"""Add roles system

Revision ID: 001_add_roles
Revises:
Create Date: 2024-12-14

"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect

# revision identifiers, used by Alembic.
revision: str = '001_add_roles'
down_revision: Union[str, None] = None
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def column_exists(table_name: str, column_name: str) -> bool:
    bind = op.get_bind()
    inspector = inspect(bind)
    columns = [col['name'] for col in inspector.get_columns(table_name)]
    return column_name in columns


def constraint_exists(table_name: str, constraint_name: str) -> bool:
    bind = op.get_bind()
    inspector = inspect(bind)
    fks = inspector.get_foreign_keys(table_name)
    return any(fk['name'] == constraint_name for fk in fks)


def upgrade() -> None:
    # Add role column to users table
    if not column_exists('users', 'role'):
        op.add_column('users', sa.Column('role', sa.String(20), nullable=False, server_default='user'))

    # Add role column to participants table
    if not column_exists('participants', 'role'):
        op.add_column('participants', sa.Column('role', sa.String(20), nullable=False, server_default='participant'))

    # Rename organizer_id to creator_id in marathons table
    if column_exists('marathons', 'organizer_id') and not column_exists('marathons', 'creator_id'):
        op.alter_column('marathons', 'organizer_id', new_column_name='creator_id')

    # Update existing participants: set role='organizer' for marathon creators
    # This is idempotent - running multiple times is safe
    op.execute("""
        UPDATE participants p
        SET role = 'organizer'
        FROM marathons m
        WHERE p.marathon_id = m.id AND p.user_id = m.creator_id
    """)

    # Add status column to games table
    if not column_exists('games', 'status'):
        op.add_column('games', sa.Column('status', sa.String(20), nullable=False, server_default='approved'))

    # Rename added_by_id to proposed_by_id in games table
    if column_exists('games', 'added_by_id') and not column_exists('games', 'proposed_by_id'):
        op.alter_column('games', 'added_by_id', new_column_name='proposed_by_id')

    # Add approved_by_id column to games table
    if not column_exists('games', 'approved_by_id'):
        op.add_column('games', sa.Column('approved_by_id', sa.Integer(), nullable=True))
        if not constraint_exists('games', 'fk_games_approved_by_id'):
            op.create_foreign_key(
                'fk_games_approved_by_id',
                'games', 'users',
                ['approved_by_id'], ['id'],
                ondelete='SET NULL'
            )


def downgrade() -> None:
    # Remove approved_by_id from games
    if constraint_exists('games', 'fk_games_approved_by_id'):
        op.drop_constraint('fk_games_approved_by_id', 'games', type_='foreignkey')
    if column_exists('games', 'approved_by_id'):
        op.drop_column('games', 'approved_by_id')

    # Rename proposed_by_id back to added_by_id
    if column_exists('games', 'proposed_by_id'):
        op.alter_column('games', 'proposed_by_id', new_column_name='added_by_id')

    # Remove status from games
    if column_exists('games', 'status'):
        op.drop_column('games', 'status')

    # Rename creator_id back to organizer_id
    if column_exists('marathons', 'creator_id'):
        op.alter_column('marathons', 'creator_id', new_column_name='organizer_id')

    # Remove role from participants
    if column_exists('participants', 'role'):
        op.drop_column('participants', 'role')

    # Remove role from users
    if column_exists('users', 'role'):
        op.drop_column('users', 'role')