"""Main PySide6 window emulating the legacy Tk interface."""

from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
from typing import Callable, Dict, List, Tuple

from PySide6 import QtCore, QtGui, QtWidgets

DEFAULT_COLOUR = "#763e92"
PRESET_COLOURS: List[Tuple[str, str]] = [
    ("Red", "#ff3b30"),
    ("Orange", "#ff9500"),
    ("Yellow", "#ffd60a"),
    ("Green", "#34c759"),
    ("Teal", "#5ac8fa"),
    ("Blue", "#0a84ff"),
    ("Violet", "#af52de"),
    ("Magenta", "#ff2d55"),
    ("White", "#ffffff"),
    ("Grey", "#8e8e93"),
    ("Black", "#000000"),
]

SLIDER_SPECS: List[Tuple[str, str, int, int, int]] = [
    ("Hue min", "hue_min", 0, 360, 0),
    ("Hue max", "hue_max", 0, 360, 360),
    ("Sat min", "sat_min", 0, 100, 25),
    ("Value min", "val_min", 0, 100, 15),
    ("Value max", "val_max", 0, 100, 100),
    ("Overlay alpha", "alpha", 0, 255, 120),
]


class ToolbarButton(QtWidgets.QPushButton):
    """Rounded toolbar button inspired by the legacy design."""

    def __init__(self, icon_text: str, label: str, callback: Callable[[], None], parent: QtWidgets.QWidget | None = None):
        super().__init__(f"{icon_text}  {label}", parent)
        self.setCursor(QtCore.Qt.PointingHandCursor)
        self.setFixedHeight(34)
        self.setStyleSheet(
            """
            QPushButton {
                padding: 8px 16px;
                border-radius: 10px;
                border: 1px solid rgba(255, 255, 255, 0.08);
                background-color: rgba(255, 255, 255, 0.04);
                color: #f7f7fb;
                font-weight: 600;
            }
            QPushButton:hover {
                background-color: rgba(255, 255, 255, 0.12);
            }
            QPushButton:pressed {
                background-color: rgba(255, 255, 255, 0.18);
            }
            """
        )
        self.clicked.connect(callback)


class ColourSwatch(QtWidgets.QPushButton):
    """Clickable palette swatch."""

    def __init__(self, name: str, hex_code: str, callback: Callable[[str, str], None], parent: QtWidgets.QWidget | None = None):
        super().__init__(parent)
        self.hex_code = hex_code
        self.name = name
        self.setToolTip(f"{name} ({hex_code})")
        self.setCursor(QtCore.Qt.PointingHandCursor)
        self.setFixedSize(28, 28)
        self.setStyleSheet(
            f"""
            QPushButton {{
                background-color: {hex_code};
                border: 2px solid rgba(255, 255, 255, 0.18);
                border-radius: 6px;
            }}
            QPushButton:hover {{
                border-color: rgba(255, 255, 255, 0.45);
            }}
            """
        )
        self.clicked.connect(lambda: callback(hex_code, name))


class SliderControl(QtWidgets.QWidget):
    """Slider with header and live value label."""

    value_changed = QtCore.Signal(str, int)

    def __init__(self, title: str, key: str, minimum: int, maximum: int, initial: int):
        super().__init__()
        self.key = key

        layout = QtWidgets.QVBoxLayout(self)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(4)

        header = QtWidgets.QHBoxLayout()
        header.setContentsMargins(0, 0, 0, 0)
        title_label = QtWidgets.QLabel(title)
        title_label.setStyleSheet("color: rgba(255,255,255,0.85); font-weight: 500;")
        header.addWidget(title_label)
        header.addStretch(1)
        self.value_label = QtWidgets.QLabel(str(initial))
        self.value_label.setStyleSheet("color: rgba(255,255,255,0.6);")
        header.addWidget(self.value_label)
        layout.addLayout(header)

