# 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 os
import hashlib
import shutil
import tempfile
import stat
import subprocess
import sys
import configparser
import typing

from . import WrapMode
from ..mesonlib import ProgressBar, MesonException

if typing.TYPE_CHECKING:
    import http.client

try:
    import ssl
    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

def build_ssl_context() -> 'ssl.SSLContext':
    ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
    ctx.options |= ssl.OP_NO_SSLv2
    ctx.options |= ssl.OP_NO_SSLv3
    ctx.verify_mode = ssl.CERT_REQUIRED
    ctx.load_default_certs()
    return ctx

def quiet_git(cmd: typing.List[str], workingdir: str) -> typing.Tuple[bool, str]:
    try:
        pc = subprocess.run(['git', '-C', workingdir] + cmd, universal_newlines=True,
                            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    except FileNotFoundError as e:
        return False, str(e)
    if pc.returncode != 0:
        return False, pc.stderr
    return True, pc.stdout

def open_wrapdburl(urlstring: str) -> 'http.client.HTTPResponse':
    global ssl_warning_printed
    if has_ssl:
        try:
            return urllib.request.urlopen(urlstring, timeout=req_timeout)# , context=build_ssl_context())
        except urllib.error.URLError:
            if not ssl_warning_printed:
                print('SSL connection failed. Falling back to unencrypted connections.', file=sys.stderr)
                ssl_warning_printed = True
    if not ssl_warning_printed:
        print('Warning: SSL not available, traffic not authenticated.', file=sys.stderr)
        ssl_warning_printed = True
    # Trying to open SSL connection to wrapdb fails because the
    # certificate is not known.
    if urlstring.startswith('https'):
        urlstring = 'http' + urlstring[5:]
    try:
        return urllib.request.urlopen(urlstring, timeout=req_timeout)
    except urllib.error.URLError:
        raise WrapException('failed to get {} is the internet available?'.format(urlstring))


class WrapException(MesonException):
    pass

class WrapNotFoundException(WrapException):
    pass

class PackageDefinition:
    def __init__(self, fname: str):
        self.filename = fname
        self.basename = os.path.basename(fname)
        self.name = self.basename[:-5]
        try:
            self.config = configparser.ConfigParser(interpolation=None)
            self.config.read(fname)
        except configparser.Error:
            raise WrapException('Failed to parse {}'.format(self.basename))
        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 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 has_patch(self) -> bool:
        return 'patch_url' in self.values

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')

    def resolve(self, packagename: str, method: str) -> str:
        self.packagename = packagename
        self.directory = packagename
        # We always have to load the wrap file, if it exists, because it could
        # override the default directory name.
        self.wrap = self.load_wrap()
        if self.wrap and 'directory' in self.wrap.values:
            self.directory = self.wrap.get('directory')
            if os.path.dirname(self.directory):
                raise WrapException('Directory key must be a name and not a path')
        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:
            # A wrap file is required to download
            if not self.wrap:
                m = 'Subproject directory not found and {}.wrap file not found'
                raise WrapNotFoundException(m.format(self.packagename))

            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))

        # 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 load_wrap(self) -> PackageDefinition:
        fname = os.path.join(self.subdir_root, self.packagename + '.wrap')
        if os.path.isfile(fname):
            return PackageDefinition(fname)
        return None

    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:
        # 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 subprocess.call(['git', '-C', self.subdir_root, 'submodule', 'update', '--init', self.dirname]) == 0:
                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(' '):
            subprocess.call(['git', 'checkout', '.'], cwd=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)
        if self.wrap.has_patch():
            self.apply_patch()

    def get_git(self) -> None:
        revno = self.wrap.get('revision')
        is_shallow = 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
            subprocess.check_call(['git', 'init', self.directory], cwd=self.subdir_root)
            subprocess.check_call(['git', 'remote', 'add', 'origin', self.wrap.get('url')],
                                  cwd=self.dirname)
            revno = self.wrap.get('revision')
            subprocess.check_call(['git', 'fetch', '--depth', self.wrap.values.get('depth'), 'origin', revno],
                                  cwd=self.dirname)
            subprocess.check_call(['git', 'checkout', revno], cwd=self.dirname)
            if self.wrap.values.get('clone-recursive', '').lower() == 'true':
                subprocess.check_call(['git', 'submodule', 'update',
                                       '--init', '--checkout', '--recursive', '--depth', self.wrap.values.get('depth')],
                                      cwd=self.dirname)
            push_url = self.wrap.values.get('push-url')
            if push_url:
                subprocess.check_call(['git', 'remote', 'set-url',
                                       '--push', 'origin', push_url],
                                      cwd=self.dirname)
        else:
            if not is_shallow:
                subprocess.check_call(['git', 'clone', self.wrap.get('url'),
                                       self.directory], cwd=self.subdir_root)
                if revno.lower() != 'head':
                    if subprocess.call(['git', 'checkout', revno], cwd=self.dirname) != 0:
                        subprocess.check_call(['git', 'fetch', self.wrap.get('url'), revno], cwd=self.dirname)
                        subprocess.check_call(['git', 'checkout', revno], cwd=self.dirname)
            else:
                subprocess.check_call(['git', 'clone', '--depth', self.wrap.values.get('depth'),
                                       '--branch', revno,
                                       self.wrap.get('url'),
                                       self.directory], cwd=self.subdir_root)
            if self.wrap.values.get('clone-recursive', '').lower() == 'true':
                subprocess.check_call(['git', 'submodule', 'update',
                                       '--init', '--checkout', '--recursive', '--depth', self.wrap.values.get('depth')],
                                      cwd=self.dirname)
            push_url = self.wrap.values.get('push-url')
            if push_url:
                subprocess.check_call(['git', 'remote', 'set-url',
                                       '--push', 'origin', push_url],
                                      cwd=self.dirname)

    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')
        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')
        subprocess.check_call(['svn', 'checkout', '-r', revno, self.wrap.get('url'),
                               self.directory], cwd=self.subdir_root)

    def get_data(self, url: str) -> typing.Tuple[str, str]:
        blocksize = 10 * 1024
        h = hashlib.sha256()
        tmpfile = tempfile.NamedTemporaryFile(mode='wb', dir=self.cachedir, delete=False)
        if url.startswith('https://wrapdb.mesonbuild.com'):
            resp = open_wrapdburl(url)
        else:
            try:
                resp = urllib.request.urlopen(url, timeout=req_timeout)
            except urllib.error.URLError:
                raise WrapException('could not get {} is the internet available?'.format(url))
        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) -> None:
        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 %s:\n %s expected\n %s actual.' % (what, expected, dhash))

    def download(self, what: str, ofname: str) -> None:
        self.check_can_download()
        srcurl = self.wrap.get(what + '_url')
        mlog.log('Downloading', mlog.bold(self.packagename), what, 'from', mlog.bold(srcurl))
        dhash, tmpfile = self.get_data(srcurl)
        expected = self.wrap.get(what + '_hash')
        if dhash != expected:
            os.remove(tmpfile)
            raise WrapException('Incorrect hash for %s:\n %s expected\n %s actual.' % (what, expected, dhash))
        os.rename(tmpfile, ofname)

    def get_file_internal(self, what: str) -> str:
        filename = self.wrap.get(what + '_filename')
        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

    def apply_patch(self) -> None:
        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)

    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)