#!/usr/bin/env bash
set -euo pipefail

REPO="/backup/borgrepo"
MOUNT_BASE="/tmp/borg-sshfs"

export BORG_PASSPHRASE
BORG_PASSPHRASE="$(cat /app/host_vars/repokey)"

HOSTS_FILE="$(dirname "$0")/host_vars/hosts"
TIMESTAMP="$(date +%Y-%m-%dT%H%M%S)"

HOSTS=()
while read -r host; do
    [[ -z "$host" || "$host" =~ ^# ]] && continue
    HOSTS+=("$host")
done < "$HOSTS_FILE"

echo "Backing up hosts:"
printf ' - %s\n' "${HOSTS[@]}"

FAILED_HOSTS=()

for HOST in "${HOSTS[@]}"; do
    ARCHIVE="${HOST}-backup-${TIMESTAMP}"
    MOUNT_DIR="${MOUNT_BASE}/${HOST}"
    echo "--- Backing up $HOST ---"

    mkdir -p "$MOUNT_DIR"

    # Pull mode: mount client's /BACKUP locally via SSHFS
    if ! sshfs "${HOST}:/BACKUP" "$MOUNT_DIR" \
        -o BatchMode=yes,reconnect,follow_symlinks,ServerAliveInterval=15,ServerAliveCountMax=3; then
        echo "WARNING: Failed to mount $HOST:/BACKUP via SSHFS"
        FAILED_HOSTS+=("$HOST")
        rmdir "$MOUNT_DIR"
        continue
    fi

    # SSHFS (FUSE/SFTP) does not guarantee stable inode numbers,
    # so instruct borg to use ctime+size for file change detection instead.
    if ! borg create \
        "$REPO::$ARCHIVE" \
        "$MOUNT_DIR" \
        --pattern "+ sh:**/current*" \
        --pattern "- *" \
        --files-cache ctime,size \
        --stats \
        --compression lz4; then

        echo "WARNING: Failed to back up $HOST"
        FAILED_HOSTS+=("$HOST")
    fi

    # Unmount and clean up regardless of borg exit status
    umount "$MOUNT_DIR"
    rmdir "$MOUNT_DIR"
done

rmdir "$MOUNT_BASE" 2>/dev/null || true

echo "Applying retention policy..."

for HOST in "${HOSTS[@]}"; do
    borg prune \
        "$REPO" \
        --keep-daily=7 \
        --keep-weekly=8 \
        --glob-archives "${HOST}-backup-*" \
        --stats
done

if [[ ${#FAILED_HOSTS[@]} -gt 0 ]]; then
    echo "DONE WITH ERRORS:"
    printf ' - %s\n' "${FAILED_HOSTS[@]}"
    exit 1
fi

echo "Done: all hosts backed up at $TIMESTAMP"