"""remove subscription_tier from tenants

Revision ID: 20251028_remove_sub_tier
Revises: 20251025_supplier_approval
Create Date: 2025-10-28 12:00:00.000000

This migration removes the denormalized subscription_tier column from the tenants table.
The subscription tier is now sourced exclusively from the subscriptions table (single source of truth).
"""
from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = '20251028_remove_sub_tier'
down_revision = '20251025_supplier_approval'
branch_labels = None
depends_on = None


def upgrade():
    """
    Remove subscription_tier column from tenants table
    """
    # Pre-flight check: Ensure all tenants have active subscriptions
    # This is important to avoid breaking the application
    connection = op.get_bind()

    # Check for tenants without subscriptions
    result = connection.execute(sa.text("""
        SELECT COUNT(*) as count
        FROM tenants t
        LEFT JOIN subscriptions s ON t.id = s.tenant_id AND s.status = 'active'
        WHERE s.id IS NULL
    """))

    orphaned_count = result.fetchone()[0]

    if orphaned_count > 0:
        # Create default subscriptions for orphaned tenants
        connection.execute(sa.text("""
            INSERT INTO subscriptions (
                id, tenant_id, plan, status, monthly_price, billing_cycle,
                max_users, max_locations, max_products, features, created_at, updated_at
            )
            SELECT
                gen_random_uuid(),
                t.id,
                'starter',
                'active',
                49.0,
                'monthly',
                5,
                1,
                50,
                '{"inventory_management": true, "demand_prediction": true}'::jsonb,
                NOW(),
                NOW()
            FROM tenants t
            LEFT JOIN subscriptions s ON t.id = s.tenant_id AND s.status = 'active'
            WHERE s.id IS NULL
        """))

        print(f"Created default subscriptions for {orphaned_count} tenants without subscriptions")

    # Drop the subscription_tier column
    op.drop_column('tenants', 'subscription_tier')

    print("Successfully removed subscription_tier column from tenants table")


def downgrade():
    """
    Re-add subscription_tier column and populate from subscriptions table

    Note: This is for rollback purposes only. Going forward, always use subscriptions table.
    """
    # Add the column back
    op.add_column('tenants',
        sa.Column('subscription_tier', sa.String(length=50), nullable=True)
    )

    # Populate from subscriptions table
    connection = op.get_bind()
    connection.execute(sa.text("""
        UPDATE tenants t
        SET subscription_tier = s.plan
        FROM subscriptions s
        WHERE t.id = s.tenant_id
        AND s.status = 'active'
    """))

    # Set default for any tenants without active subscriptions
    connection.execute(sa.text("""
        UPDATE tenants
        SET subscription_tier = 'starter'
        WHERE subscription_tier IS NULL
    """))

    # Make it non-nullable after population
    op.alter_column('tenants', 'subscription_tier', nullable=False)

    print("Restored subscription_tier column (downgrade)")