"""Seed the ``hris.full_sync`` scheduled job + trigger an immediate first run.

Revision ID: 230
Revises: 229
Create Date: 2026-06-01

Why this migration exists
-------------------------

The hourly ``hris.incremental_sync`` cron only pulls SF users whose
``lastModifiedDateTime`` is inside a 30-day hard-capped window — anyone
who flipped to ``status='f'`` more than 30 days ago lives in a permanent
blind spot. On 2026-06-01 wangdi@pingcap.com (P0175, terminated
2026-03-20, 73 days ago) was reported missing from Helix despite being a
real PingCAP ex-employee; he is one of 48 such historical leavers
currently absent from ``identity_persons``.

PR #588 (2026-05-30) fixed the **code** for the manual full-sync path
(``preview_full_employee_sync`` now calls ``list_all_users`` and routes
``status='f'`` to offboard). This migration wires the same path into
the scheduler so future drift self-heals within 7 days.

Schedule
========

Weekly, Sunday 05:00 SGT (= 21:00 UTC Saturday). Sunday low-traffic
window matches the existing ``relationships.full_sync`` cadence; SGT
aligns with the operator timezone for ``hris.incremental_sync``.

Immediate first run trick
=========================

The user-reported case (wangdi) is currently missing — we don't want to
wait until next Sunday for the cron to surface him. The worker's
schedule-attach loop in ``app/worker.py:310-328`` has a "missed beat"
branch that fires the cron 90s after worker boot when the next fire
time after ``last_run_at`` is already in the past. By seeding
``last_run_at='1970-01-01'`` the next fire after epoch is also in 1970,
which is < now, triggering an immediate run on the next worker reload
post-deploy.

After the first run the handler updates ``last_run_at`` to ``now()`` and
the cron settles into its weekly cadence. The 1970 seed leaves no real
trace in audit because no actual run row is written for the seed itself
— ``scheduled_job_runs`` only records real executions.

Idempotency
===========

Existing rows with the same ``name`` are not overwritten — preserves
any admin customisation (e.g. an operator who disabled the job or
changed the cron). A re-run of this migration after the job has fired
once is a no-op.
"""
from __future__ import annotations

import uuid

import sqlalchemy as sa

from alembic import op

revision = "230"
down_revision = "229"
branch_labels = None
depends_on = None


_JOB_NAME = "hris.full_sync"


def upgrade() -> None:
    bind = op.get_bind()

    job_exists = bind.execute(
        sa.text("SELECT 1 FROM scheduled_jobs WHERE name = :n LIMIT 1"),
        {"n": _JOB_NAME},
    ).scalar()
    if job_exists:
        return

    bind.execute(
        sa.text(
            """
            INSERT INTO scheduled_jobs
                (id, name, display_name, description, handler_key,
                 trigger_type, interval_seconds, cron_expr, timezone,
                 enabled, config, run_count, failure_count,
                 last_run_at,
                 created_at, updated_at)
            VALUES
                (:id, :name, :display_name,
                 :description, :handler_key, 'cron', NULL,
                 :cron_expr, :timezone, 1, '{}',
                 0, 0,
                 :last_run_at,
                 NOW(), NOW())
            """
        ),
        {
            "id": str(uuid.uuid4()),
            "name": _JOB_NAME,
            "display_name": "HRIS 全量同步(历史离职兜底)",
            "description": (
                "每周对每个已启用的 HRIS 实例做一次全量同步(list_all_users:"
                "active + forfeited),按 SF status 路由为 onboard / offboard"
                "事件并自动确认。closes the 30-day incremental blind spot —"
                "see migration 230 docstring for the wangdi P0175 case."
            ),
            "handler_key": _JOB_NAME,
            # Sunday 05:00 in Asia/Singapore — low-traffic window aligned
            # with other weekly reconciliations.
            "cron_expr": "0 5 * * 0",
            "timezone": "Asia/Singapore",
            # See "Immediate first run trick" in the module docstring.
            "last_run_at": "1970-01-01 00:00:00",
        },
    )


def downgrade() -> None:
    bind = op.get_bind()
    bind.execute(
        sa.text("DELETE FROM scheduled_jobs WHERE name = :n"),
        {"n": _JOB_NAME},
    )