import imp
import pkgutil
import sys
import traceback
import requests

from streamlink.utils import update_scheme
from streamlink.utils.l10n import Localization
from . import plugins, __version__
from .compat import is_win32
from .exceptions import NoPluginError, PluginError
from .logger import Logger
from .options import Options
from .plugin import api


def print_small_exception(start_after):
    type, value, traceback_ = sys.exc_info()

    tb = traceback.extract_tb(traceback_)
    index = 0

    for i, trace in enumerate(tb):
        if trace[2] == start_after:
            index = i + 1
            break

    lines = traceback.format_list(tb[index:])
    lines += traceback.format_exception_only(type, value)

    for line in lines:
        sys.stderr.write(line)

    sys.stderr.write("\n")


class Streamlink(object):
    """A Streamlink session is used to keep track of plugins,
       options and log settings."""

    def __init__(self):
        self.http = api.HTTPSession()
        self.options = Options({
            "hds-live-edge": 10.0,
            "hds-segment-attempts": 3,
            "hds-segment-threads": 1,
            "hds-segment-timeout": 10.0,
            "hds-timeout": 60.0,
            "hls-live-edge": 3,
            "hls-segment-attempts": 3,
            "hls-segment-threads": 1,
            "hls-segment-timeout": 10.0,
            "hls-timeout": 60.0,
            "hls-playlist-reload-attempts": 3,
            "http-stream-timeout": 60.0,
            "ringbuffer-size": 1024 * 1024 * 16,  # 16 MB
            "rtmp-timeout": 60.0,
            "rtmp-rtmpdump": is_win32 and "rtmpdump.exe" or "rtmpdump",
            "rtmp-proxy": None,
            "stream-segment-attempts": 3,
            "stream-segment-threads": 1,
            "stream-segment-timeout": 10.0,
            "stream-timeout": 60.0,
            "subprocess-errorlog": False,
            "subprocess-errorlog-path": None,
            "ffmpeg-ffmpeg": None,
            "ffmpeg-video-transcode": "copy",
            "ffmpeg-audio-transcode": "copy",
            "locale": None
        })
        self.plugins = {}
        self.logger = Logger()
        self.load_builtin_plugins()

    def set_option(self, key, value):
        """Sets general options used by plugins and streams originating
        from this session object.

        :param key: key of the option
        :param value: value to set the option to


        **Available options**:

        ======================== =========================================
        hds-live-edge            ( float) Specify the time live HDS
                                 streams will start from the edge of
                                 stream, default: ``10.0``

        hds-segment-attempts     (int) How many attempts should be done
                                 to download each HDS segment, default: ``3``

        hds-segment-threads      (int) The size of the thread pool used
                                 to download segments, default: ``1``

        hds-segment-timeout      (float) HDS segment connect and read
                                 timeout, default: ``10.0``

        hds-timeout              (float) Timeout for reading data from
                                 HDS streams, default: ``60.0``

        hls-live-edge            (int) How many segments from the end
                                 to start live streams on, default: ``3``

        hls-segment-attempts     (int) How many attempts should be done
                                 to download each HLS segment, default: ``3``

        hls-segment-threads      (int) The size of the thread pool used
                                 to download segments, default: ``1``

        hls-segment-timeout      (float) HLS segment connect and read
                                 timeout, default: ``10.0``

        hls-timeout              (float) Timeout for reading data from
                                 HLS streams, default: ``60.0``

        http-proxy               (str) Specify a HTTP proxy to use for
                                 all HTTP requests

        https-proxy              (str) Specify a HTTPS proxy to use for
                                 all HTTPS requests

        http-cookies             (dict or str) A dict or a semi-colon (;)
                                 delimited str of cookies to add to each
                                 HTTP request, e.g. ``foo=bar;baz=qux``

        http-headers             (dict or str) A dict or semi-colon (;)
                                 delimited str of headers to add to each
                                 HTTP request, e.g. ``foo=bar;baz=qux``

        http-query-params        (dict or str) A dict or a ampersand (&)
                                 delimited string of query parameters to
                                 add to each HTTP request,
                                 e.g. ``foo=bar&baz=qux``

        http-trust-env           (bool) Trust HTTP settings set in the
                                 environment, such as environment
                                 variables (HTTP_PROXY, etc) and
                                 ~/.netrc authentication

        http-ssl-verify          (bool) Verify SSL certificates,
                                 default: ``True``

        http-ssl-cert            (str or tuple) SSL certificate to use,
                                 can be either a .pem file (str) or a
                                 .crt/.key pair (tuple)

