"""Seed default platform_settings.

Revision ID: 029
Revises: 028
Create Date: 2026-04-18

Populates the admin UI's ``/admin/settings`` page with a minimal set of
sensible defaults so it's not empty on first boot. Values here are the
*defaults*; admin can override in the UI.

Seeded keys only — callers still need to be updated to *read* from
``platform_settings`` (follow-up PRs). This migration is idempotent:
it skips keys that already exist so admin edits made between PR
deployments are preserved.
"""
from __future__ import annotations

import json
from typing import Any

import sqlalchemy as sa
from alembic import op


revision = "029"
down_revision = "028"


_DEFAULTS: list[tuple[str, Any, str]] = [
    (
        "asset.default_currency",
        "USD",
        "资产 / 软件 / 付款记录的默认币种。新建资产未显式填写时取此值。"
        "取值须在 ALLOWED_CURRENCIES 列表内(CNY/USD/EUR/JPY/SGD/MYR/THB)。",
    ),
    (
        "offboarding.default_grace_days",
        7,
        "离职缓冲期天数。软件目录里未显式设置 offboarding_grace_days 的,"
        "平台按此值托底。负数或 0 表示立即执行。",
    ),
    (
        "approval.request_number_prefix",
        "REQ",
        "申请单号的前缀。完整格式为 {prefix}-{YYYYMMDD}-{XXXX}。"
        "替换时需保证原有单号仍可解析(建议只在初始化阶段修改)。",
    ),
    (
        "hr.overdue_leaver_check_interval_hours",
        1,
        "worker 每隔多久检查一次过期的 leaver_pending 员工并转成 left 状态。"
        "数值越小响应越快,但会增加 DB 轮询开销。",
    ),
]


def upgrade() -> None:
    bind = op.get_bind()
    # Idempotent: insert only when the key doesn't already exist.
    for key, value, description in _DEFAULTS:
        exists = bind.execute(
            sa.text("SELECT 1 FROM platform_settings WHERE `key` = :k"),
            {"k": key},
        ).scalar()
        if exists:
            continue
        bind.execute(
            sa.text(
                "INSERT INTO platform_settings (`key`, value, description) "
                "VALUES (:k, :v, :d)"
            ),
            {"k": key, "v": json.dumps(value), "d": description},
        )


def downgrade() -> None:
    bind = op.get_bind()
    for key, _value, _description in _DEFAULTS:
        bind.execute(
            sa.text("DELETE FROM platform_settings WHERE `key` = :k"),
            {"k": key},
        )