"""A file's "Added" is when it became done

Revision ID: 0104_job_ready_at
Revises: 0103_files_sha256
Create Date: 2026-10-12

`download_jobs.ready_at` is when a job became done, and the Files library sorts and dates by it: a
download that failed for days and then went through used to sit days down the list, under its
request date. Every path to done stamps it, held by `ck_download_jobs_ready_at`.

A done job from before has no record of that moment (its "ready to watch" notice never named the
job, so it cannot be matched back), so it takes its request date, which is where it already sat.
"""

import sqlalchemy as sa
from alembic import op

revision: str = "0104_job_ready_at"
down_revision: str | None = "0103_files_sha256"
branch_labels: str | None = None
depends_on: str | None = None


def upgrade() -> None:
    op.add_column("download_jobs", sa.Column("ready_at", sa.DateTime(timezone=True)))
    op.execute(
        """
        UPDATE download_jobs SET ready_at = created_at WHERE status = 'done'
        """
    )
    op.create_check_constraint(
        "ck_download_jobs_ready_at", "download_jobs", "status <> 'done' OR ready_at IS NOT NULL"
    )


def downgrade() -> None:
    op.drop_constraint("ck_download_jobs_ready_at", "download_jobs", type_="check")
    op.drop_column("download_jobs", "ready_at")