from importlib.util import module_from_spec, spec_from_file_location
from pathlib import Path

import sqlalchemy as sa


VERSIONS_DIR = Path(__file__).parents[1] / "alembic" / "versions"


def load_migration():
    path = VERSIONS_DIR / "0034_media_assets.py"
    spec = spec_from_file_location("media_asset_migration", path)
    assert spec and spec.loader
    migration = module_from_spec(spec)
    spec.loader.exec_module(migration)
    return migration


class Inspector:
    def __init__(self, tables: set[str]):
        self.tables = tables

    def get_table_names(self) -> list[str]:
        return sorted(self.tables)


def test_media_asset_migration_creates_the_upload_table_with_scope_columns(monkeypatch):
    migration = load_migration()
    created: dict[str, object] = {}
    indexes: list[tuple[object, ...]] = []

    monkeypatch.setattr(migration, "inspect", lambda _bind: Inspector({"AdminUser", "AdminDepartment"}))
    monkeypatch.setattr(migration.op, "get_bind", lambda: object())
    monkeypatch.setattr(
        migration.op,
        "create_table",
        lambda *args, **kwargs: created.update(args=args, kwargs=kwargs),
    )
    monkeypatch.setattr(
        migration.op,
        "create_index",
        lambda *args, **kwargs: indexes.append((*args, *kwargs.values())),
    )

    migration.upgrade()

    assert migration.down_revision == "0033_remove_site_versions"
    assert created["args"][0] == "MediaAsset"
    columns = {column.name: column for column in created["args"][1:] if isinstance(column, sa.Column)}
    assert set(columns) == {
        "id",
        "url",
        "name",
        "mimeType",
        "sizeBytes",
        "group",
        "deptId",
        "createdById",
        "createdAt",
        "updatedAt",
    }
    assert columns["url"].unique
    assert columns["deptId"].nullable is False
    assert columns["deptId"].server_default.arg.text.strip("'") == migration.DEFAULT_DEPT_ID
    assert columns["createdById"].nullable is True
    assert {index[0] for index in indexes} == {
        "ix_MediaAsset_deptId",
        "ix_MediaAsset_createdById",
    }
    constraints = [constraint for constraint in created["args"][1:] if isinstance(constraint, sa.ForeignKeyConstraint)]
    primary_keys = [constraint for constraint in created["args"][1:] if isinstance(constraint, sa.PrimaryKeyConstraint)]
    assert primary_keys[0]._pending_colargs == ["id"]
    assert {
        (constraint.name, tuple(constraint.column_keys), tuple(constraint.elements[0].target_fullname.split(".")))
        for constraint in constraints
    } == {
        ("fk_MediaAsset_deptId", ("deptId",), ("AdminDepartment", "id")),
        ("fk_MediaAsset_createdById", ("createdById",), ("AdminUser", "id")),
    }


def test_media_asset_migration_is_safe_when_table_already_exists(monkeypatch):
    migration = load_migration()
    calls: list[tuple[object, ...]] = []

    monkeypatch.setattr(migration, "inspect", lambda _bind: Inspector({"MediaAsset"}))
    monkeypatch.setattr(migration.op, "get_bind", lambda: object())
    monkeypatch.setattr(migration.op, "create_table", lambda *args, **_kwargs: calls.append(args))
    monkeypatch.setattr(migration.op, "create_index", lambda *args, **_kwargs: calls.append(args))

    migration.upgrade()

    assert calls == []