#!/bin/sh
# SecuBox Glances manager - LXC container support
# Copyright (C) 2025-2026 CyberMind.fr

CONFIG="glances"
LXC_NAME="glances"
OPKG_UPDATED=0

# Paths
LXC_PATH="/srv/lxc"
LXC_ROOTFS="$LXC_PATH/$LXC_NAME/rootfs"
LXC_CONFIG="$LXC_PATH/$LXC_NAME/config"

usage() {
	cat <<'EOF'
Usage: glancesctl <command>

Commands:
  install         Install prerequisites and create LXC container
  check           Run prerequisite checks
  update          Update Glances in container
  status          Show container status
  logs            Show Glances logs (use -f to follow)
  shell           Open shell in container
  service-run     Internal: run container under procd
  service-stop    Stop container

Web Interface: http://<router-ip>:61208
API Endpoint:  http://<router-ip>:61209
EOF
}

require_root() { [ "$(id -u)" -eq 0 ] || { echo "Root required" >&2; exit 1; }; }

log_info() { echo "[INFO] $*"; }
log_warn() { echo "[WARN] $*" >&2; }
log_error() { echo "[ERROR] $*" >&2; }

uci_get() { uci -q get ${CONFIG}.$1; }
uci_set() { uci set ${CONFIG}.$1="$2" && uci commit ${CONFIG}; }

# Load configuration with defaults
load_config() {
	web_port="$(uci_get main.web_port || echo 61208)"
	api_port="$(uci_get main.api_port || echo 61209)"
	web_host="$(uci_get main.web_host || echo 0.0.0.0)"
	refresh_rate="$(uci_get main.refresh_rate || echo 3)"
	memory_limit="$(uci_get main.memory_limit || echo 128M)"

	# Monitoring options
	monitor_docker="$(uci_get monitoring.monitor_docker || echo 1)"
	monitor_network="$(uci_get monitoring.monitor_network || echo 1)"
	monitor_diskio="$(uci_get monitoring.monitor_diskio || echo 1)"
	monitor_sensors="$(uci_get monitoring.monitor_sensors || echo 1)"

	# Alert thresholds
	cpu_warning="$(uci_get alerts.cpu_warning || echo 70)"
	cpu_critical="$(uci_get alerts.cpu_critical || echo 90)"
	mem_warning="$(uci_get alerts.mem_warning || echo 70)"
	mem_critical="$(uci_get alerts.mem_critical || echo 90)"
}

ensure_dir() { [ -d "$1" ] || mkdir -p "$1"; }

has_lxc() {
	command -v lxc-start >/dev/null 2>&1 && \
	command -v lxc-stop >/dev/null 2>&1
}

# Ensure required packages are installed
ensure_packages() {
	require_root
	for pkg in "$@"; do
		if ! opkg list-installed | grep -q "^$pkg "; then
			if [ "$OPKG_UPDATED" -eq 0 ]; then
				opkg update || return 1
				OPKG_UPDATED=1
			fi
			opkg install "$pkg" || return 1
		fi
	done
}

# =============================================================================
# LXC CONTAINER FUNCTIONS
# =============================================================================

lxc_check_prereqs() {
	log_info "Checking LXC prerequisites..."
	ensure_packages lxc lxc-common lxc-attach lxc-start lxc-stop lxc-destroy || return 1

	if [ ! -d /sys/fs/cgroup ]; then
		log_error "cgroups not mounted at /sys/fs/cgroup"
		return 1
	fi

	log_info "LXC ready"
}

lxc_create_rootfs() {
	load_config

	if [ -d "$LXC_ROOTFS" ] && [ -x "$LXC_ROOTFS/usr/local/bin/glances" ]; then
		log_info "LXC rootfs already exists with Glances"
		return 0
	fi

	log_info "Creating LXC rootfs for Glances..."
	ensure_dir "$LXC_PATH/$LXC_NAME"

	lxc_create_docker_rootfs || return 1
	lxc_create_config || return 1

	log_info "LXC rootfs created successfully"
}

lxc_create_docker_rootfs() {
	local rootfs="$LXC_ROOTFS"
	local image="nicolargo/glances"
	local tag="latest-full"
	local registry="registry-1.docker.io"
	local arch

