import config
from core.preprocessing import get_clean_data


class DataService:
    def __init__(self):
        self._df = None

    @property
    def df(self):
        if self._df is None:
            self._df = get_clean_data()
        return self._df

    def get_basic_stats(self):
        df = self.df
        total_records = len(df)
        total_employees = df[config.EMPLOYEE_ID_COLUMN].nunique()
        avg_absent_hours = round(df[config.TARGET_COLUMN].mean(), 2)
        max_absent_hours = round(float(df[config.TARGET_COLUMN].max()), 1)
        min_absent_hours = round(float(df[config.TARGET_COLUMN].min()), 1)
        high_risk_count = len(df[df[config.TARGET_COLUMN] > 8])
        return {
            'total_records': total_records,
            'total_employees': total_employees,
            'avg_absent_hours': avg_absent_hours,
            'max_absent_hours': max_absent_hours,
            'min_absent_hours': min_absent_hours,
            'high_risk_ratio': round(high_risk_count / total_records, 4),
            'industries_covered': int(df['所属行业'].nunique()),
        }

    def get_monthly_trend(self):
        df = self.df
        monthly = df.groupby('缺勤月份').agg({config.TARGET_COLUMN: ['sum', 'mean', 'count']}).reset_index()
        monthly.columns = ['month', 'total_hours', 'avg_hours', 'record_count']
        result = {'months': [], 'total_hours': [], 'avg_hours': [], 'record_counts': []}
        for month in range(1, 13):
            row = monthly[monthly['month'] == month]
            result['months'].append(f'{month}月')
            if len(row):
                result['total_hours'].append(round(float(row['total_hours'].values[0]), 1))
                result['avg_hours'].append(round(float(row['avg_hours'].values[0]), 2))
                result['record_counts'].append(int(row['record_count'].values[0]))
            else:
                result['total_hours'].append(0)
                result['avg_hours'].append(0)
                result['record_counts'].append(0)
        return result

    def get_weekday_distribution(self):
        df = self.df
        weekday = df.groupby('星期几').agg({config.TARGET_COLUMN: ['sum', 'mean', 'count']}).reset_index()
        weekday.columns = ['weekday', 'total_hours', 'avg_hours', 'record_count']
        result = {'weekdays': [], 'weekday_codes': [], 'total_hours': [], 'avg_hours': [], 'record_counts': []}
        for code in range(1, 8):
            row = weekday[weekday['weekday'] == code]
            result['weekdays'].append(config.WEEKDAY_NAMES.get(code, str(code)))
            result['weekday_codes'].append(code)
            if len(row):
                result['total_hours'].append(round(float(row['total_hours'].values[0]), 1))
                result['avg_hours'].append(round(float(row['avg_hours'].values[0]), 2))
                result['record_counts'].append(int(row['record_count'].values[0]))
            else:
                result['total_hours'].append(0)
                result['avg_hours'].append(0)
                result['record_counts'].append(0)
        return result

    def get_reason_distribution(self):
        df = self.df
        reason = df.groupby('请假原因大类').agg({config.TARGET_COLUMN: 'count'}).reset_index()
        reason.columns = ['name', 'count']
        reason = reason.sort_values('count', ascending=False)
        total = reason['count'].sum()
        return {
            'reasons': [
                {
                    'name': row['name'],
                    'count': int(row['count']),
                    'percentage': round(float(row['count']) / total * 100, 1),
                }
                for _, row in reason.iterrows()
            ]
        }

    def get_season_distribution(self):
        df = self.df
        season = df.groupby('季节').agg({config.TARGET_COLUMN: ['sum', 'mean', 'count']}).reset_index()
        season.columns = ['season', 'total_hours', 'avg_hours', 'record_count']
        total_records = season['record_count'].sum()
        result = {'seasons': []}
        for code in [1, 2, 3, 4]:
            row = season[season['season'] == code]
            if not len(row):
                continue
            result['seasons'].append({
                'code': code,
                'name': config.SEASON_NAMES.get(code, f'季节{code}'),
                'total_hours': round(float(row['total_hours'].values[0]), 1),
                'avg_hours': round(float(row['avg_hours'].values[0]), 2),
                'record_count': int(row['record_count'].values[0]),
                'percentage': round(float(row['record_count'].values[0]) / total_records * 100, 1),
            })
        return result


data_service = DataService()