        self.slider = QtWidgets.QSlider(QtCore.Qt.Horizontal)
        self.slider.setRange(minimum, maximum)
        self.slider.setValue(initial)
        self.slider.setCursor(QtCore.Qt.PointingHandCursor)
        self.slider.setStyleSheet(
            """
            QSlider::groove:horizontal {
                border: 1px solid rgba(255,255,255,0.08);
                height: 6px;
                background: rgba(255,255,255,0.1);
                border-radius: 4px;
            }
            QSlider::handle:horizontal {
                background: #9a4dff;
                border: 1px solid rgba(255,255,255,0.2);
                width: 14px;
                margin: -5px 0;
                border-radius: 7px;
            }
            """
        )
        self.slider.valueChanged.connect(self._sync_value)
        layout.addWidget(self.slider)

    def _sync_value(self, value: int) -> None:
        self.value_label.setText(str(value))
        self.value_changed.emit(self.key, value)

    def set_value(self, value: int) -> None:
        self.slider.blockSignals(True)
        self.slider.setValue(value)
        self.slider.blockSignals(False)
        self.value_label.setText(str(value))


class ImageView(QtWidgets.QLabel):
    """Aspect-ratio aware image view."""

    def __init__(self) -> None:
        super().__init__()
        self.setAlignment(QtCore.Qt.AlignCenter)
        self._pixmap: QtGui.QPixmap | None = None

    def set_image(self, pixmap: QtGui.QPixmap | None) -> None:
        self._pixmap = pixmap
        self._rescale()

    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
        super().resizeEvent(event)
        self._rescale()

    def _rescale(self) -> None:
        if self._pixmap is None:
            self.setPixmap(QtGui.QPixmap())
            self.setText("<No image loaded>")
            self.setStyleSheet("color: rgba(255,255,255,0.45); font-size: 14px;")
            return
        target = self._pixmap.scaled(
            self.size(),
            QtCore.Qt.KeepAspectRatio,
            QtCore.Qt.SmoothTransformation,
        )
        self.setPixmap(target)
        self.setStyleSheet("")


class TitleBar(QtWidgets.QWidget):
    """Custom title bar with native window controls."""

    HEIGHT = 40

    def __init__(self, window: "MainWindow") -> None:
        super().__init__(window)
        self.window = window
        self.setFixedHeight(self.HEIGHT)
        self.setCursor(QtCore.Qt.ArrowCursor)
        self.setAutoFillBackground(True)

        palette = self.palette()
        palette.setColor(QtGui.QPalette.Window, QtGui.QColor("#16171d"))
        self.setPalette(palette)

        layout = QtWidgets.QHBoxLayout(self)
        layout.setContentsMargins(12, 8, 12, 8)
        layout.setSpacing(8)

        logo_path = Path(__file__).resolve().parents[1] / "assets" / "logo.png"
        if logo_path.exists():
            pixmap = QtGui.QPixmap(str(logo_path))
            logo_label = QtWidgets.QLabel()
            logo_label.setPixmap(pixmap.scaled(26, 26, QtCore.Qt.KeepAspectRatio, QtCore.Qt.SmoothTransformation))
            layout.addWidget(logo_label)

        title_label = QtWidgets.QLabel("Interactive Color Range Analyzer")
        title_label.setStyleSheet("color: #f7f7fb; font-weight: 600;")
        layout.addWidget(title_label)
        layout.addStretch(1)

        self.min_btn = self._create_button("–", "Minimise window")
        self.min_btn.clicked.connect(window.showMinimized)
        layout.addWidget(self.min_btn)

        self.max_btn = self._create_button("❐", "Maximise / Restore")
        self.max_btn.clicked.connect(window.toggle_maximise)
        layout.addWidget(self.max_btn)

        close_btn = self._create_button("✕", "Close")
        close_btn.clicked.connect(window.close)
        close_btn.setStyleSheet(
            """
            QPushButton { background: transparent; color: #f7f7fb; border: none; padding: 4px 10px; }
            QPushButton:hover { background-color: #d0342c; }
            """
        )
        layout.addWidget(close_btn)

