"""
ui/windows/settings_window.py

SETTINGS window — toolbar section 5.

Tabs:
  General     — theme (dark/light/system), font sizes, polling rate
  Acquisition — sample rate, buffer size, CSV log directory
  Display     — default time window, legend, grid defaults
"""

from PyQt6.QtWidgets import (
    QWidget, QVBoxLayout, QHBoxLayout, QLabel, QPushButton,
    QTabWidget, QFrame, QFormLayout, QComboBox,
    QSpinBox, QDoubleSpinBox, QCheckBox, QLineEdit,
    QFileDialog, QScrollArea, QGroupBox, QMessageBox,
)
from PyQt6.QtCore import Qt, pyqtSignal
from PyQt6.QtGui import QCloseEvent, QFont

from devices.device_registry import DeviceRegistry
from core.acquisition import AcquisitionEngine


class SettingsWindow(QWidget):
    theme_changed           = pyqtSignal(str)   # "dark" | "light"
    settings_changed        = pyqtSignal(dict)
    plugin_enable_requested = pyqtSignal(str)   # plugin_id
    plugin_disable_requested= pyqtSignal(str)   # plugin_id
    closed                  = pyqtSignal()

    # Shared settings dict — written on Apply, read by consumers
    _defaults = {
        "theme":          "dark",
        "poll_ms":        100,
        "buffer_size":    20000,
        "log_dir":        "logs",
        "time_window_s":  30.0,
        "show_legend":    True,
        "show_grid":      True,
        "font_size":      12,
        "antialias":      True,
        "developer_mode": True,
    }

    def __init__(self, registry: DeviceRegistry,
                 engine: AcquisitionEngine,
                 current: dict = None, parent=None, *,
                 plugin_manager=None):
        super().__init__(parent, Qt.WindowType.Window | Qt.WindowType.Tool)
        self.registry       = registry
        self.engine         = engine
        self._plugin_mgr    = plugin_manager
        self._plugin_buttons: dict = {}   # plugin_id -> QPushButton
        self.cfg            = dict(self._defaults)
        if current:
            self.cfg.update(current)

        self.setWindowTitle("Settings")
        self.setMinimumSize(520, 440)
        self.resize(560, 520)
        self._build()

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

        # Header
        hdr = QWidget(); hdr.setObjectName("devWindowTitleBar"); hdr.setFixedHeight(44)
        hl  = QHBoxLayout(hdr); hl.setContentsMargins(14,0,14,0)
        hl.addWidget(QLabel("SETTINGS").also(lambda w: w.setObjectName("devWindowTitle")))
        root.addWidget(hdr)
        div = QFrame(); div.setFrameShape(QFrame.Shape.HLine)
        div.setObjectName("devWindowDivider"); root.addWidget(div)

        tabs = QTabWidget(); tabs.setObjectName("signalBuilderTabs")
        root.addWidget(tabs, 1)

        tabs.addTab(self._general_tab(),     "  General  ")
        tabs.addTab(self._acquisition_tab(), "  Acquisition  ")
        tabs.addTab(self._display_tab(),     "  Display  ")
        tabs.addTab(self._plugins_tab(),     "  Plugins  ")

        # Bottom bar
        btm = QWidget(); btm.setObjectName("cfgBottomBar")
        bl  = QHBoxLayout(btm); bl.setContentsMargins(12,8,12,8)
        bl.addStretch()
        ap = QPushButton("✓  Apply & Close"); ap.setObjectName("applyButton")
        ap.clicked.connect(self._apply); bl.addWidget(ap)
        root.addWidget(btm)

