import enum
import functools
import io
import os
import re
import subprocess
import sys
import tempfile
import time

from .fragment import FragmentFD
from ..postprocessor.ffmpeg import EXT_TO_OUT_FORMATS, FFmpegPostProcessor
from ..utils import (
    DownloadError,
    Popen,
    RetryManager,
    _configuration_args,
    _get_exe_version_output,
    check_executable,
    classproperty,
    cli_bool_option,
    cli_option,
    cli_valueless_option,
    determine_ext,
    encodeArgument,
    remove_end,
    traverse_obj,
    version_tuple,
)


class Features(enum.Enum):
    TO_STDOUT = enum.auto()
    MULTIPLE_FORMATS = enum.auto()


class ExternalFD(FragmentFD):
    SUPPORTED_PROTOCOLS = ('http', 'https', 'ftp', 'ftps')
    SUPPORTED_FEATURES = ()
    _CAPTURE_STDERR = True

    def real_download(self, filename, info_dict):
        self.report_destination(filename)
        tmpfilename = self.temp_name(filename)
        self._cookies_tempfile = None

        try:
            started = time.time()
            retval = self._call_downloader(tmpfilename, info_dict)
        except KeyboardInterrupt:
            if not info_dict.get('is_live'):
                raise
            # Live stream downloading cancellation should be considered as
            # correct and expected termination thus all postprocessing
            # should take place
            retval = 0
            self.to_screen(f'[{self.get_basename()}] Interrupted by user')
        finally:
            if self._cookies_tempfile:
                self.try_remove(self._cookies_tempfile)

        if retval == 0:
            status = {
                'filename': filename,
                'status': 'finished',
                'elapsed': time.time() - started,
            }
            if filename != '-':
                fsize = os.path.getsize(tmpfilename)
                self.try_rename(tmpfilename, filename)
                status.update({
                    'downloaded_bytes': fsize,
                    'total_bytes': fsize,
                })
            self._hook_progress(status, info_dict)
            return True
        else:
            self.to_stderr('\n')
            self.report_error('%s exited with code %d' % (
                self.get_basename(), retval))
            return False

    @classmethod
    def get_basename(cls):
        return cls.__name__[:-2].lower()

    @classproperty
    def EXE_NAME(cls):
        return cls.get_basename()

    @functools.cached_property
    def exe(self):
        return self.EXE_NAME

    @classmethod
    def available(cls, path=None):
        path = check_executable(
            cls.EXE_NAME if path in (None, cls.get_basename()) else path,
            [cls.AVAILABLE_OPT])
        if not path:
            return False
        cls.exe = path
        return path

    @classmethod
    def supports(cls, info_dict):
        return all((
            not info_dict.get('to_stdout') or Features.TO_STDOUT in cls.SUPPORTED_FEATURES,
            '+' not in info_dict['protocol'] or Features.MULTIPLE_FORMATS in cls.SUPPORTED_FEATURES,
            not traverse_obj(info_dict, ('hls_aes', ...), 'extra_param_to_segment_url', 'extra_param_to_key_url'),
            all(proto in cls.SUPPORTED_PROTOCOLS for proto in info_dict['protocol'].split('+')),
        ))

    @classmethod
    def can_download(cls, info_dict, path=None):
        return cls.available(path) and cls.supports(info_dict)

    def _option(self, command_option, param):
        return cli_option(self.params, command_option, param)

    def _bool_option(self, command_option, param, true_value='true', false_value='false', separator=None):
        return cli_bool_option(self.params, command_option, param, true_value, false_value, separator)

    def _valueless_option(self, command_option, param, expected_value=True):
        return cli_valueless_option(self.params, command_option, param, expected_value)

    def _configuration_args(self, keys=None, *args, **kwargs):
        return _configuration_args(
            self.get_basename(), self.params.get('external_downloader_args'), self.EXE_NAME,
            keys, *args, **kwargs)

