"""Handlers for private messages."""
import re
from typing import Optional, Dict
import telebot
from telebot import types
from sqlalchemy.orm import Session
from database import get_db_session, User, Chat, UserChat
from messages import THEMES, get_theme_emoji


# User states for conversation flow
user_states: Dict[int, str] = {}


def register_private_handlers(bot: telebot.TeleBot) -> None:
    """Register all private message handlers."""
    
    @bot.message_handler(commands=['start'], chat_types=['private'])
    def handle_start(message: telebot.types.Message) -> None:
        """Handle /start command in private chat."""
        if not message.from_user:
            return
        
        user_id = message.from_user.id
        username: Optional[str] = message.from_user.username
        first_name: str = message.from_user.first_name or "Пользователь"
        
        db = get_db_session()
        try:
            # Check if user exists
            user = db.query(User).filter(User.user_id == user_id).first()
            
            if user:
                # User already exists - ask if they want to update
                bot.send_message(
                    user_id,
                    f"Привет, {first_name}! Ты уже поделился со мной днем рождения.\n"
                    f"Используй /update, чтобы обновить свои данные."
                )
            else:
                # New user - ask for birthday
                user_states[user_id] = 'waiting_birthday'
                bot.send_message(
                    user_id,
                    f"Привет, {first_name}! 👋\n\n"
                    f"Пришли мне свой день рождения в формате ДД.ММ или ДД.ММ.ГГГГ\n"
                    f"Например: 15.03 или 15.03.1990"
                )
        finally:
            db.close()
    
    @bot.message_handler(commands=['update'], chat_types=['private'])
    def handle_update(message: telebot.types.Message) -> None:
        """Handle /update command in private chat."""
        if not message.from_user:
            return
        
        user_id = message.from_user.id
        first_name: str = message.from_user.first_name or "Пользователь"
        
        db = get_db_session()
        try:
            user = db.query(User).filter(User.user_id == user_id).first()
            if user:
                user_states[user_id] = 'waiting_birthday'
                bot.send_message(
                    user_id,
                    f"Хорошо, {first_name}! Пришли мне свой день рождения в формате ДД.ММ или ДД.ММ.ГГГГ"
                )
            else:
                bot.send_message(
                    user_id,
                    "Ты еще не поделился со мной днем рождения. Используй /start для начала."
                )
        finally:
            db.close()
    
    @bot.message_handler(func=lambda m: m.chat.type == 'private' and m.from_user and m.from_user.id in user_states and m.text)
    def handle_birthday_input(message: telebot.types.Message) -> None:
        """Handle birthday input from user."""
        if not message.from_user or not message.text:
            return
        
        user_id = message.from_user.id
        state = user_states.get(user_id)
        
        if state == 'waiting_birthday':
            # Parse birthday
            birthday_text = message.text.strip()
            parsed = parse_birthday(birthday_text)
            
            if not parsed:
                bot.send_message(
                    user_id,
                    "Неверный формат даты. Используй формат ДД.ММ или ДД.ММ.ГГГГ\n"
                    "Например: 15.03 или 15.03.1990"
                )
                return
            
            day, month, year = parsed
            
            # Validate date
            if not is_valid_date(day, month, year):
                bot.send_message(
                    user_id,
                    "Неверная дата. Проверь правильность дня и месяца."
                )
                return
            
            # Save birthday and ask for preference
            db = get_db_session()
            try:
                if not message.from_user:
                    return
                username: Optional[str] = message.from_user.username
                first_name: str = message.from_user.first_name or "Пользователь"
                
                user = db.query(User).filter(User.user_id == user_id).first()
                if user:
                    # Update existing user
                    user.birthday_day = day
                    user.birthday_month = month
                    user.birthday_year = year
                    user.first_name = first_name
                    user.username = username
                else:
                    # Create new user
                    user = User(
                        user_id=user_id,
                        username=username,
                        first_name=first_name,
                        birthday_day=day,
                        birthday_month=month,
                        birthday_year=year,
                        preference_theme="Музыка"  # Default theme
                    )
                    db.add(user)
                
                db.commit()
                
                # Ask for preference theme
                user_states[user_id] = 'waiting_preference'
                ask_preference_theme(bot, user_id)
            finally:
                db.close()
        
        elif state == 'waiting_preference':
            # User selected preference theme
            if not message.text:
                return
            
            theme_text = message.text.strip()
            
            if theme_text not in THEMES:
                bot.send_message(
                    user_id,
                    "Пожалуйста, выбери одну из предложенных тем, нажав на кнопку."
                )
                return
            
            # Save preference
            db = get_db_session()
            try:
                user = db.query(User).filter(User.user_id == user_id).first()
                if user:
                    user.preference_theme = theme_text
                    db.commit()
                    