        http-timeout             (float) General timeout used by all HTTP
                                 requests except the ones covered by
                                 other options, default: ``20.0``

        http-stream-timeout      (float) Timeout for reading data from
                                 HTTP streams, default: ``60.0``

        subprocess-errorlog      (bool) Log errors from subprocesses to
                                 a file located in the temp directory

        subprocess-errorlog-path (str) Log errors from subprocesses to
                                 a specific file

        ringbuffer-size          (int) The size of the internal ring
                                 buffer used by most stream types,
                                 default: ``16777216`` (16MB)

        rtmp-proxy               (str) Specify a proxy (SOCKS) that RTMP
                                 streams will use

        rtmp-rtmpdump            (str) Specify the location of the
                                 rtmpdump executable used by RTMP streams,
                                 e.g. ``/usr/local/bin/rtmpdump``

        rtmp-timeout             (float) Timeout for reading data from
                                 RTMP streams, default: ``60.0``

        ffmpeg-ffmpeg            (str) Specify the location of the
                                 ffmpeg executable use by Muxing streams
                                 e.g. ``/usr/local/bin/ffmpeg``

        ffmpeg-verbose           (bool) Log stderr from ffmpeg to the
                                 console

        ffmpeg-verbose-path      (str) Specify the location of the
                                 ffmpeg stderr log file

        ffmpeg-video-transcode   (str) The codec to use if transcoding
                                 video when muxing with ffmpeg
                                 e.g. ``h264``

        ffmpeg-audio-transcode   (str) The codec to use if transcoding
                                 audio when muxing with ffmpeg
                                 e.g. ``aac``

        stream-segment-attempts  (int) How many attempts should be done
                                 to download each segment, default: ``3``.
                                 General option used by streams not
                                 covered by other options.

        stream-segment-threads   (int) The size of the thread pool used
                                 to download segments, default: ``1``.
                                 General option used by streams not
                                 covered by other options.

        stream-segment-timeout   (float) Segment connect and read
                                 timeout, default: ``10.0``.
                                 General option used by streams not
                                 covered by other options.

        stream-timeout           (float) Timeout for reading data from
                                 stream, default: ``60.0``.
                                 General option used by streams not
                                 covered by other options.

        locale                   (str) Locale setting, in the RFC 1766 format
                                 eg. en_US or es_ES
                                 default: ``system locale``.
        ======================== =========================================

        """

        # Backwards compatibility
        if key == "rtmpdump":
            key = "rtmp-rtmpdump"
        elif key == "rtmpdump-proxy":
            key = "rtmp-proxy"
        elif key == "errorlog":
            key = "subprocess-errorlog"
        elif key == "errorlog-path":
            key = "subprocess-errorlog-path"

        if key == "http-proxy":
            self.http.proxies["http"] = update_scheme("http://", value)
        elif key == "https-proxy":
            self.http.proxies["https"] = update_scheme("https://", value)
        elif key == "http-cookies":
            if isinstance(value, dict):
                self.http.cookies.update(value)
            else:
                self.http.parse_cookies(value)
        elif key == "http-headers":
            if isinstance(value, dict):
                self.http.headers.update(value)
            else:
                self.http.parse_headers(value)
        elif key == "http-query-params":
            if isinstance(value, dict):
                self.http.params.update(value)
            else:
                self.http.parse_query_params(value)
        elif key == "http-trust-env":
            self.http.trust_env = value
        elif key == "http-ssl-verify":
            self.http.verify = value
        elif key == "http-disable-dh":
            if value:
                requests.packages.urllib3.util.ssl_.DEFAULT_CIPHERS += ':!DH'
                try:
                    requests.packages.urllib3.contrib.pyopenssl.DEFAULT_SSL_CIPHER_LIST = \
                        requests.packages.urllib3.util.ssl_.DEFAULT_CIPHERS.encode("ascii")
                except AttributeError:
                    # no ssl to disable the cipher on
                    pass
        elif key == "http-ssl-cert":
            self.http.cert = value
        elif key == "http-timeout":
            self.http.timeout = value
        else:
            self.options.set(key, value)

    def get_option(self, key):
        """Returns current value of specified option.

