"""Agent 工具集 - 任务相关"""

from datetime import UTC, datetime

from app.models.base import utc_now

from langchain_core.tools import tool
from sqlalchemy import select

from app.agents.context import get_current_user
from app.database import async_session
from app.models.task import Task, TaskPriority, TaskStatus

import asyncio
from concurrent.futures import ThreadPoolExecutor

_executor = ThreadPoolExecutor(max_workers=4)


def _run_async(coro, timeout: int = 30):
    try:
        asyncio.get_running_loop()
    except RuntimeError:
        return asyncio.run(coro)
    return _executor.submit(asyncio.run, coro).result(timeout=timeout)


def _normalize_title(title: str | None, content: str | None) -> str:
    resolved = (title or content or "").strip()
    if not resolved:
        raise ValueError("title 不能为空")
    return resolved


def _normalize_due_date(due_date: str | None, date_value: str | None) -> str | None:
    resolved = (due_date or date_value or "").strip()
    return resolved or None


def _parse_due_date(value: str | None) -> datetime | None:
    if not value:
        return None
    normalized = value.strip()
    if not normalized:
        return None
    if "T" not in normalized:
        normalized = f"{normalized}T00:00:00"
    parsed = datetime.fromisoformat(normalized.replace("Z", "+00:00"))
    if parsed.tzinfo is not None:
        return parsed.astimezone(UTC).replace(tzinfo=None)
    return parsed


def _normalize_priority(priority: int | str | None) -> TaskPriority:
    if priority is None or priority == "":
        return TaskPriority.MEDIUM
    if isinstance(priority, TaskPriority):
        return priority
    if isinstance(priority, int):
        return {
            1: TaskPriority.LOW,
            2: TaskPriority.MEDIUM,
            3: TaskPriority.HIGH,
            4: TaskPriority.URGENT,
        }.get(priority, TaskPriority.MEDIUM)
    normalized = str(priority).strip().lower()
    if not normalized:
        return TaskPriority.MEDIUM
    return TaskPriority(normalized)


def _normalize_status(status: str) -> TaskStatus:
    normalized = status.strip().lower()
    return TaskStatus(normalized)


def _format_status(value: TaskStatus | str) -> str:
    return value.value if hasattr(value, "value") else str(value)


def _format_priority(value: TaskPriority | str) -> str:
    return value.value if hasattr(value, "value") else str(value)


@tool
def get_tasks(status: str | None = None, limit: int = 20) -> str:
    """
    获取用户当前的任务列表。

    Args:
        status: 可选，筛选任务状态 (todo/in_progress/done/cancelled)
        limit: 返回数量，默认20

    Returns:
        任务列表
    """
    uid = get_current_user()

    try:
        resolved_status = _normalize_status(status) if status else None

        async def _get():
            async with async_session() as db:
                from app.models.user import User
                query = (
                    select(Task)
                    .join(User, User.id == Task.user_id)
                    .where(User.id == uid)
                )
                if resolved_status:
                    query = query.where(Task.status == resolved_status)
                query = query.order_by(Task.priority.desc(), Task.updated_at.desc()).limit(limit)
                result = await db.execute(query)
                tasks = result.scalars().all()
                if not tasks:
                    return "暂无任务"
                lines = []
                for t in tasks:
                    lines.append(
                        f"- [{t.id[:8]}] {t.title} | "
                        f"状态:{_format_status(t.status)} | 优先级:{_format_priority(t.priority)} | 截止:{t.due_date or '无'}"
                    )
                return "\n".join(lines)

        return _run_async(_get())
    except Exception as e:
        return f"获取任务失败: {str(e)}"


@tool
def create_task(
    title: str = "",
    description: str = "",
    priority: int | str = 2,
    due_date: str | None = None,
    content: str = "",
    date: str | None = None,
) -> str:
    """
    创建新任务。

    Args:
        title: 任务标题（必填，兼容 content 作为别名）
        description: 任务描述
        priority: 优先级，支持 1-4 或 low/medium/high/urgent，默认2
        due_date: 截止日期，格式 YYYY-MM-DD 或 ISO datetime
        content: title 的兼容别名
        date: due_date 的兼容别名

    Returns:
        创建结果
    """
    uid = get_current_user()

    try:
        resolved_title = _normalize_title(title, content)
        resolved_due_date = _normalize_due_date(due_date, date)
        resolved_priority = _normalize_priority(priority)

        async def _create():
            async with async_session() as db:
                task = Task(
                    user_id=uid,
                    title=resolved_title,
                    description=description or content or None,
                    priority=resolved_priority,
                    due_date=_parse_due_date(resolved_due_date),
                    status=TaskStatus.TODO,
                )
                db.add(task)
                await db.commit()
                await db.refresh(task)
                return f"任务创建成功: [{task.id[:8]}] {resolved_title}"

        return _run_async(_create())
    except Exception as e:
        return f"创建任务失败: {str(e)}"


@tool
def update_task_status(task_id: str, status: str) -> str:
    """
    更新任务状态。

    Args:
        task_id: 任务ID（完整ID或前8位）
        status: 新状态 (todo/in_progress/done/cancelled)

    Returns:
        更新结果
    """
    uid = get_current_user()

    try:
        resolved_status = _normalize_status(status)

        async def _update():
            async with async_session() as db:
                from app.models.user import User
                query = (
                    select(Task)
                    .join(User, User.id == Task.user_id)
                    .where(User.id == uid)
                )
                if len(task_id) == 8:
                    query = query.where(Task.id.like(f"{task_id}%"))
                else:
                    query = query.where(Task.id == task_id)
                result = await db.execute(query)
                task = result.scalar_one_or_none()
                if not task:
                    return f"任务不存在: {task_id}"
                task.status = resolved_status
                task.completed_at = utc_now() if resolved_status == TaskStatus.DONE else None
                await db.commit()
                return f"任务状态已更新: {task.title} -> {resolved_status.value}"

        return _run_async(_update())
    except Exception as e:
        return f"更新任务失败: {str(e)}"


__all__ = ["get_tasks", "create_task", "update_task_status"]