"""Telnet server for the MUD."""

import asyncio
import logging
import pathlib
import time
import tomllib
from typing import cast

import telnetlib3
from telnetlib3.server_shell import readline2

import mudlib.commands
import mudlib.commands.fly
import mudlib.commands.look
import mudlib.commands.movement
import mudlib.commands.quit
from mudlib.caps import parse_mtts
from mudlib.combat.commands import register_combat_commands
from mudlib.combat.engine import process_combat
from mudlib.content import load_commands
from mudlib.effects import clear_expired
from mudlib.player import Player, players
from mudlib.store import (
    PlayerData,
    account_exists,
    authenticate,
    create_account,
    init_db,
    load_player_data,
    save_player,
    update_last_login,
)
from mudlib.world.terrain import World

log = logging.getLogger(__name__)

PORT = 6789
TICK_RATE = 10  # ticks per second
TICK_INTERVAL = 1.0 / TICK_RATE
AUTOSAVE_INTERVAL = 60.0  # seconds between auto-saves

# Module-level world instance, generated once at startup
_world: World | None = None


def load_world_config(world_name: str = "earth") -> dict:
    """Load world configuration from TOML file."""
    worlds_dir = pathlib.Path(__file__).resolve().parents[2] / "worlds"
    config_path = worlds_dir / world_name / "config.toml"
    with open(config_path, "rb") as f:
        return tomllib.load(f)


async def game_loop() -> None:
    """Run periodic game tasks at TICK_RATE ticks per second."""
    log.info("game loop started (%d ticks/sec)", TICK_RATE)
    last_save_time = time.monotonic()

    while True:
        t0 = asyncio.get_event_loop().time()
        clear_expired()
        process_combat()

        # Periodic auto-save (every 60 seconds)
        current_time = time.monotonic()
        if current_time - last_save_time >= AUTOSAVE_INTERVAL:
            player_count = len(players)
            if player_count > 0:
                log.debug("auto-saving %d players", player_count)
                for player in list(players.values()):
                    save_player(player)
                last_save_time = current_time

        elapsed = asyncio.get_event_loop().time() - t0
        sleep_time = TICK_INTERVAL - elapsed
        if sleep_time > 0:
            await asyncio.sleep(sleep_time)


def find_passable_start(world: World, start_x: int, start_y: int) -> tuple[int, int]:
    """Find a passable tile starting from (start_x, start_y) and searching outward.

    Args:
        world: The world to search in
        start_x: Starting X coordinate
        start_y: Starting Y coordinate

    Returns:
        Tuple of (x, y) for the first passable tile found
    """
    # Try the starting position first
    if world.is_passable(start_x, start_y):
        return start_x, start_y

    # Spiral outward from the starting position (wrapping)
    for radius in range(1, 100):
        for dx in range(-radius, radius + 1):
            for dy in range(-radius, radius + 1):
                # Only check the perimeter of the current radius
                if abs(dx) != radius and abs(dy) != radius:
                    continue

                x, y = world.wrap(start_x + dx, start_y + dy)

                if world.is_passable(x, y):
                    return x, y

    # Fallback to starting position if nothing found
    return start_x, start_y


async def handle_login(
    name: str,
    read_func,
    write_func,
) -> dict:
    """Handle login or registration for a player.

    Args:
        name: Player name
        read_func: Async function to read input
        write_func: Async function to write output

    Returns:
        Dict with 'success' (bool) and 'player_data' (dict or None)
    """
    if account_exists(name):
        # Existing account - authenticate
        max_attempts = 3
        for attempt in range(max_attempts):
            await write_func("Password: ")
            password = await read_func()

            if password is None or not password.strip():
                return {"success": False, "player_data": None}

            if authenticate(name, password.strip()):
                # Success - load player data
                player_data = load_player_data(name)
                return {"success": True, "player_data": player_data}

            remaining = max_attempts - attempt - 1
            if remaining > 0:
                msg = f"Incorrect password. {remaining} attempts remaining.\r\n"
                await write_func(msg)
            else:
                await write_func("Too many failed attempts.\r\n")

        return {"success": False, "player_data": None}

    # New account - registration
    await write_func(f"Account '{name}' does not exist. Create new account? (y/n) ")
    response = await read_func()

    if response is None or response.strip().lower() != "y":
        return {"success": False, "player_data": None}

    # Get password with confirmation
    while True:
        await write_func("Choose a password: ")
        password1 = await read_func()

        if password1 is None or not password1.strip():
            return {"success": False, "player_data": None}

        await write_func("Confirm password: ")
        password2 = await read_func()

        if password2 is None or not password2.strip():
            return {"success": False, "player_data": None}

        if password1.strip() == password2.strip():
            # Passwords match - create account
            if create_account(name, password1.strip()):
                await write_func("Account created successfully!\r\n")
                # Return default data for new account
                player_data = load_player_data(name)
                return {"success": True, "player_data": player_data}
            await write_func("Failed to create account.\r\n")
            return {"success": False, "player_data": None}

        # Passwords don't match - retry or cancel
        await write_func("Passwords do not match. Try again? (y/n) ")
        retry = await read_func()
        if retry is None or retry.strip().lower() != "y":
            return {"success": False, "player_data": None}


async def shell(
    reader: telnetlib3.TelnetReader | telnetlib3.TelnetReaderUnicode,
    writer: telnetlib3.TelnetWriter | telnetlib3.TelnetWriterUnicode,
) -> None:
    """Shell callback that handles player connection and command loop."""
    _reader = cast(telnetlib3.TelnetReaderUnicode, reader)
    _writer = cast(telnetlib3.TelnetWriterUnicode, writer)

    assert _world is not None, "World must be initialized before accepting connections"

    log.debug("new connection from %s", _writer.get_extra_info("peername"))

