"""
motion_capture/camera_panel.py

CameraPanel for AddDeviceDialog — scans for OpenCV cameras and builds
a CameraDevice when the user clicks "Add Device".
"""

from __future__ import annotations

from PyQt6.QtCore import Qt, QThread, pyqtSignal
from PyQt6.QtWidgets import (
    QCheckBox, QGroupBox, QHBoxLayout, QLabel, QListWidget,
    QListWidgetItem, QPushButton, QVBoxLayout, QWidget,
)


class CameraScanThread(QThread):
    cameras_found = pyqtSignal(list)   # list of (index: int, label: str)

    def run(self):
        results = []
        try:
            import cv2
            for i in range(6):
                cap = cv2.VideoCapture(i)
                if cap.isOpened():
                    ret, _ = cap.read()
                    if ret:
                        w = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
                        h = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
                        results.append((i, f"Camera {i}  ({w}×{h})"))
                    cap.release()
        except ImportError:
            pass
        self.cameras_found.emit(results)


class CameraPanel(QWidget):
    """Config panel for Camera device in AddDeviceDialog."""

    def __init__(self):
        super().__init__()
        self._cameras: list = []
        self._selected_index: int = 0
        self._scanner = None

        lay = QVBoxLayout(self)
        lay.setContentsMargins(0, 4, 0, 4)
        lay.setSpacing(8)

        self.sim_chk = QCheckBox("Simulation mode  (Lissajous pattern, no camera needed)")
        self.sim_chk.setChecked(False)
        lay.addWidget(self.sim_chk)

        scan_grp = QGroupBox("Available Cameras")
        sg = QVBoxLayout(scan_grp)
        sg.setSpacing(4)

        top = QHBoxLayout()
        self._scan_btn = QPushButton("🔍  Scan Cameras")
        self._scan_btn.setObjectName("addTraceBtn")
        self._scan_btn.clicked.connect(self._scan)
        self._status = QLabel("Click Scan to detect cameras")
        self._status.setObjectName("traceSource")
        top.addWidget(self._scan_btn)
        top.addWidget(self._status, 1)
        sg.addLayout(top)

        self._list = QListWidget()
        self._list.setMaximumHeight(120)
        self._list.setObjectName("portList")
        self._list.itemClicked.connect(self._on_select)
        self._list.setToolTip("Click a camera to select it")
        sg.addWidget(self._list)

        hint = QLabel("↑  Click a camera above to select it")
        hint.setObjectName("traceSource")
        sg.addWidget(hint)

        lay.addWidget(scan_grp)

        note = QLabel(
            "Requires OpenCV:  pip install opencv-python\n"
            "Use Simulation mode if no camera is available."
        )
        note.setObjectName("traceSource")
        note.setWordWrap(True)
        lay.addWidget(note)
        lay.addStretch()

    # ── Scan ─────────────────────────────────────────────────────────────

    def _scan(self):
        self._scan_btn.setEnabled(False)
        self._status.setText("Scanning…")
        self._list.clear()
        self._scanner = CameraScanThread()
        self._scanner.cameras_found.connect(self._on_found)
        self._scanner.start()

    def _on_found(self, cameras):
        self._scan_btn.setEnabled(True)
        self._cameras = cameras
        self._list.clear()
        if not cameras:
            self._status.setText("No cameras found")
            item = QListWidgetItem("  No cameras detected")
            item.setFlags(item.flags() & ~Qt.ItemFlag.ItemIsSelectable)
            self._list.addItem(item)
        else:
            self._status.setText(f"{len(cameras)} camera(s) found")
            for idx, label in cameras:
                item = QListWidgetItem(f"  {label}")
                item.setData(Qt.ItemDataRole.UserRole, idx)
                self._list.addItem(item)
            self._list.setCurrentRow(0)
            self._selected_index = cameras[0][0]

    def _on_select(self, item: QListWidgetItem):
        idx = item.data(Qt.ItemDataRole.UserRole)
        if idx is not None:
            self._selected_index = idx

    # ── Build ─────────────────────────────────────────────────────────────

    def build_device(self, device_id: str):
        from device import CameraDevice
        return CameraDevice(
            device_id=device_id,
            camera_index=self._selected_index,
            simulate=self.sim_chk.isChecked(),
        )