# Copyright 2015 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.

from .. import mlog
import contextlib
import urllib.request
import urllib.error
import urllib.parse
import os
import hashlib
import shutil
import tempfile
import stat
import subprocess
import sys
import configparser
import typing as T

from pathlib import Path
from . import WrapMode
from .. import coredata
from ..mesonlib import git, GIT, ProgressBar, MesonException

if T.TYPE_CHECKING:
    import http.client

try:
    # Importing is just done to check if SSL exists, so all warnings
    # regarding 'imported but unused' can be safely ignored
    import ssl  # noqa
    has_ssl = True
    API_ROOT = 'https://wrapdb.mesonbuild.com/v1/'
except ImportError:
    has_ssl = False
    API_ROOT = 'http://wrapdb.mesonbuild.com/v1/'

REQ_TIMEOUT = 600.0
SSL_WARNING_PRINTED = False
WHITELIST_SUBDOMAIN = 'wrapdb.mesonbuild.com'

def quiet_git(cmd: T.List[str], workingdir: str) -> T.Tuple[bool, str]:
    if not GIT:
        return False, 'Git program not found.'
    pc = git(cmd, workingdir, universal_newlines=True,
             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    if pc.returncode != 0:
        return False, pc.stderr
    return True, pc.stdout

def verbose_git(cmd: T.List[str], workingdir: str, check: bool = False) -> bool:
    if not GIT:
        return False
    try:
        return git(cmd, workingdir, check=check).returncode == 0
    except subprocess.CalledProcessError:
        raise WrapException('Git command failed')

def whitelist_wrapdb(urlstr: str) -> urllib.parse.ParseResult:
    """ raises WrapException if not whitelisted subdomain """
    url = urllib.parse.urlparse(urlstr)
    if not url.hostname:
        raise WrapException('{} is not a valid URL'.format(urlstr))
    if not url.hostname.endswith(WHITELIST_SUBDOMAIN):
        raise WrapException('{} is not a whitelisted WrapDB URL'.format(urlstr))
    if has_ssl and not url.scheme == 'https':
        raise WrapException('WrapDB did not have expected SSL https url, instead got {}'.format(urlstr))
    return url

def open_wrapdburl(urlstring: str) -> 'http.client.HTTPResponse':
    global SSL_WARNING_PRINTED

    url = whitelist_wrapdb(urlstring)
    if has_ssl:
        try:
            return urllib.request.urlopen(urllib.parse.urlunparse(url), timeout=REQ_TIMEOUT)
        except urllib.error.URLError as excp:
            raise WrapException('WrapDB connection failed to {} with error {}'.format(urlstring, excp))

    # following code is only for those without Python SSL
    nossl_url = url._replace(scheme='http')
    if not SSL_WARNING_PRINTED:
        mlog.warning('SSL module not available in {}: WrapDB traffic not authenticated.'.format(sys.executable))
        SSL_WARNING_PRINTED = True
    try:
        return urllib.request.urlopen(urllib.parse.urlunparse(nossl_url), timeout=REQ_TIMEOUT)
    except urllib.error.URLError as excp:
        raise WrapException('WrapDB connection failed to {} with error {}'.format(urlstring, excp))


class WrapException(MesonException):
    pass

class WrapNotFoundException(WrapException):
    pass

class PackageDefinition:
    def __init__(self, fname: str):
        self.filename = fname
        self.type = None
        self.values = {} # type: T.Dict[str, str]
        self.provided_deps = {} # type: T.Dict[str, T.Optional[str]]
        self.provided_programs = [] # type: T.List[str]
        self.basename = os.path.basename(fname)
        self.name = self.basename
        if self.name.endswith('.wrap'):
            self.name = self.name[:-5]
        self.provided_deps[self.name] = None
        if fname.endswith('.wrap'):
            self.parse_wrap(fname)
        self.directory = self.values.get('directory', self.name)
        if os.path.dirname(self.directory):
            raise WrapException('Directory key must be a name and not a path')

    def parse_wrap(self, fname: str):
        try:
            self.config = configparser.ConfigParser(interpolation=None)
            self.config.read(fname)
        except configparser.Error:
            raise WrapException('Failed to parse {}'.format(self.basename))
        self.parse_wrap_section()
        self.parse_provide_section()

