"""
ui/readout_panel.py  —  Right-side numeric readout panel.
"""

from PyQt6.QtWidgets import (
    QWidget, QVBoxLayout, QHBoxLayout, QLabel,
    QScrollArea, QFrame, QProgressBar,
)
from PyQt6.QtCore import Qt, pyqtSlot
from devices.device_registry import DeviceRegistry


class ChannelReadout(QFrame):
    def __init__(self, ch_config):
        super().__init__()
        self.ch = ch_config
        self.setObjectName("channelReadout")
        self._alarm = False
        self._build()

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

        top = QHBoxLayout()
        self._name  = QLabel(self.ch.name)
        self._name.setObjectName("readoutName")
        top.addWidget(self._name, 1)

        self._val   = QLabel("— — —")
        self._val.setObjectName("readoutValue")
        self._val.setStyleSheet(f"color:{self.ch.color};")
        top.addWidget(self._val)

        unit = QLabel(f" {self.ch.unit}")
        unit.setObjectName("readoutUnit")
        top.addWidget(unit)
        layout.addLayout(top)

        self._bar = QProgressBar()
        self._bar.setObjectName("readoutBar")
        self._bar.setRange(0, 1000)
        self._bar.setValue(500)
        self._bar.setTextVisible(False)
        self._bar.setMaximumHeight(3)
        self._bar.setStyleSheet(
            f"QProgressBar::chunk {{ background:{self.ch.color}; border-radius:1px; }}"
        )
        layout.addWidget(self._bar)

    def update_value(self, v: float):
        self._val.setText(f"{v:>10.4f}".strip())
        rng = self.ch.max_value - self.ch.min_value
        norm = int(((v - self.ch.min_value) / rng) * 1000) if rng else 500
        self._bar.setValue(max(0, min(1000, norm)))

        alarm = (
            (self.ch.alarm_low  is not None and v < self.ch.alarm_low) or
            (self.ch.alarm_high is not None and v > self.ch.alarm_high)
        )
        if alarm != self._alarm:
            self._alarm = alarm
            self.setProperty("alarm", alarm)
            self.style().unpolish(self)
            self.style().polish(self)


class ReadoutPanel(QWidget):
    def __init__(self, registry: DeviceRegistry):
        super().__init__()
        self.registry  = registry
        self._readouts = {}   # (dev_id, ch_id) -> ChannelReadout
        self._build()
        self.refresh()

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

        hdr = QLabel("  CHANNELS")
        hdr.setObjectName("panelHeader")
        hdr.setMinimumHeight(28)
        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():
            w.deleteLater()
        self._readouts.clear()
        # Clear layout
        while self._inner.count() > 1:
            item = self._inner.takeAt(0)
            if item and item.widget():
                item.widget().deleteLater()

        for dev in self.registry.all_instances():
            for ch in dev.info.channels:
                if not ch.enabled:
                    continue
                ro = ChannelReadout(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, dev_id: str, ch_id: str, _ts: float, value: float):
        ro = self._readouts.get((dev_id, ch_id))
        if ro:
            ro.update_value(value)