#!/usr/bin/python3
"""
Run a backup.

Command-Line Arguments
======================
"""
import argparse
import logging
import os.path
import rbackup.rsync as rsync

from rbackup.hierarchy import Repository, Snapshot

# ========== Constants ==========
RSYNC_DEFAULT_OPTS = [
    "--archive",
    "--hard-links",
    "--prune-dirs",
    "--backup",
    "--xattrs",
    "--ignore-missing-args",
]
EXTRA_RSYNC_OPTS = {
    "dry_run": "--dry-run",
    "delete": "--delete-after",
    "checksum": "--checksum",
    "update": "--update",
}

# ========== Logging Setup ==========
console_formatter = logging.Formatter(LOGFORMAT)
syslog = logging.getLogger("packaging_scripts")
syslog.setLevel(logging.DEBUG)

stdout_handler = logging.StreamHandler(sys.stdout)
stdout_handler.setLevel(logging.INFO)
stdout_handler.setFormatter(console_formatter)
stdout_handler.addFilter(lambda record: record.levelno <= logging.INFO)

stderr_handler = logging.StreamHandler(sys.stderr)
stderr_handler.setLevel(logging.WARNING)
stderr_handler.setFormatter(console_formatter)

syslog.addHandler(stdout_handler)
syslog.addHandler(stderr_handler)

# ========== Main Script ==========
if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-c",
        "--use-checksums",
        action="store_const",
        dest="extra_rsync_opts",
        const=EXTRA_RSYNC_OPTS["checksum"],
        help="use rsync's checksumming feature to look for changed files"
    )
    parser.add_argument(
        "-d",
        "--dry-run",
        action="append_const",
        dest="extra_rsync_opts",
        const=EXTRA_RSYNC_OPTS["dry_run"],
        help="pass --dry-run to rsync",
    )
    parser.add_argument(
        "-v", "--verbose", action="store_true", help="increase script verbosity"
    )
    parser.add_argument("operation", help="the operation to perform", metavar="op")
    parser.add_argument("repository", help="repository to back up to", metavar="repo")

    args = parser.parser_args()
    repo = Repository(args.repository)

    link_dest = hier.prev_snapshot

    if args.verbose:
        stdout_handler.setLevel(logging.DEBUG)

    # Handle empty repository

    # else handle regular repository

    # Backup to hier.curr_snapshot

    # Relink 'prev' to point to latest snapshot
    os.remove(hier.prev_snapshot_link)
    os.symlink(curr_snapshot, hier.prev_snapshot_link, target_is_directory=True)