    def _create_button(self, text: str, tooltip: str) -> QtWidgets.QPushButton:
        btn = QtWidgets.QPushButton(text)
        btn.setToolTip(tooltip)
        btn.setFixedSize(36, 24)
        btn.setCursor(QtCore.Qt.ArrowCursor)
        btn.setStyleSheet(
            """
            QPushButton {
                background-color: transparent;
                color: #f7f7fb;
                border: none;
                padding: 4px 10px;
            }
            QPushButton:hover {
                background-color: rgba(255, 255, 255, 0.1);
            }
            """
        )
        return btn

    def mouseDoubleClickEvent(self, event: QtGui.QMouseEvent) -> None:
        if event.button() == QtCore.Qt.LeftButton:
            self.window.toggle_maximise()
            event.accept()

    def mousePressEvent(self, event: QtGui.QMouseEvent) -> None:
        if event.button() == QtCore.Qt.LeftButton:
            self.window.start_system_move(event.globalPosition())
            event.accept()
        super().mousePressEvent(event)


class MainWindow(QtWidgets.QMainWindow):
    """Main application window containing all controls."""

    def __init__(self) -> None:
        super().__init__()
        self.setWindowFlag(QtCore.Qt.FramelessWindowHint)
        self.setWindowFlag(QtCore.Qt.Window)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground, False)
        self.setMinimumSize(1100, 680)

        container = QtWidgets.QWidget()
        container_layout = QtWidgets.QVBoxLayout(container)
        container_layout.setContentsMargins(0, 0, 0, 0)
        container_layout.setSpacing(0)

        self.title_bar = TitleBar(self)
        container_layout.addWidget(self.title_bar)

        self.content = QtWidgets.QWidget()
        self.content.setStyleSheet("background-color: #111216;")
        content_layout = QtWidgets.QVBoxLayout(self.content)
        content_layout.setContentsMargins(24, 24, 24, 24)
        content_layout.setSpacing(18)

        content_layout.addLayout(self._build_toolbar())
        content_layout.addLayout(self._build_palette())
        content_layout.addLayout(self._build_sliders())
        content_layout.addWidget(self._build_previews(), 1)
        content_layout.addLayout(self._build_status_section())

        container_layout.addWidget(self.content, 1)
        self.setCentralWidget(container)

        self._is_maximised = False
        self._current_image_path: Path | None = None
        self._current_colour = DEFAULT_COLOUR
        self._toolbar_actions: Dict[str, Callable[[], None]] = {}
        self._slider_controls: Dict[str, SliderControl] = {}
        self._register_default_actions()
        self._update_colour_display(DEFAULT_COLOUR, "Default colour")

    # Window control helpers -------------------------------------------------

    def toggle_maximise(self) -> None:
        handle = self.windowHandle()
        if handle is None:
            return
        if self._is_maximised:
            self.showNormal()
            self._is_maximised = False
            self.title_bar.max_btn.setText("❐")
        else:
            self.showMaximized()
            self._is_maximised = True
            self.title_bar.max_btn.setText("⧉")

    def start_system_move(self, _global_position: QtCore.QPointF) -> None:
        handle = self.windowHandle()
        if handle:
            handle.startSystemMove()

    # UI builders ------------------------------------------------------------

    def _build_toolbar(self) -> QtWidgets.QHBoxLayout:
        layout = QtWidgets.QHBoxLayout()
        layout.setSpacing(12)

        buttons = [
            ("open_image", "🖼", "Open image…"),
            ("open_folder", "📂", "Open folder…"),
            ("choose_color", "🎨", "Choose colour"),
            ("pick_from_image", "🖱", "Pick from image"),
            ("save_overlay", "💾", "Save overlay"),
            ("toggle_free_draw", "△", "Toggle free-draw"),
            ("clear_excludes", "🧹", "Clear exclusions"),
            ("undo_exclude", "↩", "Undo last exclusion"),
            ("reset_sliders", "🔄", "Reset sliders"),
            ("toggle_theme", "🌓", "Toggle theme"),
        ]
        self._toolbar_buttons: Dict[str, ToolbarButton] = {}
        for key, icon_txt, label in buttons:
            button = ToolbarButton(icon_txt, label, lambda k=key: self._invoke_action(k))
            layout.addWidget(button)
            self._toolbar_buttons[key] = button