    def parse_wrap_section(self):
        if len(self.config.sections()) < 1:
            raise WrapException('Missing sections in {}'.format(self.basename))
        self.wrap_section = self.config.sections()[0]
        if not self.wrap_section.startswith('wrap-'):
            m = '{!r} is not a valid first section in {}'
            raise WrapException(m.format(self.wrap_section, self.basename))
        self.type = self.wrap_section[5:]
        self.values = dict(self.config[self.wrap_section])

    def parse_provide_section(self):
        if self.config.has_section('provide'):
            for k, v in self.config['provide'].items():
                if k == 'dependency_names':
                    # A comma separated list of dependency names that does not
                    # need a variable name
                    names = {n.strip(): None for n in v.split(',')}
                    self.provided_deps.update(names)
                    continue
                if k == 'program_names':
                    # A comma separated list of program names
                    names = [n.strip() for n in v.split(',')]
                    self.provided_programs += names
                    continue
                if not v:
                    m = ('Empty dependency variable name for {!r} in {}. '
                         'If the subproject uses meson.override_dependency() '
                         'it can be added in the "dependency_names" special key.')
                    raise WrapException(m.format(k, self.basename))
                self.provided_deps[k] = v

    def get(self, key: str) -> str:
        try:
            return self.values[key]
        except KeyError:
            m = 'Missing key {!r} in {}'
            raise WrapException(m.format(key, self.basename))

def get_directory(subdir_root: str, packagename: str) -> str:
    fname = os.path.join(subdir_root, packagename + '.wrap')
    if os.path.isfile(fname):
        wrap = PackageDefinition(fname)
        return wrap.directory
    return packagename

class Resolver:
    def __init__(self, subdir_root: str, wrap_mode=WrapMode.default):
        self.wrap_mode = wrap_mode
        self.subdir_root = subdir_root
        self.cachedir = os.path.join(self.subdir_root, 'packagecache')
        self.filesdir = os.path.join(self.subdir_root, 'packagefiles')
        self.wraps = {} # type: T.Dict[str, PackageDefinition]
        self.provided_deps = {} # type: T.Dict[str, PackageDefinition]
        self.provided_programs = {} # type: T.Dict[str, PackageDefinition]
        self.load_wraps()

    def load_wraps(self):
        if not os.path.isdir(self.subdir_root):
            return
        root, dirs, files = next(os.walk(self.subdir_root))
        for i in files:
            if not i.endswith('.wrap'):
                continue
            fname = os.path.join(self.subdir_root, i)
            wrap = PackageDefinition(fname)
            self.wraps[wrap.name] = wrap
            if wrap.directory in dirs:
                dirs.remove(wrap.directory)
        # Add dummy package definition for directories not associated with a wrap file.
        for i in dirs:
            if i in ['packagecache', 'packagefiles']:
                continue
            fname = os.path.join(self.subdir_root, i)
            wrap = PackageDefinition(fname)
            self.wraps[wrap.name] = wrap

        for wrap in self.wraps.values():
            for k in wrap.provided_deps.keys():
                if k in self.provided_deps:
                    prev_wrap = self.provided_deps[k]
                    m = 'Multiple wrap files provide {!r} dependency: {} and {}'
                    raise WrapException(m.format(k, wrap.basename, prev_wrap.basename))
                self.provided_deps[k] = wrap
            for k in wrap.provided_programs:
                if k in self.provided_programs:
                    prev_wrap = self.provided_programs[k]
                    m = 'Multiple wrap files provide {!r} program: {} and {}'
                    raise WrapException(m.format(k, wrap.basename, prev_wrap.basename))
                self.provided_programs[k] = wrap

    def find_dep_provider(self, packagename: str):
        # Return value is in the same format as fallback kwarg:
        # ['subproject_name', 'variable_name'], or 'subproject_name'.
        wrap = self.provided_deps.get(packagename)
        if wrap:
            dep_var = wrap.provided_deps.get(packagename)
            if dep_var:
                return [wrap.name, dep_var]
            return wrap.name
        return None

    def find_program_provider(self, names: T.List[str]):
        for name in names:
            wrap = self.provided_programs.get(name)
            if wrap:
                return wrap.name
        return None

    def resolve(self, packagename: str, method: str, current_subproject: str = '') -> str:
        self.current_subproject = current_subproject
        self.packagename = packagename
        self.directory = packagename
        self.wrap = self.wraps.get(packagename)
        if not self.wrap:
            m = 'Subproject directory not found and {}.wrap file not found'
            raise WrapNotFoundException(m.format(self.packagename))
        self.directory = self.wrap.directory
        self.dirname = os.path.join(self.subdir_root, self.directory)

        meson_file = os.path.join(self.dirname, 'meson.build')
        cmake_file = os.path.join(self.dirname, 'CMakeLists.txt')

        if method not in ['meson', 'cmake']:
            raise WrapException('Only the methods "meson" and "cmake" are supported')

