#!/usr/bin/env python3
"""Resolve every import of the macOS ARM64 slice against the iOS SDK's text stubs.

Usage: python3 tools/native_audit.py build/factorio.arm64 [--json out.json]

For each LC_LOAD_DYLIB the import is looked up in the iOS library with the same
framework name, following re-exported libraries. Imports that do not resolve
must be supplied by a shim. Nothing on the device is consulted, so this is a
link-level audit only; Objective-C selectors are not checked.
"""
import json
import re
import subprocess
import sys
from pathlib import Path

SDK = Path(subprocess.check_output(["xcrun", "--sdk", "iphoneos", "--show-sdk-path"], text=True).strip())


def tbd_documents():
    """Yield (install_name, symbols, reexports) for every tbd document in the SDK."""
    files = list((SDK / "usr/lib").rglob("*.tbd")) + list((SDK / "System/Library").rglob("*.tbd"))
    for path in files:
        text = path.read_text(errors="ignore")
        for doc in re.split(r"^--- !tapi-tbd", text, flags=re.M):
            name = re.search(r"^install-name:\s*'?([^'\n]+)'?", doc, re.M)
            if not name:
                continue
            exports = doc.split("\nreexports:")[0].split("\nundefineds:")[0]
            symbols = set()
            for kind, prefix in (("symbols", ""), ("weak-symbols", ""), ("thread-local-symbols", ""),
                                 ("objc-classes", "class"), ("objc-eh-types", "eh"), ("objc-ivars", "ivar")):
                for block in re.findall(rf"\b{kind}:\s*\[([^\]]*)\]", exports):
                    for item in block.split(","):
                        item = item.strip().strip("'\"")
                        if not item:
                            continue
                        if prefix == "class":
                            symbols.update({f"_OBJC_CLASS_$_{item}", f"_OBJC_METACLASS_$_{item}"})
                        elif prefix == "eh":
                            symbols.add(f"_OBJC_EHTYPE_$_{item}")
                        elif prefix == "ivar":
                            symbols.add(f"_OBJC_IVAR_$_{item}")
                        else:
                            symbols.add(item)
            reexports = set()
            for block in re.findall(r"reexported-libraries:.*?libraries:\s*\[([^\]]*)\]", doc, re.S):
                reexports.update(x.strip().strip("'\"") for x in block.split(",") if x.strip())
            yield name.group(1), symbols, reexports


def main():
    binary = sys.argv[1]
    libs = {}
    for name, symbols, reexports in tbd_documents():
        entry = libs.setdefault(name, [set(), set()])
        entry[0] |= symbols
        entry[1] |= reexports

    def resolves(install, symbol, seen=()):
        if install not in libs or install in seen:
            return False
        symbols, reexports = libs[install]
        return symbol in symbols or any(resolves(r, symbol, seen + (install,)) for r in reexports)

    def ios_path(mac_path):
        if mac_path in libs:  # e.g. IOKit keeps its Versions/A install name on iOS
            return mac_path
        m = re.match(r"/System/Library/Frameworks/(\w+)\.framework/", mac_path)
        if m:
            return f"/System/Library/Frameworks/{m.group(1)}.framework/{m.group(1)}"
        return mac_path

    loads = re.findall(r"cmd LC_LOAD(?:_WEAK)?_DYLIB\n\s+cmdsize \d+\n\s+name (\S+)",
                       subprocess.check_output(["otool", "-l", binary], text=True))
    short = {Path(p).name.replace(".dylib", "").split(".")[0]: p for p in loads}
    undef = subprocess.check_output(["nm", "-m", "-u", binary], text=True)
    report = {}
    for line in undef.splitlines():
        m = re.search(r"external (\S+) \(from (\S+)\)", line)
        if not m:
            continue
        symbol, lib = m.groups()
        mac = short.get(lib)
        target = ios_path(mac) if mac else None
        status = "resolved" if target and resolves(target, symbol) else "missing"
        lib_report = report.setdefault(lib, {"mac_path": mac, "ios_path": target,
                                             "ios_library_exists": target in libs,
                                             "resolved": 0, "missing": []})
        if status == "resolved":
            lib_report["resolved"] += 1
        else:
            lib_report["missing"].append(symbol)
    for lib, r in sorted(report.items(), key=lambda kv: -len(kv[1]["missing"])):
        print(f"{lib:20} exists={r['ios_library_exists']!s:5} resolved={r['resolved']:4} missing={len(r['missing']):3} "
              + " ".join(r["missing"][:12]) + (" ..." if len(r["missing"]) > 12 else ""))
    if "--json" in sys.argv:
        Path(sys.argv[sys.argv.index("--json") + 1]).write_text(json.dumps(report, indent=2) + "\n")


if __name__ == "__main__":
    main()