import asyncio
import logging
import secrets
import string
from aiogram import Bot, Dispatcher, F
from aiogram.types import Message, CallbackQuery, InlineKeyboardMarkup, InlineKeyboardButton
from aiogram.filters import Command, StateFilter
from aiogram.fsm.context import FSMContext
from aiogram.fsm.state import State, StatesGroup
from aiogram.fsm.storage.memory import MemoryStorage

from config import (
    TELEGRAM_BOT_TOKEN, ADMIN_TELEGRAM_IDS, 
    DEFAULT_SIP_SERVER, DEFAULT_SIP_PORT, 
    DEFAULT_SIP_DOMAIN, DEFAULT_SIP_TRANSPORT,
    DEFAULT_SIP_OUTBOUND_PROXY, DEFAULT_SIP_STUN
)
from services.database import Database
from services.mikopbx_service import MikoPBXService

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

bot = Bot(token=TELEGRAM_BOT_TOKEN)
dp = Dispatcher(storage=MemoryStorage())

db = Database()
mikopbx = MikoPBXService()

class RegistrationStates(StatesGroup):
    waiting_for_number = State()
    waiting_for_username = State()
    waiting_for_custom_secret = State()

class AdminEditStates(StatesGroup):
    waiting_for_new_number = State()
    waiting_for_new_secret = State()
    waiting_for_existing_number = State()
    waiting_for_telegram_id = State()

def is_admin(telegram_id: int) -> bool:
    return telegram_id in ADMIN_TELEGRAM_IDS

def generate_secret(length: int = 16) -> str:
    alphabet = string.ascii_letters + string.digits
    return ''.join(secrets.choice(alphabet) for _ in range(length))

# ============== KEYBOARDS ==============

def main_menu_keyboard(is_admin_user: bool = False):
    buttons = [
        [InlineKeyboardButton(text="Register new number", callback_data="register")],
        [InlineKeyboardButton(text="My accounts", callback_data="my_accounts")],
    ]
    if is_admin_user:
        buttons.append([InlineKeyboardButton(text="Admin panel", callback_data="admin_menu")])
    return InlineKeyboardMarkup(inline_keyboard=buttons)

def admin_menu_keyboard():
    return InlineKeyboardMarkup(inline_keyboard=[
        [InlineKeyboardButton(text="All registered accounts", callback_data="admin_list")],
        [InlineKeyboardButton(text="Link existing MikoPBX number", callback_data="admin_link_existing")],
        [InlineKeyboardButton(text="Back to main menu", callback_data="back_main")]
    ])

def account_list_keyboard(accounts: list, prefix: str = "account"):
    buttons = []
    for acc in accounts[:10]:  # Limit to 10
        text = f"{acc['extension_number']}"
        if acc.get('telegram_username'):
            text += f" (@{acc['telegram_username']})"
        buttons.append([InlineKeyboardButton(
            text=text, 
            callback_data=f"{prefix}_{acc['extension_number']}"
        )])
    buttons.append([InlineKeyboardButton(text="Back", callback_data="back_main")])
    return InlineKeyboardMarkup(inline_keyboard=buttons)

# ============== HANDLERS ==============

@dp.message(Command("start"))
async def cmd_start(message: Message):
    await db.init_db()
    user = await db.add_user(
        message.from_user.id,
        message.from_user.username,
        message.from_user.full_name
    )
    
    is_admin_user = is_admin(message.from_user.id)
    keyboard = main_menu_keyboard(is_admin_user)
    
    await message.answer(
        "Welcome to public SIP telephony service.\n\n"
        "Here you can register your own SIP number and get connection parameters.\n\n"
        "Please select an option:",
        reply_markup=keyboard
    )

@dp.callback_query(F.data == "register")
async def start_registration(callback: CallbackQuery, state: FSMContext):
    await callback.message.edit_text(
        "Enter the desired extension number (digits only, e.g. 1001):\n"
        "Or send /cancel to abort."
    )
    await state.set_state(RegistrationStates.waiting_for_number)
    await callback.answer()

@dp.message(RegistrationStates.waiting_for_number)
async def process_number(message: Message, state: FSMContext):
    number = message.text.strip()
    
