#!/usr/bin/env bash
#
# update-debug-rootfs.sh — Build envd and inject it (plus wrenn-init) into the debug rootfs.
#
# This script:
#   1. Builds a fresh envd static binary via make
#   2. Mounts the rootfs image
#   3. Copies envd and wrenn-init into the image
#   4. Unmounts cleanly
#
# Usage:
#   bash scripts/update-debug-rootfs.sh [rootfs_path]
#
# Defaults to /var/lib/wrenn/images/minimal.ext4

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
ROOTFS="${1:-/var/lib/wrenn/images/minimal.ext4}"
MOUNT_DIR="/tmp/wrenn-rootfs-update"

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

# Step 1: Build envd.
echo "==> Building envd..."
cd "${PROJECT_ROOT}"
make build-envd
ENVD_BIN="${PROJECT_ROOT}/builds/envd"

if [ ! -f "${ENVD_BIN}" ]; then
    echo "ERROR: envd binary not found at ${ENVD_BIN}"
    exit 1
fi

# Verify it's statically linked.
if ! file "${ENVD_BIN}" | grep -q "statically linked"; then
    echo "ERROR: envd is not statically linked!"
    exit 1
fi

# Step 2: Mount the rootfs.
echo "==> Mounting rootfs at ${MOUNT_DIR}..."
mkdir -p "${MOUNT_DIR}"
sudo mount -o loop "${ROOTFS}" "${MOUNT_DIR}"

cleanup() {
    echo "==> Unmounting rootfs..."
    sudo umount "${MOUNT_DIR}" 2>/dev/null || true
    rmdir "${MOUNT_DIR}" 2>/dev/null || true
}
trap cleanup EXIT

# Step 3: Copy files into rootfs.
echo "==> Installing envd..."
sudo mkdir -p "${MOUNT_DIR}/usr/local/bin"
sudo cp "${ENVD_BIN}" "${MOUNT_DIR}/usr/local/bin/envd"
sudo chmod 755 "${MOUNT_DIR}/usr/local/bin/envd"

echo "==> Installing wrenn-init..."
sudo cp "${PROJECT_ROOT}/images/wrenn-init.sh" "${MOUNT_DIR}/usr/local/bin/wrenn-init"
sudo chmod 755 "${MOUNT_DIR}/usr/local/bin/wrenn-init"

# Step 4: Verify.
echo ""
echo "==> Installed files:"
ls -la "${MOUNT_DIR}/usr/local/bin/envd" "${MOUNT_DIR}/usr/local/bin/wrenn-init"

echo ""
echo "==> Done. Rootfs updated: ${ROOTFS}"