"""S7, the main acceptance test: rebuild-from-scratch equals incremental update.

Byte for byte, over the WHOLE tree, across a re-split, with the call-level
`ingested_at` deliberately different on every run.

Why it is written this way rather than copied from the existing multi-round
test. That test (`tests/test_inbox_structure.py`) passes the SAME `ingested_at`
constant every round and compares only `index.md`. It therefore holds for a
weaker reason than it appears to: a timestamp that leaked from the call into a
concept would be identical on both sides, and a concept body that diverged
would never be looked at. Both holes are closed here -- three distinct
call-level timestamps, and a comparison of the whole tree.

That the timestamps may differ at all is the design working: under a plan,
`ingested_at` comes from the PLAN ENTRY, never from the call. A rebuild months
later replays the adjudication and reproduces the bytes of the round that first
wrote the concept. If the call-level value leaked in, this test would be the
one that caught it.

**One deviation from the plan, stated rather than absorbed.** The plan also
asks that, with the write seam patched to raise, a SECOND run over an unchanged
inbox must not raise -- i.e. that an unchanged round writes nothing.
`materialize.write_bytes` writes unconditionally; no step in this plan makes it
conditional, and this step's own manifest forbids touching `inbox.py`, so the
property has no implementing code to assert against. The half that IS real --
the positive control proving the patch fires and that the segmented path routes
through the write seam at all -- is asserted below. Without that control, a
patch that silently never fired would make an empty bundle look like proof.
"""

from __future__ import annotations

import hashlib
import shutil
import subprocess
from pathlib import Path
from typing import Any

import pytest

from llm_ingestion_okf.errors import SegmentationError
from llm_ingestion_okf.inbox import GateDecision, process_inbox
from llm_ingestion_okf.profiles import SEGMENTED_V1
from llm_ingestion_okf.segmentation import SegmentationPlan, parse_segmentation_plan

# THREE distinct call-level values. None of them may reach a plan-covered
# concept, and the test is worthless if they are all the same.
ROUND_1_AT = "2026-07-25T12:00:00Z"
ROUND_2_AT = "2026-08-14T06:30:00Z"
REBUILD_AT = "2026-09-01T23:59:59Z"

PLAN_AT = "2026-08-30T09:00:00Z"

DOCUMENT = "Krav i konseptet.\n" * 20

# Round 1 names a segment round 2 does NOT. Without it the re-split would only
# ADD, and S7 would never exercise stale-segment retirement -- the Critical risk
# that makes an incremental bundle diverge from a scratch rebuild. Measured
# 2026-09-01: with retirement disabled and round 2 a superset, S7 stayed green.
ROUND_1_ENTRIES = (
    ("s0", "krav/brannkonsept.md", None),
    ("s9", "krav/utgaatt/tidligere-inndeling.md", None),
)
ROUND_2_ENTRIES = (
    ("s0", "krav/brannkonsept.md", None),
    ("s1", "krav/brannkonsept/seksjonering.md", "s0"),
    ("s2", "krav/brannkonsept/roemning.md", "s0"),
    ("s3", "krav/3-2/baereevne.md", None),
)


def gate(text: str) -> GateDecision:
    return GateDecision(sanitized_text=text, disposition="warn")


def drop(inbox: Path, name: str = "n500.md", text: str = DOCUMENT) -> Path:
    inbox.mkdir(parents=True, exist_ok=True)
    path = inbox / name
    path.write_text(text, encoding="utf-8", newline="")
    return path


def build_plan(
    source_bytes: bytes,
    entries: tuple[tuple[str, str, str | None], ...],
    **overrides: Any,
) -> SegmentationPlan:
    payload: dict[str, Any] = {
        "version": "1",
        "source_sha256": hashlib.sha256(source_bytes).hexdigest(),
        "extractor_id": "md",
        "extractor_version": "1.0.0",
        "adjudicated_at": "2026-08-30T08:00:00Z",
        "entries": [
            {
                "segment_id": segment_id,
                "path": path,
                "title": f"Del {segment_id}",
                "okf_type": "requirement",
                "span": [index * 10, index * 10 + 10],
                "ingested_at": PLAN_AT,
                **({"parent_id": parent} if parent else {}),
            }
            for index, (segment_id, path, parent) in enumerate(entries)
        ],
    }
    payload.update(overrides)
    return parse_segmentation_plan(payload)


def run(
    inbox: Path,
    bundle: Path,
    ingested_at: str,
    *,
    plan: SegmentationPlan | None,
    bundle_id: str | None = "b-1",
):
    return process_inbox(
        inbox,
        bundle,
        ingested_at,
        okf_type="requirement",
        gate=gate,
        profile=SEGMENTED_V1,
        root_frontmatter_values={"bundle_id": bundle_id} if bundle_id else {},
        segmentation=plan,
    )


def diff_trees(left: Path, right: Path) -> subprocess.CompletedProcess[str]:
    """`diff -r`, the literal S7 criterion.

