from __future__ import annotations

import json
from datetime import UTC, datetime
from pathlib import Path

from broker_sync.providers._checkpoint import Checkpoint


def test_load_missing_returns_none(tmp_path: Path) -> None:
    cp = Checkpoint(tmp_path, provider="t212", account_id="isa")
    assert cp.load() is None


def test_save_then_load_roundtrip(tmp_path: Path) -> None:
    cp = Checkpoint(tmp_path, provider="t212", account_id="isa")
    cp.save("cursor-xyz")
    assert cp.load() == "cursor-xyz"


def test_save_writes_expected_filename(tmp_path: Path) -> None:
    cp = Checkpoint(tmp_path, provider="t212", account_id="isa")
    cp.save("cursor-abc")
    expected = tmp_path / "t212-isa.json"
    assert expected.exists()
    raw = json.loads(expected.read_text())
    assert raw["cursor"] == "cursor-abc"
    # updated_at is ISO-8601 with tz — just confirm it parses.
    parsed = datetime.fromisoformat(raw["updated_at"])
    assert parsed.tzinfo is not None


def test_save_overwrites_previous(tmp_path: Path) -> None:
    cp = Checkpoint(tmp_path, provider="t212", account_id="isa")
    cp.save("first")
    cp.save("second")
    assert cp.load() == "second"


def test_separate_accounts_are_isolated(tmp_path: Path) -> None:
    a = Checkpoint(tmp_path, provider="t212", account_id="isa")
    b = Checkpoint(tmp_path, provider="t212", account_id="gia")
    a.save("isa-cursor")
    b.save("gia-cursor")
    assert a.load() == "isa-cursor"
    assert b.load() == "gia-cursor"


def test_save_creates_parent_dir(tmp_path: Path) -> None:
    nested = tmp_path / "a" / "b" / "c"
    cp = Checkpoint(nested, provider="t212", account_id="isa")
    cp.save("cursor")
    assert (nested / "t212-isa.json").exists()


def test_load_rejects_legacy_future_time(tmp_path: Path) -> None:
    # Malformed file (missing 'cursor' key) → treat as absent rather than crash.
    p = tmp_path / "t212-isa.json"
    p.write_text(json.dumps({"updated_at": datetime.now(UTC).isoformat()}))
    cp = Checkpoint(tmp_path, provider="t212", account_id="isa")
    assert cp.load() is None