    # ── Tabs ──────────────────────────────────────────────────────────────

    def _general_tab(self):
        w = QWidget()
        scroll = QScrollArea(); scroll.setWidgetResizable(True)
        scroll.setObjectName("deviceScroll")
        cont = QWidget(); lay = QFormLayout(cont)
        lay.setContentsMargins(16,14,16,14); lay.setSpacing(10)

        self._theme_cb = QComboBox(); self._theme_cb.setObjectName("channelPickerCb")
        self._theme_cb.addItems(["Dark", "Light"])
        self._theme_cb.setCurrentText(self.cfg["theme"].title())
        lay.addRow("Theme:", self._theme_cb)

        self._font_sp = QSpinBox(); self._font_sp.setRange(8,18)
        self._font_sp.setValue(self.cfg["font_size"]); self._font_sp.setSuffix(" pt")
        self._font_sp.setObjectName("traceWidthSpin")
        lay.addRow("Base font size:", self._font_sp)

        self._aa_chk = QCheckBox(); self._aa_chk.setChecked(self.cfg["antialias"])
        lay.addRow("Anti-alias plots:", self._aa_chk)

        self._dev_chk = QCheckBox()
        self._dev_chk.setChecked(self.cfg["developer_mode"])
        self._dev_chk.setToolTip(
            "Controls whether the Debug window and each device's Simulation\n"
            "Mode option are available. Off = real-hardware-only, no debug tools."
        )
        lay.addRow("Developer mode:", self._dev_chk)

        from core.version import __version__ as _app_version
        version_lbl = QLabel(f"v{_app_version}")
        version_lbl.setObjectName("traceSource")
        lay.addRow("Version:", version_lbl)

        update_row = QHBoxLayout()
        self._update_btn = QPushButton("Check for Updates")
        self._update_btn.setObjectName("configButton")
        self._update_btn.clicked.connect(self._check_for_updates)
        update_row.addWidget(self._update_btn)
        update_row.addStretch()
        lay.addRow("Updates:", update_row)
        self._update_status_lbl = QLabel("")
        self._update_status_lbl.setObjectName("traceSource")
        self._update_status_lbl.setWordWrap(True)
        lay.addRow("", self._update_status_lbl)

        rst = QPushButton("Reset to Defaults"); rst.setObjectName("configButton")
        rst.clicked.connect(self._reset_to_defaults)
        lay.addRow("", rst)

        scroll.setWidget(cont)
        root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0); root.addWidget(scroll)
        return w

    def _populate_from_cfg(self):
        self._theme_cb.setCurrentText(self.cfg["theme"].title())
        self._font_sp.setValue(self.cfg["font_size"])
        self._aa_chk.setChecked(self.cfg["antialias"])
        self._dev_chk.setChecked(self.cfg["developer_mode"])
        self._poll_sp.setValue(self.cfg["poll_ms"])
        self._buf_sp.setValue(self.cfg["buffer_size"])
        self._log_edit.setText(self.cfg["log_dir"])
        self._tw_sp.setValue(self.cfg["time_window_s"])
        self._legend_chk.setChecked(self.cfg["show_legend"])
        self._grid_chk.setChecked(self.cfg["show_grid"])

    def _acquisition_tab(self):
        w = QWidget()
        scroll = QScrollArea(); scroll.setWidgetResizable(True)
        scroll.setObjectName("deviceScroll")
        cont = QWidget(); lay = QFormLayout(cont)
        lay.setContentsMargins(16,14,16,14); lay.setSpacing(10)

        self._poll_sp = QSpinBox(); self._poll_sp.setRange(10,5000)
        self._poll_sp.setValue(self.cfg["poll_ms"]); self._poll_sp.setSuffix(" ms")
        self._poll_sp.setObjectName("traceWidthSpin")
        lay.addRow("Poll interval:", self._poll_sp)

        self._buf_sp = QSpinBox(); self._buf_sp.setRange(1000,500000)
        self._buf_sp.setValue(self.cfg["buffer_size"])
        self._buf_sp.setObjectName("traceWidthSpin")
        lay.addRow("Buffer size (samples):", self._buf_sp)

        log_row = QHBoxLayout()
        self._log_edit = QLineEdit(self.cfg["log_dir"])
        self._log_edit.setObjectName("traceLabel"); log_row.addWidget(self._log_edit,1)
        br = QPushButton("Browse"); br.setObjectName("configButton")
        br.clicked.connect(self._browse_log); log_row.addWidget(br)
        lay.addRow("Log directory:", log_row)

