"""
Main Window - Primary application window with 3-panel layout
"""

from PyQt5.QtWidgets import (
    QMainWindow, QSplitter, QStatusBar, QMenuBar, QMenu,
    QAction, QMessageBox, QApplication
)
from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtGui import QKeySequence

from app import config
from app.models import Course, get_course
from app.database import Database, get_database
from .navigation_panel import NavigationPanel
from .content_viewer import ContentViewer
from .progress_panel import ProgressPanel


class MainWindow(QMainWindow):
    """Main application window with 3-panel layout"""

    def __init__(self):
        super().__init__()

        # Load course and database
        self.course = get_course()
        self.db = get_database()

        # Get or create default user
        self.user_id = self._get_or_create_user()

        # Current state
        self.current_lesson_id = None

        # Initialize UI
        self.init_ui()
        self.create_menus()

        # Connect signals
        self.connect_signals()

        # Auto-save timer
        self.auto_save_timer = QTimer(self)
        self.auto_save_timer.timeout.connect(self.auto_save)
        self.auto_save_timer.start(config.AUTO_SAVE_INTERVAL * 1000)  # Convert to ms

        # Load progress and restore state
        self.load_initial_state()

    def init_ui(self):
        """Initialize the user interface"""
        self.setWindowTitle(f"{config.APP_NAME} v{config.APP_VERSION}")
        self.setGeometry(100, 100, config.DEFAULT_WINDOW_WIDTH, config.DEFAULT_WINDOW_HEIGHT)

        # Create 3-panel splitter layout
        self.splitter = QSplitter(Qt.Horizontal)

        # Create panels
        self.navigation_panel = NavigationPanel(self.course, self)
        self.content_viewer = ContentViewer(self)
        self.progress_panel = ProgressPanel(self.course, self)

        # Add panels to splitter
        self.splitter.addWidget(self.navigation_panel)
        self.splitter.addWidget(self.content_viewer)
        self.splitter.addWidget(self.progress_panel)

        # Set initial splitter sizes
        self.splitter.setSizes([
            config.NAVIGATION_PANEL_DEFAULT_WIDTH,
            config.DEFAULT_WINDOW_WIDTH - config.NAVIGATION_PANEL_DEFAULT_WIDTH - config.PROGRESS_PANEL_DEFAULT_WIDTH,
            config.PROGRESS_PANEL_DEFAULT_WIDTH
        ])

        # Set as central widget
        self.setCentralWidget(self.splitter)

        # Create status bar
        self.status_bar = QStatusBar()
        self.setStatusBar(self.status_bar)
        self.status_bar.showMessage("Ready")

    def create_menus(self):
        """Create menu bar"""
        menubar = self.menuBar()

        # File Menu
        file_menu = menubar.addMenu("&File")

        exit_action = QAction("E&xit", self)
        exit_action.setShortcut(QKeySequence.Quit)
        exit_action.triggered.connect(self.close)
        file_menu.addAction(exit_action)

        # View Menu
        view_menu = menubar.addMenu("&View")

        toggle_nav_action = QAction("Toggle &Navigation Panel", self)
        toggle_nav_action.setShortcut("Ctrl+1")
        toggle_nav_action.triggered.connect(lambda: self.navigation_panel.setVisible(not self.navigation_panel.isVisible()))
        view_menu.addAction(toggle_nav_action)

        toggle_progress_action = QAction("Toggle &Progress Panel", self)
        toggle_progress_action.setShortcut("Ctrl+2")
        toggle_progress_action.triggered.connect(lambda: self.progress_panel.setVisible(not self.progress_panel.isVisible()))
        view_menu.addAction(toggle_progress_action)

        view_menu.addSeparator()

        reset_layout_action = QAction("&Reset Layout", self)
        reset_layout_action.triggered.connect(self.reset_layout)
        view_menu.addAction(reset_layout_action)

        # Help Menu
        help_menu = menubar.addMenu("&Help")

        about_action = QAction("&About", self)
        about_action.triggered.connect(self.show_about)
        help_menu.addAction(about_action)

    def connect_signals(self):
        """Connect signals between components"""
        self.navigation_panel.lesson_selected.connect(self.on_lesson_selected)

    def _get_or_create_user(self) -> int:
        """Get or create default user"""
        # Check if user exists
        row = self.db.fetch_one("SELECT user_id FROM users LIMIT 1")

        if row:
            return row[0]

        # Create default user
        cursor = self.db.execute("""
            INSERT INTO users (username, created_at)
            VALUES (?, datetime('now'))
        """, ("default",))
        self.db.commit()

        return cursor.lastrowid

    def load_initial_state(self):
        """Load progress and restore application state"""
        # Get overall progress
        progress = self.db.get_overall_progress(self.user_id)

