# SPDX-FileCopyrightText: 2015-2024 Damon Lynch <damonlynch@gmail.com>
# SPDX-License-Identifier: GPL-3.0-or-later

"""
Generates thumbnails for files that have already been downloaded, and
writes out FDO thumbnails for files of the type where that makes sense
e.g. RAW files

See cache.py for definitions of various caches used by Rapid Photo Downloader.

Runs as a single instance daemon process, i.e., for the lifetime of the program.
"""

import contextlib
import locale
import logging
import os
import pickle
import sys

with contextlib.suppress(locale.Error):
    # Use the default locale as defined by the LANG variable
    locale.setlocale(locale.LC_ALL, "")

import zmq

from raphodo.cache import FdoCacheLarge, FdoCacheNormal
from raphodo.constants import (
    ExtractionProcessing,
    ExtractionTask,
)
from raphodo.interprocess import (
    DaemonProcess,
    GenerateThumbnailsResults,
    ThumbnailDaemonData,
    ThumbnailExtractorArgument,
)
from raphodo.thumbnailpara import GetThumbnailFromCache, preprocess_thumbnail_from_disk


class DameonThumbnailWorker(DaemonProcess):
    """
    Generates thumbnails for files that have already been downloaded, and
    writes out FDO thumbnails for files of the type where that makes sense
    e.g. RAW files
    """

    def __init__(self):
        super().__init__("Thumbnail Daemon")

    def run(self):
        """
        Set up process and then process thumbnail requests one by one
        """

        # Always set use_thumbnail_cache to True, because this is a daemon
        # process that runs for the lifetime of the program. User can
        # change the program preferences.
        # Whether to actually use it will be determined at the time the
        # thumbnail is sought, using the user's preference at that moment.
        thumbnail_caches = GetThumbnailFromCache(use_thumbnail_cache=True)

        self.frontend = self.context.socket(zmq.PUSH)

        directive, content = self.receiver.recv_multipart()

        self.check_for_command(directive, content)

        data: ThumbnailDaemonData = pickle.loads(content)
        assert data.frontend_port is not None
        self.frontend.connect(f"tcp://localhost:{data.frontend_port}")

        # handle freedesktop.org cache files directly
        fdo_cache_large = FdoCacheLarge()
        fdo_cache_normal = FdoCacheNormal()

        while True:
            directive, content = self.receiver.recv_multipart()

            self.check_for_command(directive, content)

            data: ThumbnailDaemonData = pickle.loads(content)
            rpd_file = data.rpd_file
            if data.backup_full_file_names is not None:
                # File has been backed up, and an extractor has already generated a FDO
                # thumbnail for it. Copy and modify the existing FDO thumbnail

                # MD5 name of the existing FDO thumbnail
                md5_name = data.fdo_name
                assert md5_name

                for backup_full_file_name in data.backup_full_file_names:
                    # Check to see if existing thumbnail in FDO cache can be
                    # modified and renamed to reflect new URI
                    try:
                        mtime = os.path.getmtime(backup_full_file_name)
                    except OSError:
                        logging.debug(
                            "Backup file does not exist: %s", backup_full_file_name
                        )
                    else:
                        logging.debug(
                            "Copying and modifying existing FDO 128 thumbnail for %s",
                            backup_full_file_name,
                        )
                        fdo_cache_normal.modify_existing_thumbnail_and_save_copy(
                            existing_cache_thumbnail=md5_name,
                            full_file_name=backup_full_file_name,
                            size=rpd_file.size,
                            modification_time=mtime,
                            error_on_missing_thumbnail=True,
                        )

                        logging.debug(
                            "Copying and modifying existing FDO 256 thumbnail for %s",
                            backup_full_file_name,
                        )
                        fdo_cache_large.modify_existing_thumbnail_and_save_copy(
                            existing_cache_thumbnail=md5_name,
                            full_file_name=backup_full_file_name,
                            size=rpd_file.size,
                            modification_time=mtime,
                            error_on_missing_thumbnail=False,
                        )
            else:
                # The file has just been downloaded and renamed
                rpd_file.modified_via_daemon_process = True
                try:
                    # Check the download source to see if it's in the caches, not the
                    # file we've just downloaded

                    use_thumbnail_cache = data.use_thumbnail_cache and not (
                        data.write_fdo_thumbnail and rpd_file.should_write_fdo()
                    )
                    cache_search = thumbnail_caches.get_from_cache(
                        rpd_file=rpd_file, use_thumbnail_cache=use_thumbnail_cache
                    )
                    (
                        task,
                        thumbnail_bytes,
                        full_file_name_to_work_on,
                        origin,
                    ) = cache_search
                    processing: set[ExtractionProcessing] = set()

                    if task == ExtractionTask.undetermined:
                        # Thumbnail was not found in any cache: extract it

                        task = preprocess_thumbnail_from_disk(
                            rpd_file=rpd_file, processing=processing
                        )
                        if task != ExtractionTask.bypass:
                            if rpd_file.thm_full_name is not None:
                                full_file_name_to_work_on = (
                                    rpd_file.download_thm_full_name
                                )
                            else:
                                full_file_name_to_work_on = (
                                    rpd_file.download_full_file_name
                                )

                    if task == ExtractionTask.bypass:
                        self.content = pickle.dumps(
                            GenerateThumbnailsResults(
                                rpd_file=rpd_file, thumbnail_bytes=thumbnail_bytes
                            ),
                            pickle.HIGHEST_PROTOCOL,
                        )
                        self.send_message_to_sink()

                    elif task != ExtractionTask.undetermined:
                        # Send data to load balancer, which will send to one of its
                        # workers

                        self.content = pickle.dumps(
                            ThumbnailExtractorArgument(
                                rpd_file=rpd_file,
                                task=task,
                                processing=processing,
                                full_file_name_to_work_on=full_file_name_to_work_on,
                                secondary_full_file_name="",
                                exif_buffer=None,
                                thumbnail_bytes=thumbnail_bytes,
                                use_thumbnail_cache=data.use_thumbnail_cache,
                                file_to_work_on_is_temporary=False,
                                write_fdo_thumbnail=data.write_fdo_thumbnail,
                                send_thumb_to_main=True,
                                force_exiftool=data.force_exiftool,
                            ),
                            pickle.HIGHEST_PROTOCOL,
                        )
                        self.frontend.send_multipart([b"data", self.content])
                except SystemExit as e:
                    sys.exit(e.code)
                except Exception:
                    logging.error(
                        "Exception working on file %s", rpd_file.full_file_name
                    )
                    logging.exception("Traceback:")


if __name__ == "__main__":
    generate_thumbnails = DameonThumbnailWorker()
    generate_thumbnails.run()
