#!/bin/bash
# shellcheck disable=SC1091
source "${AGENT_PATH}/common.sh"
_check_required_env_vars "CONTAINER_NAME" "LXC_IMAGE" "TAILSCALE_AUTH_KEY" "HOST_INTERFACE" "STATIC_IP" "GATEWAY" "RELAY_PORT"

# Check LXC is available
if ! command -v lxc &>/dev/null; then
    _die "LXC is not installed. Install it with: sudo snap install lxd --channel=latest/stable && sudo lxd init"
fi

# Check LXC daemon is accessible
if ! lxc list &>/dev/null; then
    _die "Cannot connect to LXD. Ensure the LXD daemon is running and your user is in the 'lxd' group."
fi

echo "Installing Tailscale Relay (LXC)..."

# Stop and remove existing container if it exists
if lxc info "${CONTAINER_NAME}" &>/dev/null; then
    echo "Removing existing container..."
    lxc stop "${CONTAINER_NAME}" --force 2>/dev/null || true
    lxc delete "${CONTAINER_NAME}" --force 2>/dev/null || true
fi

# Create the container (without starting)
echo "Creating LXC container from ${LXC_IMAGE}..."
lxc init "${LXC_IMAGE}" "${CONTAINER_NAME}" || _die "Failed to create LXC container"

# Configure bridged networking on the host interface
echo "Configuring bridged networking on ${HOST_INTERFACE}..."
lxc config device remove "${CONTAINER_NAME}" eth0 2>/dev/null || true
lxc config device add "${CONTAINER_NAME}" eth0 nic \
    nictype=macvlan \
    parent="${HOST_INTERFACE}" || _die "Failed to configure network device"

# Enable nesting (required when running LXC inside another LXC, e.g. Proxmox)
lxc config set "${CONTAINER_NAME}" security.nesting=true

# Allow TUN device inside the container (needed by tailscale's WireGuard interface)
lxc config set "${CONTAINER_NAME}" raw.lxc "lxc.cgroup2.devices.allow = c 10:200 rwm"
lxc config device add "${CONTAINER_NAME}" tun unix-char path=/dev/net/tun 2>/dev/null || true

# Start the container
echo "Starting container..."
lxc start "${CONTAINER_NAME}" || _die "Failed to start container"

# Wait for container to be ready
echo "Waiting for container to be ready..."
READY=false
for i in $(seq 1 30); do
    if lxc exec "${CONTAINER_NAME}" -- test -d /etc/netplan 2>/dev/null; then
        READY=true
        break
    fi
    sleep 1
done
if [ "$READY" != "true" ]; then
    _die "Container did not become ready in time"
fi

# Extract IP without CIDR for display
CONTAINER_IP="${STATIC_IP%%/*}"

# Configure static IP via netplan
echo "Configuring static IP ${STATIC_IP}..."
lxc exec "${CONTAINER_NAME}" -- bash -c "rm -f /etc/netplan/*.yaml"
lxc exec "${CONTAINER_NAME}" -- bash -c "cat > /etc/netplan/10-static.yaml << 'NETPLANEOF'
network:
  version: 2
  ethernets:
    eth0:
      dhcp4: false
      addresses:
        - ${STATIC_IP}
      routes:
        - to: default
          via: ${GATEWAY}
      nameservers:
        addresses: [${DNS_SERVERS}]
NETPLANEOF"
lxc exec "${CONTAINER_NAME}" -- chmod 600 /etc/netplan/10-static.yaml
lxc exec "${CONTAINER_NAME}" -- netplan apply 2>/dev/null || true

# Wait for network to come up
sleep 3

# Verify network connectivity
echo "Verifying network connectivity..."
if ! lxc exec "${CONTAINER_NAME}" -- ping -c 1 -W 5 "${GATEWAY}" &>/dev/null; then
    echo "Warning: Cannot reach gateway ${GATEWAY} from container. Check HOST_INTERFACE and network settings."
fi

# Install Tailscale inside the container
echo "Installing Tailscale inside the container..."
lxc exec "${CONTAINER_NAME}" -- bash -c "curl -fsSL https://tailscale.com/install.sh | sh" || _die "Failed to install Tailscale"

# Connect to Tailscale network
echo "Connecting to Tailscale network..."

TAILSCALE_UP_CMD="tailscale up --authkey=${TAILSCALE_AUTH_KEY}"

if [ -n "$TAILSCALE_HOSTNAME" ]; then
    TAILSCALE_UP_CMD="${TAILSCALE_UP_CMD} --hostname=${TAILSCALE_HOSTNAME}"
fi

if [ -n "$TAILSCALE_EXTRA_ARGS" ]; then
    TAILSCALE_UP_CMD="${TAILSCALE_UP_CMD} ${TAILSCALE_EXTRA_ARGS}"
fi

# Execute tailscale up with retries
RETRY_COUNT=0
MAX_RETRIES=5
RETRY_DELAY=10

while [ $RETRY_COUNT -lt $MAX_RETRIES ]; do
    if lxc exec "${CONTAINER_NAME}" -- ${TAILSCALE_UP_CMD} 2>&1; then
        echo "Successfully connected to Tailscale network!"
        break
    else
        RETRY_COUNT=$((RETRY_COUNT + 1))
        if [ $RETRY_COUNT -lt $MAX_RETRIES ]; then
            echo "Connection attempt $RETRY_COUNT failed. Retrying in ${RETRY_DELAY} seconds..."
            sleep $RETRY_DELAY
        else
            echo "Warning: Failed to connect after $MAX_RETRIES attempts."
            echo "You may need to connect manually using:"
            echo "  lxc exec ${CONTAINER_NAME} -- tailscale up"
        fi
    fi
done

# Enable peer relay on the configured port
echo "Enabling peer relay on port ${RELAY_PORT}/udp..."
lxc exec "${CONTAINER_NAME}" -- tailscale set --relay-server-port="${RELAY_PORT}" || echo "Warning: Failed to enable peer relay. You may need to enable it manually."

# Get the Tailscale IP
TAILSCALE_IP=$(lxc exec "${CONTAINER_NAME}" -- tailscale ip -4 2>/dev/null || echo "not yet available")

echo ""
echo "=========================================="
echo "Tailscale Relay installation complete!"
echo "=========================================="
echo ""
echo "  LAN IP:       ${CONTAINER_IP}"
echo "  Tailscale IP: ${TAILSCALE_IP}"
echo "  Relay port:   ${RELAY_PORT}/udp"
echo "  Container:    ${CONTAINER_NAME}"
echo ""
echo "The container has its own IP (${CONTAINER_IP}) on your LAN."
echo "Forward ${RELAY_PORT}/udp on your router to ${CONTAINER_IP}."
echo ""
echo "You also need to add relay ACL grants in your tailnet policy."
echo "See: https://tailscale.com/kb/1403/peer-relay"
echo ""
echo "Manage at: https://login.tailscale.com/admin/machines"