"""A long-polling Telegram bot, so the chat is a remote control, not just an inbox.

Runs in a daemon thread next to the API. Commands do exactly what the buttons in
the UI do — they call the same services — so starting a pomodoro from your phone
and finishing it on the desktop is one unbroken interval.
"""

from __future__ import annotations

import logging
import threading
import time as time_module
from typing import Any, Callable

import httpx

from app.config import env_settings
from app.db import session_scope
from app.services import (
    blocker_service,
    pomodoro,
    report,
    settings_service,
    stats,
    tasks_service,
)
from app.settings_schema import AppSettings
from app.timeutil import humanize_minutes, local_date

log = logging.getLogger(__name__)

_thread: threading.Thread | None = None
_stop = threading.Event()
_POLL_TIMEOUT = 25

HELP_EN = """<b>Kadence</b>

/start_work [minutes] — start a pomodoro
/break — start a break
/stop — abandon the current interval
/pause · /resume — hold the clock
/status — what is running right now
/today — your todo list, grouped
/report — today's report, now
/week — the weekly review
/streak — streak and all-time totals
/block — what the blocker is doing
/help — this message"""

HELP_RU = """<b>Kadence</b>

/start_work [минуты] — запустить помидорку
/break — перерыв
/stop — бросить текущий интервал
/pause · /resume — пауза и продолжение
/status — что идёт сейчас
/today — список задач по группам
/report — отчёт за сегодня
/week — итоги недели
/streak — серия и общая статистика
/block — что делает блокировщик
/help — это сообщение"""


def _api(token: str, method: str, payload: dict[str, Any], timeout: int = 30) -> dict[str, Any]:
    url = f"https://api.telegram.org/bot{token}/{method}"
    with httpx.Client(timeout=timeout) as client:
        resp = client.post(url, json=payload)
    if not resp.is_success:
        raise RuntimeError(f"{method} -> {resp.status_code}: {resp.text[:200]}")
    return resp.json() or {}


def _reply(settings: AppSettings, chat_id: str, text: str, buttons: list[list[str]] | None = None) -> None:
    telegram = settings.notifications.telegram
    payload: dict[str, Any] = {
        "chat_id": chat_id,
        "text": text,
        "parse_mode": "HTML",
        "disable_web_page_preview": True,
    }
    if buttons:
        payload["reply_markup"] = {
            "inline_keyboard": [
                [{"text": label, "callback_data": label} for label in row] for row in buttons
            ]
        }
    try:
        _api(telegram.bot_token, "sendMessage", payload)
    except Exception as exc:  # pragma: no cover
        log.warning("telegram reply failed: %s", exc)


# --------------------------------------------------------------------------
# Command handlers
# --------------------------------------------------------------------------
def _cmd_status(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    state = pomodoro.state(session, settings)
    current = state["current"]
    done, goal = state["completed_today"], state["goal"]
    header = (
        f"🍅 {done}/{goal} " + ("сегодня" if ru else "today")
        + f" · {report.progress_bar(done, goal)}"
    )
    if current is None:
        return header + "\n\n" + ("Таймер стоит." if ru else "The timer is idle.")
    remaining = humanize_minutes(current["remaining_seconds"] / 60)
    kind = {
        "work": "работа" if ru else "work",
        "short_break": "короткий перерыв" if ru else "short break",
        "long_break": "длинный перерыв" if ru else "long break",
    }[current["kind"]]
    task = f"\n📌 {report._esc(current['task']['title'])}" if current.get("task") else ""
    status = ("на паузе" if ru else "paused") if current["status"] == "paused" else ("идёт" if ru else "running")
    return f"{header}\n\n▶️ <b>{kind}</b> ({status}) — {remaining} " + ("осталось" if ru else "left") + task


def _cmd_start_work(session, settings: AppSettings, args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    minutes: int | None = None
    if args.strip().isdigit():
        minutes = max(1, min(240, int(args.strip())))
    row = pomodoro.start(session, settings, kind="work", minutes=minutes)
    length = humanize_minutes(row.planned_seconds / 60)
    return (
        f"▶️ Помидорка на {length} пошла. Удачи!" if ru else f"▶️ {length} pomodoro started. Go."
    )


