#!/usr/bin/env bash
# scripts/migrate-data-directory.sh
# Migrate Nextcloud data directory content to an external host path and
# update docker-compose app volume mapping to use that path.

set -euo pipefail

REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
COMPOSE_FILE="${REPO_DIR}/docker-compose.yml"
APP_CONTAINER="${NEXTCLOUD_APP_CONTAINER:-nextcloud-app}"
TARGET_DATA_DIR="${1:-/media/rbhat/DATA/nextcloud/NextCloudData}"

if [ "${TARGET_DATA_DIR}" = "-h" ] || [ "${TARGET_DATA_DIR}" = "--help" ]; then
  echo "Usage: ./scripts/migrate-data-directory.sh [target_data_dir]"
  echo ""
  echo "Default target: /media/rbhat/DATA/nextcloud/NextCloudData"
  exit 0
fi

if ! command -v docker >/dev/null 2>&1; then
  echo "ERROR: docker is required but not installed."
  exit 1
fi

if ! command -v python3 >/dev/null 2>&1; then
  echo "ERROR: python3 is required but not installed."
  exit 1
fi

if [ ! -f "${COMPOSE_FILE}" ]; then
  echo "ERROR: Compose file not found at ${COMPOSE_FILE}"
  exit 1
fi

if ! docker ps --format '{{.Names}}' | grep -qx "${APP_CONTAINER}"; then
  echo "ERROR: Container '${APP_CONTAINER}' is not running."
  echo "Start the stack first (docker compose up -d)."
  exit 1
fi

compose() {
  if docker compose version >/dev/null 2>&1; then
    docker compose -f "${COMPOSE_FILE}" "$@"
  else
    docker-compose -f "${COMPOSE_FILE}" "$@"
  fi
}

wait_for_occ() {
  local max_attempts=30
  local attempt=1
  while [ "${attempt}" -le "${max_attempts}" ]; do
    if docker exec --user www-data "${APP_CONTAINER}" php occ status >/dev/null 2>&1; then
      return 0
    fi
    sleep 2
    attempt=$((attempt + 1))
  done
  return 1
}

if ! mkdir -p "${TARGET_DATA_DIR}" 2>/dev/null; then
  if command -v sudo >/dev/null 2>&1; then
    sudo mkdir -p "${TARGET_DATA_DIR}"
  else
    echo "ERROR: Unable to create ${TARGET_DATA_DIR}. Run as a user with write permission."
    exit 1
  fi
fi

CURRENT_BIND_SOURCE="$(docker inspect "${APP_CONTAINER}" --format '{{range .Mounts}}{{if eq .Destination "/var/www/html/data"}}{{.Source}}{{end}}{{end}}')"

maintenance_enabled=0
cleanup() {
  if [ "${maintenance_enabled}" -eq 1 ]; then
    docker exec --user www-data "${APP_CONTAINER}" php occ maintenance:mode --off >/dev/null 2>&1 || true
  fi
}
trap cleanup EXIT

echo "==> Enabling Nextcloud maintenance mode..."
docker exec --user www-data "${APP_CONTAINER}" php occ maintenance:mode --on >/dev/null
maintenance_enabled=1

if [ "${CURRENT_BIND_SOURCE}" = "${TARGET_DATA_DIR}" ]; then
  echo "==> App already mounted to target data directory; skipping data copy."
else
  echo "==> Copying data from running Nextcloud container to ${TARGET_DATA_DIR} ..."
  docker exec "${APP_CONTAINER}" sh -lc 'cd /var/www/html/data && tar -cf - .' | \
    docker run --rm -i -v "${TARGET_DATA_DIR}:/to" alpine:3.20 sh -lc 'cd /to && tar -xf -'
fi

echo "==> Normalizing ownership and permissions on target data directory..."
docker run --rm -v "${TARGET_DATA_DIR}:/to" alpine:3.20 sh -lc '\
  chown -R 33:33 /to && \
  find /to -type d -exec chmod 0750 {} + && \
  find /to -type f -exec chmod 0640 {} + && \
  touch /to/.ocdata && \
  chown 33:33 /to/.ocdata && \
  chmod 0640 /to/.ocdata\
'

echo "==> Updating compose app volume mapping to use external data directory..."
python3 - "${COMPOSE_FILE}" "${TARGET_DATA_DIR}" <<'PY'
from pathlib import Path
import sys

compose_file = Path(sys.argv[1])
target = sys.argv[2]
lines = compose_file.read_text().splitlines()

try:
    app_idx = next(i for i, line in enumerate(lines) if line.startswith("  app:"))
except StopIteration:
    raise SystemExit("ERROR: Could not find 'app' service in compose file")

app_end = len(lines)
for i in range(app_idx + 1, len(lines)):
    line = lines[i]
    if line.startswith("  ") and not line.startswith("    ") and line.endswith(":"):
        app_end = i
        break

try:
    volumes_idx = next(i for i in range(app_idx + 1, app_end) if lines[i].startswith("    volumes:"))
except StopIteration:
    raise SystemExit("ERROR: Could not find volumes block in app service")

items_start = volumes_idx + 1
while items_start < app_end and lines[items_start].strip() == "":
    items_start += 1

items_end = items_start
while items_end < app_end and lines[items_end].startswith("      - "):
    items_end += 1

new_line = f"      - {target}:/var/www/html/data"
updated = False
for i in range(items_start, items_end):
    if lines[i].strip().endswith(":/var/www/html/data"):
        if lines[i] != new_line:
            lines[i] = new_line
        updated = True
        break

if not updated:
    lines.insert(items_end, new_line)

compose_file.write_text("\n".join(lines) + "\n")
print("Updated compose file with app data bind mount")
PY

echo "==> Recreating Nextcloud app/web services with new mount..."
compose up -d app web

if ! wait_for_occ; then
  echo "ERROR: Nextcloud did not become ready after restart."
  exit 1
fi

echo "==> Disabling maintenance mode..."
docker exec --user www-data "${APP_CONTAINER}" php occ maintenance:mode --off >/dev/null
maintenance_enabled=0

echo "==> Verifying effective datadirectory and mount..."
docker exec --user www-data "${APP_CONTAINER}" php occ config:system:get datadirectory

docker inspect "${APP_CONTAINER}" --format '{{range .Mounts}}{{if eq .Destination "/var/www/html/data"}}{{println .Destination "<-" .Type ":" .Source}}{{end}}{{end}}'

echo "==> Migration complete."