"""Add algorithm column and widen public_key_b64 to Text on musehub_auth_keys.

Quantum-readiness migration: the auth key table now carries an algorithm
identifier so Ed25519 and future post-quantum algorithms (ML-DSA-65 / FIPS 204)
can coexist.  The public_key_b64 column is widened from VARCHAR(64) to TEXT
because ML-DSA-65 public keys are 1952 bytes → ~2604 base64 chars.

All existing rows default to "ed25519" — no data migration required.

Revision ID: 0008
Revises: 0007
"""
from __future__ import annotations

import sqlalchemy as sa
from alembic import op

revision = "0008"
down_revision = "0007"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # Add algorithm column with "ed25519" as the default for existing rows
    op.add_column(
        "musehub_auth_keys",
        sa.Column(
            "algorithm",
            sa.String(32),
            nullable=False,
            server_default="ed25519",
        ),
    )
    # Widen public_key_b64 from VARCHAR(64) to TEXT for post-quantum keys
    op.alter_column(
        "musehub_auth_keys",
        "public_key_b64",
        type_=sa.Text(),
        existing_nullable=False,
    )
    op.create_index(
        "ix_musehub_auth_keys_algorithm",
        "musehub_auth_keys",
        ["algorithm"],
    )


def downgrade() -> None:
    op.drop_index("ix_musehub_auth_keys_algorithm", table_name="musehub_auth_keys")
    op.alter_column(
        "musehub_auth_keys",
        "public_key_b64",
        type_=sa.String(64),
        existing_nullable=False,
    )
    op.drop_column("musehub_auth_keys", "algorithm")