from __future__ import annotations

from dataclasses import dataclass, field
from datetime import datetime, timezone
from typing import Any, Literal

TaskStatus = Literal["pending", "running", "completed", "failed", "cancelled"]
RunMode = Literal["sync", "async"]

TERMINAL_STATUSES = frozenset({"completed", "failed", "stopped"})


def _utc_now() -> datetime:
    return datetime.now(timezone.utc)


@dataclass
class TaskRecord:
    """Executor 内存中的单条任务快照。"""

    task_id: str
    trace_id: str
    task_description: str
    mode: RunMode
    metadata: dict[str, Any] = field(default_factory=dict)
    status: TaskStatus = "pending"
    created_at: datetime = field(default_factory=_utc_now)
    updated_at: datetime = field(default_factory=_utc_now)
    error_message: str | None = None
    trace_terminal_status: str | None = None

    def to_dict(self) -> dict[str, Any]:
        return {
            "task_id": self.task_id,
            "trace_id": self.trace_id,
            "task_description": self.task_description,
            "mode": self.mode,
            "metadata": dict(self.metadata),
            "status": self.status,
            "created_at": self.created_at.isoformat(),
            "updated_at": self.updated_at.isoformat(),
            "error_message": self.error_message,
            "trace_terminal_status": self.trace_terminal_status,
        }

    def touch(self, **kwargs: Any) -> None:
        for k, v in kwargs.items():
            if hasattr(self, k):
                setattr(self, k, v)
        self.updated_at = _utc_now()