# Acceptance test for time-to-green task T06 (written for the 2026-10-30 bench).
# FROZEN COPY for the time-to-green bench: acceptance test t06: add-tests-to-a-legacy-script-with-an-agent_test.py with the month-boundary pin flipped to the correct expectation; every other test as shipped.
# Edits to tasks/ are denied to the agent.
"""Characterization tests for the legacy logreport script.

These tests pin what the script DOES today, including its quirks and one latent
bug, following Michael Feathers' method: write the test, run it, paste the actual
output in as the expectation, then name the test after what you learned.

Run:  python -m unittest add-tests-to-a-legacy-script-with-an-agent_test.py
Python 3.13, standard library only.
"""
from __future__ import annotations

import importlib.util
import io
import os
import unittest

HERE = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))  # frozen copy in tasks/: modules live in the repo root
_spec = importlib.util.spec_from_file_location(
    "logreport", os.path.join(HERE, "add-tests-to-a-legacy-script-with-an-agent.py"))
logreport = importlib.util.module_from_spec(_spec)
_spec.loader.exec_module(logreport)

LINES = [
    "2026-09-05 14:03:11 ERROR auth: token expired user=42\n",
    "2026-09-05 14:03:12 INFO auth: refreshed user=42\n",
    "garbage line without a timestamp\n",
    "2026-09-05 14:04:00 INFO web: GET /health 200\n",
    "2026-09-05 14:05:30 WARN db: slow query 1.2s\n",
]


def run(lines):
    out = io.StringIO()
    logreport.run(lines, out)
    return out.getvalue()


class ReportCharacterization(unittest.TestCase):
    def test_report_for_five_lines_is_exactly_this(self):
        # Pasted from the first run; every character is intentional.
        self.assertEqual(run(LINES),
                         "WARN skipping line 3: 'garbage line without a timestamp'\n"
                         "lines: 5 (skipped 1)\n"
                         "  INFO     2\n"
                         "  ERROR    1\n"
                         "  WARN     1\n"
                         "first: 05/09/26 14:03:11\n"
                         "last:  05/09/26 14:05:30\n")

    def test_empty_input_prints_only_the_line_count(self):
        self.assertEqual(run([]), "lines: 0 (skipped 0)\n")

    def test_levels_sort_by_count_then_name(self):
        out = run(["2026-01-01 00:00:00 B x\n", "2026-01-01 00:00:00 A x\n",
                   "2026-01-01 00:00:00 A x\n", "2026-01-01 00:00:00 C x\n"])
        self.assertEqual(out.splitlines()[1:4], ["  A        2", "  B        1", "  C        1"])

    def test_level_match_is_case_sensitive(self):
        out = run(["2026-01-01 00:00:00 error x\n", "2026-01-01 00:00:00 ERROR x\n"])
        self.assertIn("  ERROR    1\n", out)
        self.assertIn("  error    1\n", out)

    def test_short_or_malformed_stamps_are_skipped_with_a_warning(self):
        cases = {
            "2026-9-5 14:03:11 INFO x\n": "WARN skipping line 1: '2026-9-5 14:03:11 INFO x'",
            "2026-09-05 14:03 INFO x\n": "WARN skipping line 1: '2026-09-05 14:03 INFO x'",
            "2026-09-05 14:03:11 INFO\n": "WARN skipping line 1: '2026-09-05 14:03:11 INFO'",
        }
        for line, expected in cases.items():
            with self.subTest(line=line):
                self.assertEqual(run([line]).splitlines()[0], expected)

    def test_run_resets_state_between_calls(self):
        run(LINES)
        self.assertEqual(run([]), "lines: 0 (skipped 0)\n")


class DateQuirks(unittest.TestCase):
    def test_dates_are_reformatted_to_dd_mm_yy(self):
        for iso, expected in {"2026-09-05": "05/09/26", "1999-12-31": "31/12/99",
                              "2000-01-01": "01/01/00"}.items():
            with self.subTest(iso=iso):
                self.assertEqual(logreport.fmt_date(iso), expected)

    def test_first_and_last_are_correct_across_a_month_boundary(self):
        # Corrected expectation (time-to-green T06): 31 August is first, 1 September is last.
        out = run(["2026-08-31 23:59:59 INFO x\n", "2026-09-01 00:00:01 INFO y\n"])
        self.assertIn("first: 31/08/26 23:59:59\n", out)
        self.assertIn("last:  01/09/26 00:00:01\n", out)


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