"""IPC-Nachrichten-Umschlag (PLAN.md §6.2)."""

from __future__ import annotations

import time
import uuid
from enum import StrEnum

from pydantic import BaseModel, Field

PROTOCOL_VERSION = 1


class MessageType(StrEnum):
    COMMAND = "command"
    EVENT = "event"
    SNAPSHOT = "snapshot"
    ACK = "ack"
    ERROR = "error"
    TELEMETRY = "telemetry"
    HEARTBEAT = "heartbeat"


class Envelope(BaseModel):
    """Jede IPC-Nachricht besitzt mindestens diese Felder (§6.2)."""

    protocol_version: int = PROTOCOL_VERSION
    message_id: str = Field(default_factory=lambda: str(uuid.uuid4()))
    type: MessageType
    revision: int = 0
    monotonic_timestamp_ns: int = Field(default_factory=lambda: time.monotonic_ns())
    payload: dict = Field(default_factory=dict)

    def model_post_init(self, _ctx: object) -> None:
        if self.protocol_version != PROTOCOL_VERSION:
            raise ValueError(
                f"protocol_version {self.protocol_version} != {PROTOCOL_VERSION}"
            )