#!/usr/bin/env python3
"""Build Blender's pinned Alembic for the existing Web CacheFile reader."""

import hashlib
from pathlib import Path
import re
import subprocess
import tarfile
import urllib.request


ROOT = Path(__file__).resolve().parents[2]
BASE = ROOT / "build_web_alembic"
OCIO = ROOT / "build_web_ocio/install"


def main():
    versions = (ROOT / "blender-5.2.0/build_files/build_environment/cmake/versions.cmake").read_text()
    version = re.search(r"set\(ALEMBIC_VERSION ([^)]+)\)", versions)[1]
    expected = re.search(r"set\(ALEMBIC_HASH ([^)]+)\)", versions)[1]
    algorithm = re.search(r"set\(ALEMBIC_HASH_TYPE ([^)]+)\)", versions)[1].lower()
    if not (OCIO / "lib/cmake/Imath/ImathConfig.cmake").is_file():
        raise SystemExit("Reuse/build the Web OCIO Imath installation first")
    BASE.mkdir(exist_ok=True)
    source = BASE / ("alembic-" + version)
    if not (source / "CMakeLists.txt").is_file():
        archive = BASE / ("alembic-" + version + ".tar.gz")
        if not archive.is_file():
            with urllib.request.urlopen(
                "https://codeload.github.com/alembic/alembic/tar.gz/" + version,
                timeout=60,
            ) as response:
                data = response.read()
            if hashlib.new(algorithm, data).hexdigest() != expected:
                raise SystemExit("Alembic download differs from Blender's pinned source hash")
            archive.write_bytes(data)
        if hashlib.new(algorithm, archive.read_bytes()).hexdigest() != expected:
            raise SystemExit("Alembic archive differs from Blender's pinned source hash")
        with tarfile.open(archive) as package:
            package.extractall(BASE, filter="data")
    toolchain = ROOT / ".emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake"
    subprocess.run([
        "cmake", "-S", str(source), "-B", str(BASE / "build"), "-G", "Ninja",
        "-DCMAKE_TOOLCHAIN_FILE=" + str(toolchain),
        "-DCMAKE_BUILD_TYPE=Release", "-DCMAKE_INSTALL_LIBDIR=lib",
        "-DCMAKE_INSTALL_PREFIX=" + str(BASE / "install"),
        "-DCMAKE_PREFIX_PATH=" + str(OCIO), "-DCMAKE_FIND_ROOT_PATH=" + str(OCIO),
        "-DImath_DIR=" + str(OCIO / "lib/cmake/Imath"),
        "-DCMAKE_CXX_FLAGS=-fexceptions", "-DALEMBIC_SHARED_LIBS=OFF",
        "-DUSE_HDF5=OFF", "-DUSE_TESTS=OFF", "-DUSE_BINARIES=OFF",
        "-DUSE_EXAMPLES=OFF", "-DUSE_PYALEMBIC=OFF", "-DUSE_MAYA=OFF",
        "-DUSE_ARNOLD=OFF", "-DUSE_PRMAN=OFF",
    ], cwd=ROOT, check=True)
    subprocess.run(["cmake", "--build", str(BASE / "build"), "--target", "install",
                    "--parallel", "8"], cwd=ROOT, check=True)


if __name__ == "__main__":
    main()