"""tools plugin baseline: the secure send table.

Creates the one table this plugin owns. Tech Tools was schemaless until secure
send arrived: a link that expires and dies on first read has to keep the
ciphertext somewhere until it is claimed. Not an asset extension: a shared
credential is a short-lived event rather than a thing the site inventories, so
there is no assetid and no asset type.

Explicit Alembic ops rather than the create_plugin_tables helper, matching the
backups baseline: the helper builds a per-plugin MetaData filtered to this
plugin's tables, so the foreign key to the core users table cannot resolve at
CreateTable-compile time.
"""
from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = 'tools0001securesend'
down_revision = None
branch_labels = None
depends_on = None


def upgrade():
    op.create_table(
        'securesendsecrets',
        sa.Column('secretid', sa.Integer(), nullable=False),
        # 128 bits of randomness as hex. With no login on the read side this is
        # the credential, so it must never be a sequence.
        sa.Column('token', sa.String(length=64), nullable=False),
        sa.Column('ciphertext', sa.Text(), nullable=False),
        sa.Column('iv', sa.String(length=64), nullable=False),
        sa.Column('expiresat', sa.DateTime(), nullable=False),
        sa.Column('viewsremaining', sa.Integer(), nullable=False,
                  server_default='1'),
        sa.Column('createdbyuserid', sa.Integer(), nullable=True),
        sa.Column('lastviewedat', sa.DateTime(), nullable=True),
        sa.Column('viewcount', sa.Integer(), nullable=False, server_default='0'),
        sa.Column('createddate', sa.DateTime(), nullable=False),
        sa.Column('modifieddate', sa.DateTime(), nullable=False),
        sa.Column('isactive', sa.Boolean(), nullable=False,
                  server_default=sa.true()),
        sa.ForeignKeyConstraint(['createdbyuserid'], ['users.userid'],
                                ondelete='SET NULL'),
        sa.PrimaryKeyConstraint('secretid'),
    )
    # Unique, because the token is looked up on every read and two rows sharing
    # one would make a link ambiguous.
    op.create_index('ixsecuresendsecretstoken', 'securesendsecrets',
                    ['token'], unique=True)
    # Expiry sweeps scan on this.
    op.create_index('ixsecuresendsecretsexpiresat', 'securesendsecrets',
                    ['expiresat'])
    op.create_index('ixsecuresendsecretscreatedby', 'securesendsecrets',
                    ['createdbyuserid'])


def downgrade():
    op.drop_index('ixsecuresendsecretscreatedby', table_name='securesendsecrets')
    op.drop_index('ixsecuresendsecretsexpiresat', table_name='securesendsecrets')
    op.drop_index('ixsecuresendsecretstoken', table_name='securesendsecrets')
    op.drop_table('securesendsecrets')