"""add difficulty (target period) to habit

Revision ID: 0007_add_habit_difficulty
Revises: 0006_add_habit_abandoned
Create Date: 2026-07-17

"""
from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op

revision: str = "0007_add_habit_difficulty"
down_revision: Union[str, None] = "0006_add_habit_abandoned"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.add_column(
        "habit",
        sa.Column("difficulty", sa.String(length=20), nullable=False, server_default="medium"),
    )
    op.create_check_constraint(
        "ck_habit_difficulty", "habit", "difficulty in ('easy','medium','hard','unlimited')"
    )


def downgrade() -> None:
    op.drop_constraint("ck_habit_difficulty", "habit", type_="check")
    op.drop_column("habit", "difficulty")