"""Every image a bundle carries must be one a model can actually SHOW.

0.10.0 carried what a document declared, in whatever format the publisher
happened to ship. Measured 2026-09-19 over the frozen R761 delivery's own
`assets/` directory (denominator 50): 29 JPEG, 2 PNG and **19 "PC bitmap,
Windows 3.x, 8-bit, compression 1"** -- RLE8 BMP. The 19 are carried byte for
byte and are correct files; they are also files no model reads, so a figure
the bundle holds is a figure no arm can see. An absence a reader is shown is
information; a picture that is present and unreadable is worse than either,
because the count says it arrived.

THE PROPERTY, and it is a property rather than a list of formats we happen to
have met: for every asset in a built bundle, the format READ OFF ITS BYTES is
in the viewable set. A source image outside that set is converted losslessly
to PNG, or refused with a published code and a line in the concept saying what
stood there. Never carried silently in a format nothing can read.

The viewable set is stated here independently of the package, because a test
that imported the package's own constant would agree with it by construction
and measure nothing. Same for the rejection codes and the pixel grids below:
each guard is pinned against a count or a literal written out in this file, and
the lossless guard decodes through Pillow -- a decoder this package does not
use and does not ship -- so "identical pixels" is not this module agreeing with
itself.
"""

from __future__ import annotations

import hashlib
import io
import struct
import warnings
from pathlib import Path

import pytest

from llm_ingestion_okf import cli, corpus
from llm_ingestion_okf.assets import ASSETS_DIR, read_image, sniff
from llm_ingestion_okf.errors import ExtractionError

BUNDLE_ID = "asset-viewable-fixture"
OKF_VERSION = "0.2"

#: What a model can be shown. Written out here, never imported: the four
#: formats a vision-capable model decodes. A `.bmp`, a `.tiff` and a JPEG 2000
#: codestream are all legitimate image files and none of them is on this list.
VIEWABLE = frozenset({"image/png", "image/jpeg", "image/gif", "image/webp"})

#: The codes this file requires. Stated here so a rename of the package's own
#: constant cannot make these guards pass by agreeing with it.
CODE_NOT_VIEWABLE = "asset_not_viewable"
CODE_TOO_LARGE = "asset_too_large"

# --- fixtures built byte by byte, so the expected pixels are known ----------

#: Four RGB triples. Index 0 is white, which is also what an RLE delta skips
#: over, so the expected grid below states what a skip leaves behind.
PALETTE = bytes((255, 255, 255, 0, 0, 0, 200, 16, 32, 16, 96, 200))

#: An 8x4 image as palette indices, TOP-DOWN. Written out rather than
#: generated: this is the fasit the two decodings are both measured against.
EXPECTED_INDICES = (
    (1, 1, 1, 1, 1, 1, 1, 1),
    (0, 1, 2, 3, 3, 2, 1, 0),
    (3, 3, 3, 0, 0, 1, 1, 1),
    (0, 0, 0, 0, 0, 1, 2, 3),
)

#: The same image as an RLE8 opcode stream, BOTTOM-UP as the format requires,
#: exercising all five opcodes: encoded run, absolute run (with its pad byte),
#: delta, end-of-line and end-of-bitmap. A fixture using runs alone would pass
#: with a decoder that never implements the other three.
RLE8_STREAM = bytes(
    (
        0x05,
        0x00,
        0x00,
        0x03,
        0x01,
        0x02,
        0x03,
        0x00,
        0x00,
        0x00,
        0x03,
        0x03,
        0x00,
        0x02,
        0x02,
        0x00,
        0x03,
        0x01,
        0x00,
        0x00,
        0x00,
        0x08,
        0x00,
        0x01,
        0x02,
        0x03,
        0x03,
        0x02,
        0x01,
        0x00,
        0x00,
        0x00,
        0x08,
        0x01,
        0x00,
        0x01,
    )
)


def expected_rgb() -> bytes:
    return b"".join(PALETTE[index * 3 : index * 3 + 3] for row in EXPECTED_INDICES for index in row)


def _dib(width: int, height: int, bits: int, compression: int, body: int, entries: int) -> bytes:
    return struct.pack(
        "<IiiHHIIiiII", 40, width, height, 1, bits, compression, body, 3779, 3779, entries, entries
    )


def _file_header(offbits: int, body: int) -> bytes:
    return b"BM" + struct.pack("<IHHI", offbits + body, 0, 0, offbits)


def bmp_rle8(width: int, height: int, palette: bytes, stream: bytes) -> bytes:
    """A Windows 3.x 8-bit RLE8 BMP, the shape 19 of R761's 50 assets have."""
    entries = len(palette) // 3
    table = b"".join(
        bytes((palette[i * 3 + 2], palette[i * 3 + 1], palette[i * 3], 0)) for i in range(entries)
    )
    offbits = 14 + 40 + len(table)
    return (
        _file_header(offbits, len(stream))
        + _dib(width, height, 8, 1, len(stream), entries)
        + table
        + stream
    )