    # Strict validation: exactly 7 digits
    if not number.isdigit() or len(number) != 7:
        await message.answer("The number must be exactly 7 digits (e.g. 1001001).")
        return
    
    # Check if number already exists in our DB
    existing = await db.get_sip_account_by_number(number)
    if existing:
        await message.answer("This number is already taken. Please choose another one.")
        return
    
    # Check if this user already has an account (one user = one number)
    user_accounts = await db.get_user_sip_accounts(message.from_user.id)
    if user_accounts:
        await message.answer(
            "You already have a registered number.\n"
            "Each user can have only one number."
        )
        await state.clear()
        is_admin_user = is_admin(message.from_user.id)
        await message.answer("Main menu:", reply_markup=main_menu_keyboard(is_admin_user))
        return
    
    await state.update_data(desired_number=number)
    await message.answer("Enter your name (optional, for the account):")
    await state.set_state(RegistrationStates.waiting_for_username)

@dp.message(RegistrationStates.waiting_for_username)
async def process_username(message: Message, state: FSMContext):
    data = await state.get_data()
    number = data["desired_number"]
    username = message.text.strip() if message.text.strip() else f"User {number}"
    
    await state.update_data(username=username)
    
    keyboard = InlineKeyboardMarkup(inline_keyboard=[
        [InlineKeyboardButton(text="Generate random password", callback_data="gen_secret")],
        [InlineKeyboardButton(text="Enter my own password", callback_data="custom_secret")]
    ])
    
    await message.answer(
        "Would you like to use a generated password or enter your own?",
        reply_markup=keyboard
    )
    await state.set_state(RegistrationStates.waiting_for_custom_secret)

@dp.callback_query(F.data == "gen_secret", StateFilter(RegistrationStates.waiting_for_custom_secret))
async def use_generated_secret(callback: CallbackQuery, state: FSMContext):
    data = await state.get_data()
    number = data["desired_number"]
    username = data.get("username", f"User {number}")
    
    secret = generate_secret(12)
    await create_account_and_reply(callback.message, state, number, username, secret, callback.from_user.id)

@dp.callback_query(F.data == "custom_secret", StateFilter(RegistrationStates.waiting_for_custom_secret))
async def ask_for_custom_secret(callback: CallbackQuery, state: FSMContext):
    await callback.message.edit_text(
        "Please enter the password you want to use for this SIP account (min 6 characters):"
    )
    await callback.answer()

@dp.message(RegistrationStates.waiting_for_custom_secret)
async def process_custom_secret(message: Message, state: FSMContext):
    secret = message.text.strip()
    
    if len(secret) < 6:
        await message.answer("Password must be at least 6 characters long. Please try again.")
        return
    
    data = await state.get_data()
    number = data["desired_number"]
    username = data.get("username", f"User {number}")
    
    await create_account_and_reply(message, state, number, username, secret, message.from_user.id)

async def create_account_and_reply(message_obj, state, number: str, username: str, secret: str, telegram_id: int):
    await message_obj.answer("Creating your SIP account with the chosen password... Please wait.")
    
    # Create via MikoPBX with custom secret (API v3)
    result = await mikopbx.create_extension(
        number=number,
        secret=secret,
        username=username
    )
    
    if result.get("success"):
        # Save to our database
        user = await db.get_user(telegram_id)
        if user:
            await db.add_sip_account(
                user_id=user["id"],
                extension_number=number,
                sip_secret=secret,
                username=username
            )
        
        connection_info = (
            f"Your SIP account has been created!\n\n"
            f"Number: {number}\n"
            f"Secret (password): {secret}\n\n"
            f"--- Full connection parameters ---\n"
            f"Domain: {DEFAULT_SIP_DOMAIN}\n"
            f"Server / Outbound Proxy: {DEFAULT_SIP_SERVER}\n"
            f"Port: {DEFAULT_SIP_PORT}\n"
            f"Transport: {DEFAULT_SIP_TRANSPORT}\n"
            f"Username / Auth ID: {number}\n"
            f"Password: {secret}\n"
        )
        
        if DEFAULT_SIP_OUTBOUND_PROXY:
            connection_info += f"Outbound Proxy: {DEFAULT_SIP_OUTBOUND_PROXY}\n"
        if DEFAULT_SIP_STUN:
            connection_info += f"STUN Server: {DEFAULT_SIP_STUN}\n"
        
        connection_info += (
            f"\nRecommended clients: Zoiper, MicroSIP, Linphone, Bria\n"
            f"Use these credentials in your SIP client."
        )
        
        await message_obj.answer(connection_info)
    else:
        error_msg = result.get("error", "Unknown error")
        await message_obj.answer(f"Failed to create account: {error_msg}\n\n"
                           f"Please try again later or contact administrator.")
    
