"""phase33 — tenant_settings table for per-tenant branding (MT-7)

Adds a single-row-per-tenant settings store in the tenant database.
Tenant-zero starts with defaults (no visual change until admin edits them).

Revision: phase33_tenant_settings
Down:      phase32_device_token_columns
"""

revision      = 'phase33_tenant_settings'
down_revision = 'phase32_device_token_columns'
branch_labels = None
depends_on    = None

import sqlalchemy as sa
from alembic import op


def _table_exists(bind, table_name):
    result = bind.execute(sa.text(
        "SELECT COUNT(*) FROM information_schema.tables "
        "WHERE table_schema = DATABASE() AND table_name = :t"
    ), {'t': table_name})
    return result.scalar() > 0


def upgrade():
    bind = op.get_bind()
    if not _table_exists(bind, 'tenant_settings'):
        op.execute(sa.text("""
            CREATE TABLE tenant_settings (
                id              INT          NOT NULL AUTO_INCREMENT PRIMARY KEY,
                company_name    VARCHAR(150) NULL,
                logo_url        VARCHAR(500) NULL,
                primary_color   VARCHAR(7)   NOT NULL DEFAULT '#1a56db',
                accent_color    VARCHAR(7)   NOT NULL DEFAULT '#16a34a',
                support_email   VARCHAR(255) NULL,
                updated_at      DATETIME     NOT NULL,
                updated_by      INT          NULL,
                CONSTRAINT fk_tenant_settings_user
                    FOREIGN KEY (updated_by) REFERENCES users(id) ON DELETE SET NULL
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
        """))


def downgrade():
    bind = op.get_bind()
    if _table_exists(bind, 'tenant_settings'):
        op.execute(sa.text('DROP TABLE tenant_settings'))