def bmp_24(rows: tuple[tuple[tuple[int, int, int], ...], ...]) -> bytes:
    """An uncompressed 24-bit BMP -- the other half of the order's fixture."""
    height = len(rows)
    width = len(rows[0])
    pad = b"\x00" * ((-width * 3) % 4)
    body = b"".join(
        b"".join(bytes((blue, green, red)) for (red, green, blue) in row) + pad
        for row in reversed(rows)
    )
    offbits = 14 + 40
    return _file_header(offbits, len(body)) + _dib(width, height, 24, 0, len(body), 0) + body


#: A minimal little-endian TIFF: one IFD with no usable entries. It is a real
#: TIFF by its magic and it is not a format this package can decode with the
#: stdlib, so it is the order's "cannot be converted" case.
TIFF_STUB = b"II\x2a\x00" + struct.pack("<I", 8) + struct.pack("<H", 0) + struct.pack("<I", 0)

RGB_ROWS = (
    ((255, 0, 0), (0, 255, 0), (0, 0, 255), (255, 255, 0), (0, 0, 0)),
    ((1, 2, 3), (4, 5, 6), (7, 8, 9), (10, 11, 12), (13, 14, 15)),
    ((255, 255, 255), (128, 128, 128), (0, 0, 0), (17, 34, 51), (68, 85, 102)),
)


def png_1x1() -> bytes:
    """A real PNG, built with zlib alone -- the already-viewable control."""
    import zlib

    def chunk(kind: bytes, payload: bytes) -> bytes:
        return (
            len(payload).to_bytes(4, "big")
            + kind
            + payload
            + zlib.crc32(kind + payload).to_bytes(4, "big")
        )

    ihdr = struct.pack(">IIBBBBB", 1, 1, 8, 2, 0, 0, 0)
    return (
        b"\x89PNG\r\n\x1a\n"
        + chunk(b"IHDR", ihdr)
        + chunk(b"IDAT", zlib.compress(b"\x00\x10\x20\x30", 9))
        + chunk(b"IEND", b"")
    )


def jpeg_bytes() -> bytes:
    """A real baseline JPEG, encoded by Pillow -- the second viewable control."""
    Image = pytest.importorskip("PIL.Image")
    buffer = io.BytesIO()
    Image.new("RGB", (4, 3), (10, 20, 30)).save(buffer, format="JPEG")
    return buffer.getvalue()


def _try_decode(data: bytes) -> tuple[tuple[int, int], bytes] | None:
    """`decode_rgb`, or `None` where the independent decoder cannot read it.

    Needed because this guard scans EVERY carried asset, and the point of the
    round is that a bundle may hold one nothing can decode. A raised
    `UnidentifiedImageError` would make the guard red for the helper's reason
    instead of for the claim's.
    """
    try:
        return decode_rgb(data)
    except Exception:
        return None


def decode_rgb(data: bytes) -> tuple[tuple[int, int], bytes]:
    """An INDEPENDENT decoding: Pillow, which this package neither uses nor ships."""
    Image = pytest.importorskip("PIL.Image")
    with Image.open(io.BytesIO(data)) as image:
        return image.size, image.convert("RGB").tobytes()


# --- the inbox and the build ------------------------------------------------


def _inbox(root: Path) -> Path:
    inbox = root / "inbox"
    (inbox / "graphics").mkdir(parents=True)
    (inbox / "graphics" / "figur-rle8.bmp").write_bytes(bmp_rle8(8, 4, PALETTE, RLE8_STREAM))
    (inbox / "graphics" / "figur-flat.bmp").write_bytes(bmp_24(RGB_ROWS))
    (inbox / "graphics" / "skjema.tiff").write_bytes(TIFF_STUB)
    (inbox / "prosess.html").write_text(
        "<!doctype html>\n<html><head><title>Prosess 84</title></head>\n<body>\n"
        "<h1>84 Konstruksjoner av betong</h1>\n"
        "<p>Toleranseklassene staar i figuren under.</p>\n"
        '<img src="graphics/figur-rle8.bmp" alt="Figur 84-1 Toleranseklasser">\n'
        "<p>Og prinsippet:</p>\n"
        '<img src="graphics/figur-flat.bmp" alt="Figur 84-2 Prinsipp">\n'
        "<p>Og skjemaet:</p>\n"
        '<img src="graphics/skjema.tiff" alt="Skjema 84-3">\n'
        "</body></html>\n",
        encoding="utf-8",
    )
    return inbox


def _build(inbox: Path, bundle: Path, *extra: str) -> int:
    with warnings.catch_warnings():
        warnings.simplefilter("ignore")
        return cli.main(
            [
                "build",
                str(inbox),
                "--bundle",
                str(bundle),
                "--bundle-id",
                BUNDLE_ID,
                "--okf-version",
                OKF_VERSION,
                *extra,
            ]
        )


def _concepts(bundle: Path) -> list[Path]:
    return [
        path
        for path in sorted(bundle.rglob("*.md"))
        if path.name not in {"index.md", corpus.LOG_NAME}
    ]


def _assets(bundle: Path) -> list[Path]:
    directory = bundle / ASSETS_DIR
    return sorted(p for p in directory.iterdir() if p.is_file()) if directory.is_dir() else []


