from __future__ import annotations

from contextlib import contextmanager
from typing import Any, Iterator

from app.db.platform_store import PlatformStore, dataset_file_version_summary, parse_size_bytes


class _DatasetCursor:
    def __init__(self, rows: list[dict[str, Any]]) -> None:
        self.rows = rows

    def fetchall(self) -> list[dict[str, Any]]:
        return self.rows


class _DatasetConnection:
    def __init__(self) -> None:
        self.queries: list[str] = []

    def execute(self, sql: str, params: tuple[Any, ...] | None = None) -> _DatasetCursor:
        self.queries.append(sql)
        if "FROM datasets dataset" in sql:
            return _DatasetCursor(
                [
                    {
                        "id": "dataset-train",
                        "name": "cash-数据集-训练集",
                        "type": "train",
                        "storage_type": "local",
                        "source": "task",
                        "task_id": "task-cash",
                        "source_task_id": "task-cash",
                        "task_name": "cash",
                        "size": "0 B",
                        "size_bytes": 0,
                        "metadata": "{}",
                    }
                ]
            )
        if "FROM dataset_files" in sql or "FROM dataset_records" in sql:
            return _DatasetCursor([])
        raise AssertionError(f"unexpected query: {sql}")


def test_parse_size_bytes_supports_legacy_units() -> None:
    assert parse_size_bytes("21563 B") == 21563
    assert parse_size_bytes("1.5 KB") == 1536
    assert parse_size_bytes("2 MB") == 2 * 1024**2
    assert parse_size_bytes(4096) == 4096
    assert parse_size_bytes("unknown") == 0


def test_dataset_file_version_summary_uses_active_version_metadata() -> None:
    summary = dataset_file_version_summary(
        {
            "active_version_id": "file-1-v3",
            "current_version_id": "file-1-v1",
            "version_no": 1,
            "versions": (
                '[{"id":"file-1-v1","version":1},'
                '{"id":"file-1-v3","version_no":3}]'
            ),
        }
    )

    assert summary == {
        "active_version_id": "file-1-v3",
        "current_version_id": "file-1-v3",
        "current_version_no": 3,
        "version_count": 2,
    }


def test_dataset_file_version_summary_uses_normalized_version_number_as_fallback() -> None:
    summary = dataset_file_version_summary(
        {
            "active_version_id": "",
            "current_version_id": None,
            "version_no": 1,
            "versions": "[]",
        }
    )

    assert summary["current_version_no"] == 1
    assert summary["version_count"] == 0


def test_dataset_list_exposes_source_task_name() -> None:
    store = PlatformStore.__new__(PlatformStore)
    conn = _DatasetConnection()

    @contextmanager
    def connect() -> Iterator[_DatasetConnection]:
        yield conn

    store.connect = connect  # type: ignore[method-assign]

    [dataset] = store.datasets()

    assert dataset["task_name"] == "cash"
    assert dataset["name"] == "cash-数据集-训练集"
    assert any("task.name AS task_name" in query for query in conn.queries)