#!/usr/bin/env bash
# Usage: tools/sync-host-config [-h] [--apply] <ssh-target> <repo>...
#
# Compares the inline host config WERKREVISOR_CONFIG_TOML in ~/<repo>/.git/werkator/.werkator.yml
# of each <repo> on the Werkator host <ssh-target> with config/<repo>.toml.
# With --apply it replaces each block that differs, after a backup .werkator.yml.bak-config-<time>,
# and keeps the two newest of these backups.
# It prints only the numbers of the differing lines of a block, since a machine config holds tokens.
# Exit code: 0 if every block equals its file or was replaced, 1 if one differs without --apply,
# 2 if a machine config has no such block.
# Run it from the repository root; it opens one connection and retries a refused one.
#
# Example:
#   tools/sync-host-config mih09-werkator@mih09.hostsharing.net werkregie werkator
set -euo pipefail

usage() {
    awk 'NR > 1 && /^#/ { sub(/^# ?/, ""); print; next } NR > 1 { exit }' "$0"
    exit "$1"
}
[[ "${1:-}" =~ ^(-h|-\?|--help)$ ]] && usage 0
mode=check
[[ "${1:-}" == "--apply" ]] && { mode=apply; shift; }
[[ $# -ge 2 ]] || usage 2
target="$1"
shift
for repo in "$@"; do
    [[ -f "config/$repo.toml" ]] || { echo "no config/$repo.toml" >&2; exit 2; }
done
payload=$(python3 -c 'import json, sys; print(json.dumps({r: open(f"config/{r}.toml").read() for r in sys.argv[1:]}))' "$@")

# As in deploy-rootfs: the host refuses connections that follow too quickly.
retrying() {
    local attempt
    for attempt in 1 2 3 4 5 6; do
        "$@" && return 0
        local status=$?
        [[ $status -eq 255 ]] || return $status
        [[ $attempt -lt 6 ]] || break
        echo "connection refused, retry in $((30 * attempt)) s" >&2
        sleep $((30 * attempt))
    done
    return 1
}

# A function, so that a retry sends the payload again.
send() {
    ssh -o BatchMode=yes "$target" \
        "python3 -c $(printf '%q' "$(cat "$(dirname "$0")/host_config_block.py")") $mode" <<< "$payload"
}
retrying send