"""
Download LBRY Files from LBRYnet and save them to disk.
"""
import logging

from zope.interface import implements
from twisted.internet import defer

from lbrynet.core.client.StreamProgressManager import FullStreamProgressManager
from lbrynet.core.Error import NoSuchStreamHash
from lbrynet.core.utils import short_hash
from lbrynet.core.StreamDescriptor import StreamMetadata
from lbrynet.lbry_file.client.EncryptedFileDownloader import EncryptedFileSaver
from lbrynet.lbry_file.client.EncryptedFileDownloader import EncryptedFileDownloader
from lbrynet.file_manager.EncryptedFileStatusReport import EncryptedFileStatusReport
from lbrynet.interfaces import IStreamDownloaderFactory
from lbrynet.lbry_file.StreamDescriptor import save_sd_info

log = logging.getLogger(__name__)


def log_status(file_name, sd_hash, status):
    if status == ManagedEncryptedFileDownloader.STATUS_RUNNING:
        status_string = "running"
    elif status == ManagedEncryptedFileDownloader.STATUS_STOPPED:
        status_string = "stopped"
    elif status == ManagedEncryptedFileDownloader.STATUS_FINISHED:
        status_string = "finished"
    else:
        status_string = "unknown"
    log.info("%s (%s) is %s", file_name, short_hash(sd_hash), status_string)


class ManagedEncryptedFileDownloader(EncryptedFileSaver):
    STATUS_RUNNING = "running"
    STATUS_STOPPED = "stopped"
    STATUS_FINISHED = "finished"

    def __init__(self, rowid, stream_hash, peer_finder, rate_limiter,
                 blob_manager, stream_info_manager, lbry_file_manager,
                 payment_rate_manager, wallet, download_directory,
                 file_name=None):
        EncryptedFileSaver.__init__(self, stream_hash, peer_finder,
                                    rate_limiter, blob_manager,
                                    stream_info_manager,
                                    payment_rate_manager, wallet,
                                    download_directory,
                                    file_name)
        self.sd_hash = None
        self.rowid = rowid
        self.lbry_file_manager = lbry_file_manager
        self._saving_status = False

    @property
    def saving_status(self):
        return self._saving_status

    @defer.inlineCallbacks
    def restore(self):
        yield self.load_file_attributes()

        status = yield self.lbry_file_manager.get_lbry_file_status(self)
        log_status(self.file_name, self.sd_hash, status)

        if status == ManagedEncryptedFileDownloader.STATUS_RUNNING:
            # start returns self.finished_deferred
            # which fires when we've finished downloading the file
            # and we don't want to wait for the entire download
            self.start()
        elif status == ManagedEncryptedFileDownloader.STATUS_STOPPED:
            defer.returnValue(False)
        elif status == ManagedEncryptedFileDownloader.STATUS_FINISHED:
            self.completed = True
            defer.returnValue(True)
        else:
            raise Exception("Unknown status for stream %s: %s", self.stream_hash, status)

    @defer.inlineCallbacks
    def stop(self, err=None, change_status=True):
        log.debug('Stopping download for stream %s', short_hash(self.stream_hash))
        # EncryptedFileSaver deletes metadata when it's stopped. We don't want that here.
        yield EncryptedFileDownloader.stop(self, err=err)
        if change_status is True:
            status = yield self._save_status()
        defer.returnValue(status)

    @defer.inlineCallbacks
    def status(self):
        blobs = yield self.stream_info_manager.get_blobs_for_stream(self.stream_hash)
        blob_hashes = [b[0] for b in blobs if b[0] is not None]
        completed_blobs = yield self.blob_manager.completed_blobs(blob_hashes)
        num_blobs_completed = len(completed_blobs)
        num_blobs_known = len(blob_hashes)

        if self.completed:
            status = "completed"
        elif self.stopped:
            status = "stopped"
        else:
            status = "running"
        defer.returnValue(EncryptedFileStatusReport(self.file_name, num_blobs_completed,
                                                    num_blobs_known, status))

    @defer.inlineCallbacks
    def load_file_attributes(self, sd_hash=None):
        if not sd_hash:
            sd_hash = yield self.stream_info_manager.get_sd_blob_hashes_for_stream(self.stream_hash)
            if sd_hash:
                self.sd_hash = sd_hash[0]
            else:
                raise NoSuchStreamHash(self.stream_hash)
        else:
            self.sd_hash = sd_hash

        defer.returnValue(None)

    @defer.inlineCallbacks
    def _start(self):
        yield EncryptedFileSaver._start(self)
        yield self.load_file_attributes()
        status = yield self._save_status()
        log_status(self.file_name, self.sd_hash, status)
        defer.returnValue(status)

    def _get_finished_deferred_callback_value(self):
        if self.completed is True:
            return "Download successful"
        else:
            return "Download stopped"

    @defer.inlineCallbacks
    def _save_status(self):
        self._saving_status = True
        if self.completed is True:
            status = ManagedEncryptedFileDownloader.STATUS_FINISHED
        elif self.stopped is True:
            status = ManagedEncryptedFileDownloader.STATUS_STOPPED
        else:
            status = ManagedEncryptedFileDownloader.STATUS_RUNNING
        status = yield self.lbry_file_manager.change_lbry_file_status(self, status)
        self._saving_status = False
        defer.returnValue(status)

    def save_status(self):
        return self._save_status()

    def _get_progress_manager(self, download_manager):
        return FullStreamProgressManager(self._finished_downloading,
                                         self.blob_manager, download_manager)


class ManagedEncryptedFileDownloaderFactory(object):
    implements(IStreamDownloaderFactory)

    def __init__(self, lbry_file_manager):
        self.lbry_file_manager = lbry_file_manager

    def can_download(self, sd_validator):
        # TODO: add a sd_validator for non live streams, use it
        return True

    @defer.inlineCallbacks
    def make_downloader(self, metadata, options, payment_rate_manager, download_directory=None,
                        file_name=None):
        assert len(options) == 1
        data_rate = options[0]
        stream_hash = yield save_sd_info(self.lbry_file_manager.stream_info_manager,
                                         metadata.validator.raw_info)
        if metadata.metadata_source == StreamMetadata.FROM_BLOB:
            yield self.lbry_file_manager.save_sd_blob_hash_to_stream(stream_hash,
                                                                     metadata.source_blob_hash)
        lbry_file = yield self.lbry_file_manager.add_lbry_file(stream_hash, payment_rate_manager,
                                                               data_rate,
                                                               download_directory, file_name)
        defer.returnValue(lbry_file)

    @staticmethod
    def get_description():
        return "Save the file to disk"