#!/usr/bin/env python3
# PYTHON_ARGCOMPLETE_OKAY
# -
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2018 Alex Richardson <arichardson@FreeBSD.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
#

# This script makes it easier to build on non-FreeBSD systems by bootstrapping
# bmake and inferring required compiler variables.
#
# On FreeBSD you can use it the same way as just calling make:
# `MAKEOBJDIRPREFIX=~/obj ./tools/build/make.py buildworld -DWITH_FOO`
#
# On Linux and MacOS you may need to explicitly indicate the cross toolchain
# to use.  You can do this by:
# - setting XCC/XCXX/XLD/XCPP to the paths of each tool
# - using --cross-bindir to specify the path to the cross-compiler bindir:
#   `MAKEOBJDIRPREFIX=~/obj ./tools/build/make.py
#    --cross-bindir=/path/to/cross/compiler buildworld -DWITH_FOO TARGET=foo
#    TARGET_ARCH=bar`
# - using --cross-toolchain to specify the package containing the cross-compiler
#   (MacOS only currently):
#   `MAKEOBJDIRPREFIX=~/obj ./tools/build/make.py
#    --cross-toolchain=llvm@NN buildworld -DWITH_FOO TARGET=foo
#    TARGET_ARCH=bar`
#
# On MacOS, this tool will search for an llvm toolchain installed via brew and
# use it as the cross toolchain if an explicit toolchain is not specified.

import argparse
import functools
import os
import shlex
import shutil
import subprocess
import sys
from pathlib import Path


# List of targets that are independent of TARGET/TARGET_ARCH and thus do not
# need them to be set. Keep in the same order as Makefile documents them (if
# they are documented).
mach_indep_targets = [
    "cleanuniverse",
    "universe",
    "universe-toolchain",
    "tinderbox",
    "worlds",
    "kernels",
    "kernel-toolchains",
    "targets",
    "toolchains",
    "makeman",
    "sysent",
]


def run(cmd, **kwargs):
    cmd = list(map(str, cmd))  # convert all Path objects to str
    debug("Running", cmd)
    subprocess.check_call(cmd, **kwargs)


# Always bootstraps in order to control bmake's config to ensure compatibility
def bootstrap_bmake(source_root, objdir_prefix):
    bmake_source_dir = source_root / "contrib/bmake"
    bmake_build_dir = objdir_prefix / "bmake-build"
    bmake_install_dir = objdir_prefix / "bmake-install"
    bmake_binary = bmake_install_dir / "bin/bmake"
    bmake_config = bmake_install_dir / ".make-py-config"

    bmake_source_version = subprocess.run([
        "sh", "-c", ". \"$0\"/VERSION; echo $_MAKE_VERSION", bmake_source_dir],
        stdout=subprocess.PIPE, stderr=subprocess.PIPE).stdout.strip()
    try:
        bmake_source_version = int(bmake_source_version)
    except ValueError:
        sys.exit("Invalid source bmake version '" + bmake_source_version + "'")

    bmake_installed_version = 0
    if bmake_binary.exists():
        bmake_installed_version = subprocess.run([
            bmake_binary, "-r", "-f", "/dev/null", "-V", "MAKE_VERSION"],
            stdout=subprocess.PIPE, stderr=subprocess.PIPE).stdout.strip()
        try:
            bmake_installed_version = int(bmake_installed_version.strip())
        except ValueError:
            print("Invalid installed bmake version '" +
                  bmake_installed_version + "', treating as not present")

    configure_args = [
        "--with-default-sys-path=.../share/mk:" +
        str(bmake_install_dir / "share/mk"),
        "--with-machine=amd64",  # TODO? "--with-machine-arch=amd64",
        "--without-filemon", "--prefix=" + str(bmake_install_dir)]

    configure_args_str = ' '.join([shlex.quote(x) for x in configure_args])
    if bmake_config.exists():
        last_configure_args_str = bmake_config.read_text()
    else:
        last_configure_args_str = ""

    debug("Source bmake version: " + str(bmake_source_version))
    debug("Installed bmake version: " + str(bmake_installed_version))
    debug("Configure args: " + configure_args_str)
    debug("Last configure args: " + last_configure_args_str)

    if bmake_installed_version == bmake_source_version and \
       configure_args_str == last_configure_args_str:
        return bmake_binary

    print("Bootstrapping bmake...")
    if bmake_build_dir.exists():
        shutil.rmtree(str(bmake_build_dir))
    if bmake_install_dir.exists():
        shutil.rmtree(str(bmake_install_dir))

    os.makedirs(str(bmake_build_dir))

    env = os.environ.copy()
    global new_env_vars
    env.update(new_env_vars)

    run(["sh", bmake_source_dir / "boot-strap"] + configure_args,
        cwd=str(bmake_build_dir), env=env)
    run(["sh", bmake_source_dir / "boot-strap", "op=install"] + configure_args,
        cwd=str(bmake_build_dir))
    bmake_config.write_text(configure_args_str)