# --- 1. visibility, as a property of every carried asset --------------------


def test_every_carried_asset_is_a_format_a_model_can_show(tmp_path: Path) -> None:
    """Eval point 1. RED before the conversion: two BMPs are carried as BMP.

    The denominator is counted in this test from the inbox itself, so a build
    that silently carried nothing would fail here rather than pass over an
    empty set -- the failure mode a "0 of 0 violations" assertion cannot see.
    """
    pytest.importorskip("llm_ingestion_guard")
    inbox = _inbox(tmp_path)
    dropped = [p for p in sorted((inbox / "graphics").iterdir()) if p.is_file()]
    assert len(dropped) == 3, dropped
    not_viewable_in = [p for p in dropped if (sniff(p.read_bytes()) or ("", ""))[0] not in VIEWABLE]
    assert len(not_viewable_in) == 3, not_viewable_in

    bundle = tmp_path / "bundle"
    assert _build(inbox, bundle) == 0
    carried = _assets(bundle)
    assert carried, "the build carried no asset at all"
    offending = [
        (path.name, (sniff(path.read_bytes()) or (None,))[0])
        for path in carried
        if (sniff(path.read_bytes()) or (None,))[0] not in VIEWABLE
    ]
    assert offending == [], (
        f"{len(offending)} of {len(carried)} carried assets are in a format no model "
        f"can show: {offending}"
    )


# --- 2. lossless, against a decoder this package does not use ---------------


def test_the_rle8_source_decodes_to_the_grid_this_file_states() -> None:
    """The fixture's own known-positive: without it, guard 2 could compare two
    wrong decodings and agree."""
    size, rgb = decode_rgb(bmp_rle8(8, 4, PALETTE, RLE8_STREAM))
    assert size == (8, 4)
    assert rgb == expected_rgb()


def test_the_carried_png_holds_the_source_pixels_exactly(tmp_path: Path) -> None:
    """Eval point 2. Same RGB per pixel, through the palette, 8x4 = 32 pixels."""
    pytest.importorskip("llm_ingestion_guard")
    bundle = tmp_path / "bundle"
    assert _build(_inbox(tmp_path), bundle) == 0
    sources = {
        "rle8": bmp_rle8(8, 4, PALETTE, RLE8_STREAM),
        "flat24": bmp_24(RGB_ROWS),
    }
    carried = {path.name: path.read_bytes() for path in _assets(bundle)}
    assert len(carried) >= 2, carried

    matched = 0
    for label, source in sources.items():
        source_size, source_rgb = decode_rgb(source)
        # VIEWABLE is part of the claim, not decoration: a BMP carried verbatim
        # trivially holds its own pixels, so a guard that did not require the
        # holder to be viewable would be green before the conversion exists.
        hits = [
            data
            for data in carried.values()
            if (sniff(data) or (None,))[0] in VIEWABLE
            and _try_decode(data) == (source_size, source_rgb)
        ]
        assert len(hits) == 1, f"{label}: {len(hits)} carried assets hold these pixels"
        matched += 1
    assert matched == 2
    assert len(expected_rgb()) == 8 * 4 * 3


# --- 3. the bundle says what happened ---------------------------------------


def test_the_bundle_records_the_conversion_per_asset(tmp_path: Path) -> None:
    """Eval point 3: original format, original checksum, new checksum."""
    pytest.importorskip("llm_ingestion_guard")
    bundle = tmp_path / "bundle"
    assert _build(_inbox(tmp_path), bundle) == 0
    text = "\n".join(path.read_text("utf-8") for path in _concepts(bundle))
    sources = (bmp_rle8(8, 4, PALETTE, RLE8_STREAM), bmp_24(RGB_ROWS))
    for source in sources:
        before = hashlib.sha256(source).hexdigest()
        assert before in text, f"the bundle never states the source checksum {before[:12]}"
    assert text.count("image/bmp") >= 2, "the bundle never states the original format"
    for path in _assets(bundle):
        after = hashlib.sha256(path.read_bytes()).hexdigest()
        assert path.name.startswith(after[:12]), path.name
    converted = [p for p in _assets(bundle) if p.suffix == ".png"]
    assert len(converted) == 2, converted
    for path in converted:
        assert hashlib.sha256(path.read_bytes()).hexdigest() in text


def test_a_converted_asset_is_one_asset_and_not_two(tmp_path: Path) -> None:
    """The accounting's rule: converting is not a second element.

