#!/usr/bin/env python3
"""
Positive controls for the reduction tooling.

Control Kernel v1.0 §3: "Each check ships with a positive control — a fixture it
is shown to fail on — before any result from it is believed. An absence is not
evidence until the instrument is shown capable of detecting presence."

So every gate below is shown FAILING on a fixture built to break it, and passing
on one built not to. A gate only ever demonstrated passing has demonstrated
nothing.

Usage: ./test_reduce.py
"""

from __future__ import annotations

import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent))
from reduce import (  # noqa: E402
    FORBIDDEN_HEADING_RE,
    TAGGABLE,
    split_spans,
    verify_tiling,
)

failures: list[str] = []


def check(name: str, got, want, detail: str = "") -> None:
    if got != want:
        failures.append(f"{name}: expected {want!r}, got {got!r}. {detail}")
        print(f"  FAIL  {name}")
    else:
        print(f"  ok    {name}")


SAMPLE = """# A heading

Some prose here. It has two sentences.

- a list item
- another

> a quoted block

```
code that must not be split. really.
```

Final paragraph, e.g. with an abbreviation inside it. And a second sentence.
"""

print("Tiling invariant — the gate everything else depends on:")
spans = split_spans(SAMPLE)
check("sample tiles cleanly", verify_tiling(spans, SAMPLE), [])
check(
    "spans reproduce source byte-for-byte",
    "".join(SAMPLE[s["start"]:s["end"]] for s in spans),
    SAMPLE,
)

print("\nPositive control — the gate must DETECT a broken tiling:")
gap = [dict(s) for s in spans]
gap[2]["start"] += 1  # open a one-byte hole
check("gap detected", len(verify_tiling(gap, SAMPLE)) > 0, True, "gate blind to a gap")

overlap = [dict(s) for s in spans]
overlap[2]["start"] -= 1  # overlap the previous span
check("overlap detected", len(verify_tiling(overlap, SAMPLE)) > 0, True)

truncated = [dict(s) for s in spans[:-1]]
check("truncation detected", len(verify_tiling(truncated, SAMPLE)) > 0, True)

print("\nSplitter behaviour:")
prose = [s for s in spans if s["kind"] == "prose"]
texts = [SAMPLE[s["start"]:s["end"]] for s in prose]
check("abbreviation did not split 'e.g.'", sum("e.g." in t for t in texts), 1)
check(
    "'e.g.' sentence not broken after the abbreviation",
    any(t.strip().startswith("Final paragraph, e.g. with") for t in texts),
    True,
    f"prose units: {texts}",
)
check("two sentences found in para 1", sum("Some prose here." in t for t in texts), 1)
check(
    "code fence never becomes prose",
    any("code that must not be split" in SAMPLE[s["start"]:s["end"]] and s["kind"] == "code"
        for s in spans),
    True,
)
check(
    "list items are not prose",
    all("a list item" not in t for t in texts),
    True,
)
check("headings are taggable", "heading" in TAGGABLE, True,
      "kernel §4 rules a heading can assert")

print("\nDefects found by contact with a real ruling (splitter v1.1.0):")

FENCED = """Ready to paste:

```
## REVIEWED-85 — a heading INSIDE a fence
**Date:** 2026-08-01
```

After the fence.
"""
fspans = split_spans(FENCED)
check("fenced doc tiles", verify_tiling(fspans, FENCED), [])
check(
    "(a) '##' inside a fence is code, not a taggable heading",
    any(s["kind"] == "heading" and "REVIEWED-85" in FENCED[s["start"]:s["end"]]
        for s in fspans),
    False,
    "quoted content must not become structure of the quoting document",
)

RULE = "Some prose.\n\n---\n\nMore prose.\n"
rspans2 = split_spans(RULE)
check("rule doc tiles", verify_tiling(rspans2, RULE), [])
check(
    "(b) '---' is not taggable",
    any(s["kind"] in TAGGABLE and RULE[s["start"]:s["end"]].strip() == "---"
        for s in rspans2),
    False,
)

QUOTED = 'The alternative — collapse to "does it change what X asserts?" alone — is less safe.\n'
qspans = split_spans(QUOTED)
check("quoted-question doc tiles", verify_tiling(qspans, QUOTED), [])
check(
    "(c) '?' inside a quotation does not create a fragment",
    len([s for s in qspans if s["kind"] == "prose"]),
    1,
    f"got {[QUOTED[s['start']:s['end']] for s in qspans if s['kind'] == 'prose']}",
)
TWO = 'Is it sound? It is not.\n'
check(
    "(c) a real sentence boundary still splits",
    len([s for s in split_spans(TWO) if s["kind"] == "prose"]),
    2,
    "over-suppression would hide real boundaries",
)

print("\nForbidden-heading detector (§3.3) — must fire, and must not over-fire:")
for h in ("## Limitations", "## What this does not do", "### Open questions",
          "## Caveats and scope", "## Assumptions"):
    check(f"fires on {h!r}", bool(FORBIDDEN_HEADING_RE.search(h)), True)
for h in ("## Part I — Grounding", "## The ruling", "## Conditions",
          "## What changed"):
    check(f"quiet on {h!r}", bool(FORBIDDEN_HEADING_RE.search(h)), False)

print("\nReal document — the splitter must tile actual governance prose:")
REAL = Path(__file__).resolve().parent.parent / "skill-harvest-fix-lane-JURIST-RULING-2026-08-01.md"
if REAL.is_file():
    text = REAL.read_text(encoding="utf-8")
    rspans = split_spans(text)
    check(f"{REAL.name} tiles cleanly", verify_tiling(rspans, text), [])
else:
    failures.append(f"real document absent: {REAL}")
    print(f"  FAIL  {REAL.name} not found")

if failures:
    print(f"\nINSTRUMENT NOT VERIFIED — {len(failures)} failure(s):")
    for f in failures:
        print(f"  - {f}")
    sys.exit(1)

print("\nAll gates verified, each shown failing on a fixture built to break it.")