"""
Utilities for working with the Telegram API itself (such as handy methods
to convert between an entity like an User, Chat, etc. into its Input version)
"""
import math
import re
from mimetypes import add_type, guess_extension

from .tl.types import (
    Channel, ChannelForbidden, Chat, ChatEmpty, ChatForbidden, ChatFull,
    ChatPhoto, InputPeerChannel, InputPeerChat, InputPeerUser, InputPeerEmpty,
    MessageMediaDocument, MessageMediaPhoto, PeerChannel, InputChannel,
    UserEmpty, InputUser, InputUserEmpty, InputUserSelf, InputPeerSelf,
    PeerChat, PeerUser, User, UserFull, UserProfilePhoto, Document,
    MessageMediaContact, MessageMediaEmpty, MessageMediaGame, MessageMediaGeo,
    MessageMediaUnsupported, MessageMediaVenue, InputMediaContact,
    InputMediaDocument, InputMediaEmpty, InputMediaGame,
    InputMediaGeoPoint, InputMediaPhoto, InputMediaVenue, InputDocument,
    DocumentEmpty, InputDocumentEmpty, Message, GeoPoint, InputGeoPoint,
    GeoPointEmpty, InputGeoPointEmpty, Photo, InputPhoto, PhotoEmpty,
    InputPhotoEmpty, FileLocation, ChatPhotoEmpty, UserProfilePhotoEmpty,
    FileLocationUnavailable, InputMediaUploadedDocument, ChannelFull,
    InputMediaUploadedPhoto, DocumentAttributeFilename, photos
)

USERNAME_RE = re.compile(
    r'@|(?:https?://)?(?:telegram\.(?:me|dog)|t\.me)/(joinchat/)?'
)


def get_display_name(entity):
    """Gets the input peer for the given "entity" (user, chat or channel)
       Returns None if it was not found"""
    if isinstance(entity, User):
        if entity.last_name and entity.first_name:
            return '{} {}'.format(entity.first_name, entity.last_name)
        elif entity.first_name:
            return entity.first_name
        elif entity.last_name:
            return entity.last_name
        else:
            return ''

    elif isinstance(entity, (Chat, Channel)):
        return entity.title

    return ''

# For some reason, .webp (stickers' format) is not registered
add_type('image/webp', '.webp')


def get_extension(media):
    """Gets the corresponding extension for any Telegram media"""

    # Photos are always compressed as .jpg by Telegram
    if isinstance(media, (UserProfilePhoto, ChatPhoto, MessageMediaPhoto)):
        return '.jpg'

    # Documents will come with a mime type
    if isinstance(media, MessageMediaDocument):
        if isinstance(media.document, Document):
            if media.document.mime_type == 'application/octet-stream':
                # Octet stream are just bytes, which have no default extension
                return ''
            else:
                extension = guess_extension(media.document.mime_type)
                return extension if extension else ''

    return ''


def _raise_cast_fail(entity, target):
    raise TypeError('Cannot cast {} to any kind of {}.'.format(
        type(entity).__name__, target))


def get_input_peer(entity, allow_self=True):
    """Gets the input peer for the given "entity" (user, chat or channel).
       A TypeError is raised if the given entity isn't a supported type."""
    try:
        if entity.SUBCLASS_OF_ID == 0xc91c90b6:  # crc32(b'InputPeer')
            return entity
    except AttributeError:
        _raise_cast_fail(entity, 'InputPeer')

    if isinstance(entity, User):
        if entity.is_self and allow_self:
            return InputPeerSelf()
        else:
            return InputPeerUser(entity.id, entity.access_hash or 0)

    if isinstance(entity, (Chat, ChatEmpty, ChatForbidden)):
        return InputPeerChat(entity.id)

    if isinstance(entity, (Channel, ChannelForbidden)):
        return InputPeerChannel(entity.id, entity.access_hash or 0)

    # Less common cases
    if isinstance(entity, UserEmpty):
        return InputPeerEmpty()

    if isinstance(entity, InputUser):
        return InputPeerUser(entity.user_id, entity.access_hash)

    if isinstance(entity, InputUserSelf):
        return InputPeerSelf()

    if isinstance(entity, UserFull):
        return get_input_peer(entity.user)

    if isinstance(entity, ChatFull):
        return InputPeerChat(entity.id)

    if isinstance(entity, PeerChat):
        return InputPeerChat(entity.chat_id)

