"""The Files library: a file's SHA-256, and the expired rows retired

Revision ID: 0103_files_sha256
Revises: 0102_file_folders
Create Date: 2026-10-11

`media_assets.sha256` holds the file's hash once it is known (an upload is hashed while it streams
in, any other file on the first ask), so a machine fetching a file can check what it got.

An expired file now leaves its user's library (`downloads.gc`). Before, an expired download stayed
as a fileless "expired · download again" row (a done job with no asset). Those rows hold nothing on
disk and the library no longer shows them, so they are deleted here rather than left behind
unseen; their shares and public links go with them (ON DELETE CASCADE), and those already served
nothing. The downgrade cannot bring them back.
"""

import sqlalchemy as sa
from alembic import op

revision: str = "0103_files_sha256"
down_revision: str | None = "0102_file_folders"
branch_labels: str | None = None
depends_on: str | None = None


def upgrade() -> None:
    op.add_column("media_assets", sa.Column("sha256", sa.String(64)))
    op.execute("DELETE FROM download_jobs WHERE status = 'done' AND asset_id IS NULL")


def downgrade() -> None:
    op.drop_column("media_assets", "sha256")