	# Detect architecture for Docker manifest
	case "$(uname -m)" in
		x86_64) arch="amd64" ;;
		aarch64) arch="arm64" ;;
		armv7l) arch="arm" ;;
		*) arch="amd64" ;;
	esac

	log_info "Extracting Glances Docker image ($arch)..."
	ensure_dir "$rootfs"

	# Get Docker Hub token
	local token=$(wget -q -O - "https://auth.docker.io/token?service=registry.docker.io&scope=repository:$image:pull" | jsonfilter -e '@.token')
	[ -z "$token" ] && { log_error "Failed to get Docker Hub token"; return 1; }

	# Get manifest list
	local manifest=$(wget -q -O - --header="Authorization: Bearer $token" \
		--header="Accept: application/vnd.docker.distribution.manifest.list.v2+json" \
		"https://$registry/v2/$image/manifests/$tag")

	# Find digest for our architecture
	local digest=$(echo "$manifest" | jsonfilter -e "@.manifests[@.platform.architecture='$arch'].digest")
	[ -z "$digest" ] && { log_error "No manifest found for $arch"; return 1; }

	# Get image manifest
	local img_manifest=$(wget -q -O - --header="Authorization: Bearer $token" \
		--header="Accept: application/vnd.docker.distribution.manifest.v2+json" \
		"https://$registry/v2/$image/manifests/$digest")

	# Extract layers and download them
	log_info "Downloading and extracting layers..."
	local layers=$(echo "$img_manifest" | jsonfilter -e '@.layers[*].digest')

	for layer_digest in $layers; do
		log_info "  Layer: ${layer_digest:7:12}..."
		wget -q -O - --header="Authorization: Bearer $token" \
			"https://$registry/v2/$image/blobs/$layer_digest" | \
			tar xzf - -C "$rootfs" 2>&1 | grep -v "Cannot change ownership" || true
	done

	# Configure container
	echo "nameserver 8.8.8.8" > "$rootfs/etc/resolv.conf"
	mkdir -p "$rootfs/var/log/glances" "$rootfs/etc/glances" "$rootfs/tmp"
	mkdir -p "$rootfs/host" "$rootfs/rom" "$rootfs/overlay" "$rootfs/boot" "$rootfs/srv"
	mkdir -p "$rootfs/run"
	touch "$rootfs/run/docker.sock"

	# Ensure /bin/sh exists
	if [ ! -x "$rootfs/bin/sh" ]; then
		if [ -x "$rootfs/bin/dash" ]; then
			ln -sf dash "$rootfs/bin/sh"
		elif [ -x "$rootfs/bin/bash" ]; then
			ln -sf bash "$rootfs/bin/sh"
		elif [ -x "$rootfs/usr/bin/dash" ]; then
			mkdir -p "$rootfs/bin"
			ln -sf /usr/bin/dash "$rootfs/bin/sh"
		fi
	fi

	# Patch Glances: disable @exit_after on fs plugin (multiprocessing
	# fails inside LXC containers, causing all disk_usage calls to return None)
	local fs_init="$rootfs/app/glances/plugins/fs/__init__.py"
	if [ -f "$fs_init" ]; then
		sed -i 's/^@exit_after(/#@exit_after(/' "$fs_init"
		log_info "Patched Glances fs plugin for LXC compatibility"
	fi

	# Generate /etc/mtab from host mounts (psutil reads this for disk_partitions)
	grep -E '^(/dev/|overlayfs:)' /proc/mounts | \
		grep -v '/srv/docker/overlay' > "$rootfs/etc/mtab" 2>/dev/null

