"""guides plugin baseline: guides, guiderevisions, guideimages.

A new plugin, so this builds its tables rather than stamping an anchor over
core-owned ones (contrast the cutover plugins, whose 0001 is a no-op).

Idempotent: each table is created only if it is not already there, so a database
where an earlier run half-succeeded can be upgraded again without hand-editing
alembic_version_guides.
"""
from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect


revision = 'guides0001baseline'
down_revision = None
branch_labels = None
depends_on = None


def _tables():
    return set(inspect(op.get_bind()).get_table_names())


def upgrade():
    existing = _tables()

    if 'guides' not in existing:
        op.create_table(
            'guides',
            sa.Column('guideid', sa.Integer(), nullable=False),
            sa.Column('title', sa.String(length=300), nullable=False),
            # 191 because this is UNIQUE-indexed and MySQL caps an index key at
            # 767 bytes; utf8mb4 is 4 bytes per character.
            sa.Column('slug', sa.String(length=191), nullable=False),
            sa.Column('summary', sa.String(length=1000)),
            sa.Column('tags', sa.String(length=500)),
            sa.Column('status', sa.String(length=20), nullable=False,
                      server_default='draft'),
            sa.Column('blocksjson', sa.dialects.mysql.MEDIUMTEXT()
                      if op.get_bind().dialect.name == 'mysql' else sa.Text(),
                      nullable=False),
            sa.Column('publishedrevisionid', sa.Integer()),
            sa.Column('createdby', sa.Integer()),
            sa.Column('updatedby', sa.Integer()),
            sa.Column('publishedat', sa.DateTime()),
            # BaseModel contributes these to every model in the app; a plugin
            # migration has to spell them out or the table is missing columns
            # the ORM selects on every query.
            sa.Column('createddate', sa.DateTime(), nullable=False),
            sa.Column('modifieddate', sa.DateTime(), nullable=False),
            sa.Column('isactive', sa.Boolean(), nullable=False),
            sa.Column('revision', sa.Integer(), nullable=False, server_default='1'),
            sa.PrimaryKeyConstraint('guideid'),
            sa.UniqueConstraint('slug', name='uq_guides_slug'),
        )
        op.create_index('idx_guides_status', 'guides', ['status'])

    if 'guiderevisions' not in existing:
        op.create_table(
            'guiderevisions',
            sa.Column('guiderevisionid', sa.Integer(), nullable=False),
            sa.Column('guideid', sa.Integer(), nullable=False),
            sa.Column('revision', sa.Integer(), nullable=False),
            sa.Column('title', sa.String(length=300), nullable=False),
            sa.Column('summary', sa.String(length=1000)),
            sa.Column('tags', sa.String(length=500)),
            sa.Column('blocksjson', sa.dialects.mysql.MEDIUMTEXT()
                      if op.get_bind().dialect.name == 'mysql' else sa.Text(),
                      nullable=False),
            sa.Column('contenthash', sa.String(length=64), nullable=False),
            sa.Column('note', sa.String(length=500)),
            sa.Column('createdby', sa.Integer()),
            # BaseModel contributes these to every model in the app; a plugin
            # migration has to spell them out or the table is missing columns
            # the ORM selects on every query.
            sa.Column('createddate', sa.DateTime(), nullable=False),
            sa.Column('modifieddate', sa.DateTime(), nullable=False),
            sa.Column('isactive', sa.Boolean(), nullable=False),
            sa.PrimaryKeyConstraint('guiderevisionid'),
            sa.ForeignKeyConstraint(['guideid'], ['guides.guideid'],
                                    ondelete='CASCADE'),
        )
        op.create_index('idx_guiderevisions_guide', 'guiderevisions', ['guideid'])
        op.create_index('idx_guiderevisions_hash', 'guiderevisions', ['contenthash'])

    if 'guideimages' not in existing:
        op.create_table(
            'guideimages',
            sa.Column('guideimageid', sa.Integer(), nullable=False),
            sa.Column('guideid', sa.Integer()),
            sa.Column('filename', sa.String(length=255)),
            sa.Column('mimetype', sa.String(length=100), nullable=False),
            sa.Column('bytesize', sa.Integer(), nullable=False),
            sa.Column('data', sa.dialects.mysql.MEDIUMBLOB()
                      if op.get_bind().dialect.name == 'mysql' else sa.LargeBinary(),
                      nullable=False),
            sa.Column('uploadedby', sa.Integer()),
            # BaseModel contributes these to every model in the app; a plugin
            # migration has to spell them out or the table is missing columns
            # the ORM selects on every query.
            sa.Column('createddate', sa.DateTime(), nullable=False),
            sa.Column('modifieddate', sa.DateTime(), nullable=False),
            sa.Column('isactive', sa.Boolean(), nullable=False),
            sa.PrimaryKeyConstraint('guideimageid'),
            sa.ForeignKeyConstraint(['guideid'], ['guides.guideid'],
                                    ondelete='CASCADE'),
        )
        op.create_index('idx_guideimages_guide', 'guideimages', ['guideid'])


def downgrade():
    for table in ('guideimages', 'guiderevisions', 'guides'):
        op.drop_table(table)