        # The directory is there and has meson.build? Great, use it.
        if method == 'meson' and os.path.exists(meson_file):
            return self.directory
        if method == 'cmake' and os.path.exists(cmake_file):
            return self.directory

        # Check if the subproject is a git submodule
        self.resolve_git_submodule()

        if os.path.exists(self.dirname):
            if not os.path.isdir(self.dirname):
                raise WrapException('Path already exists but is not a directory')
        else:
            if self.wrap.type == 'file':
                self.get_file()
            else:
                self.check_can_download()
                if self.wrap.type == 'git':
                    self.get_git()
                elif self.wrap.type == "hg":
                    self.get_hg()
                elif self.wrap.type == "svn":
                    self.get_svn()
                else:
                    raise WrapException('Unknown wrap type {!r}'.format(self.wrap.type))
            self.apply_patch()

        # A meson.build or CMakeLists.txt file is required in the directory
        if method == 'meson' and not os.path.exists(meson_file):
            raise WrapException('Subproject exists but has no meson.build file')
        if method == 'cmake' and not os.path.exists(cmake_file):
            raise WrapException('Subproject exists but has no CMakeLists.txt file')

        return self.directory

    def check_can_download(self) -> None:
        # Don't download subproject data based on wrap file if requested.
        # Git submodules are ok (see above)!
        if self.wrap_mode is WrapMode.nodownload:
            m = 'Automatic wrap-based subproject downloading is disabled'
            raise WrapException(m)

    def resolve_git_submodule(self) -> bool:
        if not GIT:
            raise WrapException('Git program not found.')
        # Are we in a git repository?
        ret, out = quiet_git(['rev-parse'], self.subdir_root)
        if not ret:
            return False
        # Is `dirname` a submodule?
        ret, out = quiet_git(['submodule', 'status', self.dirname], self.subdir_root)
        if not ret:
            return False
        # Submodule has not been added, add it
        if out.startswith('+'):
            mlog.warning('git submodule might be out of date')
            return True
        elif out.startswith('U'):
            raise WrapException('git submodule has merge conflicts')
        # Submodule exists, but is deinitialized or wasn't initialized
        elif out.startswith('-'):
            if verbose_git(['submodule', 'update', '--init', self.dirname], self.subdir_root):
                return True
            raise WrapException('git submodule failed to init')
        # Submodule looks fine, but maybe it wasn't populated properly. Do a checkout.
        elif out.startswith(' '):
            verbose_git(['checkout', '.'], self.dirname)
            # Even if checkout failed, try building it anyway and let the user
            # handle any problems manually.
            return True
        elif out == '':
            # It is not a submodule, just a folder that exists in the main repository.
            return False
        m = 'Unknown git submodule output: {!r}'
        raise WrapException(m.format(out))

    def get_file(self) -> None:
        path = self.get_file_internal('source')
        extract_dir = self.subdir_root
        # Some upstreams ship packages that do not have a leading directory.
        # Create one for them.
        if 'lead_directory_missing' in self.wrap.values:
            os.mkdir(self.dirname)
            extract_dir = self.dirname
        shutil.unpack_archive(path, extract_dir)