        # Update progress panel
        completed_lessons = progress.get('lessons_completed', 0)
        total_points = progress.get('total_points', 0)
        total_time = progress.get('total_time', 0)

        self.progress_panel.update_progress(completed_lessons, total_points, total_time)

        # Update part progress
        for part in self.course.parts:
            part_completed = 0
            for lesson in part.lessons:
                lesson_prog = self.db.get_lesson_progress(self.user_id, lesson.id)
                if lesson_prog and lesson_prog['status'] == 'completed':
                    part_completed += 1
            part_total = len(part.lessons)
            self.progress_panel.update_part_progress(part.number, part_completed, part_total)

        # Update study streak
        streak = self.db.get_study_streak(self.user_id) if hasattr(self.db, 'get_study_streak') else 0
        self.progress_panel.update_streak(streak)

        # Update exercises
        if hasattr(self.db, 'get_exercise_progress'):
            exercise_progress = self.db.get_exercise_progress(self.user_id)
            if exercise_progress:
                self.progress_panel.update_exercises(
                    exercise_progress.get('completed', 0),
                    self.course.total_exercises
                )
        else:
            self.progress_panel.update_exercises(0, self.course.total_exercises)

        # Update lesson statuses in navigation
        for lesson in self.course.get_all_lessons():
            lesson_progress = self.db.get_lesson_progress(self.user_id, lesson.id)
            status = lesson_progress['status'] if lesson_progress else 'not_started'
            self.navigation_panel.update_lesson_status(lesson.id, status)

        # Get last viewed lesson
        row = self.db.fetch_one("""
            SELECT lesson_id FROM lesson_progress
            WHERE user_id = ?
            ORDER BY last_accessed DESC
            LIMIT 1
        """, (self.user_id,))

        if row:
            last_lesson_id = row[0]
            # Don't auto-load, just highlight it
            self.navigation_panel.set_current_lesson(last_lesson_id)

    def on_lesson_selected(self, lesson_id: str):
        """Handle lesson selection from navigation"""
        lesson = self.course.get_lesson(lesson_id)
        if not lesson:
            return

        self.current_lesson_id = lesson_id

        # Update navigation highlight
        self.navigation_panel.set_current_lesson(lesson_id)

        # Load lesson content
        self.content_viewer.load_lesson(lesson)

        # Update progress panel
        self.progress_panel.update_current_lesson(
            lesson.title,
            lesson.points,
            lesson.estimated_time
        )

        # Update database (mark as in_progress if not already completed)
        lesson_progress = self.db.get_lesson_progress(self.user_id, lesson_id)
        current_status = lesson_progress['status'] if lesson_progress else 'not_started'
        if current_status == 'not_started':
            self.db.update_lesson_progress(
                self.user_id,
                lesson_id,
                status='in_progress'
            )
            self.navigation_panel.update_lesson_status(lesson_id, 'in_progress')

        # Update last accessed
        self.db.update_lesson_progress(
            self.user_id,
            lesson_id,
            last_accessed=True
        )

        # Update status bar
        self.status_bar.showMessage(f"Lesson {lesson.order}: {lesson.title}")

    def auto_save(self):
        """Auto-save progress"""
        if not self.current_lesson_id:
            return

        # Get scroll position
        scroll_pos = self.content_viewer.get_scroll_position()

        # Update in database
        self.db.update_lesson_progress(
            self.user_id,
            self.current_lesson_id,
            scroll_position=scroll_pos,
            time_spent_increment=config.AUTO_SAVE_INTERVAL
        )

    def reset_layout(self):
        """Reset window layout to defaults"""
        self.splitter.setSizes([
            config.NAVIGATION_PANEL_DEFAULT_WIDTH,
            config.DEFAULT_WINDOW_WIDTH - config.NAVIGATION_PANEL_DEFAULT_WIDTH - config.PROGRESS_PANEL_DEFAULT_WIDTH,
            config.PROGRESS_PANEL_DEFAULT_WIDTH
        ])
        self.navigation_panel.setVisible(True)
        self.progress_panel.setVisible(True)

    def show_about(self):
        """Show about dialog"""
        QMessageBox.about(self, "About", f"""
            <h2>{config.APP_NAME}</h2>
            <p>Version {config.APP_VERSION}</p>
            <p>By {config.APP_AUTHOR}</p>
            <br>
            <p>An interactive desktop application for learning about Tesla coils
            and electromagnetic theory.</p>
            <br>
            <p><b>Course Statistics:</b></p>
            <ul>
                <li>{self.course.total_lessons} Lessons</li>
                <li>{self.course.total_exercises} Exercises</li>
                <li>{self.course.total_points} Total Points</li>
                <li>{len(self.course.parts)} Parts</li>
            </ul>
        """)

    def closeEvent(self, event):
        """Handle window close event"""
        # Final auto-save
        self.auto_save()

        # Accept close
        event.accept()