    def _write_cookies(self):
        if not self.ydl.cookiejar.filename:
            tmp_cookies = tempfile.NamedTemporaryFile(suffix='.cookies', delete=False)
            tmp_cookies.close()
            self._cookies_tempfile = tmp_cookies.name
            self.to_screen(f'[download] Writing temporary cookies file to "{self._cookies_tempfile}"')
        # real_download resets _cookies_tempfile; if it's None then save() will write to cookiejar.filename
        self.ydl.cookiejar.save(self._cookies_tempfile, True, True)
        return self.ydl.cookiejar.filename or self._cookies_tempfile

    def _call_downloader(self, tmpfilename, info_dict):
        """ Either overwrite this or implement _make_cmd """
        cmd = [encodeArgument(a) for a in self._make_cmd(tmpfilename, info_dict)]

        self._debug_cmd(cmd)

        if 'fragments' not in info_dict:
            _, stderr, returncode = self._call_process(cmd, info_dict)
            if returncode and stderr:
                self.to_stderr(stderr)
            return returncode

        skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)

        retry_manager = RetryManager(self.params.get('fragment_retries'), self.report_retry,
                                     frag_index=None, fatal=not skip_unavailable_fragments)
        for retry in retry_manager:
            _, stderr, returncode = self._call_process(cmd, info_dict)
            if not returncode:
                break
            # TODO: Decide whether to retry based on error code
            # https://aria2.github.io/manual/en/html/aria2c.html#exit-status
            if stderr:
                self.to_stderr(stderr)
            retry.error = Exception()
            continue
        if not skip_unavailable_fragments and retry_manager.error:
            return -1

        decrypt_fragment = self.decrypter(info_dict)
        dest, _ = self.sanitize_open(tmpfilename, 'wb')
        for frag_index, fragment in enumerate(info_dict['fragments']):
            fragment_filename = f'{tmpfilename}-Frag{frag_index}'
            try:
                src, _ = self.sanitize_open(fragment_filename, 'rb')
            except OSError as err:
                if skip_unavailable_fragments and frag_index > 1:
                    self.report_skip_fragment(frag_index, err)
                    continue
                self.report_error(f'Unable to open fragment {frag_index}; {err}')
                return -1
            dest.write(decrypt_fragment(fragment, src.read()))
            src.close()
            if not self.params.get('keep_fragments', False):
                self.try_remove(fragment_filename)
        dest.close()
        self.try_remove(f'{tmpfilename}.frag.urls')
        return 0

    def _call_process(self, cmd, info_dict):
        return Popen.run(cmd, text=True, stderr=subprocess.PIPE if self._CAPTURE_STDERR else None)


class CurlFD(ExternalFD):
    AVAILABLE_OPT = '-V'
    _CAPTURE_STDERR = False  # curl writes the progress to stderr
    _MIN_VERSION_FOR_STDIN_COOKIES = (7, 59)

    @classmethod
    def available(cls, path=None):
        if path is None:
            path = 'curl'
        output = _get_exe_version_output(path, ['-V'])
        if not output:
            return False
        parts = output.split(' ', maxsplit=2)
        if len(parts) < 3:
            return False

        cls.exe = path
        cls._curl_version = version_tuple(parts[1], lenient=True)
        return path

    def _make_cmd(self, tmpfilename, info_dict):
        cmd = [self.exe, '--location', '-o', tmpfilename, '--compressed']

        if self._curl_version >= self._MIN_VERSION_FOR_STDIN_COOKIES:
            # Supports `--cookies -`
            cmd += ['--cookie', '-']
        elif os.path.islink('/dev/fd/0'):
            cmd += ['--cookie', '/dev/fd/0']
        else:
            cookies_file = self._write_cookies()
            if '=' in cookies_file:
                raise DownloadError('curl version too old or temp directory contains `=`; please use another downloader or update curl')
            assert cookies_file != '-'
            cmd += ['--cookie', cookies_file]

        if info_dict.get('http_headers') is not None:
            for key, val in info_dict['http_headers'].items():
                cmd += ['--header', f'{key}: {val}']

