# Copyright 2013 The Servo Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.

import os.path
import shutil
import subprocess
import sys
from typing import Set

# This file is called as a script from components/servo/build.rs, so
# we need to explicitly modify the search path here.
sys.path[0:0] = [os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))]
from servo.platform.build_target import BuildTarget  # noqa: E402

GSTREAMER_BASE_LIBS = [
    # gstreamer
    "gstbase",
    "gstcontroller",
    "gstnet",
    "gstreamer",
    # gst-plugins-base
    "gstapp",
    "gstaudio",
    "gstfft",
    "gstgl",
    "gstpbutils",
    "gstplay",
    "gstriff",
    "gstrtp",
    "gstrtsp",
    "gstsctp",
    "gstsdp",
    "gsttag",
    "gstvideo",
    # gst-plugins-bad
    "gstcodecparsers",
    "gstplayer",
    "gstwebrtc",
    "gstwebrtcnice",
]
"""
These are the GStreamer base libraries used by both MacOS and Windows
platforms. These are distinct from GStreamer plugins, but GStreamer plugins
may have shared object dependencies on them.
"""

GSTREAMER_PLUGIN_LIBS = [
    # gstreamer
    "gstcoreelements",
    "gstnice",
    # gst-plugins-base
    "gstapp",
    "gstaudioconvert",
    "gstaudioresample",
    "gstgio",
    "gstogg",
    "gstopengl",
    "gstopus",
    "gstplayback",
    "gsttheora",
    "gsttypefindfunctions",
    "gstvideoconvertscale",
    "gstvolume",
    "gstvorbis",
    # gst-plugins-good
    "gstaudiofx",
    "gstaudioparsers",
    "gstautodetect",
    "gstdeinterlace",
    "gstid3demux",
    "gstinterleave",
    "gstisomp4",
    "gstmatroska",
    "gstrtp",
    "gstrtpmanager",
    "gstvideofilter",
    "gstvpx",
    "gstwavparse",
    # gst-plugins-bad
    "gstaudiobuffersplit",
    "gstdtls",
    "gstid3tag",
    "gstproxy",
    "gstvideoparsersbad",
    "gstwebrtc",
    # gst-libav
    "gstlibav",
]
"""
The list of plugin libraries themselves, used for both MacOS and Windows.
"""

GSTREAMER_MAC_PLUGIN_LIBS = [
    # gst-plugins-good
    "gstosxaudio",
    "gstosxvideo",
    # gst-plugins-bad
    "gstapplemedia",
]
"""
Plugins that are only used for MacOS.
"""

GSTREAMER_WIN_PLUGIN_LIBS = [
    # gst-plugins-bad
    "gstwasapi"
]
"""
Plugins that are only used for Windows.
"""

GSTREAMER_WIN_DEPENDENCY_LIBS = [
    "avcodec-59.dll",
    "avfilter-8.dll",
    "avformat-59.dll",
    "avutil-57.dll",
    "bz2.dll",
    "ffi-7.dll",
    "gio-2.0-0.dll",
    "glib-2.0-0.dll",
    "gmodule-2.0-0.dll",
    "gobject-2.0-0.dll",
    "graphene-1.0-0.dll",
    "intl-8.dll",
    "libcrypto-1_1-x64.dll",
    "libjpeg-8.dll",
    "libogg-0.dll",
    "libpng16-16.dll",
    "libssl-1_1-x64.dll",
    "libvorbis-0.dll",
    "libvorbisenc-2.dll",
    "libwinpthread-1.dll",
    "nice-10.dll",
    "opus-0.dll",
    "orc-0.4-0.dll",
    "pcre2-8-0.dll",
    "swresample-4.dll",
    "theora-0.dll",
    "theoradec-1.dll",
    "theoraenc-1.dll",
    "z-1.dll",
]
"""
DLLs that GStreamer ships in the Windows distribution that are necessary for
using the plugin selection that we have. This list is curated by a combination
of using `dumpbin` and the errors that appear when starting Servo.
"""


def windows_dlls():
    return GSTREAMER_WIN_DEPENDENCY_LIBS + [f"{lib}-1.0-0.dll" for lib in GSTREAMER_BASE_LIBS]


def windows_plugins():
    libs = [
        *GSTREAMER_PLUGIN_LIBS,
        *GSTREAMER_WIN_PLUGIN_LIBS
    ]
    return [f"{lib}.dll" for lib in libs]


def macos_plugins():
    plugins = [
        *GSTREAMER_PLUGIN_LIBS,
        *GSTREAMER_MAC_PLUGIN_LIBS
    ]

    return [f"lib{plugin}.dylib" for plugin in plugins]


def write_plugin_list(target):
    plugins = []
    if "apple-" in target:
        plugins = macos_plugins()
    elif '-windows-' in target:
        plugins = windows_plugins()
    print('''/* This is a generated file. Do not modify. */

pub(crate) static GSTREAMER_PLUGINS: &[&str] = &[
%s
];
''' % ',\n'.join(map(lambda x: '"' + x + '"', plugins)))


def is_macos_system_library(library_path: str) -> bool:
    """Returns true if if the given dependency line from otool refers to
       a system library that should not be packaged."""
    return (library_path.startswith("/System/Library")
            or library_path.startswith("/usr/lib")
            or ".asan." in library_path)


def rewrite_dependencies_to_be_relative(binary: str, dependency_lines: Set[str], relative_path: str):
    """Given a path to a binary (either an executable or a dylib), rewrite the
       the given dependency lines to be found at the given relative path to
       the executable in which they are used. In our case, this is typically servoshell."""
    for dependency_line in dependency_lines:
        if is_macos_system_library(dependency_line) or dependency_line.startswith("@rpath/"):
            continue

        new_path = os.path.join("@executable_path", relative_path, os.path.basename(dependency_line))
        arguments = ['install_name_tool', '-change', dependency_line, new_path, binary]
        try:
            subprocess.check_call(arguments)
        except subprocess.CalledProcessError as exception:
            print(f"{arguments} install_name_tool exited with return value {exception.returncode}")


def make_rpath_path_absolute(dylib_path_from_otool: str, rpath: str):
    """Given a dylib dependency from otool, resolve the path into a full path if it
       contains `@rpath`."""
    if not dylib_path_from_otool.startswith("@rpath/"):
        return dylib_path_from_otool