    print("Finished bootstrapping bmake...")
    return bmake_binary


def debug(*args, **kwargs):
    global parsed_args
    if parsed_args.debug:
        print(*args, **kwargs)


def is_make_var_set(var):
    return any(
        x.startswith(var + "=") or x == ("-D" + var) for x in sys.argv[1:])


def check_required_make_env_var(varname, binary_name, bindir):
    global new_env_vars
    if os.getenv(varname):
        return
    if not bindir:
        sys.exit("Could not infer value for $" + varname + ". Either set $" +
                 varname + " or pass --cross-bindir=/cross/compiler/dir/bin" +
                 " or --cross-toolchain=<package>")
    # try to infer the path to the tool
    guess = os.path.join(bindir, binary_name)
    if not os.path.isfile(guess):
        sys.exit("Could not infer value for $" + varname + ": " + guess +
                 " does not exist")
    new_env_vars[varname] = guess
    debug("Inferred", varname, "as", guess)
    global parsed_args
    if parsed_args.debug:
        run([guess, "--version"])


def check_xtool_make_env_var(varname, binary_name):
    # Avoid calling brew --prefix on macOS if all variables are already set:
    if os.getenv(varname):
        return
    global parsed_args
    if parsed_args.cross_bindir is None:
        cross_bindir = cross_toolchain_bindir(binary_name,
                                              parsed_args.cross_toolchain)
    else:
        cross_bindir = parsed_args.cross_bindir
    return check_required_make_env_var(varname, binary_name,
                                       cross_bindir)


@functools.cache
def brew_prefix(package: str) -> str:
    path = subprocess.run(["brew", "--prefix", package], stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE).stdout.strip()
    debug("Inferred", package, "dir as", path)
    return path.decode("utf-8")

def binary_path(bindir: str, binary_name: str) -> "Optional[str]":
    try:
        if bindir and Path(bindir, "bin", binary_name).exists():
            return str(Path(bindir, "bin"))
    except OSError:
        pass
    return None

def cross_toolchain_bindir(binary_name: str, package: "Optional[str]") -> str:
    # default to homebrew-installed clang on MacOS if available
    if sys.platform.startswith("darwin"):
        if shutil.which("brew"):
            if not package:
                package = "llvm"
            bindir = binary_path(brew_prefix(package), binary_name)
            if bindir:
                return bindir

            # brew installs lld as a separate package for LLVM 19 and later
            if binary_name == "ld.lld":
                lld_package = package.replace("llvm", "lld")
                bindir = binary_path(brew_prefix(lld_package), binary_name)
                if bindir:
                    return bindir
    return None


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser.add_argument("--host-bindir",
                        help="Directory to look for cc/c++/cpp/ld to build "
                             "host (" + sys.platform + ") binaries",
                        default="/usr/bin")
    parser.add_argument("--cross-bindir", default=None,
                        help="Directory to look for cc/c++/cpp/ld to build "
                             "target binaries (only needed if XCC/XCPP/XLD "
                             "are not set)")
    parser.add_argument("--cross-compiler-type", choices=("clang", "gcc"),
                        default="clang",
                        help="Compiler type to find in --cross-bindir (only "
                             "needed if XCC/XCPP/XLD are not set)"
                             "Note: using CC is currently highly experimental")
    parser.add_argument("--cross-toolchain", default=None,
                        help="Name of package containing cc/c++/cpp/ld to build "
                             "target binaries (only needed if XCC/XCPP/XLD "
                             "are not set)")
    parser.add_argument("--host-compiler-type", choices=("cc", "clang", "gcc"),
                        default="cc",
                        help="Compiler type to find in --host-bindir (only "
                             "needed if CC/CPP/CXX are not set). ")
    parser.add_argument("--debug", action="store_true",
                        help="Print information on inferred env vars")
    parser.add_argument("--bootstrap-toolchain", action="store_true",
                        help="Bootstrap the toolchain instead of using an "
                             "external one (experimental and not recommended)")
    parser.add_argument("--clean", action="store_true",
                        help="Do a clean rebuild instead of building with "
                             "-DWITHOUT_CLEAN")
    parser.add_argument("--no-clean", action="store_false", dest="clean",
                        help="Do a clean rebuild instead of building with "
                             "-DWITHOUT_CLEAN")
    try:
        import argcomplete  # bash completion:

        argcomplete.autocomplete(parser)
    except ImportError:
        pass
    parsed_args, bmake_args = parser.parse_known_args()