        cmd += self._bool_option('--continue-at', 'continuedl', '-', '0')
        cmd += self._valueless_option('--silent', 'noprogress')
        cmd += self._valueless_option('--verbose', 'verbose')
        cmd += self._option('--limit-rate', 'ratelimit')
        retry = self._option('--retry', 'retries')
        if len(retry) == 2:
            if retry[1] in ('inf', 'infinite'):
                retry[1] = '2147483647'
            cmd += retry
        cmd += self._option('--max-filesize', 'max_filesize')
        cmd += self._option('--interface', 'source_address')
        cmd += self._option('--proxy', 'proxy')
        cmd += self._valueless_option('--insecure', 'nocheckcertificate')
        cmd += self._configuration_args()
        cmd += ['--', info_dict['url']]
        return cmd

    def _call_process(self, cmd, info_dict):
        if self._curl_version > self._MIN_VERSION_FOR_STDIN_COOKIES or os.path.islink('/dev/fd/0'):
            # Supports `--cookies -` or reading from device file as `--cookies /dev/fd/0`
            buffer = io.StringIO()
            self.ydl.cookiejar._really_save(buffer, True, True)
            return Popen.run(cmd, text=True, input=buffer.getvalue())

        # Cookies already passed via cookiesfile
        return Popen.run(cmd, text=True)


class AxelFD(ExternalFD):
    AVAILABLE_OPT = '-V'

    def _make_cmd(self, tmpfilename, info_dict):
        cmd = [self.exe, '-o', tmpfilename]
        if info_dict.get('http_headers') is not None:
            for key, val in info_dict['http_headers'].items():
                cmd += ['-H', f'{key}: {val}']
        cookie_header = self.ydl.cookiejar.get_cookie_header(info_dict['url'])
        if cookie_header:
            cmd += ['-H', f'Cookie: {cookie_header}', '--max-redirect=0']
        cmd += self._configuration_args()
        cmd += ['--', info_dict['url']]
        return cmd


class WgetFD(ExternalFD):
    AVAILABLE_OPT = '--version'

    def _make_cmd(self, tmpfilename, info_dict):
        cmd = [self.exe, '-O', tmpfilename, '-nv', '--compression=auto']
        cmd += ['--load-cookies', self._write_cookies()]
        if info_dict.get('http_headers') is not None:
            for key, val in info_dict['http_headers'].items():
                cmd += ['--header', f'{key}: {val}']
        cmd += self._option('--limit-rate', 'ratelimit')
        retry = self._option('--tries', 'retries')
        if len(retry) == 2:
            if retry[1] in ('inf', 'infinite'):
                retry[1] = '0'
            cmd += retry
        cmd += self._option('--bind-address', 'source_address')
        proxy = self.params.get('proxy')
        if proxy:
            for var in ('http_proxy', 'https_proxy'):
                cmd += ['--execute', f'{var}={proxy}']
        cmd += self._valueless_option('--no-check-certificate', 'nocheckcertificate')
        cmd += self._configuration_args()
        cmd += ['--', info_dict['url']]
        return cmd


class Aria2cFD(ExternalFD):
    AVAILABLE_OPT = '-v'
    SUPPORTED_PROTOCOLS = ('http', 'https', 'ftp', 'ftps')

    @staticmethod
    def _aria2c_filename(fn):
        return fn if os.path.isabs(fn) else f'.{os.path.sep}{fn}'

    def _make_cmd(self, tmpfilename, info_dict):
        cmd = [self.exe, '--no-conf', '--auto-save-interval=10',
               '--console-log-level=warn', '--summary-interval=0', '--download-result=hide',
               '--http-accept-gzip=true', '--file-allocation=none', '-x16', '-j16', '-s16',
               '--min-split-size', '1M']

        cmd += [f'--load-cookies={self._write_cookies()}']
        if info_dict.get('http_headers') is not None:
            for key, val in info_dict['http_headers'].items():
                cmd += ['--header', f'{key}: {val}']
        cmd += self._option('--max-overall-download-limit', 'ratelimit')
        cmd += self._option('--interface', 'source_address')
        cmd += self._option('--all-proxy', 'proxy')
        cmd += self._bool_option('--check-certificate', 'nocheckcertificate', 'false', 'true', '=')
        cmd += self._bool_option('--remote-time', 'updatetime', 'true', 'false', '=')
        cmd += self._bool_option('--show-console-readout', 'noprogress', 'false', 'true', '=')
        cmd += self._bool_option('--remove-control-file', 'continuedl', 'false', 'true', '=')
        cmd += self._configuration_args()
        # do not allow changing these flags
        cmd += ['--allow-overwrite=true']
        cmd += ['--always-resume=false']
        cmd += ['--auto-file-renaming=false']
        cmd += ['--force-save=false']