    # Not every dependency is in the same directory as the binary that is references. For
    # instance, plugins dylibs can be found in "gstreamer-1.0".
    path_relative_to_rpath = dylib_path_from_otool.replace('@rpath/', '')
    for relative_directory in ["", "..", "gstreamer-1.0"]:
        full_path = os.path.join(rpath, relative_directory, path_relative_to_rpath)
        if os.path.exists(full_path):
            return os.path.normpath(full_path)

    raise Exception("Unable to satisfy rpath dependency: " + dylib_path_from_otool)


def find_non_system_dependencies_with_otool(binary_path: str) -> Set[str]:
    """Given a binary path, find all dylib dependency lines that do not refer to
       system libraries."""
    process = subprocess.Popen(['/usr/bin/otool', '-L', binary_path], stdout=subprocess.PIPE)
    output = set()

    for line in map(lambda line: line.decode('utf8'), process.stdout):
        if not line.startswith("\t"):
            continue
        dependency = line.split(' ', 1)[0][1:]

        # No need to do any processing for system libraries. They should be
        # present on all macOS systems.
        if not is_macos_system_library(dependency):
            output.add(dependency)
    return output


def package_gstreamer_dylibs(binary_path: str, library_target_directory: str, target: BuildTarget):
    """Copy all GStreamer dependencies to the "lib" subdirectory of a built version of
       Servo. Also update any transitive shared library paths so that they are relative to
       this subdirectory."""

    # This import only works when called from `mach`.
    import servo.platform

    gstreamer_root = servo.platform.get().gstreamer_root(target)
    gstreamer_version = servo.platform.macos.GSTREAMER_PLUGIN_VERSION
    gstreamer_root_libs = os.path.join(gstreamer_root, "lib")

    # This is the relative path from the directory we are packaging the dylibs into and
    # the binary we are packaging them for.
    relative_path = os.path.relpath(library_target_directory, os.path.dirname(binary_path)) + "/"

    # This might be None if we are cross-compiling.
    if not gstreamer_root:
        return True

    # Detect when the packaged library versions do not reflect our current version of GStreamer,
    # by writing a marker file with the packaged GStreamer version into the target directory.
    marker_file = os.path.join(library_target_directory, f".gstreamer-{gstreamer_version}")

    print()
    if os.path.exists(library_target_directory) and os.path.exists(marker_file):
        print(" • GStreamer packaging is up-to-date")
        return True

    if os.path.exists(library_target_directory):
        print(f" • Packaged GStreamer is out of date. Rebuilding into {library_target_directory}")
        shutil.rmtree(library_target_directory)
    else:
        print(f" • Packaging GStreamer into {library_target_directory}")

    os.makedirs(library_target_directory, exist_ok=True)
    try:
        # Collect all the initial binary dependencies for Servo and the plugins that it uses,
        # which are loaded dynmically at runtime and don't appear in `otool` output.
        binary_dependencies = set(find_non_system_dependencies_with_otool(binary_path))
        binary_dependencies.update(
            [os.path.join(gstreamer_root_libs, "gstreamer-1.0", plugin)
                for plugin in macos_plugins()]
        )

        rewrite_dependencies_to_be_relative(binary_path, binary_dependencies, relative_path)

        number_copied = 0
        pending_to_be_copied = binary_dependencies
        already_copied = set()

        while pending_to_be_copied:
            checking = set(pending_to_be_copied)
            pending_to_be_copied.clear()

            for otool_dependency in checking:
                already_copied.add(otool_dependency)

                original_dylib_path = make_rpath_path_absolute(otool_dependency, gstreamer_root_libs)
                transitive_dependencies = set(find_non_system_dependencies_with_otool(original_dylib_path))

                # First copy the dylib into the directory where we are collecting them all for
                # packaging, and rewrite its dependencies to be relative to the executable we
                # are packaging them for.
                new_dylib_path = os.path.join(library_target_directory, os.path.basename(original_dylib_path))
                if not os.path.exists(new_dylib_path):
                    number_copied += 1
                    shutil.copyfile(original_dylib_path, new_dylib_path)
                    rewrite_dependencies_to_be_relative(new_dylib_path, transitive_dependencies, relative_path)

                # Now queue up any transitive dependencies for processing in further iteration loops.
                transitive_dependencies.difference_update(already_copied)
                pending_to_be_copied.update(transitive_dependencies)

    except Exception as exception:
        print(f"ERROR: could not package required dylibs: {exception}")
        raise exception

    with open(marker_file, "w") as file:
        file.write(gstreamer_version)

    if number_copied:
        print(f" • Processed {number_copied} GStreamer dylibs. ")
        print("   This can cause the startup to be slow due to macOS security protections.")
    return True


if __name__ == "__main__":
    write_plugin_list(sys.argv[1])