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

BACKUP_DIR="${BACKUP_DIR:-/mnt2/homey-backup}"
RESTORE_BASE="${RESTORE_BASE:-/mnt/replicas}"

usage() {
    echo "Usage: $0 <pvc-name-or-friendly-name> [--dry-run]"
    echo ""
    echo "Restores a Longhorn volume backup to the replicas directory."
    echo ""
    echo "Arguments:"
    echo "  pvc-name-or-friendly-name  The PVC ID or friendly name"
    echo "  --dry-run                  Show what would be done without copying"
    echo ""
    echo "Examples:"
    echo "  $0 nextcloud-data-pvc"
    echo "  $0 nextcloud-data-pvc --dry-run"
    echo ""
    echo "WARNING: This will overwrite existing data in $RESTORE_BASE"
    exit 1
}

if [[ $# -lt 1 ]]; then
    usage
fi

SEARCH_NAME="$1"
DRY_RUN=false

if [[ "${2:-}" == "--dry-run" ]]; then
    DRY_RUN=true
fi

MANIFEST="$BACKUP_DIR/manifest.json"

if [[ ! -f "$MANIFEST" ]]; then
    echo "Error: Manifest not found at $MANIFEST_DIR"
    exit 1
fi

find_volume() {
    local search="$1"
    
    while IFS= read -r line; do
        pvc_id=$(echo "$line" | grep -oP '"pvc_id":\s*"\K[^"]+')
        friendly=$(echo "$line" | grep -oP '"friendly_name":\s*"\K[^"]+')
        
        if [[ "$pvc_id" == "$search" ]] || [[ "$friendly" == "$search" ]]; then
            echo "$pvc_id:$friendly"
            return 0
        fi
    done < <(grep -A6 '"volumes"' "$MANIFEST" | grep -E '"pvc_id"|"friendly_name"')
    
    return 1
}

VOLUME_INFO=$(find_volume "$SEARCH_NAME")

if [[ -z "$VOLUME_INFO" ]]; then
    echo "Error: Volume '$SEARCH_NAME' not found in manifest."
    echo ""
    echo "Available volumes:"
    grep -oP '"friendly_name":\s*"\K[^"]+' "$MANIFEST" | while read -r name; do
        echo "  - $name"
    done
    exit 1
fi

PVC_ID="${VOLUME_INFO%%:*}"
FRIENDLY_NAME="${VOLUME_INFO#*:}"

BACKUP_VOLUME_DIR="$BACKUP_DIR/volumes/$PVC_ID"
RESTORE_VOLUME_DIR="$RESTORE_BASE/$PVC_ID"

echo "========================================"
echo "  Restore Longhorn Volume"
echo "========================================"
echo ""
echo "PVC ID:       $PVC_ID"
echo "Name:         $FRIENDLY_NAME"
echo "Source:       $BACKUP_VOLUME_DIR"
echo "Destination:  $RESTORE_VOLUME_DIR"
echo "Dry run:      $DRY_RUN"
echo ""

if [[ "$DRY_RUN" == "true" ]]; then
    echo "[DRY RUN] Would copy:"
    du -sh "$BACKUP_VOLUME_DIR" 2>/dev/null || echo "  (size unknown)"
    echo ""
    echo "Files to copy:"
    find "$BACKUP_VOLUME_DIR" -type f | head -20
    exit 0
fi

if [[ -d "$RESTORE_VOLUME_DIR" ]]; then
    echo "WARNING: Destination already exists!"
    echo ""
    read -p "Overwrite existing data? [y/N] " -n 1 -r
    echo ""
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        echo "Aborted."
        exit 1
    fi
    echo ""
    echo "Removing existing data..."
    sudo rm -rf "$RESTORE_VOLUME_DIR"
fi

echo "Creating destination directory..."
sudo mkdir -p "$RESTORE_VOLUME_DIR"

echo "Copying volume data..."
sudo rsync -a --no-owner --no-group --info=progress2 \
    "$BACKUP_VOLUME_DIR/" \
    "$RESTORE_VOLUME_DIR/"

echo ""
echo "Setting permissions..."
sudo chmod 700 "$RESTORE_VOLUME_DIR"

echo ""
echo "========================================"
echo "  Restore Complete!"
echo "========================================"
echo ""
echo "Restored to: $RESTORE_VOLUME_DIR"
echo ""
echo "Size:"
sudo du -sh "$RESTORE_VOLUME_DIR"
echo ""
echo "Next steps:"
echo "1. Ensure Longhorn is configured to use $RESTORE_BASE"
echo "2. Restart Longhorn or the affected pod"
echo "3. Verify data integrity"