        layout.addStretch(1)
        self.status_label = QtWidgets.QLabel("No image loaded")
        self.status_label.setStyleSheet("color: rgba(255,255,255,0.7); font-weight: 500;")
        layout.addWidget(self.status_label, 0, QtCore.Qt.AlignRight)
        return layout

    def _build_palette(self) -> QtWidgets.QHBoxLayout:
        layout = QtWidgets.QHBoxLayout()
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(16)

        current_group = QtWidgets.QHBoxLayout()
        current_group.setSpacing(8)
        current_label = QtWidgets.QLabel("Current colour")
        current_label.setStyleSheet("color: rgba(255,255,255,0.75); font-weight: 500;")
        current_group.addWidget(current_label)

        self.current_colour_swatch = QtWidgets.QLabel()
        self.current_colour_swatch.setFixedSize(28, 28)
        self.current_colour_swatch.setStyleSheet(f"background-color: {DEFAULT_COLOUR}; border-radius: 6px;")
        current_group.addWidget(self.current_colour_swatch)

        self.current_colour_label = QtWidgets.QLabel(f"({DEFAULT_COLOUR})")
        self.current_colour_label.setStyleSheet("color: rgba(255,255,255,0.65);")
        current_group.addWidget(self.current_colour_label)
        layout.addLayout(current_group)

        more_label = QtWidgets.QLabel("More colours")
        more_label.setStyleSheet("color: rgba(255,255,255,0.65); font-weight: 500;")
        layout.addWidget(more_label)

        swatch_container = QtWidgets.QHBoxLayout()
        swatch_container.setSpacing(8)
        for name, hex_code in PRESET_COLOURS:
            swatch = ColourSwatch(name, hex_code, self._update_colour_display)
            swatch_container.addWidget(swatch)
        layout.addLayout(swatch_container)
        layout.addStretch(1)
        return layout

    def _build_sliders(self) -> QtWidgets.QHBoxLayout:
        layout = QtWidgets.QHBoxLayout()
        layout.setSpacing(16)
        self._slider_controls.clear()
        for title, key, minimum, maximum, initial in SLIDER_SPECS:
            control = SliderControl(title, key, minimum, maximum, initial)
            control.value_changed.connect(self._on_slider_change)
            layout.addWidget(control)
            self._slider_controls[key] = control
        return layout

    def _build_previews(self) -> QtWidgets.QWidget:
        container = QtWidgets.QWidget()
        layout = QtWidgets.QGridLayout(container)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setHorizontalSpacing(16)
        layout.setVerticalSpacing(0)

        self.prev_button = QtWidgets.QToolButton()
        self.prev_button.setText("◀")
        self.prev_button.setCursor(QtCore.Qt.PointingHandCursor)
        self.prev_button.setFixedSize(44, 44)
        self.prev_button.setStyleSheet(
            """
            QToolButton {
                border-radius: 22px;
                background-color: rgba(255, 255, 255, 0.08);
                color: #f7f7fb;
                font-size: 18px;
            }
            QToolButton:hover {
                background-color: rgba(255, 255, 255, 0.16);
            }
            """
        )
        self.prev_button.clicked.connect(lambda: self._invoke_action("show_previous_image"))
        layout.addWidget(self.prev_button, 0, 0, QtCore.Qt.AlignVCenter)

        self.image_view = ImageView()
        self.image_view.setStyleSheet("border: 1px solid rgba(255,255,255,0.08); border-radius: 12px;")
        layout.addWidget(self.image_view, 0, 1)

        self.overlay_view = ImageView()
        self.overlay_view.setStyleSheet("border: 1px solid rgba(255,255,255,0.08); border-radius: 12px;")
        layout.addWidget(self.overlay_view, 0, 2)

