# Copyright 2012 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Generates a sysroot tarball for building a specific package.

Meant for use after cros build-packases has been ran.
"""

import os

from chromite.lib import build_target_lib
from chromite.lib import commandline
from chromite.lib import constants
from chromite.lib import cros_build_lib
from chromite.lib import osutils
from chromite.lib import sudo
from chromite.lib import sysroot_lib
from chromite.lib import toolchain


DEFAULT_NAME = "sysroot_%(package)s.tar.xz"
PACKAGE_SEPARATOR = "/"
SYSROOT = "sysroot"


def ParseCommandLine(argv):
    """Parse args, and run environment-independent checks."""
    parser = commandline.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--board", required=True, help="The board to generate the sysroot for."
    )
    parser.add_argument(
        "--package",
        required=True,
        help="The packages to generate the sysroot for.",
    )
    parser.add_argument(
        "--deps-only",
        action="store_true",
        default=False,
        help="Build dependencies only.",
    )
    parser.add_argument(
        "--out-dir",
        type="path",
        required=True,
        help="Directory to place the generated tarball.",
    )
    parser.add_argument(
        "--out-file",
        default=DEFAULT_NAME,
        help="The name to give to the tarball. Defaults to %(default)s.",
    )
    options = parser.parse_args(argv)

    options.out_file %= {
        "package": options.package.split()[0].replace(PACKAGE_SEPARATOR, "_"),
    }

    return options


class GenerateSysroot:
    """Wrapper for generation functionality."""

    PARALLEL_EMERGE = constants.CHROMITE_BIN_DIR / "parallel_emerge"

    def __init__(self, sysroot, options):
        """Initialize

        Args:
            sysroot: Path to sysroot.
            options: Parsed options.
        """
        self.sysroot = sysroot
        self.options = options
        self.extra_env = {
            "ROOT": self.sysroot,
            "USE": os.environ.get("USE", ""),
        }

    def _Emerge(self, *args, **kwargs):
        """Emerge the given packages using parallel_emerge."""
        cmd = [
            self.PARALLEL_EMERGE,
            "--board=%s" % self.options.board,
            "--usepkgonly",
            "--noreplace",
        ] + list(args)
        kwargs.setdefault("extra_env", self.extra_env)
        cros_build_lib.sudo_run(cmd, **kwargs)

    def _WriteConfig(self, sysroot):
        sysroot.WriteConfig(
            sysroot.GenerateBoardSetupConfig(self.options.board)
        )
        # For the config to be correctly read, a stub make.conf is needed.
        # pylint: disable=protected-access
        make_conf_path = os.path.join(self.sysroot, sysroot_lib._MAKE_CONF)
        assert not os.path.exists(make_conf_path), "Expecting an empty sysroot."
        osutils.WriteFile(
            os.path.join(make_conf_path),
            "source make.conf.board_setup",
            makedirs=True,
            sudo=True,
        )

    def _InstallToolchain(self):
        # Create the sysroot's config.
        sysroot = sysroot_lib.Sysroot(self.sysroot)
        self._WriteConfig(sysroot)
        toolchain.InstallToolchain(sysroot, configure=False)

    def _InstallKernelHeaders(self):
        self._Emerge("sys-kernel/linux-headers")

    def _InstallBuildDependencies(self):
        # Calculate buildtime deps that are not runtime deps.
        raw_sysroot = build_target_lib.get_default_sysroot_path(
            self.options.board
        )
        packages = []
        if not self.options.deps_only:
            packages = self.options.package.split()
        else:
            for pkg in self.options.package.split():
                cmd = [
                    "qdepends",
                    "-q",
                    "-C",
                    "--depend",
                    "--root",
                    raw_sysroot,
                    pkg,
                ]
                output = cros_build_lib.run(
                    cmd,
                    capture_output=True,
                    encoding="utf-8",
                ).stdout

                if output.count("\n") > 1:
                    raise AssertionError(
                        "Too many packages matched for given pattern"
                    )

                # qdepend outputs "package: deps", so only grab the deps.
                deps = output.partition(":")[2].split()
                packages.extend(deps)
        # Install the required packages.
        if packages:
            self._Emerge(*packages)

    def _CreateTarball(self):
        tarball_path = os.path.join(self.options.out_dir, self.options.out_file)
        cros_build_lib.CreateTarball(tarball_path, self.sysroot, sudo=True)

    def Perform(self):
        """Generate the sysroot."""
        self._InstallToolchain()
        self._InstallKernelHeaders()
        self._InstallBuildDependencies()
        self._CreateTarball()


def FinishParsing(options):
    """Run environment dependent checks on parsed args."""
    target = os.path.join(options.out_dir, options.out_file)
    if os.path.exists(target):
        cros_build_lib.Die("Output file %r already exists.", target)

    if not os.path.isdir(options.out_dir):
        cros_build_lib.Die(
            "Non-existent directory %r specified for --out-dir"
            % options.out_dir
        )


def main(argv):
    options = ParseCommandLine(argv)
    FinishParsing(options)

    cros_build_lib.AssertInsideChroot()

    with sudo.SudoKeepAlive(ttyless_sudo=False):
        with osutils.TempDir(set_global=True, sudo_rm=True) as tempdir:
            sysroot = os.path.join(tempdir, SYSROOT)
            os.mkdir(sysroot)
            GenerateSysroot(sysroot, options).Perform()