"""add roles and user_roles tables

Revision ID: add_roles_tables
Revises: add_article_views
Create Date: 2025-11-21
"""

from typing import Tuple

import sqlalchemy as sa
from alembic import op
from sqlalchemy import func, text
from sqlalchemy.dialects.postgresql import JSONB

revision = "add_roles_tables"
down_revision = "add_article_views"
branch_labels = None
depends_on = None


def timestamps() -> Tuple[sa.Column, sa.Column]:
    return (
        sa.Column(
            "created_at",
            sa.TIMESTAMP(timezone=True),
            nullable=False,
            server_default=func.now(),
        ),
        sa.Column(
            "updated_at",
            sa.TIMESTAMP(timezone=True),
            nullable=False,
            server_default=func.now(),
            onupdate=func.current_timestamp(),
        ),
    )


def upgrade() -> None:
    op.create_table(
        "roles",
        sa.Column("id", sa.Integer, primary_key=True),
        sa.Column("name", sa.String(length=64), nullable=False, unique=True),
        sa.Column("description", sa.Text, nullable=False, server_default=""),
        sa.Column(
            "permissions",
            JSONB,
            nullable=False,
            server_default=text("'[]'::jsonb"),
        ),
        *timestamps(),
    )
    op.execute(
        """
        CREATE TRIGGER update_role_modtime
            BEFORE UPDATE
            ON roles
            FOR EACH ROW
        EXECUTE PROCEDURE update_updated_at_column();
        """,
    )

    op.create_table(
        "user_roles",
        sa.Column(
            "user_id",
            sa.Integer,
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "role_id",
            sa.Integer,
            sa.ForeignKey("roles.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "assigned_at",
            sa.TIMESTAMP(timezone=True),
            nullable=False,
            server_default=func.now(),
        ),
    )
    op.create_primary_key(
        "pk_user_roles",
        "user_roles",
        ["user_id", "role_id"],
    )
    op.create_index("ix_user_roles_role_id", "user_roles", ["role_id"])

    op.execute(
        """
        INSERT INTO roles (name, description, permissions)
        VALUES ('admin', 'System administrator with full privileges', '["*"]')
        ON CONFLICT (name) DO NOTHING;
        """,
    )
    op.execute(
        """
        DO $$
        DECLARE
            admin_role_id INTEGER;
            first_user_id INTEGER;
        BEGIN
            SELECT id INTO admin_role_id FROM roles WHERE name = 'admin';
            SELECT id INTO first_user_id FROM users ORDER BY id ASC LIMIT 1;
            IF admin_role_id IS NOT NULL AND first_user_id IS NOT NULL THEN
                INSERT INTO user_roles (user_id, role_id)
                VALUES (first_user_id, admin_role_id)
                ON CONFLICT DO NOTHING;
            END IF;
        END $$;
        """,
    )


def downgrade() -> None:
    op.drop_index("ix_user_roles_role_id", table_name="user_roles")
    op.drop_table("user_roles")
    op.drop_table("roles")