        self.next_button = QtWidgets.QToolButton()
        self.next_button.setText("▶")
        self.next_button.setCursor(QtCore.Qt.PointingHandCursor)
        self.next_button.setFixedSize(44, 44)
        self.next_button.setStyleSheet(self.prev_button.styleSheet())
        self.next_button.clicked.connect(lambda: self._invoke_action("show_next_image"))
        layout.addWidget(self.next_button, 0, 3, QtCore.Qt.AlignVCenter)
        layout.setColumnStretch(1, 1)
        layout.setColumnStretch(2, 1)
        return container

    def _build_status_section(self) -> QtWidgets.QVBoxLayout:
        layout = QtWidgets.QVBoxLayout()
        layout.setSpacing(8)
        layout.setContentsMargins(0, 0, 0, 0)

        self.filename_label = QtWidgets.QLabel("—")
        self.filename_label.setAlignment(QtCore.Qt.AlignCenter)
        self.filename_label.setStyleSheet("color: rgba(255,255,255,0.85); font-weight: 600;")
        layout.addWidget(self.filename_label)

        self.ratio_label = QtWidgets.QLabel("Matches with exclusions: —")
        self.ratio_label.setAlignment(QtCore.Qt.AlignCenter)
        self.ratio_label.setStyleSheet("color: #e6b84b; font-weight: 600;")
        layout.addWidget(self.ratio_label)
        return layout

    # Action wiring ----------------------------------------------------------

    def _register_default_actions(self) -> None:
        self._toolbar_actions = {
            "open_image": self.open_image,
            "open_folder": self._coming_soon,
            "choose_color": self._coming_soon,
            "pick_from_image": self._coming_soon,
            "save_overlay": self._coming_soon,
            "toggle_free_draw": self._coming_soon,
            "clear_excludes": self._coming_soon,
            "undo_exclude": self._coming_soon,
            "reset_sliders": self._reset_sliders,
            "toggle_theme": self._coming_soon,
            "show_previous_image": self._coming_soon,
            "show_next_image": self._coming_soon,
        }

    def _invoke_action(self, key: str) -> None:
        action = self._toolbar_actions.get(key)
        if action:
            action()

    # Image handling ---------------------------------------------------------

    def open_image(self) -> None:
        filters = "Images (*.png *.jpg *.jpeg *.bmp *.webp)"
        path_str, _ = QtWidgets.QFileDialog.getOpenFileName(self, "Select image", "", filters)
        if not path_str:
            return
        path = Path(path_str)
        pixmap = QtGui.QPixmap(str(path))
        if pixmap.isNull():
            QtWidgets.QMessageBox.warning(self, "ICRA", "Unable to open the selected image.")
            return
        self.image_view.set_image(pixmap)
        self.overlay_view.set_image(None)
        self._current_image_path = path
        self.status_label.setText(f"{path.name}  ·  {pixmap.width()}×{pixmap.height()}")
        self.filename_label.setText(f"{path.name}  ({pixmap.width()}×{pixmap.height()})")
        self.ratio_label.setText("Matches with exclusions: pending")

    # Helpers ----------------------------------------------------------------

    def _update_colour_display(self, hex_code: str, label: str) -> None:
        self._current_colour = hex_code
        self.current_colour_swatch.setStyleSheet(f"background-color: {hex_code}; border-radius: 6px;")
        self.current_colour_label.setText(f"({hex_code})")
        self.status_label.setText(f"{label}: {hex_code}")

    def _on_slider_change(self, key: str, value: int) -> None:
        formatted = key.replace("_", " ").title()
        self.status_label.setText(f"{formatted} → {value}")

    def _reset_sliders(self) -> None:
        for _, key, _, _, initial in SLIDER_SPECS:
            control = self._slider_controls.get(key)
            if control:
                control.set_value(initial)
        self.status_label.setText("Sliders reset to defaults")

    def _coming_soon(self) -> None:
        QtWidgets.QMessageBox.information(
            self,
            "Coming soon",
            "This action is not yet wired up in the PySide6 migration prototype.",
        )