        scroll.setWidget(cont)
        root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0); root.addWidget(scroll)
        return w

    def _display_tab(self):
        w = QWidget()
        scroll = QScrollArea(); scroll.setWidgetResizable(True)
        scroll.setObjectName("deviceScroll")
        cont = QWidget(); lay = QFormLayout(cont)
        lay.setContentsMargins(16,14,16,14); lay.setSpacing(10)

        self._tw_sp = QDoubleSpinBox(); self._tw_sp.setRange(1,3600)
        self._tw_sp.setValue(self.cfg["time_window_s"]); self._tw_sp.setSuffix(" s")
        self._tw_sp.setObjectName("cfgGlobalSpin")
        lay.addRow("Default time window:", self._tw_sp)

        self._legend_chk = QCheckBox(); self._legend_chk.setChecked(self.cfg["show_legend"])
        lay.addRow("Show legend by default:", self._legend_chk)

        self._grid_chk = QCheckBox(); self._grid_chk.setChecked(self.cfg["show_grid"])
        lay.addRow("Show grid by default:", self._grid_chk)

        scroll.setWidget(cont)
        root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0); root.addWidget(scroll)
        return w

    def _plugins_tab(self):
        w = QWidget()
        scroll = QScrollArea(); scroll.setWidgetResizable(True)
        scroll.setObjectName("deviceScroll")
        cont = QWidget(); lay = QVBoxLayout(cont)
        lay.setContentsMargins(14, 12, 14, 12); lay.setSpacing(10)

        if self._plugin_mgr is None:
            lay.addWidget(QLabel("Plugin manager not available."))
            lay.addStretch()
            scroll.setWidget(cont)
            root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0)
            root.addWidget(scroll); return w

        manifests = self._plugin_mgr.get_manifests()

        if not manifests:
            info = QLabel(
                "No plugins found.\n\n"
                "Drop a plugin folder into the  plugins/  directory next to main.py.\n"
                "Each plugin needs a  manifest.json  and a  plugin.py."
            )
            info.setObjectName("traceSource"); info.setWordWrap(True)
            lay.addWidget(info)
            lay.addStretch()
            scroll.setWidget(cont)
            root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0)
            root.addWidget(scroll); return w

        for manifest in manifests:
            lay.addWidget(self._plugin_card(manifest))

        lay.addStretch()
        scroll.setWidget(cont)
        root = QVBoxLayout(w); root.setContentsMargins(0,0,0,0)
        root.addWidget(scroll); return w

    def _plugin_card(self, manifest):
        """One card per discovered plugin."""
        card = QGroupBox()
        card.setObjectName("pluginCard")
        cl = QVBoxLayout(card); cl.setContentsMargins(10, 8, 10, 8); cl.setSpacing(4)

        # Header row: name + version + enable toggle
        hdr = QHBoxLayout()
        name_lbl = QLabel(f"<b>{manifest.name}</b>  <small>v{manifest.version}</small>")
        name_lbl.setObjectName("traceLabel")
        hdr.addWidget(name_lbl, 1)

        enabled = self._plugin_mgr.is_enabled(manifest.plugin_id)
        toggle = QPushButton("Disable" if enabled else "Enable")
        toggle.setObjectName("configButton")
        toggle.setFixedWidth(72)
        toggle.clicked.connect(
            lambda _, pid=manifest.plugin_id, btn=toggle: self._toggle_plugin(pid, btn)
        )
        self._plugin_buttons[manifest.plugin_id] = toggle
        hdr.addWidget(toggle)
        cl.addLayout(hdr)

        # Description / author
        if manifest.description:
            desc = QLabel(manifest.description)
            desc.setObjectName("traceSource"); desc.setWordWrap(True)
            cl.addWidget(desc)

        if manifest.author:
            author = QLabel(f"Author: {manifest.author}")
            author.setObjectName("traceSource")
            cl.addWidget(author)