        :param key: key of the option

        """
        # Backwards compatibility
        if key == "rtmpdump":
            key = "rtmp-rtmpdump"
        elif key == "rtmpdump-proxy":
            key = "rtmp-proxy"
        elif key == "errorlog":
            key = "subprocess-errorlog"

        if key == "http-proxy":
            return self.http.proxies.get("http")
        elif key == "https-proxy":
            return self.http.proxies.get("https")
        elif key == "http-cookies":
            return self.http.cookies
        elif key == "http-headers":
            return self.http.headers
        elif key == "http-query-params":
            return self.http.params
        elif key == "http-trust-env":
            return self.http.trust_env
        elif key == "http-ssl-verify":
            return self.http.verify
        elif key == "http-ssl-cert":
            return self.http.cert
        elif key == "http-timeout":
            return self.http.timeout
        else:
            return self.options.get(key)

    def set_plugin_option(self, plugin, key, value):
        """Sets plugin specific options used by plugins originating
        from this session object.

        :param plugin: name of the plugin
        :param key: key of the option
        :param value: value to set the option to

        """

        if plugin in self.plugins:
            plugin = self.plugins[plugin]
            plugin.set_option(key, value)

    def get_plugin_option(self, plugin, key):
        """Returns current value of plugin specific option.

        :param plugin: name of the plugin
        :param key: key of the option

        """

        if plugin in self.plugins:
            plugin = self.plugins[plugin]
            return plugin.get_option(key)

    def set_loglevel(self, level):
        """Sets the log level used by this session.

        Valid levels are: "none", "error", "warning", "info"
        and "debug".

        :param level: level of logging to output

        """

        self.logger.set_level(level)

    def set_logoutput(self, output):
        """Sets the log output used by this session.

        :param output: a file-like object with a write method

        """
        self.logger.set_output(output)

    def resolve_url(self, url, follow_redirect=True):
        """Attempts to find a plugin that can use this URL.

        The default protocol (http) will be prefixed to the URL if
        not specified.

        Raises :exc:`NoPluginError` on failure.

        :param url: a URL to match against loaded plugins
        :param follow_redirect: follow redirects

        """
        url = update_scheme("http://", url)

        available_plugins = []
        for name, plugin in self.plugins.items():
            if plugin.can_handle_url(url):
                available_plugins.append(plugin)

        available_plugins.sort(key=lambda x: x.priority(url), reverse=True)
        if available_plugins:
            return available_plugins[0](url)

        if follow_redirect:
            # Attempt to handle a redirect URL
            try:
                res = self.http.head(url, allow_redirects=True, acceptable_status=[501])

                # Fall back to GET request if server doesn't handle HEAD.
                if res.status_code == 501:
                    res = self.http.get(url, stream=True)

                if res.url != url:
                    return self.resolve_url(res.url, follow_redirect=follow_redirect)
            except PluginError:
                pass

        raise NoPluginError

    def resolve_url_no_redirect(self, url):
        """Attempts to find a plugin that can use this URL.

        The default protocol (http) will be prefixed to the URL if
        not specified.

        Raises :exc:`NoPluginError` on failure.

        :param url: a URL to match against loaded plugins

        """
        return self.resolve_url(url, follow_redirect=False)

    def streams(self, url, **params):
        """Attempts to find a plugin and extract streams from the *url*.

        *params* are passed to :func:`Plugin.streams`.

        Raises :exc:`NoPluginError` if no plugin is found.
        """

        plugin = self.resolve_url(url)
        return plugin.streams(**params)

    def get_plugins(self):
        """Returns the loaded plugins for the session."""

        return self.plugins

    def load_builtin_plugins(self):
        self.load_plugins(plugins.__path__[0])

    def load_plugins(self, path):
        """Attempt to load plugins from the path specified.

        :param path: full path to a directory where to look for plugins

        """

        for loader, name, ispkg in pkgutil.iter_modules([path]):
            file, pathname, desc = imp.find_module(name, [path])

            try:
                self.load_plugin(name, file, pathname, desc)
            except Exception:
                sys.stderr.write("Failed to load plugin {0}:\n".format(name))
                print_small_exception("load_plugin")

                continue

    def load_plugin(self, name, file, pathname, desc):
        # Set the global http session for this plugin
        api.http = self.http
        module = imp.load_module(name, file, pathname, desc)

        if hasattr(module, "__plugin__"):
            module_name = getattr(module, "__name__")

            plugin = getattr(module, "__plugin__")
            plugin.bind(self, module_name)

            self.plugins[plugin.module] = plugin

        if file:
            file.close()

    @property
    def version(self):
        return __version__

    @property
    def localization(self):
        return Localization(self.get_option("locale"))


__all__ = ["Streamlink"]
