#!/usr/bin/env python3
"""Generate device_chain.inc: the structures a VkDeviceCreateInfo chain may hold, with their sizes.

The Xclipse layer copies the chain ahead of the VkPhysicalDeviceFeatures2 it edits, and copying a
structure needs its size. Run against the Vulkan-Headers release the build compiles with (Ubuntu
24.04's libvulkan-dev is 1.3.275):

    gen_device_chain.py Vulkan-Headers/registry/vk.xml Vulkan-Headers/include/vulkan/vulkan_core.h
"""
import re
import sys
import xml.etree.ElementTree as ElementTree
from pathlib import Path


def main(registry, core_header, output):
    core = Path(core_header).read_text()
    root = ElementTree.parse(registry).getroot()
    entries = []
    for struct in root.iter("type"):
        if struct.get("category") != "struct" or struct.get("alias"):
            continue
        if "VkDeviceCreateInfo" not in (struct.get("structextends") or "").split(","):
            continue
        name = struct.get("name")
        stype = next((member.get("values") for member in struct.findall("member")
                      if member.findtext("name") == "sType"), None)
        # Platform and provisional structures live outside vulkan_core.h; the layer never builds them.
        if not stype or not re.search(r"\}\s*" + re.escape(name) + r"\s*;", core):
            continue
        entries.append((stype, name))
    version = re.search(r"#define VK_HEADER_VERSION (\d+)", core).group(1)
    lines = ["/* Generated by gen_device_chain.py from Vulkan-Headers 1.3.%s; do not edit. */" % version]
    lines += ["DEVICE_CHAIN(%s, %s)" % entry for entry in sorted(entries)]
    Path(output).write_text("\n".join(lines) + "\n")
    print("%d structures" % len(entries))


if __name__ == "__main__":
    if len(sys.argv) not in (3, 4):
        sys.exit(__doc__)
    main(sys.argv[1], sys.argv[2], sys.argv[3] if len(sys.argv) == 4 else
         Path(__file__).with_name("device_chain.inc"))