    def get_git(self) -> None:
        if not GIT:
            raise WrapException('Git program not found.')
        revno = self.wrap.get('revision')
        is_shallow = False
        depth_option = []    # type: T.List[str]
        if self.wrap.values.get('depth', '') != '':
            is_shallow = True
            depth_option = ['--depth', self.wrap.values.get('depth')]
        # for some reason git only allows commit ids to be shallowly fetched by fetch not with clone
        if is_shallow and self.is_git_full_commit_id(revno):
            # git doesn't support directly cloning shallowly for commits,
            # so we follow https://stackoverflow.com/a/43136160
            verbose_git(['init', self.directory], self.subdir_root, check=True)
            verbose_git(['remote', 'add', 'origin', self.wrap.get('url')], self.dirname, check=True)
            revno = self.wrap.get('revision')
            verbose_git(['fetch', *depth_option, 'origin', revno], self.dirname, check=True)
            verbose_git(['checkout', revno], self.dirname, check=True)
            if self.wrap.values.get('clone-recursive', '').lower() == 'true':
                verbose_git(['submodule', 'update', '--init', '--checkout',
                             '--recursive', *depth_option], self.dirname, check=True)
            push_url = self.wrap.values.get('push-url')
            if push_url:
                verbose_git(['remote', 'set-url', '--push', 'origin', push_url], self.dirname, check=True)
        else:
            if not is_shallow:
                verbose_git(['clone', self.wrap.get('url'), self.directory], self.subdir_root, check=True)
                if revno.lower() != 'head':
                    if not verbose_git(['checkout', revno], self.dirname):
                        verbose_git(['fetch', self.wrap.get('url'), revno], self.dirname, check=True)
                        verbose_git(['checkout', revno], self.dirname, check=True)
            else:
                verbose_git(['clone', *depth_option, '--branch', revno, self.wrap.get('url'),
                             self.directory], self.subdir_root, check=True)
            if self.wrap.values.get('clone-recursive', '').lower() == 'true':
                verbose_git(['submodule', 'update', '--init', '--checkout', '--recursive', *depth_option],
                            self.dirname, check=True)
            push_url = self.wrap.values.get('push-url')
            if push_url:
                verbose_git(['remote', 'set-url', '--push', 'origin', push_url], self.dirname, check=True)

    def is_git_full_commit_id(self, revno: str) -> bool:
        result = False
        if len(revno) in (40, 64): # 40 for sha1, 64 for upcoming sha256
            result = all((ch in '0123456789AaBbCcDdEeFf' for ch in revno))
        return result

    def get_hg(self) -> None:
        revno = self.wrap.get('revision')
        hg = shutil.which('hg')
        if not hg:
            raise WrapException('Mercurial program not found.')
        subprocess.check_call([hg, 'clone', self.wrap.get('url'),
                               self.directory], cwd=self.subdir_root)
        if revno.lower() != 'tip':
            subprocess.check_call([hg, 'checkout', revno],
                                  cwd=self.dirname)

    def get_svn(self) -> None:
        revno = self.wrap.get('revision')
        svn = shutil.which('svn')
        if not svn:
            raise WrapException('SVN program not found.')
        subprocess.check_call([svn, 'checkout', '-r', revno, self.wrap.get('url'),
                               self.directory], cwd=self.subdir_root)

    def get_data(self, urlstring: str) -> T.Tuple[str, str]:
        blocksize = 10 * 1024
        h = hashlib.sha256()
        tmpfile = tempfile.NamedTemporaryFile(mode='wb', dir=self.cachedir, delete=False)
        url = urllib.parse.urlparse(urlstring)
        if url.hostname and url.hostname.endswith(WHITELIST_SUBDOMAIN):
            resp = open_wrapdburl(urlstring)
        elif WHITELIST_SUBDOMAIN in urlstring:
            raise WrapException('{} may be a WrapDB-impersonating URL'.format(urlstring))
        else:
            try:
                req = urllib.request.Request(urlstring, headers={'User-Agent': 'mesonbuild/{}'.format(coredata.version)})
                resp = urllib.request.urlopen(req, timeout=REQ_TIMEOUT)
            except urllib.error.URLError as e:
                mlog.log(str(e))
                raise WrapException('could not get {} is the internet available?'.format(urlstring))
        with contextlib.closing(resp) as resp:
            try:
                dlsize = int(resp.info()['Content-Length'])
            except TypeError:
                dlsize = None
            if dlsize is None:
                print('Downloading file of unknown size.')
                while True:
                    block = resp.read(blocksize)
                    if block == b'':
                        break
                    h.update(block)
                    tmpfile.write(block)
                hashvalue = h.hexdigest()
                return hashvalue, tmpfile.name
            sys.stdout.flush()
            progress_bar = ProgressBar(bar_type='download', total=dlsize,
                                       desc='Downloading')
            while True:
                block = resp.read(blocksize)
                if block == b'':
                    break
                h.update(block)
                tmpfile.write(block)
                progress_bar.update(len(block))
            progress_bar.close()
            hashvalue = h.hexdigest()
        return hashvalue, tmpfile.name

