"""Story-to-test traceability.

Every mapped story must map to test files that exist, every test file must be
claimed by a story (so a new test can't go unexercised), and all Phase A stories
US01-01..US01-07 must be present. Whether those tests *pass* is proven by running
the suite; this guards the mapping's completeness.
"""

import json
from pathlib import Path

REPO = Path(__file__).resolve().parents[2]
MAP = json.loads((REPO / "tests" / "story_traceability.json").read_text())["stories"]
PHASE_A_STORIES = {f"US01-0{n}" for n in range(1, 8)}
PHASE_D_STORIES = {f"US04-0{n}" for n in range(1, 7)}
PHASE_E_STORIES = {f"US05-0{n}" for n in range(1, 7)}
PHASE_F_STORIES = {f"US06-0{n}" for n in range(1, 7)}


def test_all_phase_a_stories_are_mapped():
    assert PHASE_A_STORIES <= set(MAP)


def test_all_phase_d_stories_are_mapped():
    """US04-06 acceptance: every guarded-rename story, plan through browser, is tied
    to automated tests — renaming is the first thing that mutates the real library."""
    assert PHASE_D_STORIES <= set(MAP)


def test_all_phase_e_stories_are_mapped():
    """US05-06 acceptance: every upload story, preflight through browser, is tied to
    automated tests — upload is the one stage the app cannot take back."""
    assert PHASE_E_STORIES <= set(MAP)


def test_all_phase_f_stories_are_mapped():
    """US06-06 acceptance: every archive-lifecycle story, destination through
    restore, is tied to automated tests — archiving is the only stage that removes
    an original."""
    assert PHASE_F_STORIES <= set(MAP)


def test_every_mapped_test_file_exists_and_is_nonempty():
    for story, files in MAP.items():
        assert files, f"{story} maps to no tests"
        for rel in files:
            path = REPO / rel
            assert path.is_file(), f"{story}: missing {rel}"
            assert path.stat().st_size > 0, f"{story}: empty {rel}"
            assert "def test_" in path.read_text(), f"{story}: no tests in {rel}"


def test_no_unexercised_phase_a_test_files():
    """Every test_*.py under tests/ is claimed by a story (no orphan coverage)."""
    mapped = {rel for files in MAP.values() for rel in files}
    on_disk = {
        str(p.relative_to(REPO))
        for p in (REPO / "tests").rglob("test_*.py")
        if "__pycache__" not in p.parts
    }
    unmapped = on_disk - mapped
    assert not unmapped, f"test files not tied to any story: {sorted(unmapped)}"