        # aria2c strips out spaces from the beginning/end of filenames and paths.
        # We work around this issue by adding a "./" to the beginning of the
        # filename and relative path, and adding a "/" at the end of the path.
        # See: https://github.com/yt-dlp/yt-dlp/issues/276
        # https://github.com/ytdl-org/youtube-dl/issues/20312
        # https://github.com/aria2/aria2/issues/1373
        dn = os.path.dirname(tmpfilename)
        if dn:
            cmd += ['--dir', self._aria2c_filename(dn) + os.path.sep]

        cmd += [
            '--out',
            self._aria2c_filename(os.path.basename(tmpfilename)),
            '--',
            info_dict['url'],
        ]

        return cmd


class HttpieFD(ExternalFD):
    AVAILABLE_OPT = '--version'
    EXE_NAME = 'http'

    def _make_cmd(self, tmpfilename, info_dict):
        cmd = ['http', '--download', '--output', tmpfilename, info_dict['url']]

        if info_dict.get('http_headers') is not None:
            for key, val in info_dict['http_headers'].items():
                cmd += [f'{key}:{val}']

        # httpie 3.1.0+ removes the Cookie header on redirect, so this should be safe for now. [1]
        # If we ever need cookie handling for redirects, we can export the cookiejar into a session. [2]
        # 1: https://github.com/httpie/httpie/security/advisories/GHSA-9w4w-cpc8-h2fq
        # 2: https://httpie.io/docs/cli/sessions
        cookie_header = self.ydl.cookiejar.get_cookie_header(info_dict['url'])
        if cookie_header:
            cmd += [f'Cookie:{cookie_header}']
        return cmd


class FFmpegFD(ExternalFD):
    SUPPORTED_PROTOCOLS = ('http', 'https', 'ftp', 'ftps', 'm3u8', 'm3u8_native', 'rtmp', 'rtmp_ffmpeg', 'http_dash_segments')
    SUPPORTED_FEATURES = (Features.TO_STDOUT, Features.MULTIPLE_FORMATS)

    @classmethod
    def available(cls, path=None):
        # TODO: Fix path for ffmpeg
        # Fixme: This may be wrong when --ffmpeg-location is used
        return FFmpegPostProcessor().available

    def on_process_started(self, proc, stdin):
        """ Override this in subclasses  """
        pass

    @classmethod
    def can_merge_formats(cls, info_dict, params):
        return (
            info_dict.get('requested_formats')
            and info_dict.get('protocol')
            and not params.get('allow_unplayable_formats')
            and 'no-direct-merge' not in params.get('compat_opts', [])
            and cls.can_download(info_dict))

    def _call_downloader(self, tmpfilename, info_dict):
        ffpp = FFmpegPostProcessor(downloader=self)
        if not ffpp.available:
            self.report_error('m3u8 download detected but ffmpeg could not be found. Please install')
            return False
        ffpp.check_version()

        args = [ffpp.executable, '-y']

        for log_level in ('quiet', 'verbose'):
            if self.params.get(log_level, False):
                args += ['-loglevel', log_level]
                break
        if not self.params.get('verbose'):
            args += ['-hide_banner']

        env = None
        proxy = self.params.get('proxy')
        if proxy:
            if not re.match(r'[\da-zA-Z]+://', proxy):
                proxy = f'http://{proxy}'

            if proxy.startswith('socks'):
                self.report_warning(
                    f'{self.get_basename()} does not support SOCKS proxies. Downloading is likely to fail. '
                    'Consider adding --hls-prefer-native to your command.')

