#!/usr/bin/env python3
"""Deterministic authored ZIP inputs for the bounded-input expansion guard."""
import hashlib
import json
from pathlib import Path
import struct
import zlib

ROOT = Path(__file__).resolve().parent


def build(output_size: int, padded_size: int | None = None) -> tuple[bytes, dict]:
    plain = b"x" * output_size
    compressor = zlib.compressobj(9, zlib.DEFLATED, -15)
    compressed = compressor.compress(plain) + compressor.flush()
    payload = compressed if padded_size is None else compressed.ljust(padded_size, b"\0")
    name = b"index.html"
    crc = zlib.crc32(plain)
    local = struct.pack("<IHHHHHIIIHH", 0x04034B50, 20, 0x800, 8, 0, 33,
                        crc, len(payload), len(plain), len(name), 0)
    central = struct.pack("<IHHHHHHIIIHHHHHII", 0x02014B50, (3 << 8) | 20,
                          20, 0x800, 8, 0, 33, crc, len(payload), len(plain),
                          len(name), 0, 0, 0, 0, 0o100600 << 16, 0) + name
    offset = len(local) + len(name) + len(payload)
    end = struct.pack("<IHHHHIIH", 0x06054B50, 0, 0, 1, 1, len(central), offset, 0)
    archive = local + name + payload + central + end
    return archive, {
        "output_bytes": len(plain), "deflate_stream_bytes": len(compressed),
        "zip_declared_compressed_bytes": len(payload),
        "sha256": hashlib.sha256(archive).hexdigest(),
        "output_sha256": hashlib.sha256(plain).hexdigest(),
    }


def main() -> None:
    manifest = {"generator": "generate.py; Python stdlib zlib, raw DEFLATE",
                "content": "Authored repeated ASCII x; no external material or fonts.", "files": {}}
    for name, size, padded, expectation in [
        ("padded-33mib.zip", 33 * 1024 * 1024, 256 * 1024, "open succeeds; extraction E_ARCHIVE_LIMIT before more than 32 MiB is sent"),
        ("threshold-32mib.zip", 32 * 1024 * 1024, None, "open and extraction succeed; ratio threshold is strictly greater than 32 MiB"),
        ("unpadded-33mib.zip", 33 * 1024 * 1024, None, "open E_ARCHIVE_LIMIT from metadata preflight"),
    ]:
        archive, info = build(size, padded)
        (ROOT / name).write_bytes(archive)
        manifest["files"][name] = info | {"expected": expectation}
    (ROOT / "manifest.json").write_text(json.dumps(manifest, indent=2) + "\n")


if __name__ == "__main__":
    main()