"""Unit tests for platform cursor pagination helpers."""

from __future__ import annotations

import datetime

import pytest
from fastapi import HTTPException

from backend.api.platform._pagination import (
    decode_cursor,
    encode_cursor,
    page_meta,
)


def test_encode_decode_roundtrip() -> None:
    created_at = datetime.datetime(2026, 3, 15, 12, 30, 45, 123000)
    row_id = "01HXY9C5B8N3K4P7Q6RT2V0J8D"
    cursor = encode_cursor(created_at, row_id)
    decoded_ts, decoded_id = decode_cursor(cursor)
    assert decoded_ts == created_at
    assert decoded_id == row_id


def test_decode_strips_timezone() -> None:
    created_at = datetime.datetime(2026, 1, 1, 0, 0, 0, tzinfo=datetime.timezone.utc)
    cursor = encode_cursor(created_at, "abc")
    decoded_ts, decoded_id = decode_cursor(cursor)
    assert decoded_ts.tzinfo is None
    assert decoded_id == "abc"


def test_decode_invalid_cursor_raises_400() -> None:
    with pytest.raises(HTTPException) as exc_info:
        decode_cursor("not-a-valid-cursor!!!")
    assert exc_info.value.status_code == 400


def test_page_meta_has_more() -> None:
    meta = page_meta(
        limit=10,
        page_count=10,
        total_count=25,
        next_cursor="abc",
    )
    assert meta["has_more"] is True
    assert meta["next_cursor"] == "abc"
    assert meta["total_count"] == 25

    meta_end = page_meta(
        limit=10,
        page_count=5,
        total_count=25,
        next_cursor=None,
    )
    assert meta_end["has_more"] is False