# Copyright 2017 The Meson development team

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import gzip
import os
import sys
import shutil
import subprocess
import hashlib
import json
from glob import glob
from pathlib import Path
from mesonbuild.environment import detect_ninja
from mesonbuild.mesonlib import (MesonException, RealPathAction, quiet_git,
                                 windows_proof_rmtree)
from mesonbuild.wrap import wrap
from mesonbuild import mlog, build
from .scripts.meson_exe import run_exe

archive_choices = ['gztar', 'xztar', 'zip']

archive_extension = {'gztar': '.tar.gz',
                     'xztar': '.tar.xz',
                     'zip': '.zip'}

def add_arguments(parser):
    parser.add_argument('-C', dest='wd', action=RealPathAction,
                        help='directory to cd into before running')
    parser.add_argument('--formats', default='xztar',
                        help='Comma separated list of archive types to create. Supports xztar (default), gztar, and zip.')
    parser.add_argument('--include-subprojects', action='store_true',
                        help='Include source code of subprojects that have been used for the build.')
    parser.add_argument('--no-tests', action='store_true',
                        help='Do not build and test generated packages.')


def create_hash(fname):
    hashname = fname + '.sha256sum'
    m = hashlib.sha256()
    m.update(open(fname, 'rb').read())
    with open(hashname, 'w', encoding='utf-8') as f:
        # A space and an asterisk because that is the format defined by GNU coreutils
        # and accepted by busybox and the Perl shasum tool.
        f.write('{} *{}\n'.format(m.hexdigest(), os.path.basename(fname)))


def del_gitfiles(dirname):
    for f in glob(os.path.join(dirname, '.git*')):
        if os.path.isdir(f) and not os.path.islink(f):
            windows_proof_rmtree(f)
        else:
            os.unlink(f)

def process_submodules(dirname):
    module_file = os.path.join(dirname, '.gitmodules')
    if not os.path.exists(module_file):
        return
    subprocess.check_call(['git', 'submodule', 'update', '--init', '--recursive'], cwd=dirname)
    for line in open(module_file, encoding='utf-8'):
        line = line.strip()
        if '=' not in line:
            continue
        k, v = line.split('=', 1)
        k = k.strip()
        v = v.strip()
        if k != 'path':
            continue
        del_gitfiles(os.path.join(dirname, v))


def run_dist_scripts(src_root, bld_root, dist_root, dist_scripts, subprojects):
    assert(os.path.isabs(dist_root))
    env = {}
    env['MESON_DIST_ROOT'] = dist_root
    env['MESON_SOURCE_ROOT'] = src_root
    env['MESON_BUILD_ROOT'] = bld_root
    for d in dist_scripts:
        if d.subproject and d.subproject not in subprojects:
            continue
        subdir = subprojects.get(d.subproject, '')
        env['MESON_PROJECT_DIST_ROOT'] = os.path.join(dist_root, subdir)
        env['MESON_PROJECT_SOURCE_ROOT'] = os.path.join(src_root, subdir)
        env['MESON_PROJECT_BUILD_ROOT'] = os.path.join(bld_root, subdir)
        name = ' '.join(d.cmd_args)
        print(f'Running custom dist script {name!r}')
        try:
            rc = run_exe(d, env)
            if rc != 0:
                sys.exit('Dist script errored out')
        except OSError:
            print(f'Failed to run dist script {name!r}')
            sys.exit(1)

def git_root(src_root):
    # Cannot use --show-toplevel here because git in our CI prints cygwin paths
    # that python cannot resolve. Workaround this by taking parent of src_root.
    prefix = quiet_git(['rev-parse', '--show-prefix'], src_root, check=True)[1].strip()
    if not prefix:
        return Path(src_root)
    prefix_level = len(Path(prefix).parents)
    return Path(src_root).parents[prefix_level - 1]

def is_git(src_root):
    '''
    Checks if meson.build file at the root source directory is tracked by git.
    It could be a subproject part of the parent project git repository.
    '''
    return quiet_git(['ls-files', '--error-unmatch', 'meson.build'], src_root)[0]

def git_have_dirty_index(src_root):
    '''Check whether there are uncommitted changes in git'''
    ret = subprocess.call(['git', '-C', src_root, 'diff-index', '--quiet', 'HEAD'])
    return ret == 1

