"""create class memberships table if missing

Revision ID: 20260427_create_memberships
Revises: 20260426_remove_legacy
Create Date: 2026-04-27 10:45:00
"""

from __future__ import annotations

from alembic import op
import sqlalchemy as sa


revision = "20260427_create_memberships"
down_revision = "20260426_remove_legacy"
branch_labels = None
depends_on = None


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

    if "class_memberships" not in set(inspector.get_table_names()):
        op.create_table(
            "class_memberships",
            sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
            sa.Column("user_id", sa.Integer(), nullable=False),
            sa.Column("class_id", sa.Integer(), nullable=False),
            sa.Column("membership_role", sa.String(length=20), nullable=False, server_default="student"),
            sa.Column("committee_role", sa.String(length=50), nullable=True),
            sa.Column("class_permissions", sa.Text(), nullable=True),
            sa.Column("created_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
            sa.Column("updated_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
            sa.ForeignKeyConstraint(["user_id"], ["users.id"]),
            sa.ForeignKeyConstraint(["class_id"], ["classes.id"]),
            sa.PrimaryKeyConstraint("id"),
            sa.UniqueConstraint("user_id", "class_id", name="uq_class_membership_user_class"),
        )
        op.create_index("ix_class_memberships_user_id", "class_memberships", ["user_id"])
        op.create_index("ix_class_memberships_class_id", "class_memberships", ["class_id"])


def downgrade() -> None:
    bind = op.get_bind()
    inspector = sa.inspect(bind)
    tables = set(inspector.get_table_names())
    if "class_memberships" in tables:
        indexes = {index["name"] for index in inspector.get_indexes("class_memberships")}
        if "ix_class_memberships_class_id" in indexes:
            op.drop_index("ix_class_memberships_class_id", table_name="class_memberships")
        if "ix_class_memberships_user_id" in indexes:
            op.drop_index("ix_class_memberships_user_id", table_name="class_memberships")
        op.drop_table("class_memberships")