"""What the instruction surfaces must say that one owner per topic cannot enforce.

tests/test_guidance_ownership.py enforces who states each topic: every topic
stated in full by exactly one owner, with a one-line pointer in the server's
index. How to ask for a rule and what an empty session means are the rules
topic, owned by using-scribe and indexed in `_INSTRUCTIONS`; the Systems
reflex and the snippet-recording triggers are their topics' markers, required
on their owners.

WHAT STAYS HERE

Properties of a CLAIM rather than of who owns a topic: the index fits the
fold; a surface that says rules bind also names what does not; using-scribe
still sends a session to the reporting-back skill.
"""
from __future__ import annotations

import pathlib

ROOT = pathlib.Path(__file__).resolve().parents[1]


def _all_surfaces() -> list[tuple[str, str]]:
    """(label, text) for every file a SESSION loads as instructions.

    Deliberately not every markdown file under plugin/: `README.md` describes
    the push channel to the operator installing the plugin, and telling a human
    what the hook does is not the same act as telling an agent it need not pull.
    The boundary is "does a session read this", which is skills (loaded by
    description match, and each reference file a skill links is read on its
    own, so it is its own surface), the hook-injected static context, and the MCP server's
    own instructions.
    """
    found = [(str(p.relative_to(ROOT)), p.read_text())
             for p in (ROOT / "plugin" / "skills").rglob("*.md")]
    found += [(str(p.relative_to(ROOT)), p.read_text())
              for p in (ROOT / "plugin" / "hooks").glob("*.md")]
    server = ROOT / "src" / "scribe" / "mcp" / "server.py"
    found.append((str(server.relative_to(ROOT)), server.read_text()))
    return found


def _instructions_text() -> str:
    """The _INSTRUCTIONS literal from server.py, as the client would see it."""
    import re
    src = (ROOT / "src" / "scribe" / "mcp" / "server.py").read_text()
    match = re.search(r'_INSTRUCTIONS = """(.*?)"""', src, re.S)
    assert match, "server.py no longer defines _INSTRUCTIONS as a triple-quoted literal"
    return match.group(1).strip()


# Claude Code injects only the first ~2,048 characters of an MCP server's
# instructions and silently cuts the rest mid-word, so guidance past the cap
# never reaches a session. The budget is set below the cap, not at it: the
# field runs ~600–1,600 characters, and
# a block pressed against 2,048 is being used for depth that belongs in a
# skill.
INSTRUCTIONS_BUDGET = 1600


def test_instructions_fit_the_fold():
    text = _instructions_text()
    assert len(text) <= INSTRUCTIONS_BUDGET, (
        f"_INSTRUCTIONS is {len(text)} chars; Claude Code injects only ~2,048 "
        f"and silently cuts the rest. This block is an INDEX — state "
        f"the topic in full on its owner (a skill or the tool's docstring) "
        f"and give it at most a line here; see the comment "
        f"above _INSTRUCTIONS."
    )


# ── force: a surface that says rules bind must say what does not ────────
#
# With a preference kind beside rules, "rules bind" is half of the truth, and
# the missing half is the dangerous half to omit: a session reading
# only "rules bind" and then receiving a preference has been told, by the most
# authoritative surface it has, to treat it as binding.
#
# That failure is silent in both directions. Treating a preference as a rule
# produces a session that refuses to proceed over something the operator only
# preferred; and it removes the reason preferences exist, which is that they
# can be brought up to date rather than obeyed.
#
# Same bargain as every test in this file: STRUCTURE, not wording. A surface
# passes by mentioning the other kind at all, so the prose stays free.
#
# PINNED ON THE CLAIM, NOT THE WORD "bind". A bare substring also matches
# `bind_repo`, `list_repo_bindings` and the DNS-rebinding comment in
# server.py — so it would one day fail a skill that mentions repo binding and
# has nothing to do with force — a guard
# raising a false alarm about the very thing it protects. These phrases are
# the ones that actually assert bindingness to a reader.
BINDING_CLAIMS = (
    "rules bind",
    "binding rules",
    "rules are binding",
    "treat every one as binding",
)
OTHER_KIND = "preference"


