"""
Annotation tab for the microscopy object detection application.
Future feature for manual annotation.
"""

from PySide6.QtWidgets import (
    QWidget,
    QVBoxLayout,
    QHBoxLayout,
    QLabel,
    QGroupBox,
    QPushButton,
    QFileDialog,
    QMessageBox,
)
from PySide6.QtCore import Qt, QSettings
from pathlib import Path

from src.database.db_manager import DatabaseManager
from src.utils.config_manager import ConfigManager
from src.utils.image import Image, ImageLoadError
from src.utils.logger import get_logger
from src.gui.widgets import ImageDisplayWidget

logger = get_logger(__name__)


class AnnotationTab(QWidget):
    """Annotation tab placeholder (future feature)."""

    def __init__(
        self, db_manager: DatabaseManager, config_manager: ConfigManager, parent=None
    ):
        super().__init__(parent)
        self.db_manager = db_manager
        self.config_manager = config_manager
        self.current_image = None
        self.current_image_path = None

        self._setup_ui()

    def _setup_ui(self):
        """Setup user interface."""
        layout = QVBoxLayout()

        # Image loading section
        load_group = QGroupBox("Image Loading")
        load_layout = QVBoxLayout()

        # Load image button
        button_layout = QHBoxLayout()
        self.load_image_btn = QPushButton("Load Image")
        self.load_image_btn.clicked.connect(self._load_image)
        button_layout.addWidget(self.load_image_btn)
        button_layout.addStretch()

        load_layout.addLayout(button_layout)

        # Image info label
        self.image_info_label = QLabel("No image loaded")
        load_layout.addWidget(self.image_info_label)

        load_group.setLayout(load_layout)
        layout.addWidget(load_group)

        # Image display section
        display_group = QGroupBox("Image Display")
        display_layout = QVBoxLayout()

        # Use the reusable ImageDisplayWidget
        self.image_display_widget = ImageDisplayWidget()
        self.image_display_widget.zoom_changed.connect(self._on_zoom_changed)
        display_layout.addWidget(self.image_display_widget)

        display_group.setLayout(display_layout)
        layout.addWidget(display_group)

        # Future features info
        info_group = QGroupBox("Annotation Tool (Future Feature)")
        info_layout = QVBoxLayout()
        info_label = QLabel(
            "Full annotation functionality will be implemented in future version.\n\n"
            "Planned Features:\n"
            "- Drawing tools for bounding boxes\n"
            "- Class label assignment\n"
            "- Export annotations to YOLO format\n"
            "- Annotation verification"
        )
        info_layout.addWidget(info_label)
        info_group.setLayout(info_layout)

        layout.addWidget(info_group)

        # Zoom controls info
        zoom_info = QLabel("Zoom: Mouse wheel or +/- keys to zoom in/out")
        zoom_info.setStyleSheet("QLabel { color: #888; font-style: italic; }")
        layout.addWidget(zoom_info)

        self.setLayout(layout)

    def _load_image(self):
        """Load and display an image file."""
        # Get last opened directory from QSettings
        settings = QSettings("microscopy_app", "object_detection")
        last_dir = settings.value("annotation_tab/last_directory", None)

        # Fallback to image repository path or home directory
        if last_dir and Path(last_dir).exists():
            start_dir = last_dir
        else:
            repo_path = self.config_manager.get_image_repository_path()
            start_dir = repo_path if repo_path else str(Path.home())

        # Open file dialog
        file_path, _ = QFileDialog.getOpenFileName(
            self,
            "Select Image",
            start_dir,
            "Images (*.jpg *.jpeg *.png *.tif *.tiff *.bmp)",
        )

        if not file_path:
            return

        try:
            # Load image using Image class
            self.current_image = Image(file_path)
            self.current_image_path = file_path

            # Store the directory for next time
            settings.setValue(
                "annotation_tab/last_directory", str(Path(file_path).parent)
            )

            # Display image using the ImageDisplayWidget
            self.image_display_widget.load_image(self.current_image)

            # Update info label
            self._update_image_info()

            logger.info(f"Loaded image: {file_path}")

        except ImageLoadError as e:
            logger.error(f"Failed to load image: {e}")
            QMessageBox.critical(
                self, "Error Loading Image", f"Failed to load image:\n{str(e)}"
            )
        except Exception as e:
            logger.error(f"Unexpected error loading image: {e}")
            QMessageBox.critical(self, "Error", f"Unexpected error:\n{str(e)}")

    def _update_image_info(self):
        """Update the image info label with current image details."""
        if self.current_image is None:
            self.image_info_label.setText("No image loaded")
            return

        zoom_percentage = self.image_display_widget.get_zoom_percentage()
        info_text = (
            f"File: {Path(self.current_image_path).name}\n"
            f"Size: {self.current_image.width}x{self.current_image.height} pixels\n"
            f"Channels: {self.current_image.channels}\n"
            f"Data type: {self.current_image.dtype}\n"
            f"Format: {self.current_image.format.upper()}\n"
            f"File size: {self.current_image.size_mb:.2f} MB\n"
            f"Zoom: {zoom_percentage}%"
        )
        self.image_info_label.setText(info_text)

    def _on_zoom_changed(self, zoom_scale: float):
        """Handle zoom level changes from the image display widget."""
        self._update_image_info()

    def refresh(self):
        """Refresh the tab."""
        pass