    def check_hash(self, what: str, path: str, hash_required: bool = True) -> None:
        if what + '_hash' not in self.wrap.values and not hash_required:
            return
        expected = self.wrap.get(what + '_hash')
        h = hashlib.sha256()
        with open(path, 'rb') as f:
            h.update(f.read())
        dhash = h.hexdigest()
        if dhash != expected:
            raise WrapException('Incorrect hash for {}:\n {} expected\n {} actual.'.format(what, expected, dhash))

    def download(self, what: str, ofname: str, fallback=False) -> None:
        self.check_can_download()
        srcurl = self.wrap.get(what + ('_fallback_url' if fallback else '_url'))
        mlog.log('Downloading', mlog.bold(self.packagename), what, 'from', mlog.bold(srcurl))
        try:
            dhash, tmpfile = self.get_data(srcurl)
            expected = self.wrap.get(what + '_hash')
            if dhash != expected:
                os.remove(tmpfile)
                raise WrapException('Incorrect hash for {}:\n {} expected\n {} actual.'.format(what, expected, dhash))
        except WrapException:
            if not fallback:
                if what + '_fallback_url' in self.wrap.values:
                    return self.download(what, ofname, fallback=True)
                mlog.log('A fallback URL could be specified using',
                         mlog.bold(what + '_fallback_url'), 'key in the wrap file')
            raise
        os.rename(tmpfile, ofname)

    def get_file_internal(self, what: str) -> str:
        filename = self.wrap.get(what + '_filename')
        if what + '_url' in self.wrap.values:
            cache_path = os.path.join(self.cachedir, filename)

            if os.path.exists(cache_path):
                self.check_hash(what, cache_path)
                mlog.log('Using', mlog.bold(self.packagename), what, 'from cache.')
                return cache_path

            if not os.path.isdir(self.cachedir):
                os.mkdir(self.cachedir)
            self.download(what, cache_path)
            return cache_path
        else:
            from ..interpreterbase import FeatureNew
            FeatureNew('Local wrap patch files without {}_url'.format(what), '0.55.0').use(self.current_subproject)
            path = Path(self.filesdir) / filename

            if not path.exists():
                raise WrapException('File "{}" does not exist'.format(path))
            self.check_hash(what, path.as_posix(), hash_required=False)

            return path.as_posix()

    def apply_patch(self) -> None:
        if 'patch_filename' in self.wrap.values and 'patch_directory' in self.wrap.values:
            m = 'Wrap file {!r} must not have both "patch_filename" and "patch_directory"'
            raise WrapException(m.format(self.wrap.basename))
        if 'patch_filename' in self.wrap.values:
            path = self.get_file_internal('patch')
            try:
                shutil.unpack_archive(path, self.subdir_root)
            except Exception:
                with tempfile.TemporaryDirectory() as workdir:
                    shutil.unpack_archive(path, workdir)
                    self.copy_tree(workdir, self.subdir_root)
        elif 'patch_directory' in self.wrap.values:
            from ..interpreterbase import FeatureNew
            FeatureNew('patch_directory', '0.55.0').use(self.current_subproject)
            patch_dir = self.wrap.values['patch_directory']
            src_dir = os.path.join(self.filesdir, patch_dir)
            if not os.path.isdir(src_dir):
                raise WrapException('patch directory does not exists: {}'.format(patch_dir))
            self.copy_tree(src_dir, self.dirname)

    def copy_tree(self, root_src_dir: str, root_dst_dir: str) -> None:
        """
        Copy directory tree. Overwrites also read only files.
        """
        for src_dir, _, files in os.walk(root_src_dir):
            dst_dir = src_dir.replace(root_src_dir, root_dst_dir, 1)
            if not os.path.exists(dst_dir):
                os.makedirs(dst_dir)
            for file_ in files:
                src_file = os.path.join(src_dir, file_)
                dst_file = os.path.join(dst_dir, file_)
                if os.path.exists(dst_file):
                    try:
                        os.remove(dst_file)
                    except PermissionError:
                        os.chmod(dst_file, stat.S_IWUSR)
                        os.remove(dst_file)
                shutil.copy2(src_file, dst_dir)
