amount_vnd": float(row[4]) if row[4] else 0.0,
                        "running_balance_vnd": float(row[5]) if row[5] else None
                    }
                    transactions.append(tx)
                except Exception as e:
                    # Skip invalid rows
                    continue
                    
        return transactions