"""Acceptance test for time-to-green task T01 (written for the 2026-10-30 bench; the protocol names it, does not ship it).

T01: tally: add a --json flag to `stats` that prints the same seven fields as one JSON object on stdout;
text output unchanged when the flag is absent.
Green: python -m unittest tasks.t01_test   (run from the repo root)

Shape follows the published page: main(["stats", path, "--col", "price", "--json"]), json.loads on the
captured stdout, an equality check on the seven keys. Values are compared as numbers (a number or a
numeric string both pass: the task does not fix the JSON type). "Text output unchanged" is the shipped
suite, run from a frozen copy in tasks/ so edits to the root test file cannot weaken it.
"""
from __future__ import annotations

import importlib.util
import io
import json
import os
import tempfile
import unittest

from tasks.regress_tally import HeadTests, StatsTests  # noqa: F401  (collected as regression tests)

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
_spec = importlib.util.spec_from_file_location(
    "tally_t01", os.path.join(ROOT, "build-a-cli-tool-with-an-agent-from-a-spec.py"))
tally = importlib.util.module_from_spec(_spec)
_spec.loader.exec_module(tally)

SAMPLE = "name,price,qty\nbolt,1.5,10\nnut,,4\nwasher,0.25,100\nscrew,2,\n"
SEVEN = {"column", "count", "blank", "min", "max", "mean", "median"}


def run(argv, text=SAMPLE):
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "data.csv")
        with open(path, "w", encoding="utf-8", newline="") as fh:
            fh.write(text)
        argv = [path if a == "FILE" else a for a in argv]
        out, err = io.StringIO(), io.StringIO()
        code = tally.main(argv, out=out, err=err)
    return code, out.getvalue(), err.getvalue()


class StatsJsonTests(unittest.TestCase):
    def test_json_flag_prints_one_object_with_the_seven_fields(self):
        code, out, err = run(["stats", "FILE", "--col", "price", "--json"])
        self.assertEqual(code, 0, err)
        obj = json.loads(out)
        self.assertIsInstance(obj, dict)
        self.assertEqual(set(obj), SEVEN)
        self.assertEqual(obj["column"], "price")
        for key, want in {"count": 3, "blank": 1, "min": 0.25, "max": 2,
                          "mean": 1.25, "median": 1.5}.items():
            with self.subTest(key=key):
                self.assertAlmostEqual(float(obj[key]), want)

    def test_text_output_unchanged_without_the_flag(self):
        code, out, _ = run(["stats", "FILE", "--col", "price"])
        self.assertEqual(code, 0)
        self.assertEqual(out, "column: price\ncount:  3\nblank:  1\nmin:    0.25\n"
                              "max:    2\nmean:   1.25\nmedian: 1.5\n")


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