        # Plugin-specific settings widget (only when loaded)
        plugin = self._plugin_mgr.get_plugin(manifest.plugin_id)
        if plugin:
            sw = plugin.get_settings_widget()
            if sw is not None:
                cl.addWidget(sw)

        return card

    def _toggle_plugin(self, plugin_id: str, btn: QPushButton):
        if self._plugin_mgr.is_enabled(plugin_id):
            self.plugin_disable_requested.emit(plugin_id)
            btn.setText("Enable")
        else:
            # Don't flip to "Disable" yet — enabling can fail (missing
            # dependencies, bad plugin code). main_window confirms the
            # real outcome via sync_plugin_button() once enable() returns.
            self.plugin_enable_requested.emit(plugin_id)

    def sync_plugin_button(self, plugin_id: str):
        """Refresh one plugin's toggle button to match its actual enabled state."""
        btn = self._plugin_buttons.get(plugin_id)
        if btn is not None and self._plugin_mgr is not None:
            btn.setText("Disable" if self._plugin_mgr.is_enabled(plugin_id) else "Enable")

    # ── Actions ───────────────────────────────────────────────────────────

    def _check_for_updates(self):
        from core.updater import is_frozen

        if not is_frozen():
            self._update_status_lbl.setText("Not available outside the packaged app (dev mode).")
            return

        from PyQt6.QtWidgets import QApplication
        from core.updater import apply_update, check_for_update

        self._update_btn.setEnabled(False)
        self._update_status_lbl.setText("Checking…")
        QApplication.processEvents()
        try:
            new_version = check_for_update()
        except Exception as e:
            self._update_status_lbl.setText(f"Check failed: {e}")
            self._update_btn.setEnabled(True)
            return
        self._update_btn.setEnabled(True)

        if not new_version:
            self._update_status_lbl.setText("Up to date.")
            return

        self._update_status_lbl.setText(f"Version {new_version} available.")
        reply = QMessageBox.question(
            self, "Update Available",
            f"Version {new_version} is available. Download and install now?\n\n"
            f"The app will close and relaunch to complete the update.",
            QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
            QMessageBox.StandardButton.No,
        )
        if reply == QMessageBox.StandardButton.Yes:
            try:
                apply_update()  # may close/relaunch the process during this call
            except Exception as e:
                QMessageBox.critical(self, "Update Failed", str(e))

    def _reset_to_defaults(self):
        reply = QMessageBox.question(
            self, "Reset Settings",
            "Reset all settings to defaults?\nThis cannot be undone.",
            QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
            QMessageBox.StandardButton.No,
        )
        if reply == QMessageBox.StandardButton.Yes:
            self.cfg = dict(self._defaults)
            self._populate_from_cfg()

    def _browse_log(self):
        path = QFileDialog.getExistingDirectory(self, "Select Log Directory")
        if path:
            self._log_edit.setText(path)

    def _apply(self):
        theme = self._theme_cb.currentText().lower()
        self.cfg.update({
            "theme":         theme,
            "font_size":     self._font_sp.value(),
            "antialias":     self._aa_chk.isChecked(),
            "developer_mode": self._dev_chk.isChecked(),
            "poll_ms":       self._poll_sp.value(),
            "buffer_size":   self._buf_sp.value(),
            "log_dir":       self._log_edit.text(),
            "time_window_s": self._tw_sp.value(),
            "show_legend":   self._legend_chk.isChecked(),
            "show_grid":     self._grid_chk.isChecked(),
        })
        self.theme_changed.emit(theme)
        self.settings_changed.emit(dict(self.cfg))
        self.hide()

    def closeEvent(self, e: QCloseEvent):
        self.closed.emit(); e.accept()


# monkey-patch QLabel.also
from PyQt6.QtWidgets import QLabel as _QL
def _also3(self, fn): fn(self); return self
if not hasattr(_QL, "also"): _QL.also = _also3