"""C11 upload retry — additive ``upload_attempts`` counter on tiles.

Per ``_docs/02_tasks/todo/AZ-320_c11_idempotent_retry.md``. The migration:

- adds the ``tiles.upload_attempts INTEGER NOT NULL DEFAULT 0`` column
  (per-tile retry budget for the C11 ``IdempotentRetryTileUploader``);
- widens the ``tiles.voting_status`` CHECK to also accept the new
  ``upload_giveup`` enum value (terminal state for a tile that
  exhausted its per-tile retry budget — see ``VotingStatus`` v1.3.0).

The migration is strictly additive on ``0002_c6_tile_identity_and_lru``.
Existing rows default to ``upload_attempts = 0``; existing voting_status
values (``pending``, ``trusted``, ``rejected``) remain valid. Reverse
``downgrade()`` drops the column and restores the legacy CHECK to its
v1.2.0 vocabulary; downgrade is destructive for any rows that hold
``upload_giveup`` and is documented operator-only.

Revision ID: 0003_c11_upload_attempts
Revises: 0002_c6_tile_identity_and_lru
Create Date: 2026-05-13
"""

from __future__ import annotations

from collections.abc import Sequence

import sqlalchemy as sa
from alembic import op

revision: str = "0003_c11_upload_attempts"
down_revision: str | None = "0002_c6_tile_identity_and_lru"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


_VOTING_STATUS_LEGACY = (
    "voting_status IS NULL OR voting_status IN ('pending','trusted','rejected')"
)
_VOTING_STATUS_UNION = (
    "voting_status IS NULL OR "
    "voting_status IN ('pending','trusted','rejected','upload_giveup')"
)
_VOTING_STATUS_CHECK = "ck_tiles_voting_status"


def upgrade() -> None:
    op.add_column(
        "tiles",
        sa.Column(
            "upload_attempts",
            sa.Integer(),
            nullable=False,
            server_default=sa.text("0"),
        ),
    )
    op.create_check_constraint(
        "ck_tiles_upload_attempts_nonneg",
        "tiles",
        "upload_attempts >= 0",
    )
    # Voting-status CHECK: drop-and-recreate. AZ-263's 0001 created the
    # constraint under the legacy vocabulary; widening to include
    # 'upload_giveup' keeps the constraint as the SQL-level enforcement
    # of the VotingStatus enum.
    op.execute(f"ALTER TABLE tiles DROP CONSTRAINT IF EXISTS {_VOTING_STATUS_CHECK}")
    op.create_check_constraint(
        _VOTING_STATUS_CHECK,
        "tiles",
        _VOTING_STATUS_UNION,
    )


def downgrade() -> None:
    op.execute(f"ALTER TABLE tiles DROP CONSTRAINT IF EXISTS {_VOTING_STATUS_CHECK}")
    op.create_check_constraint(
        _VOTING_STATUS_CHECK,
        "tiles",
        _VOTING_STATUS_LEGACY,
    )
    op.drop_constraint(
        "ck_tiles_upload_attempts_nonneg", "tiles", type_="check"
    )
    op.drop_column("tiles", "upload_attempts")