"""Splitter tab for extracting files from aggregated markdown."""

import os
from PyQt6.QtWidgets import (
    QWidget, QVBoxLayout, QHBoxLayout, QLabel, QLineEdit,
    QPushButton, QProgressBar, QFileDialog, QMessageBox
)
from PyQt6.QtCore import Qt, QCoreApplication
from core.splitter import Splitter
from core.exceptions import ObsidianToolException


class SplitterTab(QWidget):
    """Tab for splitting aggregated markdown files."""

    def __init__(self):
        """Initialize the splitter tab."""
        super().__init__()
        self.splitter = Splitter()
        self.init_ui()

    def init_ui(self):
        """Initialize the user interface."""
        layout = QVBoxLayout(self)
        layout.setSpacing(15)
        layout.setContentsMargins(20, 20, 20, 20)

        # Aggregated File section
        layout.addWidget(QLabel("<b>Aggregated File:</b>"))

        file_layout = QHBoxLayout()
        self.file_edit = QLineEdit()
        self.file_edit.setReadOnly(True)
        self.file_edit.setPlaceholderText("Select an aggregated .md file...")
        file_layout.addWidget(self.file_edit)

        self.file_btn = QPushButton("Browse...")
        self.file_btn.setMaximumWidth(100)
        self.file_btn.clicked.connect(self.browse_file)
        file_layout.addWidget(self.file_btn)

        layout.addLayout(file_layout)

        # Output Directory section
        layout.addWidget(QLabel("<b>Output Directory:</b>"))

        output_layout = QHBoxLayout()
        self.output_edit = QLineEdit()
        self.output_edit.setReadOnly(True)
        self.output_edit.setPlaceholderText("Select output directory...")
        output_layout.addWidget(self.output_edit)

        self.output_btn = QPushButton("Browse...")
        self.output_btn.setMaximumWidth(100)
        self.output_btn.clicked.connect(self.browse_output)
        output_layout.addWidget(self.output_btn)

        layout.addLayout(output_layout)

        # Spacer
        layout.addSpacing(20)

        # Action button
        self.split_btn = QPushButton("Split Files")
        self.split_btn.setMinimumHeight(40)
        self.split_btn.clicked.connect(self.split_files)
        layout.addWidget(self.split_btn)

        # Progress bar
        self.progress_bar = QProgressBar()
        self.progress_bar.setValue(0)
        layout.addWidget(self.progress_bar)

        # Status label
        self.status_label = QLabel("Ready")
        self.status_label.setAlignment(Qt.AlignmentFlag.AlignCenter)
        self.status_label.setStyleSheet("color: #666; font-style: italic;")
        layout.addWidget(self.status_label)

        # Add stretch to push everything to the top
        layout.addStretch()

    def browse_file(self):
        """Open dialog to select aggregated file."""
        file_path, _ = QFileDialog.getOpenFileName(
            self,
            "Select Aggregated File",
            os.path.expanduser("~"),
            "Markdown Files (*.md);;All Files (*)"
        )

        if file_path:
            self.file_edit.setText(file_path)
            self.status_label.setText("Aggregated file selected")

    def browse_output(self):
        """Open dialog to select output directory."""
        directory = QFileDialog.getExistingDirectory(
            self,
            "Select Output Directory",
            os.path.expanduser("~")
        )

        if directory:
            self.output_edit.setText(directory)
            self.status_label.setText("Output directory selected")

    def split_files(self):
        """Perform the split operation."""
        aggregated_file = self.file_edit.text()
        output_dir = self.output_edit.text()

        # Validate inputs
        if not aggregated_file:
            QMessageBox.warning(
                self,
                "Input Required",
                "Please select an aggregated file."
            )
            return

        if not output_dir:
            QMessageBox.warning(
                self,
                "Input Required",
                "Please select an output directory."
            )
            return

        # Confirm if output directory is not empty
        if os.path.exists(output_dir) and os.listdir(output_dir):
            reply = QMessageBox.question(
                self,
                "Directory Not Empty",
                "The output directory is not empty. Files may be overwritten.\n\n"
                "Do you want to continue?",
                QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
                QMessageBox.StandardButton.No
            )
            if reply == QMessageBox.StandardButton.No:
                return

        # Disable UI during operation
        self.set_ui_enabled(False)
        self.progress_bar.setValue(0)
        self.status_label.setText("Splitting files...")

        try:
            # Progress callback
            def update_progress(percentage, message):
                self.progress_bar.setValue(percentage)
                self.status_label.setText(message)
                QCoreApplication.processEvents()  # Keep UI responsive

            # Perform split
            result = self.splitter.split(
                aggregated_file,
                output_dir,
                update_progress
            )

            # Show success message
            QMessageBox.information(
                self,
                "Success",
                f"Split complete!\n\n"
                f"Files created: {result['files_created']}\n"
                f"Directories created: {result['directories_created']}\n"
                f"Output directory: {result['output_dir']}"
            )

            self.status_label.setText("Split completed successfully")

        except ObsidianToolException as e:
            QMessageBox.critical(
                self,
                "Error",
                f"Split failed:\n\n{str(e)}"
            )
            self.status_label.setText("Split failed")
            self.progress_bar.setValue(0)

        except Exception as e:
            QMessageBox.critical(
                self,
                "Unexpected Error",
                f"An unexpected error occurred:\n\n{str(e)}"
            )
            self.status_label.setText("Split failed")
            self.progress_bar.setValue(0)

        finally:
            # Re-enable UI
            self.set_ui_enabled(True)

    def set_ui_enabled(self, enabled: bool):
        """Enable or disable UI elements during operation."""
        self.file_btn.setEnabled(enabled)
        self.output_btn.setEnabled(enabled)
        self.split_btn.setEnabled(enabled)