    _raise_cast_fail(entity, 'InputPeer')


def get_input_channel(entity):
    """Similar to get_input_peer, but for InputChannel's alone"""
    try:
        if entity.SUBCLASS_OF_ID == 0x40f202fd:  # crc32(b'InputChannel')
            return entity
    except AttributeError:
        _raise_cast_fail(entity, 'InputChannel')

    if isinstance(entity, (Channel, ChannelForbidden)):
        return InputChannel(entity.id, entity.access_hash or 0)

    if isinstance(entity, InputPeerChannel):
        return InputChannel(entity.channel_id, entity.access_hash)

    _raise_cast_fail(entity, 'InputChannel')


def get_input_user(entity):
    """Similar to get_input_peer, but for InputUser's alone"""
    try:
        if entity.SUBCLASS_OF_ID == 0xe669bf46:  # crc32(b'InputUser'):
            return entity
    except AttributeError:
        _raise_cast_fail(entity, 'InputUser')

    if isinstance(entity, User):
        if entity.is_self:
            return InputUserSelf()
        else:
            return InputUser(entity.id, entity.access_hash or 0)

    if isinstance(entity, InputPeerSelf):
        return InputUserSelf()

    if isinstance(entity, (UserEmpty, InputPeerEmpty)):
        return InputUserEmpty()

    if isinstance(entity, UserFull):
        return get_input_user(entity.user)

    if isinstance(entity, InputPeerUser):
        return InputUser(entity.user_id, entity.access_hash)

    _raise_cast_fail(entity, 'InputUser')


def get_input_document(document):
    """Similar to get_input_peer, but for documents"""
    try:
        if document.SUBCLASS_OF_ID == 0xf33fdb68:  # crc32(b'InputDocument'):
            return document
    except AttributeError:
        _raise_cast_fail(document, 'InputDocument')

    if isinstance(document, Document):
        return InputDocument(id=document.id, access_hash=document.access_hash)

    if isinstance(document, DocumentEmpty):
        return InputDocumentEmpty()

    if isinstance(document, MessageMediaDocument):
        return get_input_document(document.document)

    if isinstance(document, Message):
        return get_input_document(document.media)

    _raise_cast_fail(document, 'InputDocument')


def get_input_photo(photo):
    """Similar to get_input_peer, but for documents"""
    try:
        if photo.SUBCLASS_OF_ID == 0x846363e0:  # crc32(b'InputPhoto'):
            return photo
    except AttributeError:
        _raise_cast_fail(photo, 'InputPhoto')

    if isinstance(photo, photos.Photo):
        photo = photo.photo

    if isinstance(photo, Photo):
        return InputPhoto(id=photo.id, access_hash=photo.access_hash)

    if isinstance(photo, PhotoEmpty):
        return InputPhotoEmpty()

    _raise_cast_fail(photo, 'InputPhoto')


def get_input_geo(geo):
    """Similar to get_input_peer, but for geo points"""
    try:
        if geo.SUBCLASS_OF_ID == 0x430d225:  # crc32(b'InputGeoPoint'):
            return geo
    except AttributeError:
        _raise_cast_fail(geo, 'InputGeoPoint')

    if isinstance(geo, GeoPoint):
        return InputGeoPoint(lat=geo.lat, long=geo.long)

    if isinstance(geo, GeoPointEmpty):
        return InputGeoPointEmpty()

    if isinstance(geo, MessageMediaGeo):
        return get_input_geo(geo.geo)

    if isinstance(geo, Message):
        return get_input_geo(geo.media)

    _raise_cast_fail(geo, 'InputGeoPoint')


def get_input_media(media, user_caption=None, is_photo=False):
    """Similar to get_input_peer, but for media.

       If the media is a file location and is_photo is known to be True,
       it will be treated as an InputMediaUploadedPhoto.
    """
    try:
        if media.SUBCLASS_OF_ID == 0xfaf846f4:  # crc32(b'InputMedia'):
            return media
    except AttributeError:
        _raise_cast_fail(media, 'InputMedia')

    if isinstance(media, MessageMediaPhoto):
        return InputMediaPhoto(
            id=get_input_photo(media.photo),
            ttl_seconds=media.ttl_seconds,
            caption=((media.caption if user_caption is None else user_caption)
                     or '')
        )

    if isinstance(media, MessageMediaDocument):
        return InputMediaDocument(
            id=get_input_document(media.document),
            ttl_seconds=media.ttl_seconds,
            caption=((media.caption if user_caption is None else user_caption)
                     or '')
        )

    if isinstance(media, FileLocation):
        if is_photo:
            return InputMediaUploadedPhoto(
                file=media,
                caption=user_caption or ''
            )
        else:
            return InputMediaUploadedDocument(
                file=media,
                mime_type='application/octet-stream',  # unknown, assume bytes
                attributes=[DocumentAttributeFilename('unnamed')],
                caption=user_caption or ''
            )