def git_clone(src_root, distdir):
    if git_have_dirty_index(src_root):
        mlog.warning('Repository has uncommitted changes that will not be included in the dist tarball')
    if os.path.exists(distdir):
        windows_proof_rmtree(distdir)
    repo_root = git_root(src_root)
    if repo_root.samefile(src_root):
        os.makedirs(distdir)
        subprocess.check_call(['git', 'clone', '--shared', src_root, distdir])
    else:
        subdir = Path(src_root).relative_to(repo_root)
        tmp_distdir = distdir + '-tmp'
        if os.path.exists(tmp_distdir):
            windows_proof_rmtree(tmp_distdir)
        os.makedirs(tmp_distdir)
        subprocess.check_call(['git', 'clone', '--shared', '--no-checkout', str(repo_root), tmp_distdir])
        subprocess.check_call(['git', 'checkout', 'HEAD', '--', str(subdir)], cwd=tmp_distdir)
        Path(tmp_distdir, subdir).rename(distdir)
        windows_proof_rmtree(tmp_distdir)
    process_submodules(distdir)
    del_gitfiles(distdir)

def create_dist_git(dist_name, archives, src_root, bld_root, dist_sub, dist_scripts, subprojects):
    distdir = os.path.join(dist_sub, dist_name)
    git_clone(src_root, distdir)
    for path in subprojects.values():
        sub_src_root = os.path.join(src_root, path)
        sub_distdir = os.path.join(distdir, path)
        if os.path.exists(sub_distdir):
            continue
        if is_git(sub_src_root):
            git_clone(sub_src_root, sub_distdir)
        else:
            shutil.copytree(sub_src_root, sub_distdir)
    run_dist_scripts(src_root, bld_root, distdir, dist_scripts, subprojects)
    output_names = []
    for a in archives:
        compressed_name = distdir + archive_extension[a]
        shutil.make_archive(distdir, a, root_dir=dist_sub, base_dir=dist_name)
        output_names.append(compressed_name)
    windows_proof_rmtree(distdir)
    return output_names

def is_hg(src_root):
    return os.path.isdir(os.path.join(src_root, '.hg'))

def hg_have_dirty_index(src_root):
    '''Check whether there are uncommitted changes in hg'''
    out = subprocess.check_output(['hg', '-R', src_root, 'summary'])
    return b'commit: (clean)' not in out

def create_dist_hg(dist_name, archives, src_root, bld_root, dist_sub, dist_scripts):
    if hg_have_dirty_index(src_root):
        mlog.warning('Repository has uncommitted changes that will not be included in the dist tarball')
    if dist_scripts:
        mlog.warning('dist scripts are not supported in Mercurial projects')

    os.makedirs(dist_sub, exist_ok=True)
    tarname = os.path.join(dist_sub, dist_name + '.tar')
    xzname = tarname + '.xz'
    gzname = tarname + '.gz'
    zipname = os.path.join(dist_sub, dist_name + '.zip')
    # Note that -X interprets relative paths using the current working
    # directory, not the repository root, so this must be an absolute path:
    # https://bz.mercurial-scm.org/show_bug.cgi?id=6267
    #
    # .hg[a-z]* is used instead of .hg* to keep .hg_archival.txt, which may
    # be useful to link the tarball to the Mercurial revision for either
    # manual inspection or in case any code interprets it for a --version or
    # similar.
    subprocess.check_call(['hg', 'archive', '-R', src_root, '-S', '-t', 'tar',
                           '-X', src_root + '/.hg[a-z]*', tarname])
    output_names = []
    if 'xztar' in archives:
        import lzma
        with lzma.open(xzname, 'wb') as xf, open(tarname, 'rb') as tf:
            shutil.copyfileobj(tf, xf)
        output_names.append(xzname)
    if 'gztar' in archives:
        with gzip.open(gzname, 'wb') as zf, open(tarname, 'rb') as tf:
            shutil.copyfileobj(tf, zf)
        output_names.append(gzname)
    os.unlink(tarname)
    if 'zip' in archives:
        subprocess.check_call(['hg', 'archive', '-R', src_root, '-S', '-t', 'zip', zipname])
        output_names.append(zipname)
    return output_names

