"""Main PySide6 window with custom title bar."""

from __future__ import annotations

from pathlib import Path

from PySide6 import QtCore, QtGui, QtWidgets


class TitleBar(QtWidgets.QWidget):
    """Custom title bar mimicking modern Windows applications."""

    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(24, 24, 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-color: 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, 0.12);
            }
            """
        )
        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 ImageView(QtWidgets.QLabel):
    """Simple image display widget that keeps aspect ratio."""

    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.clear()
            self.setText("<No image loaded>")
            self.setStyleSheet("color: rgba(255,255,255,0.5); font-size: 14px;")
            return
        target = self._pixmap.scaled(
            self.size(),
            QtCore.Qt.KeepAspectRatio,
            QtCore.Qt.SmoothTransformation,
        )
        self.setPixmap(target)
        self.setStyleSheet("")


class MainWindow(QtWidgets.QMainWindow):
    """Main application window containing custom chrome and content area."""

    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(900, 600)

        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)

        toolbar = QtWidgets.QHBoxLayout()
        toolbar.setSpacing(12)

        self.open_button = QtWidgets.QPushButton("Open Image…")
        self.open_button.setCursor(QtCore.Qt.PointingHandCursor)
        self.open_button.setStyleSheet(
            """
            QPushButton {
                background: linear-gradient(135deg, #5168ff, #9a4dff);
                border: none;
                color: #ffffff;
                font-weight: 600;
                padding: 10px 16px;
                border-radius: 10px;
            }
            QPushButton:hover {
                filter: brightness(1.1);
            }
            """
        )
        self.open_button.clicked.connect(self.open_image)
        toolbar.addWidget(self.open_button)

        toolbar.addStretch(1)

        self.status_label = QtWidgets.QLabel("No image loaded")
        self.status_label.setStyleSheet("color: rgba(255,255,255,0.7); font-weight: 500;")
        toolbar.addWidget(self.status_label)

        content_layout.addLayout(toolbar)

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

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

        self._is_maximised = False
        self._current_image_path: Path | None = None

    # 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()

    # 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._current_image_path = path
        self.status_label.setText(f"{path.name}  ·  {pixmap.width()}×{pixmap.height()}")