    if isinstance(media, MessageMediaGame):
        return InputMediaGame(id=media.game.id)

    if isinstance(media, (ChatPhoto, UserProfilePhoto)):
        if isinstance(media.photo_big, FileLocationUnavailable):
            return get_input_media(media.photo_small, is_photo=True)
        else:
            return get_input_media(media.photo_big, is_photo=True)

    if isinstance(media, MessageMediaContact):
        return InputMediaContact(
            phone_number=media.phone_number,
            first_name=media.first_name,
            last_name=media.last_name
        )

    if isinstance(media, MessageMediaGeo):
        return InputMediaGeoPoint(geo_point=get_input_geo(media.geo))

    if isinstance(media, MessageMediaVenue):
        return InputMediaVenue(
            geo_point=get_input_geo(media.geo),
            title=media.title,
            address=media.address,
            provider=media.provider,
            venue_id=media.venue_id,
            venue_type=''
        )

    if isinstance(media, (
            MessageMediaEmpty, MessageMediaUnsupported,
            ChatPhotoEmpty, UserProfilePhotoEmpty, FileLocationUnavailable)):
        return InputMediaEmpty()

    if isinstance(media, Message):
        return get_input_media(media.media)

    _raise_cast_fail(media, 'InputMedia')


def is_image(file):
    """Returns True if the file extension looks like an image file"""
    return (isinstance(file, str) and
            bool(re.search(r'\.(png|jpe?g|gif)$', file, re.IGNORECASE)))


def parse_phone(phone):
    """Parses the given phone, or returns None if it's invalid"""
    if isinstance(phone, int):
        return str(phone)
    else:
        phone = re.sub(r'[+()\s-]', '', str(phone))
        if phone.isdigit():
            return phone


def parse_username(username):
    """Parses the given username or channel access hash, given
       a string, username or URL. Returns a tuple consisting of
       both the stripped, lowercase username and whether it is
       a joinchat/ hash (in which case is not lowercase'd).
    """
    username = username.strip()
    m = USERNAME_RE.match(username)
    if m:
        result = username[m.end():]
        is_invite = bool(m.group(1))
        return result if is_invite else result.lower(), is_invite
    else:
        return username.lower(), False


def get_peer_id(peer):
    """
    Finds the ID of the given peer, and converts it to the "bot api" format
    so it the peer can be identified back. User ID is left unmodified,
    chat ID is negated, and channel ID is prefixed with -100.

    The original ID and the peer type class can be returned with
    a call to utils.resolve_id(marked_id).
    """
    # First we assert it's a Peer TLObject, or early return for integers
    if isinstance(peer, int):
        return peer

    try:
        if peer.SUBCLASS_OF_ID not in (0x2d45687, 0xc91c90b6):
            # Not a Peer or an InputPeer, so first get its Input version
            peer = get_input_peer(peer, allow_self=False)
    except AttributeError:
        _raise_cast_fail(peer, 'int')

    # Set the right ID/kind, or raise if the TLObject is not recognised
    if isinstance(peer, (PeerUser, InputPeerUser)):
        return peer.user_id
    elif isinstance(peer, (PeerChat, InputPeerChat)):
        return -peer.chat_id
    elif isinstance(peer, (PeerChannel, InputPeerChannel, ChannelFull)):
        if isinstance(peer, ChannelFull):
            # Special case: .get_input_peer can't return InputChannel from
            # ChannelFull since it doesn't have an .access_hash attribute.
            i = peer.id
        else:
            i = peer.channel_id
        # Concat -100 through math tricks, .to_supergroup() on Madeline
        # IDs will be strictly positive -> log works
        return -(i + pow(10, math.floor(math.log10(i) + 3)))

    _raise_cast_fail(peer, 'int')


def resolve_id(marked_id):
    """Given a marked ID, returns the original ID and its Peer type"""
    if marked_id >= 0:
        return marked_id, PeerUser

    if str(marked_id).startswith('-100'):
        return int(str(marked_id)[4:]), PeerChannel

    return -marked_id, PeerChat


def get_appropriated_part_size(file_size):
    """Gets the appropriated part size when uploading or downloading files,
       given an initial file size"""
    if file_size <= 104857600:  # 100MB
        return 128
    if file_size <= 786432000:  # 750MB
        return 256
    if file_size <= 1572864000:  # 1500MB
        return 512

    raise ValueError('File size too large')