    MAKEOBJDIRPREFIX = os.getenv("MAKEOBJDIRPREFIX")
    if not MAKEOBJDIRPREFIX:
        sys.exit("MAKEOBJDIRPREFIX is not set, cannot continue!")
    if not Path(MAKEOBJDIRPREFIX).is_dir():
        sys.exit(
            "Chosen MAKEOBJDIRPREFIX=" + MAKEOBJDIRPREFIX + " doesn't exist!")
    objdir_prefix = Path(MAKEOBJDIRPREFIX).absolute()
    source_root = Path(__file__).absolute().parent.parent.parent

    new_env_vars = {}
    if not sys.platform.startswith("freebsd"):
        if not is_make_var_set("TARGET") or not is_make_var_set("TARGET_ARCH"):
            if not set(sys.argv).intersection(set(mach_indep_targets)):
                sys.exit("TARGET= and TARGET_ARCH= must be set explicitly "
                         "when building on non-FreeBSD")
    if not parsed_args.bootstrap_toolchain:
        # infer values for CC/CXX/CPP
        if parsed_args.host_compiler_type == "gcc":
            default_cc, default_cxx, default_cpp = ("gcc", "g++", "cpp")
        # FIXME: this should take values like `clang-9` and then look for
        # clang-cpp-9, etc. Would alleviate the need to set the bindir on
        # ubuntu/debian at least.
        elif parsed_args.host_compiler_type == "clang":
            default_cc, default_cxx, default_cpp = (
                "clang", "clang++", "clang-cpp")
        else:
            default_cc, default_cxx, default_cpp = ("cc", "c++", "cpp")

        check_required_make_env_var("CC", default_cc, parsed_args.host_bindir)
        check_required_make_env_var("CXX", default_cxx,
                                    parsed_args.host_bindir)
        check_required_make_env_var("CPP", default_cpp,
                                    parsed_args.host_bindir)
        # Using the default value for LD is fine (but not for XLD!)

        # On non-FreeBSD we need to explicitly pass XCC/XLD/X_COMPILER_TYPE
        use_cross_gcc = parsed_args.cross_compiler_type == "gcc"
        check_xtool_make_env_var("XCC", "gcc" if use_cross_gcc else "clang")
        check_xtool_make_env_var("XCXX", "g++" if use_cross_gcc else "clang++")
        check_xtool_make_env_var("XCPP",
                                 "cpp" if use_cross_gcc else "clang-cpp")
        check_xtool_make_env_var("XLD", "ld" if use_cross_gcc else "ld.lld")

        # We also need to set STRIPBIN if there is no working strip binary
        # in $PATH.
        if not shutil.which("strip"):
            if sys.platform.startswith("darwin"):
                # On macOS systems we have to use /usr/bin/strip.
                sys.exit("Cannot find required tool 'strip'. Please install "
                         "the host compiler and command line tools.")
            if parsed_args.host_compiler_type == "clang":
                strip_binary = "llvm-strip"
            else:
                strip_binary = "strip"
            check_required_make_env_var("STRIPBIN", strip_binary,
                                        parsed_args.host_bindir)
        if os.getenv("STRIPBIN") or "STRIPBIN" in new_env_vars:
            # If we are setting STRIPBIN, we have to set XSTRIPBIN to the
            # default if it is not set otherwise already.
            if not os.getenv("XSTRIPBIN") and not is_make_var_set("XSTRIPBIN"):
                # Use the bootstrapped elftoolchain strip:
                new_env_vars["XSTRIPBIN"] = "strip"

    bmake_binary = bootstrap_bmake(source_root, objdir_prefix)
    # at -j1 cleandir+obj is unbearably slow. AUTO_OBJ helps a lot
    debug("Adding -DWITH_AUTO_OBJ")
    bmake_args.append("-DWITH_AUTO_OBJ")
    if parsed_args.clean is False:
        bmake_args.append("-DWITHOUT_CLEAN")
    if (parsed_args.clean is None and not is_make_var_set("NO_CLEAN")
            and not is_make_var_set("WITHOUT_CLEAN")):
        # Avoid accidentally deleting all of the build tree and wasting lots of
        # time cleaning directories instead of just doing a rm -rf ${.OBJDIR}
        want_clean = input("You did not set -DWITHOUT_CLEAN/--(no-)clean."
                           " Did you really mean to do a clean build? y/[N] ")
        if not want_clean.lower().startswith("y"):
            bmake_args.append("-DWITHOUT_CLEAN")

    env_cmd_str = " ".join(
        shlex.quote(k + "=" + v) for k, v in new_env_vars.items())
    make_cmd_str = " ".join(
        shlex.quote(s) for s in [str(bmake_binary)] + bmake_args)
    debug("Running `env ", env_cmd_str, " ", make_cmd_str, "`", sep="")
    os.environ.update(new_env_vars)

    # Fedora defines bash function wrapper for some shell commands and this
    # makes 'which <command>' return the function's source code instead of
    # the binary path. Undefine it to restore the original behavior.
    os.unsetenv("BASH_FUNC_which%%")
    os.unsetenv("BASH_FUNC_ml%%")
    os.unsetenv("BASH_FUNC_module%%")

    os.chdir(str(source_root))
    os.execv(str(bmake_binary), [str(bmake_binary)] + bmake_args)