                    # Update user in all chats
                    update_user_in_chats(bot, db, user)
                    
                    bot.send_message(
                        user_id,
                        f"Отлично! Я запомнил твои предпочтения: {theme_text}\n\n"
                        f"Теперь я буду поздравлять тебя с днем рождения во всех чатах, где ты состоишь!"
                    )
                    user_states.pop(user_id, None)
            finally:
                db.close()
    
    @bot.callback_query_handler(func=lambda call: call.data and call.data.startswith('theme_'))
    def handle_theme_selection(call: telebot.types.CallbackQuery) -> None:
        """Handle theme selection from inline keyboard."""
        if not call.from_user or not call.data or not call.message:
            return
        
        user_id = call.from_user.id
        
        if user_states.get(user_id) != 'waiting_preference':
            bot.answer_callback_query(call.id, "Это действие недоступно сейчас.")
            return
        
        theme = call.data.replace('theme_', '')
        
        if theme not in THEMES:
            bot.answer_callback_query(call.id, "Неверная тема.")
            return
        
        # Save preference
        db = get_db_session()
        try:
            user = db.query(User).filter(User.user_id == user_id).first()
            if user:
                user.preference_theme = theme
                db.commit()
                
                # Update user in all chats
                update_user_in_chats(bot, db, user)
                
                bot.answer_callback_query(call.id, f"Выбрано: {theme}")
                bot.edit_message_text(
                    f"Отлично! Я запомнил твои предпочтения: {theme}\n\n"
                    f"Теперь я буду поздравлять тебя с днем рождения во всех чатах, где ты состоишь!",
                    chat_id=call.message.chat.id,
                    message_id=call.message.message_id
                )
                user_states.pop(user_id, None)
        finally:
            db.close()


def parse_birthday(text: str) -> Optional[tuple[int, int, Optional[int]]]:
    """Parse birthday from text. Returns (day, month, year) or None."""
    # Try DD.MM.YYYY format
    match = re.match(r'^(\d{1,2})\.(\d{1,2})\.(\d{4})$', text)
    if match:
        day, month, year = int(match.group(1)), int(match.group(2)), int(match.group(3))
        return (day, month, year)
    
    # Try DD.MM format
    match = re.match(r'^(\d{1,2})\.(\d{1,2})$', text)
    if match:
        day, month = int(match.group(1)), int(match.group(2))
        return (day, month, None)
    
    return None


def is_valid_date(day: int, month: int, year: Optional[int]) -> bool:
    """Check if date is valid."""
    if month < 1 or month > 12:
        return False
    if day < 1 or day > 31:
        return False
    
    # Check specific month limits
    if month in [4, 6, 9, 11] and day > 30:
        return False
    if month == 2:
        if year:
            # Check leap year
            if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
                max_day = 29
            else:
                max_day = 28
        else:
            max_day = 29  # Assume leap year if year not provided
        if day > max_day:
            return False
    
    return True


def ask_preference_theme(bot: telebot.TeleBot, user_id: int) -> None:
    """Ask user to select preference theme."""
    keyboard = types.InlineKeyboardMarkup(row_width=2)
    
    # Show hobbies (themes) in 2 buttons per row
    for i in range(0, len(THEMES), 2):
        theme1 = THEMES[i]
        emoji1 = get_theme_emoji(theme1)
        btn1 = types.InlineKeyboardButton(
            text=f"{emoji1} {theme1}",
            callback_data=f'theme_{theme1}'
        )

        # Optional second button in the same row
        if i + 1 < len(THEMES):
            theme2 = THEMES[i + 1]
            emoji2 = get_theme_emoji(theme2)
            btn2 = types.InlineKeyboardButton(
                text=f"{emoji2} {theme2}",
                callback_data=f'theme_{theme2}'
            )
            keyboard.add(btn1, btn2)
        else:
            keyboard.add(btn1)
    
    bot.send_message(
        user_id,
        "Что тебе нравится? Выбери одну из тем:",
        reply_markup=keyboard
    )


def update_user_in_chats(bot: telebot.TeleBot, db: Session, user: User) -> None:
    """Update user information in all chats where bot is admin."""
    # Get all chats where bot is admin
    admin_chats = db.query(Chat).filter(Chat.bot_is_admin == True).all()
    
    for chat in admin_chats:
        try:
            # Check if user is member of this chat
            member = bot.get_chat_member(chat.chat_id, user.user_id)
            if member.status not in ['left', 'kicked']:
                # User is in chat - add/update relationship
                user_chat = db.query(UserChat).filter(
                    UserChat.user_id == user.user_id,
                    UserChat.chat_id == chat.chat_id
                ).first()
                
                if not user_chat:
                    user_chat = UserChat(user_id=user.user_id, chat_id=chat.chat_id)
                    db.add(user_chat)
                    db.commit()
        except Exception:
            # User might have blocked bot or bot was removed from chat
            pass