    await state.clear()
    
    # Show main menu again
    is_admin_user = is_admin(telegram_id)
    keyboard = main_menu_keyboard(is_admin_user)
    await message_obj.answer("What would you like to do next?", reply_markup=keyboard)

@dp.callback_query(F.data == "my_accounts")
async def show_my_accounts(callback: CallbackQuery):
    accounts = await db.get_user_sip_accounts(callback.from_user.id)
    
    if not accounts:
        await callback.message.edit_text(
            "You don't have any registered accounts yet.",
            reply_markup=main_menu_keyboard(is_admin(callback.from_user.id))
        )
    else:
        text = "Your SIP accounts:\n\n"
        for acc in accounts:
            text += f"Number: {acc['extension_number']}\n"
            if acc['sip_secret']:
                text += f"Password: {acc['sip_secret']}\n"
            text += f"Created: {acc['created_at']}\n\n"
        
        await callback.message.edit_text(
            text,
            reply_markup=main_menu_keyboard(is_admin(callback.from_user.id))
        )
    await callback.answer()

# ============== ADMIN HANDLERS ==============

@dp.callback_query(F.data == "admin_menu")
async def show_admin_menu(callback: CallbackQuery):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    await callback.message.edit_text(
        "Administrator panel\n\n"
        "Select an action:",
        reply_markup=admin_menu_keyboard()
    )
    await callback.answer()

# ============== LINK EXISTING MIKOPBX ACCOUNT ==============

@dp.callback_query(F.data == "admin_link_existing")
async def admin_start_link_existing(callback: CallbackQuery, state: FSMContext):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    await callback.message.edit_text(
        "Enter the existing MikoPBX extension number (exactly 7 digits) that you want to link to a Telegram user:"
    )
    await state.set_state(AdminEditStates.waiting_for_existing_number)
    await callback.answer()

@dp.message(AdminEditStates.waiting_for_existing_number)
async def admin_process_existing_number(message: Message, state: FSMContext):
    if not is_admin(message.from_user.id):
        await message.answer("Access denied.")
        await state.clear()
        return
    
    number = message.text.strip()
    
    if not number.isdigit() or len(number) != 7:
        await message.answer("Number must be exactly 7 digits.")
        return
    
    # Check if already linked in our DB
    existing = await db.get_sip_account_by_number(number)
    if existing:
        await message.answer(
            f"Number {number} is already linked to Telegram ID {existing.get('telegram_id', 'unknown')}."
        )
        await state.clear()
        return
    
    await state.update_data(existing_number=number)
    await message.answer(
        "Enter the Telegram user ID to link this number to (or forward a message from the user):"
    )
    await state.set_state(AdminEditStates.waiting_for_telegram_id)

@dp.message(AdminEditStates.waiting_for_telegram_id)
async def admin_process_telegram_id(message: Message, state: FSMContext):
    if not is_admin(message.from_user.id):
        await message.answer("Access denied.")
        await state.clear()
        return
    
    data = await state.get_data()
    number = data["existing_number"]
    
    try:
        telegram_id = int(message.text.strip())
    except ValueError:
        await message.answer("Please enter a valid numeric Telegram ID.")
        return
    
    # Check if this Telegram user already has an account
    user_accounts = await db.get_user_sip_accounts(telegram_id)
    if user_accounts:
        await message.answer(
            f"Telegram user {telegram_id} already has a registered number."
        )
        await state.clear()
        return
    