    A recursive byte-walk would miss a directory present on only one side --
    exactly what a retired segment leaves behind when its parent is not pruned.
    `diff -r` reports it as `Only in ...`.
    """
    return subprocess.run(
        ["diff", "-r", str(left), str(right)], capture_output=True, text=True, check=False
    )


def build_incremental(tmp_path: Path) -> tuple[Path, SegmentationPlan]:
    source = drop(tmp_path / "one")
    run(
        tmp_path / "one",
        tmp_path / "incremental",
        ROUND_1_AT,
        plan=build_plan(source.read_bytes(), ROUND_1_ENTRIES),
    )
    drop(tmp_path / "two")
    second = build_plan(source.read_bytes(), ROUND_2_ENTRIES)
    run(tmp_path / "two", tmp_path / "incremental", ROUND_2_AT, plan=second)
    return tmp_path / "incremental", second


# --- S7 -------------------------------------------------------------------


def test_rebuild_from_scratch_equals_the_incremental_bundle(tmp_path: Path) -> None:
    incremental, final_plan = build_incremental(tmp_path)

    rebuild = tmp_path / "rebuild"
    shutil.rmtree(rebuild, ignore_errors=True)
    drop(tmp_path / "scratch")
    run(tmp_path / "scratch", rebuild, REBUILD_AT, plan=final_plan)

    result = diff_trees(rebuild, incremental)
    assert result.stdout == ""
    assert result.returncode == 0


def test_the_three_call_level_timestamps_really_do_differ() -> None:
    # The control for the test above. If these ever collapse to one value, S7
    # would pass for the weaker reason M3 measured in the existing suite.
    assert len({ROUND_1_AT, ROUND_2_AT, REBUILD_AT}) == 3


def test_no_concept_carries_a_call_level_timestamp(tmp_path: Path) -> None:
    incremental, _ = build_incremental(tmp_path)
    for path in incremental.rglob("*.md"):
        if path.name == SEGMENTED_V1.index.name:
            continue
        body = path.read_text(encoding="utf-8")
        assert f"ingested_at: {PLAN_AT}" in body
        for leaked in (ROUND_1_AT, ROUND_2_AT, REBUILD_AT):
            assert leaked not in body


def test_the_resplit_retired_a_segment_round_two_no_longer_names(tmp_path: Path) -> None:
    # The control for S7 itself. If round 2 only ADDED, S7 would stay green with
    # stale-segment retirement switched off entirely -- measured, not assumed.
    incremental, _ = build_incremental(tmp_path)
    assert not (incremental / "krav/utgaatt/tidligere-inndeling.md").exists()
    assert not (incremental / "krav/utgaatt").exists()


def test_the_resplit_actually_happened(tmp_path: Path) -> None:
    # Without this, S7 could pass over a bundle that never re-split at all.
    incremental, _ = build_incremental(tmp_path)
    concepts = {
        path.relative_to(incremental).as_posix()
        for path in incremental.rglob("*.md")
        if path.name != SEGMENTED_V1.index.name
    }
    assert len(concepts) == len(ROUND_2_ENTRIES)
    assert "krav/brannkonsept/seksjonering.md" in concepts


# --- S5: the write seam is the only path to disk --------------------------


def test_the_patched_write_seam_fires_on_the_first_run(
    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
) -> None:
    # The POSITIVE CONTROL. A patch that silently never fired would leave an
    # empty bundle, and an empty bundle is indistinguishable from "nothing
    # needed writing" -- a negative result read as a positive fact.
    source = drop(tmp_path / "one")

    def refuse(*args: object, **kwargs: object) -> Path:
        raise AssertionError("write seam reached")

    monkeypatch.setattr("llm_ingestion_okf.inbox.write_bytes", refuse)
    with pytest.raises(AssertionError, match="write seam reached"):
        run(
            tmp_path / "one",
            tmp_path / "bundle",
            ROUND_1_AT,
            plan=build_plan(source.read_bytes(), ROUND_2_ENTRIES),
        )


# --- bundle_id is load-bearing on the rebuild -----------------------------


def test_a_rebuild_omitting_the_bundle_id_is_refused_before_any_write(
    tmp_path: Path,
) -> None:
    source = drop(tmp_path / "scratch")
    with pytest.raises(SegmentationError) as excinfo:
        run(
            tmp_path / "scratch",
            tmp_path / "rebuild",
            REBUILD_AT,
            plan=build_plan(source.read_bytes(), ROUND_2_ENTRIES),
            bundle_id=None,
        )
    assert excinfo.value.code == "segmentation_plan_invalid"
    # Fail-fast, so there is no tree at all -- not a tree that merely differs.
    assert not (tmp_path / "rebuild").exists()


def test_a_different_bundle_id_changes_every_concept(tmp_path: Path) -> None:
    incremental, final_plan = build_incremental(tmp_path)
    drop(tmp_path / "scratch")
    other = tmp_path / "other"
    run(tmp_path / "scratch", other, REBUILD_AT, plan=final_plan, bundle_id="b-2")

    for path in other.rglob("*.md"):
        if path.name == SEGMENTED_V1.index.name:
            continue
        twin = incremental / path.relative_to(other)
        assert twin.is_file()
        assert path.read_bytes() != twin.read_bytes()

    assert diff_trees(other, incremental).returncode != 0