"""Acceptance test for time-to-green task T08 (written for the 2026-10-30 bench; the protocol names it, does not ship it).

T08: logreport (refactored): add a --top N flag that limits the level table to the N most frequent levels.
Green: python -m unittest tasks.t08_test   (run from the repo root)

Driven through the command line as a user would run it: `python <script> <logfile> --top N`. "Most
frequent" uses the report's existing order (count descending, then name); the test data has no tie at the
cut. Everything outside the level table is unchanged. The shipped tests (legacy and refactored
characterization plus the pure-function tests) run as regression from a frozen copy in tasks/.
"""
from __future__ import annotations

import os
import subprocess
import sys
import tempfile
import unittest

from tasks.regress_refactor import LegacyBehaviour, PureFunctions, RefactoredBehaviour  # noqa: F401

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
SCRIPT = os.path.join(ROOT, "refactor-with-an-agent-characterization-tests.py")

LOG = ("2026-09-05 14:00:01 INFO a\n"
       "2026-09-05 14:00:02 ERROR b\n"
       "2026-09-05 14:00:03 INFO c\n"
       "2026-09-05 14:00:04 WARN d\n"
       "2026-09-05 14:00:05 ERROR e\n"
       "2026-09-05 14:00:06 INFO f\n")
HEAD = "lines: 6 (skipped 0)\n"
TABLE = ["  INFO     3\n", "  ERROR    2\n", "  WARN     1\n"]
TAIL = "first: 05/09/26 14:00:01\nlast:  05/09/26 14:00:06\n"


def cli(*args):
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "app.log")
        with open(path, "w", encoding="utf-8", newline="\n") as fh:
            fh.write(LOG)
        argv = [path if a == "FILE" else a for a in args]
        p = subprocess.run([sys.executable, SCRIPT, *argv], cwd=ROOT, capture_output=True,
                           text=True, timeout=60)
    return p.returncode, p.stdout, p.stderr


class TopFlagTests(unittest.TestCase):
    def test_top_2_keeps_the_two_most_frequent_levels(self):
        code, out, err = cli("FILE", "--top", "2")
        self.assertEqual(code, 0, err)
        self.assertEqual(out, HEAD + "".join(TABLE[:2]) + TAIL)

    def test_top_1(self):
        code, out, err = cli("FILE", "--top", "1")
        self.assertEqual(code, 0, err)
        self.assertEqual(out, HEAD + TABLE[0] + TAIL)

    def test_top_larger_than_the_number_of_levels_prints_them_all(self):
        code, out, err = cli("FILE", "--top", "10")
        self.assertEqual(code, 0, err)
        self.assertEqual(out, HEAD + "".join(TABLE) + TAIL)

    def test_without_the_flag_the_report_is_unchanged(self):
        code, out, err = cli("FILE")
        self.assertEqual(code, 0, err)
        self.assertEqual(out, HEAD + "".join(TABLE) + TAIL)


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