"""
Notification routing matrix — ADR-093
======================================
單一矩陣決定每種通知類型的發送目標，取代 telegram_gateway.py 內 24 處硬碼 chat_id。

設計原則：
- 正式告警目的地一律 SRE_GROUP_CHAT_ID 優先
- OPENCLAW_TG_CHAT_ID 只在 SRE_GROUP_CHAT_ID 缺失時作 fail-soft fallback
- 未知通知類型預設發群組

2026-04-25 ogt + Claude Sonnet 4.6
"""
from __future__ import annotations
from dataclasses import dataclass
from enum import Enum


class Destination(str, Enum):
    DM = "dm"           # OPENCLAW_TG_CHAT_ID (僅缺群組設定時 fallback)
    GROUP = "group"     # SRE_GROUP_CHAT_ID
    BOTH = "both"       # legacy alias: 2026-04-30 起視為 group-first


@dataclass(frozen=True)
class RoutingRule:
    destination: Destination
    strip_buttons_for_group: bool = False   # BOTH 時群組版是否去除 Callback Button


# ADR-093 D1-D4 路由矩陣
# 2026-04-30 Codex: 所有告警類型群組優先，DM 只作缺群組設定 fallback。
NOTIFICATION_ROUTING: dict[str, RoutingRule] = {
    "TYPE-1":  RoutingRule(Destination.GROUP),
    "TYPE-2":  RoutingRule(Destination.GROUP),
    "TYPE-3":  RoutingRule(Destination.GROUP),
    "TYPE-4":  RoutingRule(Destination.GROUP),
    "TYPE-4D": RoutingRule(Destination.GROUP),
    "TYPE-5S": RoutingRule(Destination.GROUP),
    "TYPE-6B": RoutingRule(Destination.GROUP),
    "TYPE-7E": RoutingRule(Destination.GROUP),
    "TYPE-8M": RoutingRule(Destination.GROUP),
}

_DEFAULT_RULE = RoutingRule(Destination.GROUP)


def get_routing_rule(notification_type: str) -> RoutingRule:
    """根據通知類型回傳路由規則。未知類型預設發群組。"""
    return NOTIFICATION_ROUTING.get(notification_type, _DEFAULT_RULE)


def resolve_chat_ids(
    notification_type: str,
    dm_chat_id: str,
    group_chat_id: str,
    *,
    tg_group_cutover: bool = False,
) -> list[str]:
    """
    回傳此通知應發送的 chat_id 清單。
    tg_group_cutover 僅保留為舊 caller 相容參數；正式策略永遠群組優先。
    """
    rule = get_routing_rule(notification_type)
    if rule.destination == Destination.DM and not group_chat_id:
        return [dm_chat_id] if dm_chat_id else []
    return [group_chat_id or dm_chat_id] if (group_chat_id or dm_chat_id) else []