"""
matplotlib 기반 차트 위젯.

stats_view에서 주간/월간 추세를 시각화. matplotlib 미설치 시
ImportError 안내 라벨로 fallback.
"""
from typing import List, Tuple

from PyQt5.QtWidgets import QWidget, QVBoxLayout, QLabel
from PyQt5.QtCore import Qt

try:
    from matplotlib.figure import Figure
    from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
    import matplotlib
    matplotlib.rcParams['font.family'] = ['Malgun Gothic', 'Apple SD Gothic Neo', 'sans-serif']
    matplotlib.rcParams['axes.unicode_minus'] = False
    _MPL = True
except ImportError:
    _MPL = False


class _Fallback(QWidget):
    """matplotlib 미설치 시 안내."""
    def __init__(self, message: str):
        super().__init__()
        layout = QVBoxLayout()
        label = QLabel(message)
        label.setAlignment(Qt.AlignCenter)
        label.setWordWrap(True)
        label.setStyleSheet("color: #888; padding: 20px;")
        layout.addWidget(label)
        self.setLayout(layout)


def make_chart_widget(parent=None) -> QWidget:
    """차트가 그려질 빈 캔버스 위젯. matplotlib 없으면 fallback."""
    if not _MPL:
        return _Fallback("차트 표시에는 matplotlib가 필요합니다.\npip install matplotlib")
    widget = QWidget(parent)
    layout = QVBoxLayout()
    layout.setContentsMargins(0, 0, 0, 0)
    fig = Figure(figsize=(5, 3), dpi=100, tight_layout=True)
    canvas = FigureCanvas(fig)
    layout.addWidget(canvas)
    widget.setLayout(layout)
    widget._figure = fig
    widget._canvas = canvas
    return widget


def draw_daily_hours(widget: QWidget, records: List[dict]) -> None:
    """일별 근무시간 막대 그래프.

    Args:
        widget: make_chart_widget()로 만든 위젯
        records: [{date, total_hours, overtime_minutes}, ...]
    """
    if not getattr(widget, '_figure', None):
        return
    fig = widget._figure
    fig.clear()
    if not records:
        ax = fig.add_subplot(111)
        ax.text(0.5, 0.5, '기록 없음', ha='center', va='center', transform=ax.transAxes)
        widget._canvas.draw()
        return

    dates = [r['date'][5:] for r in records]  # MM-DD만
    hours = [r.get('total_hours', 0) or 0 for r in records]
    overtimes = [(r.get('overtime_minutes', 0) or 0) / 60 for r in records]
    base = [max(h - o, 0) for h, o in zip(hours, overtimes)]

    ax = fig.add_subplot(111)
    ax.bar(dates, base, label='정상', color='#4a90e2')
    ax.bar(dates, overtimes, bottom=base, label='연장', color='#ff6b6b')
    ax.set_ylabel('시간')
    ax.legend(loc='upper left', fontsize=8)
    ax.tick_params(axis='x', labelrotation=45, labelsize=8)
    ax.grid(axis='y', alpha=0.3)
    widget._canvas.draw()


def draw_weekday_avg(widget: QWidget, records: List[dict]) -> None:
    """요일별 평균 근무시간 막대 그래프."""
    if not getattr(widget, '_figure', None):
        return
    fig = widget._figure
    fig.clear()

    from datetime import datetime as _dt
    weekday_totals = [0.0] * 7
    weekday_counts = [0] * 7
    for r in records:
        try:
            d = _dt.strptime(r['date'], '%Y-%m-%d')
        except (ValueError, TypeError):
            continue
        weekday_totals[d.weekday()] += r.get('total_hours', 0) or 0
        weekday_counts[d.weekday()] += 1

    avg = [(t / c) if c else 0 for t, c in zip(weekday_totals, weekday_counts)]
    labels = ['월', '화', '수', '목', '금', '토', '일']

    ax = fig.add_subplot(111)
    colors = ['#4a90e2'] * 5 + ['#ff6b6b'] * 2  # 주말 강조
    ax.bar(labels, avg, color=colors)
    ax.set_ylabel('평균 시간')
    ax.set_title('요일별 평균 근무시간')
    ax.grid(axis='y', alpha=0.3)
    widget._canvas.draw()