def run_dist_steps(meson_command, unpacked_src_dir, builddir, installdir, ninja_args):
    if subprocess.call(meson_command + ['--backend=ninja', unpacked_src_dir, builddir]) != 0:
        print('Running Meson on distribution package failed')
        return 1
    if subprocess.call(ninja_args, cwd=builddir) != 0:
        print('Compiling the distribution package failed')
        return 1
    if subprocess.call(ninja_args + ['test'], cwd=builddir) != 0:
        print('Running unit tests on the distribution package failed')
        return 1
    myenv = os.environ.copy()
    myenv['DESTDIR'] = installdir
    if subprocess.call(ninja_args + ['install'], cwd=builddir, env=myenv) != 0:
        print('Installing the distribution package failed')
        return 1
    return 0

def check_dist(packagename, meson_command, extra_meson_args, bld_root, privdir):
    print(f'Testing distribution package {packagename}')
    unpackdir = os.path.join(privdir, 'dist-unpack')
    builddir = os.path.join(privdir, 'dist-build')
    installdir = os.path.join(privdir, 'dist-install')
    for p in (unpackdir, builddir, installdir):
        if os.path.exists(p):
            windows_proof_rmtree(p)
        os.mkdir(p)
    ninja_args = detect_ninja()
    shutil.unpack_archive(packagename, unpackdir)
    unpacked_files = glob(os.path.join(unpackdir, '*'))
    assert(len(unpacked_files) == 1)
    unpacked_src_dir = unpacked_files[0]
    with open(os.path.join(bld_root, 'meson-info', 'intro-buildoptions.json'), encoding='utf-8') as boptions:
        meson_command += ['-D{name}={value}'.format(**o) for o in json.load(boptions)
                          if o['name'] not in ['backend', 'install_umask', 'buildtype']]
    meson_command += extra_meson_args

    ret = run_dist_steps(meson_command, unpacked_src_dir, builddir, installdir, ninja_args)
    if ret > 0:
        print(f'Dist check build directory was {builddir}')
    else:
        windows_proof_rmtree(unpackdir)
        windows_proof_rmtree(builddir)
        windows_proof_rmtree(installdir)
        print(f'Distribution package {packagename} tested')
    return ret

def determine_archives_to_generate(options):
    result = []
    for i in options.formats.split(','):
        if i not in archive_choices:
            sys.exit(f'Value "{i}" not one of permitted values {archive_choices}.')
        result.append(i)
    if len(i) == 0:
        sys.exit('No archive types specified.')
    return result

def run(options):
    buildfile = Path(options.wd) / 'meson-private' / 'build.dat'
    if not buildfile.is_file():
        raise MesonException(f'Directory {options.wd!r} does not seem to be a Meson build directory.')
    b = build.load(options.wd)
    # This import must be load delayed, otherwise it will get the default
    # value of None.
    from mesonbuild.mesonlib import get_meson_command
    src_root = b.environment.source_dir
    bld_root = b.environment.build_dir
    priv_dir = os.path.join(bld_root, 'meson-private')
    dist_sub = os.path.join(bld_root, 'meson-dist')

    dist_name = b.project_name + '-' + b.project_version

    archives = determine_archives_to_generate(options)

    subprojects = {}
    extra_meson_args = []
    if options.include_subprojects:
        subproject_dir = os.path.join(src_root, b.subproject_dir)
        for sub in b.subprojects:
            directory = wrap.get_directory(subproject_dir, sub)
            subprojects[sub] = os.path.join(b.subproject_dir, directory)
        extra_meson_args.append('-Dwrap_mode=nodownload')

    if is_git(src_root):
        names = create_dist_git(dist_name, archives, src_root, bld_root, dist_sub, b.dist_scripts, subprojects)
    elif is_hg(src_root):
        if subprojects:
            print('--include-subprojects option currently not supported with Mercurial')
            return 1
        names = create_dist_hg(dist_name, archives, src_root, bld_root, dist_sub, b.dist_scripts)
    else:
        print('Dist currently only works with Git or Mercurial repos')
        return 1
    if names is None:
        return 1
    rc = 0
    if not options.no_tests:
        # Check only one.
        rc = check_dist(names[0], get_meson_command(), extra_meson_args, bld_root, priv_dir)
    if rc == 0:
        for name in names:
            create_hash(name)
            print('Created', os.path.relpath(name))
    return rc