    Two BMPs in, two files in `assets/`, two pointers, and the concept's own
    `images:` count agreeing with the pointers it holds.
    """
    pytest.importorskip("llm_ingestion_guard")
    bundle = tmp_path / "bundle"
    assert _build(_inbox(tmp_path), bundle) == 0
    assert len(_assets(bundle)) == 2, _assets(bundle)
    pointers = sum(path.read_text("utf-8").count("](/assets/") for path in _concepts(bundle))
    assert pointers == 2, pointers
    for path in _concepts(bundle):
        body = path.read_text("utf-8")
        if "\nimages: " in body:
            line = next(row for row in body.splitlines() if row.startswith("images: "))
            assert int(line.split(":", 1)[1]) == body.count("](/assets/")


# --- 4. the ceiling is checked before the pixels exist ----------------------


def test_a_bmp_declaring_a_huge_size_is_refused_before_it_is_decoded() -> None:
    """Eval point 4. The bound is on the DECLARATION, paid before the pixels."""
    import tracemalloc

    bomb = bmp_rle8(50_000, 50_000, PALETTE, bytes([0xFF, 0x01] * 64))
    assert len(bomb) < 4096, len(bomb)
    tracemalloc.start()
    try:
        with pytest.raises(ExtractionError) as caught:
            read_image(bomb, name="bombe.bmp")
    finally:
        _, peak = tracemalloc.get_traced_memory()
        tracemalloc.stop()
    assert caught.value.code == CODE_TOO_LARGE, caught.value.code
    assert peak < 4 * 1024 * 1024, peak


def test_an_rle_stream_longer_than_its_declared_image_costs_the_declaration() -> None:
    """An RLE8 run list that paints far past an 8x4 frame pays for 8x4."""
    import tracemalloc

    flood = bytes([0xFF, 0x02] * 400_000) + bytes((0x00, 0x01))
    bomb = bmp_rle8(8, 4, PALETTE, flood)
    assert len(bomb) > 800_000, len(bomb)
    tracemalloc.start()
    try:
        try:
            image = read_image(bomb, name="flom.bmp")
        except ExtractionError as exc:
            code = exc.code
            image = None
        else:
            code = None
    finally:
        _, peak = tracemalloc.get_traced_memory()
        tracemalloc.stop()
    if image is not None:
        assert sniff(image.data) is not None
        assert (sniff(image.data) or (None,))[0] in VIEWABLE
    else:
        assert code is not None
    # The whole file is 800 KB; decoding it must not cost a multiple of that.
    assert peak < 16 * 1024 * 1024, peak


# --- 5. the known-positive: what is already viewable does not move ----------


def test_a_png_is_carried_byte_for_byte() -> None:
    """Eval point 5, in-test half. Conversion must reach nothing already viewable."""
    data = png_1x1()
    image = read_image(data, name="figur.png")
    assert image.data == data
    assert image.media_type == "image/png"
    assert image.suffix == ".png"


def test_a_jpeg_is_carried_byte_for_byte() -> None:
    data = jpeg_bytes()
    image = read_image(data, name="figur.jpg")
    assert image.data == data
    assert image.media_type == "image/jpeg"
    assert image.suffix == ".jpg"


# --- 6. what cannot be converted is refused out loud ------------------------


def test_a_tiff_is_refused_with_a_published_code() -> None:
    """Eval point 6: never silently carried in a format nothing reads."""
    with pytest.raises(ExtractionError) as caught:
        read_image(TIFF_STUB, name="skjema.tiff")
    assert caught.value.code == CODE_NOT_VIEWABLE, caught.value.code


def test_a_corrupt_bmp_is_refused_with_a_published_code() -> None:
    """A BMP header with a body that stops mid-stream is a refusal, not a guess."""
    truncated = bmp_rle8(8, 4, PALETTE, RLE8_STREAM)[:60]
    with pytest.raises(ExtractionError) as caught:
        read_image(truncated, name="kuttet.bmp")
    assert caught.value.code.startswith("asset_"), caught.value.code


def test_the_refused_image_leaves_a_row_the_reader_can_see(tmp_path: Path) -> None:
    """A refusal is a line in the concept and a row in the run log."""
    pytest.importorskip("llm_ingestion_guard")
    bundle = tmp_path / "bundle"
    assert _build(_inbox(tmp_path), bundle) == 0
    text = "\n".join(path.read_text("utf-8") for path in _concepts(bundle))
    assert "not carried" in text
    assert "skjema.tiff" in text
    log = (bundle / corpus.LOG_NAME).read_text("utf-8")
    assert "image" in log.lower()