def test_a_surface_claiming_rules_bind_also_names_what_does_not():
    offenders = [
        label for label, text in _all_surfaces()
        if any(c in text.lower() for c in BINDING_CLAIMS)
        and OTHER_KIND not in text.lower()
    ]
    assert not offenders, (
        f"these surfaces tell a session that rules bind and never mention "
        f"preferences: {offenders}. A preference arrives through the same arms "
        f"and renders in the same line shape, so a surface that describes only "
        f"the binding kind is read as covering both — and the session treats "
        f"'how the operator likes this done' as something it may not proceed "
        f"past. Name the other kind, however briefly."
    )


# ── the index names every strength, and who keeps the middle one current ──
#
# Milestones 385 and 399 both end here, and for the same reason. The index is
# the one guidance surface EVERY MCP client receives — a client that reads no
# Agent Skills still gets it — so a strength the index omits does not exist for
# that session. Before the lesson kind, "rules bind; preferences guide" was the
# whole corpus; a session that meets a third line shape with no name for it
# falls back on the nearest one it has, which is the binding one.
#
# The currency half is the central claim: a preference is the
# one record a session updates ITSELF, without asking. Stated only in the
# skill, it reaches a session that loaded the skill — which is exactly the
# session least likely to need telling. In the index it reaches everyone.
#
# Words, not wording: each entry is a family, and a rewrite satisfies it by
# saying the thing in any of these ways.
INDEX_STRENGTHS = {
    "that rules bind": ("rules bind",),
    "that preferences guide": ("preferences guide",),
    "that lessons inform": ("lessons inform", "lessons are", "a lesson informs"),
    "that a preference is kept current": ("current",),
}


def test_the_index_names_all_three_strengths():
    text = " ".join(_instructions_text().split()).lower()
    missing = [claim for claim, family in INDEX_STRENGTHS.items()
               if not any(t in text for t in family)]
    assert not missing, (
        f"_INSTRUCTIONS no longer says {missing}. It is the only guidance every "
        f"client receives, and a record kind it does not name is one the session "
        f"has to guess the force of — which it does by reaching for the kind it "
        f"does know. Keep it to a clause; the full statement lives on "
        f"using-scribe."
    )


def test_the_strength_guard_can_fail():
    """The guard has to be able to bite, and it bites on omission —
    the failure that actually happens, when a kind is added to the product and
    the index is left describing the corpus that came before it."""
    text = "rules bind; preferences guide and you keep them current."
    missing = [claim for claim, family in INDEX_STRENGTHS.items()
               if not any(t in text for t in family)]
    assert missing == ["that lessons inform"]


# ── Reporting back ─────────────────────────────────────────────────────
#
# The reporting-back skill carries the shapes, but a skill only helps if it
# fires. The reflex that sends a session to it is stated in using-scribe, and
# the in-band cue on update_task (`placement`, `report_back`) is the half that
# fires on its own in every client. The server's index carries no REPORT line:
# reporting is a mid-work stance, not a session-start practice.

REPORT_REFLEX = "report back in a shape the operator can read"
REPORT_SURFACES = (
    ROOT / "plugin" / "skills" / "using-scribe" / "SKILL.md",
)


def test_the_reporting_reflex_is_stated_in_using_scribe():
    missing = []
    for path in REPORT_SURFACES:
        text = " ".join(path.read_text().split()).lower()
        if REPORT_REFLEX not in text or "reporting-back" not in text:
            missing.append(str(path.relative_to(ROOT)))
    assert not missing, (
        f"these surfaces no longer send a session to the reporting-back skill "
        f"({REPORT_REFLEX!r} plus the skill's name): {missing}. Without the "
        f"reflex the skill loads only when its description happens to match."
    )


def test_the_reporting_reflex_takes_placement_from_the_record():
    """A placement reconstructed from memory reads exactly like a real one
    when it is wrong."""
    for path in REPORT_SURFACES:
        text = " ".join(path.read_text().split())
        assert "`placement`" in text, f"{path.relative_to(ROOT)} no longer points at the placement block"