"""Unit tests for the bounded GUI log-panel buffer.

The buffer decouples logging handlers (any thread, potentially very chatty at
DEBUG) from the GUI: records are batched by a flush timer instead of posting one
queued Qt event per record, and overflow drops the oldest records with a count.
"""

from __future__ import annotations

import unittest

from python_app.gui.app_window import _PanelLogBuffer


class PanelLogBufferTest(unittest.TestCase):
    """Bounded capacity, oldest-first eviction, and accurate drop accounting."""

    def test_drain_returns_entries_in_order_and_clears(self) -> None:
        buffer = _PanelLogBuffer()
        buffer.append("INFO", "first", None, None)
        buffer.append("WARN", "second", "details", "key")

        entries, dropped_count = buffer.drain()

        self.assertEqual(dropped_count, 0)
        self.assertEqual(
            entries,
            [("INFO", "first", None, None), ("WARN", "second", "details", "key")],
        )
        self.assertEqual(buffer.drain(), ([], 0))

    def test_overflow_drops_oldest_and_counts(self) -> None:
        buffer = _PanelLogBuffer()
        overflow = 100
        total = _PanelLogBuffer._CAPACITY + overflow
        for index in range(total):
            buffer.append("DEBUG", f"m{index}", None, None)

        entries, dropped_count = buffer.drain()

        self.assertEqual(dropped_count, overflow)
        self.assertEqual(len(entries), _PanelLogBuffer._CAPACITY)
        self.assertEqual(entries[0][1], f"m{overflow}")
        self.assertEqual(entries[-1][1], f"m{total - 1}")


if __name__ == "__main__":
    unittest.main()