"""
Keyword-based salary transaction analysis module.
"""

import re
import pandas as pd
from .config import SALARY_KEYWORDS

class KeywordAnalyzer:
    def __init__(self, df):
        self.df = df
        self.desc_df = None

    def identify_salary_transactions(self):
        """
        Identifies potential salary-related transactions based on keywords
        and month-year patterns in the 'description' column.
        """
        month_year_patterns = [
            r"\b(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)\s?\d{2,4}\b",
            r"\b(?:JANUARY|FEBRUARY|MARCH|APRIL|MAY|JUNE|JULY|AUGUST|SEPTEMBER|OCTOBER|NOVEMBER|DECEMBER)\s?\d{2,4}\b"
        ]

        escaped_keywords = [re.escape(keyword.lower()) for keyword in SALARY_KEYWORDS]
        combined_pattern = (
            r'\b(?:' + '|'.join(escaped_keywords) + r')\b|' +
            '|'.join(month_year_patterns)
        )

        self.df['is_salary_related'] = self.df['description'].str.lower().str.contains(
            combined_pattern,
            na=False,
            regex=True
        )

        self.desc_df = self.df.copy()
        return self.df

    def get_salary_related_data(self):
        """Get transactions identified as salary-related."""
        if self.desc_df is None:
            self.identify_salary_transactions()
        
        return self.desc_df[
            (self.desc_df['is_salary_related'] == True) & 
            (self.desc_df['initiated_by'] == 'C')
        ]