"""
ui/readout_panel.py

Right-side numeric readout panel. Shows current value for every channel
with a colored bar indicator and alarm highlighting.
"""

from PyQt6.QtWidgets import (
    QWidget, QVBoxLayout, QHBoxLayout, QLabel,
    QScrollArea, QFrame, QProgressBar
)
from PyQt6.QtCore import Qt, pyqtSlot
from PyQt6.QtGui import QColor

from devices.device_registry import DeviceRegistry


class ChannelReadout(QFrame):
    def __init__(self, device_name: str, channel_config, parent=None):
        super().__init__(parent)
        self.ch = channel_config
        self.device_name = device_name
        self.setObjectName("channelReadout")
        self._alarm_active = False
        self._build()

    def _build(self):
        layout = QVBoxLayout(self)
        layout.setContentsMargins(8, 6, 8, 6)
        layout.setSpacing(2)

        top = QHBoxLayout()
        self.name_lbl = QLabel(f"{self.ch.name}")
        self.name_lbl.setObjectName("readoutName")
        top.addWidget(self.name_lbl)
        top.addStretch()
        self.value_lbl = QLabel("---")
        self.value_lbl.setObjectName("readoutValue")
        self.value_lbl.setStyleSheet(f"color: {self.ch.color};")
        top.addWidget(self.value_lbl)
        unit = QLabel(self.ch.unit)
        unit.setObjectName("readoutUnit")
        top.addWidget(unit)
        layout.addLayout(top)

        # Mini bar
        self.bar = QProgressBar()
        self.bar.setRange(0, 1000)
        self.bar.setValue(0)
        self.bar.setTextVisible(False)
        self.bar.setMaximumHeight(4)
        self.bar.setObjectName("readoutBar")
        self.bar.setStyleSheet(
            f"QProgressBar::chunk {{ background: {self.ch.color}; border-radius: 2px; }}"
        )
        layout.addWidget(self.bar)

    def update_value(self, value: float):
        self.value_lbl.setText(f"{value:.3f}")
        rng = self.ch.max_value - self.ch.min_value
        if rng > 0:
            norm = int(((value - self.ch.min_value) / rng) * 1000)
            self.bar.setValue(max(0, min(1000, norm)))

    def set_alarm(self, active: bool):
        if active != self._alarm_active:
            self._alarm_active = active
            self.setProperty("alarm", active)
            self.style().unpolish(self)
            self.style().polish(self)


class ReadoutPanel(QWidget):
    def __init__(self, registry: DeviceRegistry):
        super().__init__()
        self.registry = registry
        self._readouts: dict = {}  # (device_id, channel_id) -> ChannelReadout
        self._build_ui()
        self.refresh()

    def _build_ui(self):
        layout = QVBoxLayout(self)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)

        hdr = QLabel("  CHANNELS")
        hdr.setObjectName("panelHeader")
        layout.addWidget(hdr)

        scroll = QScrollArea()
        scroll.setWidgetResizable(True)
        scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)

        self._container = QWidget()
        self._inner = QVBoxLayout(self._container)
        self._inner.setContentsMargins(6, 6, 6, 6)
        self._inner.setSpacing(4)
        self._inner.addStretch()

        scroll.setWidget(self._container)
        layout.addWidget(scroll)

    def refresh(self):
        for w in self._readouts.values():
            self._inner.removeWidget(w)
            w.deleteLater()
        self._readouts.clear()

        for dev in self.registry.all_instances():
            for ch in dev.info.channels:
                if not ch.enabled:
                    continue
                ro = ChannelReadout(dev.info.name, ch)
                self._inner.insertWidget(self._inner.count() - 1, ro)
                self._readouts[(dev.info.device_id, ch.channel_id)] = ro

    @pyqtSlot(str, str, float, float)
    def on_new_data(self, device_id: str, channel_id: str, timestamp: float, value: float):
        ro = self._readouts.get((device_id, channel_id))
        if ro:
            ro.update_value(value)
            ch = ro.ch
            alarm = False
            if ch.alarm_low is not None and value < ch.alarm_low:
                alarm = True
            if ch.alarm_high is not None and value > ch.alarm_high:
                alarm = True
            ro.set_alarm(alarm)