"""endpoint commands queue + cached MTConnect state.

Adds the endpointcommands queue (one WebUI-issued, server-allowlisted action
per row, claimed and finalized by the agent long-poll) and two cached MTConnect
run-state columns on endpointstates so the WebUI toggle can show a real state
between command polls.

Idempotent: create_table_if_missing guards the new table, and the column adds
check the live schema first so a db.create_all() site (which already built the
columns) re-runs clean on strict MySQL 8.
"""
from alembic import op

from shopdb.plugins.alembic_template import (
    create_index_if_missing,
    create_table_if_missing,
)
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = 'endpoints0002commands'
down_revision = 'endpoints0001baseline'
branch_labels = None
depends_on = None


def _has_column(table_name, column_name):
    from sqlalchemy import inspect

    inspector = inspect(op.get_bind())
    if not inspector.has_table(table_name):
        return False
    return any(col['name'] == column_name
               for col in inspector.get_columns(table_name))


def upgrade():
    if not _has_column('endpointstates', 'mtconnectrunning'):
        op.add_column('endpointstates',
                      sa.Column('mtconnectrunning', sa.Boolean(),
                                nullable=True))
    if not _has_column('endpointstates', 'mtconnectcheckedat'):
        op.add_column('endpointstates',
                      sa.Column('mtconnectcheckedat', sa.DateTime(),
                                nullable=True))

    create_table_if_missing(
        'endpointcommands',
        sa.Column('endpointcommandid', sa.Integer(), nullable=False),
        sa.Column('assetid', sa.Integer(), nullable=False),
        sa.Column('action', sa.String(length=64), nullable=False),
        sa.Column('status', sa.String(length=20), nullable=False),
        sa.Column('requestedby', sa.Integer(), nullable=True),
        sa.Column('resultmessage', sa.Text(), nullable=True),
        sa.Column('resultjson', sa.Text(length=16777215), nullable=True),
        sa.Column('createdat', sa.DateTime(), nullable=False),
        sa.Column('claimedat', sa.DateTime(), nullable=True),
        sa.Column('completedat', sa.DateTime(), nullable=True),
        sa.ForeignKeyConstraint(['assetid'], ['assets.assetid'],
                                ondelete='CASCADE'),
        sa.PrimaryKeyConstraint('endpointcommandid'),
    )
    create_index_if_missing('ix_endpointcommands_assetid',
                            'endpointcommands', ['assetid'])
    create_index_if_missing('ix_endpointcommands_status',
                            'endpointcommands', ['status'])
    create_index_if_missing('idx_endpointcommands_assetstatus',
                            'endpointcommands', ['assetid', 'status'])


def downgrade():
    op.drop_index('idx_endpointcommands_assetstatus',
                  table_name='endpointcommands')
    op.drop_index('ix_endpointcommands_status',
                  table_name='endpointcommands')
    op.drop_index('ix_endpointcommands_assetid',
                  table_name='endpointcommands')
    op.drop_table('endpointcommands')

    if _has_column('endpointstates', 'mtconnectcheckedat'):
        op.drop_column('endpointstates', 'mtconnectcheckedat')
    if _has_column('endpointstates', 'mtconnectrunning'):
        op.drop_column('endpointstates', 'mtconnectrunning')