    # Add user to database if not exists
    user_id = await db.add_user(telegram_id)
    
    # Link the existing number (secret will be empty - admin can set it later)
    await db.add_sip_account(
        user_id=user_id,
        extension_number=number,
        sip_secret=None,  # Admin can set password later
        username=f"Linked user {telegram_id}"
    )
    
    await message.answer(
        f"Successfully linked existing MikoPBX number {number} to Telegram user {telegram_id}.\n\n"
        f"The user can now view their account via the bot.\n"
        f"You can set the password using 'Change password' in admin panel."
    )
    
    await state.clear()
    
    # Return to admin menu
    await message.answer(
        "Administrator panel",
        reply_markup=admin_menu_keyboard()
    )

@dp.callback_query(F.data == "admin_list")
async def admin_list_accounts(callback: CallbackQuery):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    accounts = await db.get_all_sip_accounts()
    
    if not accounts:
        await callback.message.edit_text(
            "No accounts registered yet.",
            reply_markup=admin_menu_keyboard()
        )
    else:
        await callback.message.edit_text(
            "Registered accounts (click to view details):",
            reply_markup=account_list_keyboard(accounts, prefix="admin_view")
        )
    await callback.answer()

@dp.callback_query(F.data.startswith("admin_view_"))
async def admin_view_account(callback: CallbackQuery):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    number = callback.data.replace("admin_view_", "")
    account = await db.get_sip_account_by_number(number)
    
    if not account:
        await callback.answer("Account not found.")
        return
    
    text = (
        f"Account details:\n\n"
        f"Number: {account['extension_number']}\n"
        f"Password: {account['sip_secret'] or 'Not set'}\n"
        f"Username: {account.get('username', 'N/A')}\n"
        f"Owner Telegram ID: {account.get('telegram_id', 'N/A')}\n"
        f"Created: {account['created_at']}\n\n"
        f"Actions:"
    )
    
    keyboard = InlineKeyboardMarkup(inline_keyboard=[
        [InlineKeyboardButton(text="Change number", callback_data=f"admin_change_number_{number}")],
        [InlineKeyboardButton(text="Change password", callback_data=f"admin_change_secret_{number}")],
        [InlineKeyboardButton(text="Delete account", callback_data=f"admin_delete_{number}")],
        [InlineKeyboardButton(text="Back to list", callback_data="admin_list")]
    ])
    
    await callback.message.edit_text(text, reply_markup=keyboard)
    await callback.answer()

@dp.callback_query(F.data.startswith("admin_change_number_"))
async def admin_start_change_number(callback: CallbackQuery, state: FSMContext):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    number = callback.data.replace("admin_change_number_", "")
    await state.update_data(old_number=number)
    
    await callback.message.edit_text(
        f"Enter new number for extension {number}:"
    )
    await state.set_state(AdminEditStates.waiting_for_new_number)
    await callback.answer()

@dp.message(AdminEditStates.waiting_for_new_number)
async def admin_process_new_number(message: Message, state: FSMContext):
    if not is_admin(message.from_user.id):
        await message.answer("Access denied.")
        await state.clear()
        return
    
    new_number = message.text.strip()
    data = await state.get_data()
    old_number = data["old_number"]
    
    if not new_number.isdigit() or len(new_number) < 3:
        await message.answer("Please enter a valid number (at least 3 digits).")
        return
    
    # Check if new number already exists
    existing = await db.get_sip_account_by_number(new_number)
    if existing:
        await message.answer("This number is already taken.")
        return
    
    account = await db.get_sip_account_by_number(old_number)
    if not account:
        await message.answer("Account not found in local database.")
        await state.clear()
        return
    
    await message.answer("Changing number in MikoPBX and local database...")
    
