#!/usr/bin/env python3

import re
import sys
import os
import shutil
import stat
import subprocess

is_bad_lib = re.compile(r'(/usr/local|/opt)').match
is_sys_lib = re.compile(r'(/usr|/System)').match
otool_libname_extract = re.compile(r'\s+([/@].*?)[(\s:]').search
goodlist = []
badlist = []
badlist_orig = []
link_map = {}


def otool(cmdline):
    with subprocess.Popen(['otool'] + cmdline, stdout=subprocess.PIPE,
                          encoding='utf-8') as p:
        return p.stdout.readlines()


def get_rpath(lib):
    info = otool(['-l', lib])
    commands = []
    command = []
    for line in info:
        line = line.strip()
        if line.startswith("Load command "):
            commands.append(command)
            command = []
        else:
            command.append(line)
    commands.append(command)

    # yuck
    return [line.split()[1] for command in commands if "cmd LC_RPATH" in command for line in command if line.startswith("path")]


def collectlibs(lib, masterlist, targetdir):
    global goodlist, link_map
    liblist = otool(['-L', lib])
    locallist = []

    for l in liblist:
        l = otool_libname_extract(l)
        if not l:
            continue

        l = l.group(1)
        l_orig = l

        if l.startswith("@rpath/"):
            rpath = get_rpath(lib)

            if not rpath:
                print(f"{lib} uses @rpath but has no rpath set!")
                exit(-1)

            # all cases of libs using rpath so far just had a single directory in rpath...
            # so let's just hope it stays that way and worry about the other cases when we get to them
            if len(rpath) >= 2:
                print(f"Warning: {lib} uses @rpath with more than one entry in rpath. Guessing one entry...")

            l = os.path.join(rpath[0], l[len("@rpath/"):])

        if l.startswith("@loader_path/"):
            l = os.path.join(os.path.dirname(lib), l[len("@loader_path/"):])

        if is_bad_lib(l):
            if l not in badlist:
                badlist.append(l)
            if l_orig not in badlist_orig:
                badlist_orig.append(l_orig)
        if ((not is_sys_lib(l)) or is_bad_lib(l)) and l not in masterlist:
            locallist.append(l)
            print("found %s:" % l)

            check = l
            link_list = []
            while check:
                basename = os.path.basename(check)
                target = os.path.join(targetdir, basename)

                if os.path.islink(target):
                    # If a library was a symlink to a file with the same name in another directory,
                    # this could otherwise cause a FileNotFoundError
                    os.remove(target)

                if os.path.isfile(check) and not os.path.islink(check):
                    try:
                        shutil.copy(check, target)
                    except PermissionError:
                        print("    FILE %s ... skipped" % check)
                        break
                    print("    FILE %s ... copied to target" % check)
                    if link_list:
                        for link in link_list:
                            link_map[link] = basename
                    break

                if os.path.islink(check):
                    link_dst = os.readlink(check)
                    if os.path.basename(check) == os.path.basename(link_dst):
                        check = os.path.join(os.path.dirname(check), link_dst)
                        continue

                    try:
                        os.symlink(link_dst, target)
                    except FileExistsError:
                        print("    LINK %s ... existed" % check)
                        break
                    print("    LINK %s (%s) ... copied to target" % (check, link_dst))
                    link_list.append(basename)
                    check = os.path.join(os.path.dirname(check), link_dst)
        elif l not in goodlist and l not in masterlist:
            goodlist.append(l)
    masterlist.extend(locallist)

    for l in locallist:
        collectlibs(l, masterlist, targetdir)


if __name__ == '__main__':
    binname = sys.argv[1]
    targetdir = os.path.dirname(binname)
    print("Searching for libraries in", binname, "...")
    libs = [binname]
    collectlibs(binname, libs, targetdir)

    print()
    print("System libraries used...")
    goodlist.sort()
    for l in goodlist:
        print(l)

    print()
    print("Fixing library install names...")
    in_tool_cmdline = ['install_name_tool']
    for lib in badlist_orig:
        libbase = os.path.basename(lib)
        if libbase in link_map:
            print("%s -> @executable_path/%s (REMAPPED)" % (lib, libbase))
            libbase = link_map[libbase]
        else:
            print("%s -> @executable_path/%s" % (lib, libbase))
        in_tool_cmdline = in_tool_cmdline + ['-change', lib,
                                             '@executable_path/' + libbase]
    for lib in libs:
        libbase = os.path.basename(lib)

        if libbase in link_map:
            libbase = link_map[libbase]

        targetlib = targetdir + '/' + libbase
        orig_permission = os.stat(targetlib).st_mode
        if not(orig_permission & stat.S_IWUSR):
            os.chmod(targetlib, orig_permission | stat.S_IWUSR)
        subprocess.run(in_tool_cmdline + ['-id', '@executable_path/' + libbase,
                                          targetlib])
        if not(orig_permission & stat.S_IWUSR):
            os.chmod(targetlib, orig_permission)

    if badlist:
        print()
        print("WARNING: The following libraries have blacklisted paths:")
        for lib in sorted(badlist):
            print(lib)
        print(
            "These paths normally have files from a package manager, which means that end result may not work if copied to another machine.")

    print()
    print("All done!")