import logging
import os

import tqdm
from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer
from django.conf import settings
from django.db.models.signals import post_save
from documents import barcodes
from documents import index
from documents import sanity_checker
from documents.classifier import DocumentClassifier
from documents.classifier import load_classifier
from documents.consumer import Consumer
from documents.consumer import ConsumerError
from documents.models import Correspondent
from documents.models import Document
from documents.models import DocumentType
from documents.models import StoragePath
from documents.models import Tag
from documents.sanity_checker import SanityCheckFailedException
from whoosh.writing import AsyncWriter


logger = logging.getLogger("paperless.tasks")


def index_optimize():
    ix = index.open_index()
    writer = AsyncWriter(ix)
    writer.commit(optimize=True)


def index_reindex(progress_bar_disable=False):
    documents = Document.objects.all()

    ix = index.open_index(recreate=True)

    with AsyncWriter(ix) as writer:
        for document in tqdm.tqdm(documents, disable=progress_bar_disable):
            index.update_document(writer, document)


def train_classifier():
    if (
        not Tag.objects.filter(matching_algorithm=Tag.MATCH_AUTO).exists()
        and not DocumentType.objects.filter(matching_algorithm=Tag.MATCH_AUTO).exists()
        and not Correspondent.objects.filter(matching_algorithm=Tag.MATCH_AUTO).exists()
        and not StoragePath.objects.filter(matching_algorithm=Tag.MATCH_AUTO).exists()
    ):

        return

    classifier = load_classifier()

    if not classifier:
        classifier = DocumentClassifier()

    try:
        if classifier.train():
            logger.info(
                f"Saving updated classifier model to {settings.MODEL_FILE}...",
            )
            classifier.save()
        else:
            logger.debug("Training data unchanged.")

    except Exception as e:
        logger.warning("Classifier error: " + str(e))


def consume_file(
    path,
    override_filename=None,
    override_title=None,
    override_correspondent_id=None,
    override_document_type_id=None,
    override_tag_ids=None,
    task_id=None,
    override_created=None,
):

    # check for separators in current document
    if settings.CONSUMER_ENABLE_BARCODES:

        mime_type = barcodes.get_file_mime_type(path)

        if not barcodes.supported_file_type(mime_type):
            # if not supported, skip this routine
            logger.warning(
                f"Unsupported file format for barcode reader: {str(mime_type)}",
            )
        else:
            separators = []
            document_list = []
            converted_tiff = None

            if mime_type == "image/tiff":
                file_to_process = barcodes.convert_from_tiff_to_pdf(path)
            else:
                file_to_process = path

            separators = barcodes.scan_file_for_separating_barcodes(file_to_process)

            if separators:
                logger.debug(
                    f"Pages with separators found in: {str(path)}",
                )
                document_list = barcodes.separate_pages(file_to_process, separators)

            if document_list:
                for n, document in enumerate(document_list):
                    # save to consumption dir
                    # rename it to the original filename  with number prefix
                    if override_filename:
                        newname = f"{str(n)}_" + override_filename
                    else:
                        newname = None
                    barcodes.save_to_dir(document, newname=newname)
                # if we got here, the document was successfully split
                # and can safely be deleted
                if converted_tiff is not None:
                    logger.debug(f"Deleting file {file_to_process}")
                    os.unlink(file_to_process)
                logger.debug(f"Deleting file {path}")
                os.unlink(path)
                # notify the sender, otherwise the progress bar
                # in the UI stays stuck
                payload = {
                    "filename": override_filename,
                    "task_id": task_id,
                    "current_progress": 100,
                    "max_progress": 100,
                    "status": "SUCCESS",
                    "message": "finished",
                }
                try:
                    async_to_sync(get_channel_layer().group_send)(
                        "status_updates",
                        {"type": "status_update", "data": payload},
                    )
                except OSError as e:
                    logger.warning(
                        "OSError. It could be, the broker cannot be reached.",
                    )
                    logger.warning(str(e))
                # consuming stops here, since the original document with
                # the barcodes has been split and will be consumed separately
                return "File successfully split"

    # continue with consumption if no barcode was found
    document = Consumer().try_consume_file(
        path,
        override_filename=override_filename,
        override_title=override_title,
        override_correspondent_id=override_correspondent_id,
        override_document_type_id=override_document_type_id,
        override_tag_ids=override_tag_ids,
        task_id=task_id,
        override_created=override_created,
    )

    if document:
        return f"Success. New document id {document.pk} created"
    else:
        raise ConsumerError(
            "Unknown error: Returned document was null, but "
            "no error message was given.",
        )


def sanity_check():
    messages = sanity_checker.check_sanity()

    messages.log_messages()

    if messages.has_error:
        raise SanityCheckFailedException("Sanity check failed with errors. See log.")
    elif messages.has_warning:
        return "Sanity check exited with warnings. See log."
    elif len(messages) > 0:
        return "Sanity check exited with infos. See log."
    else:
        return "No issues detected."


def bulk_update_documents(document_ids):
    documents = Document.objects.filter(id__in=document_ids)

    ix = index.open_index()

    for doc in documents:
        post_save.send(Document, instance=doc, created=False)

    with AsyncWriter(ix) as writer:
        for doc in documents:
            index.update_document(writer, doc)