def _cmd_break(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    kind = pomodoro.next_kind(session, settings)
    if kind == "work":
        kind = "short_break"
    row = pomodoro.start(session, settings, kind=kind)
    return (
        f"☕ Перерыв {humanize_minutes(row.planned_seconds / 60)}."
        if ru
        else f"☕ {humanize_minutes(row.planned_seconds / 60)} break."
    )


def _cmd_stop(session, settings: AppSettings, args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    try:
        pomodoro.abandon(session, settings, reason=args.strip() or "stopped from Telegram")
    except pomodoro.TimerError as exc:
        return str(exc)
    return "⏹ Остановлено." if ru else "⏹ Stopped."


def _cmd_pause(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    try:
        pomodoro.pause(session, settings)
    except pomodoro.TimerError as exc:
        return str(exc)
    return "⏸ Пауза." if ru else "⏸ Paused."


def _cmd_resume(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    try:
        pomodoro.resume(session)
    except pomodoro.TimerError as exc:
        return str(exc)
    return "▶️ Продолжаем." if ru else "▶️ Resumed."


def _cmd_today(session, settings: AppSettings, _args: str) -> str:
    """The todo list, grouped by deadline and numbered for reading."""
    ru = settings.notifications.report.language == "ru"
    today = local_date(settings.timezone)
    tasks = tasks_service.list_tasks(session)
    buckets = tasks_service.bucket_tasks(tasks, today)
    ordered = buckets["overdue"] + buckets["today"] + buckets["upcoming"] + buckets["someday"]
    if not ordered:
        return "✨ Задач нет." if ru else "✨ Nothing on the list."

    limit = settings.notifications.report.max_tasks_listed
    lines = [f"<b>{'📋 Задачи' if ru else '📋 Your tasks'}</b>"]
    marks = {"overdue": "🔴", "today": "🟡", "upcoming": "🔵", "someday": "⚪"}
    position = 0
    for bucket_name in ("overdue", "today", "upcoming", "someday"):
        for task in buckets[bucket_name]:
            position += 1
            if position > limit:
                continue
            due = f" ({task.due_date.isoformat()})" if task.due_date else ""
            lines.append(
                f"{marks[bucket_name]} <b>{position}.</b> {report._esc(task.title)}{due}"
            )
    if position > limit:
        lines.append(("… и ещё " if ru else "… and ") + f"{position - limit}")
    return "\n".join(lines)


def _cmd_report(session, settings: AppSettings, _args: str) -> str:
    today = local_date(settings.timezone)
    _, payload = report.get_or_build_daily(session, settings, today, rebuild=True)
    return report.render_daily_telegram(payload, settings)


def _cmd_week(session, settings: AppSettings, _args: str) -> str:
    today = local_date(settings.timezone)
    payload = report.build_weekly(session, settings, today)
    return report.render_weekly_telegram(payload, settings)


def _cmd_streak(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    streak = stats.streak(session, settings)
    lifetime = stats.lifetime(session, settings)
    return "\n".join(
        [
            f"🔥 <b>{'Серия' if ru else 'Streak'}</b>: {streak['current']} "
            + ("дн." if ru else "days"),
            f"🏆 {'Рекорд' if ru else 'Best'}: {streak['best']} · "
            f"{'дней с целью' if ru else 'goal streak'}: {streak['goal_streak']}",
            "",
            f"🍅 {'Всего помидорок' if ru else 'All-time pomodoros'}: {lifetime['pomodoros']}",
            f"⏱ {'Всего фокуса' if ru else 'All-time focus'}: {lifetime['focus_hours']}h",
            f"✅ {'Закрыто задач' if ru else 'Tasks closed'}: {lifetime['tasks_completed']}",
            f"🚫 {'Заблокировано попыток' if ru else 'Blocked attempts'}: {lifetime['blocked_attempts']}",
        ]
    )