    # Try to change number in MikoPBX
    mikopbx_result = await mikopbx.change_extension_number(old_number, new_number)
    
    if mikopbx_result.get("success"):
        # Update local database
        await db.update_extension_number(old_number, new_number)
        
        await message.answer(
            f"Number successfully changed from {old_number} to {new_number} in both MikoPBX and database."
        )
    else:
        # Fallback: update only local DB + inform admin
        await db.update_extension_number(old_number, new_number)
        error = mikopbx_result.get("error", "Unknown error")
        await message.answer(
            f"Number changed only in local database.\n"
            f"MikoPBX sync failed: {error}\n\n"
            f"You may need to manually adjust the number in the MikoPBX web interface."
        )
    
    await state.clear()
    
    # Return to admin menu
    await message.answer(
        "Administrator panel",
        reply_markup=admin_menu_keyboard()
    )

@dp.callback_query(F.data.startswith("admin_delete_"))
async def admin_delete_account(callback: CallbackQuery):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    number = callback.data.replace("admin_delete_", "")
    
    keyboard = InlineKeyboardMarkup(inline_keyboard=[
        [InlineKeyboardButton(text="Yes, delete", callback_data=f"confirm_delete_{number}")],
        [InlineKeyboardButton(text="Cancel", callback_data="admin_list")]
    ])
    
    await callback.message.edit_text(
        f"Are you sure you want to delete extension {number}?\n"
        f"This will remove it from both the database and MikoPBX.",
        reply_markup=keyboard
    )
    await callback.answer()

@dp.callback_query(F.data.startswith("confirm_delete_"))
async def admin_confirm_delete(callback: CallbackQuery):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    number = callback.data.replace("confirm_delete_", "")
    
    await callback.message.edit_text("Deleting account...")
    
    # Delete from MikoPBX
    mikopbx_result = await mikopbx.delete_extension(number)
    
    # Delete from local DB
    db_success = await db.delete_sip_account(number)
    
    if mikopbx_result.get("success") or db_success:
        await callback.message.edit_text(
            f"Extension {number} has been deleted.",
            reply_markup=admin_menu_keyboard()
        )
    else:
        await callback.message.edit_text(
            f"Failed to delete {number}.",
            reply_markup=admin_menu_keyboard()
        )
    await callback.answer()

@dp.callback_query(F.data.startswith("admin_change_secret_"))
async def admin_start_change_secret(callback: CallbackQuery, state: FSMContext):
    if not is_admin(callback.from_user.id):
        await callback.answer("Access denied.")
        return
    
    number = callback.data.replace("admin_change_secret_", "")
    await state.update_data(edit_number=number)
    
    await callback.message.edit_text(
        f"Enter new password (secret) for extension {number}:"
    )
    await state.set_state(AdminEditStates.waiting_for_new_secret)
    await callback.answer()

@dp.message(AdminEditStates.waiting_for_new_secret)
async def admin_process_new_secret(message: Message, state: FSMContext):
    if not is_admin(message.from_user.id):
        await message.answer("Access denied.")
        await state.clear()
        return
    
    new_secret = message.text.strip()
    if len(new_secret) < 6:
        await message.answer("Password must be at least 6 characters.")
        return
    
    data = await state.get_data()
    number = data["edit_number"]
    
    await message.answer("Updating password in MikoPBX and database...")
    
    # Update in MikoPBX
    mikopbx_result = await mikopbx.set_extension_secret(number, new_secret)
    
    # Update local database regardless
    db_success = await db.update_sip_secret(number, new_secret)
    
    if mikopbx_result.get("success") and db_success:
        await message.answer(f"Password for {number} successfully updated in both MikoPBX and database.")
    elif db_success:
        await message.answer(
            f"Password updated in local database.\n"
            f"MikoPBX sync failed: {mikopbx_result.get('error', 'Unknown error')}"
        )
    else:
        await message.answer("Failed to update password.")
    
    await state.clear()
    await message.answer(
        "Administrator panel",
        reply_markup=admin_menu_keyboard()
    )

@dp.callback_query(F.data == "back_main")
async def back_to_main(callback: CallbackQuery):
    is_admin_user = is_admin(callback.from_user.id)
    keyboard = main_menu_keyboard(is_admin_user)
    await callback.message.edit_text(
        "Main menu:",
        reply_markup=keyboard
    )
    await callback.answer()

@dp.message(Command("cancel"))
async def cancel_handler(message: Message, state: FSMContext):
    current_state = await state.get_state()
    if current_state is not None:
        await state.clear()
    await message.answer("Operation cancelled.")

async def main():
    await db.init_db()
    logger.info("Starting MikoPBX Telegram Bot...")
    await dp.start_polling(bot)

if __name__ == "__main__":
    asyncio.run(main())