    _writer.write("Welcome to the MUD!\r\n")
    _writer.write("What is your name? ")
    await _writer.drain()

    name_input = await readline2(_reader, _writer)
    if name_input is None or not name_input.strip():
        _writer.close()
        return

    player_name = name_input.strip()

    # Handle login/registration
    async def read_input():
        result = await readline2(_reader, _writer)
        return result

    async def write_output(msg: str):
        _writer.write(msg)
        await _writer.drain()

    login_result = await handle_login(player_name, read_input, write_output)

    if not login_result["success"]:
        _writer.write("Login failed. Disconnecting.\r\n")
        await _writer.drain()
        _writer.close()
        return

    # Update last login timestamp
    update_last_login(player_name)

    # Load player data from database or use defaults for new player
    player_data: PlayerData | None = login_result["player_data"]
    if player_data is None:
        # New player - find a passable starting position
        center_x = _world.width // 2
        center_y = _world.height // 2
        start_x, start_y = find_passable_start(_world, center_x, center_y)
        player_data = {
            "x": start_x,
            "y": start_y,
            "pl": 100.0,
            "stamina": 100.0,
            "max_stamina": 100.0,
            "flying": False,
        }
    else:
        # Existing player - verify spawn position is still passable
        if not _world.is_passable(player_data["x"], player_data["y"]):
            # Saved position is no longer passable, find a new one
            start_x, start_y = find_passable_start(
                _world, player_data["x"], player_data["y"]
            )
            player_data["x"] = start_x
            player_data["y"] = start_y

    # Create player instance
    player = Player(
        name=player_name,
        x=player_data["x"],
        y=player_data["y"],
        pl=player_data["pl"],
        stamina=player_data["stamina"],
        max_stamina=player_data["max_stamina"],
        flying=player_data["flying"],
        writer=_writer,
        reader=_reader,
    )

    # Parse and store client capabilities from MTTS
    ttype3 = _writer.get_extra_info("ttype3")
    player.caps = parse_mtts(ttype3)
    log.debug(
        "%s capabilities: %s (color_depth=%s)",
        player_name,
        player.caps,
        player.color_depth,
    )

    # Register player
    players[player_name] = player
    log.info(
        "%s connected at (%d, %d)",
        player_name,
        player_data["x"],
        player_data["y"],
    )

    _writer.write(f"\r\nWelcome, {player_name}!\r\n")
    _writer.write("Type 'help' for commands or 'quit' to disconnect.\r\n\r\n")
    await _writer.drain()

    # Show initial map
    await mudlib.commands.look.cmd_look(player, "")

    # Command loop
    try:
        while not _writer.is_closing():
            _writer.write("mud> ")
            await _writer.drain()

            inp = await readline2(_reader, _writer)
            if inp is None:
                break

            command = inp.strip()
            if not command:
                continue

            # Dispatch command
            await mudlib.commands.dispatch(player, command)

            # Check if writer was closed by quit command
            if _writer.is_closing():
                break
    finally:
        # Save player state on disconnect (if not already saved by quit command)
        if player_name in players:
            save_player(player)
            del players[player_name]
            log.info("%s disconnected", player_name)

        _writer.close()


async def run_server() -> None:
    """Start the MUD telnet server."""
    global _world

    # Initialize database
    data_dir = pathlib.Path(__file__).resolve().parents[2] / "data"
    db_path = data_dir / "mud.db"
    log.info("initializing database at %s", db_path)
    init_db(db_path)

    # Generate world once at startup (cached to build/ after first run)
    cache_dir = pathlib.Path(__file__).resolve().parents[2] / "build"
    config = load_world_config()
    world_cfg = config["world"]
    log.info(
        "loading world (seed=%d, %dx%d)...",
        world_cfg["seed"],
        world_cfg["width"],
        world_cfg["height"],
    )
    t0 = time.monotonic()
    _world = World(
        seed=world_cfg["seed"],
        width=world_cfg["width"],
        height=world_cfg["height"],
        cache_dir=cache_dir,
    )
    elapsed = time.monotonic() - t0
    if _world.cached:
        log.info("world loaded from cache in %.2fs", elapsed)
    else:
        log.info("world generated in %.2fs (cached for next run)", elapsed)

    # Inject world into command modules
    mudlib.commands.fly.world = _world
    mudlib.commands.look.world = _world
    mudlib.commands.movement.world = _world

    # Load content-defined commands from TOML files
    content_dir = pathlib.Path(__file__).resolve().parents[2] / "content" / "commands"
    if content_dir.exists():
        log.info("loading content from %s", content_dir)
        content_commands = load_commands(content_dir)
        for cmd_def in content_commands:
            mudlib.commands.register(cmd_def)
            log.debug("registered content command: %s", cmd_def.name)

    # Load combat moves and register as commands
    combat_dir = pathlib.Path(__file__).resolve().parents[2] / "content" / "combat"
    if combat_dir.exists():
        log.info("loading combat moves from %s", combat_dir)
        register_combat_commands(combat_dir)
        log.info("registered combat commands")

    # connect_maxwait: how long to wait for telnet option negotiation (CHARSET
    # etc) before starting the shell. default is 4.0s which is painful.
    # MUD clients like tintin++ reject CHARSET immediately via MTTS, but
    # telnetlib3 still waits for the full timeout. 0.5s is plenty.
    server = await telnetlib3.create_server(
        host="127.0.0.1", port=PORT, shell=shell, connect_maxwait=0.5
    )
    log.info("listening on 127.0.0.1:%d", PORT)

    loop_task = asyncio.create_task(game_loop())

    try:
        while True:
            await asyncio.sleep(3600)
    except KeyboardInterrupt:
        log.info("shutting down...")
        loop_task.cancel()
        server.close()
        await server.wait_closed()