def _cmd_block(session, settings: AppSettings, _args: str) -> str:
    ru = settings.notifications.report.language == "ru"
    policy = blocker_service.policy(session, settings)
    events = blocker_service.events_for_day(session, settings)
    state = ("включён" if ru else "ON") if policy["active"] else ("выключен" if ru else "OFF")
    lines = [
        f"🛡 <b>{'Блокировщик' if ru else 'Blocker'}</b>: {state} ({report._esc(policy['reason'])})",
        f"{'Сайтов' if ru else 'Domains'}: {len(policy['all_domains'])} · "
        f"{'приложений' if ru else 'apps'}: {len(policy['all_apps'])}",
        f"{'Попыток сегодня' if ru else 'Attempts today'}: {events['total']}",
    ]
    for entry in events["by_target"][:5]:
        lines.append(f"• {report._esc(entry['target'])} × {entry['count']}")
    return "\n".join(lines)


def _cmd_help(_session, settings: AppSettings, _args: str) -> str:
    return HELP_RU if settings.notifications.report.language == "ru" else HELP_EN


COMMANDS: dict[str, Callable] = {
    "start": _cmd_help,
    "help": _cmd_help,
    "status": _cmd_status,
    "start_work": _cmd_start_work,
    "work": _cmd_start_work,
    "break": _cmd_break,
    "stop": _cmd_stop,
    "pause": _cmd_pause,
    "resume": _cmd_resume,
    "today": _cmd_today,
    "tasks": _cmd_today,
    "report": _cmd_report,
    "week": _cmd_week,
    "streak": _cmd_streak,
    "stats": _cmd_streak,
    "block": _cmd_block,
}


def handle_text(text: str) -> str | None:
    """Run one command and return the reply, or None when it is not for us."""
    text = (text or "").strip()
    if not text.startswith("/"):
        return None
    head, _, args = text[1:].partition(" ")
    name = head.split("@", 1)[0].lower()
    handler = COMMANDS.get(name)
    if handler is None:
        return None

    with session_scope() as session:
        settings = settings_service.load_settings(session)
        try:
            return handler(session, settings, args)
        except Exception as exc:  # pragma: no cover - a bad command must not kill the bot
            log.exception("command /%s failed", name)
            return f"⚠️ {exc}"


# --------------------------------------------------------------------------
# Polling loop
# --------------------------------------------------------------------------
def _loop() -> None:
    offset: int | None = None
    while not _stop.is_set():
        try:
            with session_scope() as session:
                settings = settings_service.load_settings(session)
            telegram = settings.notifications.telegram
            if not (telegram.enabled and telegram.commands_enabled and telegram.bot_token):
                _stop.wait(30)
                continue

            payload: dict[str, Any] = {"timeout": _POLL_TIMEOUT}
            if offset is not None:
                payload["offset"] = offset
            data = _api(
                telegram.bot_token, "getUpdates", payload, timeout=_POLL_TIMEOUT + 10
            )
            for update in data.get("result", []):
                offset = update["update_id"] + 1
                message = update.get("message") or update.get("edited_message") or {}
                chat_id = str((message.get("chat") or {}).get("id", ""))
                if telegram.chat_id and chat_id and chat_id != str(telegram.chat_id):
                    continue  # only the configured chat may drive the timer
                reply = handle_text(message.get("text", ""))
                if reply:
                    with session_scope() as session:
                        fresh = settings_service.load_settings(session)
                    _reply(fresh, chat_id or telegram.chat_id, reply)
        except Exception as exc:  # pragma: no cover
            log.warning("telegram polling hiccup: %s", exc)
            _stop.wait(10)
        else:
            time_module.sleep(0.3)


def start() -> None:
    """Start the polling thread if the environment allows it."""
    global _thread
    if not env_settings().telegram_bot_enabled or _thread is not None:
        return
    _stop.clear()
    _thread = threading.Thread(target=_loop, name="telegram-bot", daemon=True)
    _thread.start()
    log.info("telegram command bot started")


def shutdown() -> None:
    global _thread
    _stop.set()
    _thread = None