            # Since December 2015 ffmpeg supports -http_proxy option (see
            # http://git.videolan.org/?p=ffmpeg.git;a=commit;h=b4eb1f29ebddd60c41a2eb39f5af701e38e0d3fd)
            # We could switch to the following code if we are able to detect version properly
            # args += ['-http_proxy', proxy]
            env = os.environ.copy()
            env['HTTP_PROXY'] = proxy
            env['http_proxy'] = proxy

        start_time, end_time = info_dict.get('section_start') or 0, info_dict.get('section_end')

        fallback_input_args = traverse_obj(info_dict, ('downloader_options', 'ffmpeg_args', ...))

        selected_formats = info_dict.get('requested_formats') or [info_dict]
        for i, fmt in enumerate(selected_formats):
            is_http = re.match(r'https?://', fmt['url'])
            cookies = self.ydl.cookiejar.get_cookies_for_url(fmt['url']) if is_http else []
            if cookies:
                args.extend(['-cookies', ''.join(
                    f'{cookie.name}={cookie.value}; path={cookie.path}; domain={cookie.domain};\r\n'
                    for cookie in cookies)])
            http_headers = fmt.get('http_headers') or info_dict.get('http_headers')
            if http_headers and is_http:
                # Trailing \r\n after each HTTP header is important to prevent warning from ffmpeg:
                # [http @ 00000000003d2fa0] No trailing CRLF found in HTTP header.
                args.extend(['-headers', ''.join(f'{key}: {val}\r\n' for key, val in http_headers.items())])

            if start_time:
                args += ['-ss', str(start_time)]
            if end_time:
                args += ['-t', str(end_time - start_time)]

            protocol = fmt.get('protocol')

            if protocol == 'rtmp':
                player_url = fmt.get('player_url')
                page_url = fmt.get('page_url')
                app = fmt.get('app')
                play_path = fmt.get('play_path')
                tc_url = fmt.get('tc_url')
                flash_version = fmt.get('flash_version')
                live = fmt.get('rtmp_live', False)
                conn = fmt.get('rtmp_conn')
                if player_url is not None:
                    args += ['-rtmp_swfverify', player_url]
                if page_url is not None:
                    args += ['-rtmp_pageurl', page_url]
                if app is not None:
                    args += ['-rtmp_app', app]
                if play_path is not None:
                    args += ['-rtmp_playpath', play_path]
                if tc_url is not None:
                    args += ['-rtmp_tcurl', tc_url]
                if flash_version is not None:
                    args += ['-rtmp_flashver', flash_version]
                if live:
                    args += ['-rtmp_live', 'live']
                if isinstance(conn, list):
                    for entry in conn:
                        args += ['-rtmp_conn', entry]
                elif isinstance(conn, str):
                    args += ['-rtmp_conn', conn]

            elif protocol == 'http_dash_segments' and info_dict.get('is_live'):
                # ffmpeg may try to read past the latest available segments for
                # live DASH streams unless we pass `-re`. In modern ffmpeg, this
                # is an alias of `-readrate 1`, but `-readrate` was not added
                # until ffmpeg 5.0, so we must stick to using `-re`
                args += ['-re']

            url = fmt['url']
            if self.params.get('enable_file_urls') and url.startswith('file:'):
                # The default protocol_whitelist is 'file,crypto,data' when reading local m3u8 URLs,
                # so only local segments can be read unless we also include 'http,https,tcp,tls'
                args += ['-protocol_whitelist', 'file,crypto,data,http,https,tcp,tls']
                # ffmpeg incorrectly handles 'file:' URLs by only removing the
                # 'file:' prefix and treating the rest as if it's a normal filepath.
                # FFmpegPostProcessor also depends on this behavior, so we need to fixup the URLs:
                # - On Windows/Cygwin, replace 'file:///' and 'file://localhost/' with 'file:'
                # - On *nix, replace 'file://localhost/' with 'file:/'
                # Ref: https://github.com/yt-dlp/yt-dlp/issues/13781
                #      https://trac.ffmpeg.org/ticket/2702
                url = re.sub(r'^file://(?:localhost)?/', 'file:' if os.name == 'nt' else 'file:/', url)

