"""Network notifications kill switch — default OFF.

Revision ID: 174
Revises: 173
Create Date: 2026-05-17

Why this exists
---------------
The network module (domains / DNS / CDN) ships to ~500 users imminently
and a pre-launch audit flagged three system-push notification paths
that, in their current shape, would burn user trust on day one:

* ``cmdb.domain_expiry_alert`` — broadcasts the same expired/expiring
  list to a shared Feishu group every cron tick, no per-domain dedup,
  no owner routing, no payload size cap.
* ``cmdb.dns_owner_recertify`` — never stamps
  ``cmdb_dns_records.last_owner_review_at`` after the DM, so every
  cron tick re-nags the same owner with the same record list.
* ``cmdb.dns_pre_leaver_handover`` — no idempotency log, so a leaver
  in the 7-day window gets the same handover card daily.

Until those bugs are fixed AND admin verifies one cycle end-to-end on
a tame allowlist of recipients, we want a single boolean to keep the
three handlers silent. The handlers themselves check this setting at
entry and short-circuit with ``status="skipped"``; user-initiated
flows (DNS request submit → Feishu approval, domain registration
submit → Feishu approval) are NOT gated — those are not nags, they
are the human approval path the user explicitly invoked.

Flip to ``true`` via the admin Settings UI (``Settings → 平台设置``)
or direct SQL once the bug-fix PRs land and a dry-run verifies the
content/dedup behaviour.

Idempotency
-----------
``INSERT ... ON DUPLICATE KEY UPDATE description`` so re-running the
migration refreshes the description without overwriting an admin's
flipped value.
"""
from __future__ import annotations

import json

import sqlalchemy as sa

from alembic import op

revision = "174"
down_revision = "173"
branch_labels = None
depends_on = None


SETTING_KEY = "network.user_notifications_enabled"
DEFAULT_VALUE = False
DESCRIPTION = (
    "网络模块(域名 / DNS / CDN) 系统侧推送告警总开关。false 时,以下"
    "三个定时任务在进入处理器后立即 short-circuit,不会向员工/共享群"
    "推送任何 Feishu 消息:cmdb.domain_expiry_alert / "
    "cmdb.dns_owner_recertify / cmdb.dns_pre_leaver_handover。"
    "用户主动发起的 DNS / 域名审批流程不受影响。上线前先 false 静默,"
    "验证完一轮内容 + 去重再翻 true 正式启用。"
)


def _table_exists(bind, name: str) -> bool:
    return bind.execute(
        sa.text(
            "SELECT 1 FROM information_schema.TABLES "
            "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = :n"
        ),
        {"n": name},
    ).scalar() is not None


def upgrade() -> None:
    bind = op.get_bind()
    if not _table_exists(bind, "platform_settings"):
        return
    bind.execute(
        sa.text(
            "INSERT INTO platform_settings (`key`, value, description, "
            "created_at, updated_at) "
            "VALUES (:k, :v, :d, NOW(), NOW()) "
            "ON DUPLICATE KEY UPDATE "
            "description = VALUES(description), updated_at = NOW()"
        ),
        {
            "k": SETTING_KEY,
            "v": json.dumps(DEFAULT_VALUE),
            "d": DESCRIPTION,
        },
    )


def downgrade() -> None:
    bind = op.get_bind()
    if not _table_exists(bind, "platform_settings"):
        return
    bind.execute(
        sa.text("DELETE FROM platform_settings WHERE `key` = :k"),
        {"k": SETTING_KEY},
    )