"""Add leave_wish.window_mode ('fixed' | 'flexible').

PLANNING_ENGINE_SPEC.md §10.1 — "när det passar bäst" flexible wishes. For a
'flexible' wish the EXISTING window_start_*/window_end_* columns are
reinterpreted as the bounding range the allocator searches within, rather
than the exact placement; no new columns are needed for the bound itself.
Defaults to 'fixed' so every existing row (and every existing construction
site) keeps its current, unchanged meaning.

Revision ID: 006
Revises: 005
Create Date: 2026-09-13
"""

from __future__ import annotations

from alembic import op

revision: str = "006"
down_revision: str | None = "005"
branch_labels: str | None = None
depends_on: str | None = None

_UPGRADE_SQL = """
ALTER TABLE leave_wish ADD COLUMN window_mode TEXT NOT NULL DEFAULT 'fixed'
    CHECK (window_mode IN ('fixed','flexible'));
"""

_DOWNGRADE_SQL = """
ALTER TABLE leave_wish DROP COLUMN window_mode;
"""


def upgrade() -> None:
    from sqlalchemy import text

    for stmt in [s.strip() for s in _UPGRADE_SQL.split(";") if s.strip()]:
        op.execute(text(stmt))


def downgrade() -> None:
    from sqlalchemy import text

    for stmt in [s.strip() for s in _DOWNGRADE_SQL.split(";") if s.strip()]:
        op.execute(text(stmt))