            args += traverse_obj(fmt, ('downloader_options', 'ffmpeg_args', ...)) or fallback_input_args
            args += [*self._configuration_args((f'_i{i + 1}', '_i')), '-i', url]

        if not (start_time or end_time) or not self.params.get('force_keyframes_at_cuts'):
            args += ['-c', 'copy']

        if info_dict.get('requested_formats') or protocol == 'http_dash_segments':
            for i, fmt in enumerate(selected_formats):
                stream_number = fmt.get('manifest_stream_number', 0)
                args.extend(['-map', f'{i}:{stream_number}'])

        if self.params.get('test', False):
            args += ['-fs', str(self._TEST_FILE_SIZE)]

        ext = info_dict['ext']
        if protocol in ('m3u8', 'm3u8_native'):
            use_mpegts = (tmpfilename == '-') or self.params.get('hls_use_mpegts')
            if use_mpegts is None:
                use_mpegts = info_dict.get('is_live')
            if use_mpegts:
                args += ['-f', 'mpegts']
            else:
                args += ['-f', 'mp4']
                if (ffpp.basename == 'ffmpeg' and ffpp._features.get('needs_adtstoasc')) and (not info_dict.get('acodec') or info_dict['acodec'].split('.')[0] in ('aac', 'mp4a')):
                    args += ['-bsf:a', 'aac_adtstoasc']
        elif protocol == 'rtmp':
            args += ['-f', 'flv']
        elif ext == 'mp4' and tmpfilename == '-':
            args += ['-f', 'mpegts']
        elif ext == 'unknown_video':
            ext = determine_ext(remove_end(tmpfilename, '.part'))
            if ext == 'unknown_video':
                self.report_warning(
                    'The video format is unknown and cannot be downloaded by ffmpeg. '
                    'Explicitly set the extension in the filename to attempt download in that format')
            else:
                self.report_warning(f'The video format is unknown. Trying to download as {ext} according to the filename')
                args += ['-f', EXT_TO_OUT_FORMATS.get(ext, ext)]
        else:
            args += ['-f', EXT_TO_OUT_FORMATS.get(ext, ext)]

        args += traverse_obj(info_dict, ('downloader_options', 'ffmpeg_args_out', ...))

        args += self._configuration_args(('_o1', '_o', ''))

        args = [encodeArgument(opt) for opt in args]
        args.append(ffpp._ffmpeg_filename_argument(tmpfilename))
        self._debug_cmd(args)

        piped = any(fmt['url'] in ('-', 'pipe:') for fmt in selected_formats)
        with Popen(args, stdin=subprocess.PIPE, env=env) as proc:
            if piped:
                self.on_process_started(proc, proc.stdin)
            try:
                retval = proc.wait()
            except BaseException as e:
                # subprocces.run would send the SIGKILL signal to ffmpeg and the
                # mp4 file couldn't be played, but if we ask ffmpeg to quit it
                # produces a file that is playable (this is mostly useful for live
                # streams). Note that Windows is not affected and produces playable
                # files (see https://github.com/ytdl-org/youtube-dl/issues/8300).
                if isinstance(e, KeyboardInterrupt) and sys.platform != 'win32' and not piped:
                    proc.communicate_or_kill(b'q')
                else:
                    proc.kill(timeout=None)
                raise
            return retval


_BY_NAME = {
    klass.get_basename(): klass
    for name, klass in globals().items()
    if name.endswith('FD') and name not in ('ExternalFD', 'FragmentFD')
}


def list_external_downloaders():
    return sorted(_BY_NAME.keys())


def get_external_downloader(external_downloader):
    """ Given the name of the executable, see whether we support the given downloader """
    bn = os.path.splitext(os.path.basename(external_downloader))[0]
    return _BY_NAME.get(bn) or next((
        klass for klass in _BY_NAME.values() if klass.EXE_NAME in bn
    ), None)
