# lufs_meter_widget.py

from PySide6.QtWidgets import QFrame, QVBoxLayout, QLabel
from PySide6.QtCore import Qt, QTimer, QRect
from PySide6.QtGui import QFont, QPainter, QColor, QLinearGradient


class LUFSMeterWidget(QFrame):
    """
    Vertical LUFS meter for broadcast monitoring.
    EBU R128 standard: Target -23 LUFS ±1 LU (Loudness Units).
    """

    def __init__(self, engine, parent=None):
        super().__init__(parent)
        self.engine = engine

        self.setFixedWidth(80)
        self.setFrameStyle(QFrame.Box | QFrame.Raised)
        self.setStyleSheet("""
            QFrame {
                background-color: #0d0d0d;
                border: 2px solid #444444;
                border-radius: 6px;
            }
        """)

        self._build_ui()

        self.timer = QTimer(self)
        self.timer.setInterval(100)
        self.timer.timeout.connect(self.update)
        self.timer.start()

    def _build_ui(self):
        layout = QVBoxLayout(self)
        layout.setContentsMargins(6, 8, 6, 8)

        header = QLabel("LUFS")
        header.setFont(QFont("Arial", 10, QFont.Bold))
        header.setStyleSheet("color: #888888; background: transparent; border: none;")
        header.setAlignment(Qt.AlignCenter)
        layout.addWidget(header)

        # Meter canvas
        self.meter_canvas = QFrame()
        self.meter_canvas.setStyleSheet("""
            QFrame {
                background-color: #000000;
                border: 1px solid #333333;
                border-radius: 3px;
            }
        """)
        layout.addWidget(self.meter_canvas, stretch=1)

        # Numeric readout
        self.readout = QLabel("-70.0")
        self.readout.setFont(QFont("Courier New", 12, QFont.Bold))
        self.readout.setStyleSheet("color: #00ff41; background: transparent; border: none;")
        self.readout.setAlignment(Qt.AlignCenter)
        layout.addWidget(self.readout)

    def paintEvent(self, event):
        super().paintEvent(event)

        lufs = self.engine.lufs_current
        self.readout.setText(f"{lufs:.1f}")

        painter = QPainter(self.meter_canvas)
        rect    = self.meter_canvas.rect().adjusted(2, 2, -2, -2)

        # LUFS scale: -70 (bottom) to 0 (top)
        # Target zone: -24 to -22 (±1 LU around -23)
        lufs_range = 70.0  # -70 to 0

        if lufs < -70:
            lufs = -70
        if lufs > 0:
            lufs = 0

        fill_pct = (lufs + 70) / lufs_range
        fill_h   = int(rect.height() * fill_pct)

        # Draw gradient meter
        gradient = QLinearGradient(0, rect.height(), 0, 0)
        
        # Color zones (broadcast standard)
        if lufs < -30:
            gradient.setColorAt(0, QColor("#003300"))  # Very quiet - dark green
            gradient.setColorAt(1, QColor("#005500"))
        elif lufs < -24:
            gradient.setColorAt(0, QColor("#00aa00"))  # Quiet - green
            gradient.setColorAt(1, QColor("#00dd00"))
        elif lufs < -22:
            gradient.setColorAt(0, QColor("#00ff00"))  # Target zone - bright green
            gradient.setColorAt(1, QColor("#00ff00"))
        elif lufs < -9:
            gradient.setColorAt(0, QColor("#ffcc00"))  # Getting hot - yellow
            gradient.setColorAt(1, QColor("#ffaa00"))
        else:
            gradient.setColorAt(0, QColor("#ff0000"))  # Too hot - red
            gradient.setColorAt(1, QColor("#ff0000"))

        painter.fillRect(
            rect.x(),
            rect.y() + rect.height() - fill_h,
            rect.width(),
            fill_h,
            gradient
        )

        # Draw target line at -23 LUFS
        target_y = rect.y() + int(rect.height() * (1.0 - ((-23 + 70) / lufs_range)))
        painter.setPen(QColor("#ffffff"))
        painter.drawLine(rect.x(), target_y, rect.x() + rect.width(), target_y)