	# Create startup script (written via file, not heredoc, to preserve shebang)
	printf '%s\n' '#!/bin/sh' \
		'export PATH="/usr/local/bin:/usr/bin:/bin:$PATH"' \
		'export PYTHONPATH="/app:$PYTHONPATH"' \
		'cd /' \
		'' \
		'# Set hostname from host kernel (proc:mixed exposes this)' \
		'REAL_HOSTNAME=$(cat /proc/sys/kernel/hostname 2>/dev/null || echo glances)' \
		'hostname "$REAL_HOSTNAME" 2>/dev/null' \
		'printf "127.0.0.1\tlocalhost %s glances\n::1\t\tlocalhost ip6-localhost\n" "$REAL_HOSTNAME" > /etc/hosts' \
		'' \
		'# Copy host os-release so Glances reports OpenWrt, not Alpine' \
		'if [ -f /host/openwrt_release ]; then' \
		"    RELEASE=\$(grep DISTRIB_RELEASE /host/openwrt_release 2>/dev/null | cut -d\"'\" -f2)" \
		'    printf '"'"'NAME="OpenWrt"\nVERSION="%s"\nID=openwrt\nPRETTY_NAME="OpenWrt %s"\n'"'"' "$RELEASE" "$RELEASE" > /etc/os-release' \
		'fi' \
		'' \
		'WEB_PORT="${GLANCES_WEB_PORT:-61208}"' \
		'WEB_HOST="${GLANCES_WEB_HOST:-0.0.0.0}"' \
		'REFRESH="${GLANCES_REFRESH:-3}"' \
		'' \
		'ARGS="-w -B $WEB_HOST -p $WEB_PORT -t $REFRESH --disable-autodiscover --disable-check-update"' \
		'[ "$GLANCES_NO_DOCKER" = "1" ] && ARGS="$ARGS --disable-plugin docker"' \
		'[ "$GLANCES_NO_SENSORS" = "1" ] && ARGS="$ARGS --disable-plugin sensors"' \
		'' \
		'echo "Starting Glances on ${WEB_HOST}:${WEB_PORT} host=${REAL_HOSTNAME}..."' \
		'exec /venv/bin/python -m glances $ARGS' \
		> "$rootfs/opt/start-glances.sh"
	chmod +x "$rootfs/opt/start-glances.sh"

	log_info "Glances Docker image extracted successfully"
}

lxc_create_config() {
	load_config

	local hostname=$(cat /proc/sys/kernel/hostname 2>/dev/null || echo glances)
	local mem_bytes=$(echo "$memory_limit" | sed 's/M/000000/')

	cat > "$LXC_CONFIG" << EOF
# Glances LXC Configuration — full host visibility
lxc.uts.name = $hostname
lxc.rootfs.path = dir:$LXC_ROOTFS

# Network - host network for full visibility
lxc.net.0.type = none

# Auto-mounts
lxc.mount.auto = proc:mixed sys:ro cgroup:mixed

# Host filesystem bind mounts (read-only) for disk monitoring
lxc.mount.entry = /rom rom none bind,ro,create=dir 0 0
lxc.mount.entry = /overlay overlay none bind,ro,create=dir 0 0
lxc.mount.entry = /boot boot none bind,ro,create=dir 0 0
lxc.mount.entry = /srv srv none bind,ro,create=dir 0 0

# Host info for OS identification
lxc.mount.entry = /etc/openwrt_release host/openwrt_release none bind,ro,create=file 0 0
lxc.mount.entry = /etc/openwrt_version host/openwrt_version none bind,ro,create=file 0 0

# Docker socket for container monitoring (mount at /run, not /var/run which is a symlink)
lxc.mount.entry = /var/run/docker.sock run/docker.sock none bind,create=file 0 0

# Environment variables
lxc.environment = GLANCES_WEB_PORT=$web_port
lxc.environment = GLANCES_WEB_HOST=$web_host
lxc.environment = GLANCES_REFRESH=$refresh_rate
lxc.environment = GLANCES_NO_DOCKER=$([ "$monitor_docker" = "0" ] && echo 1 || echo 0)
lxc.environment = GLANCES_NO_SENSORS=$([ "$monitor_sensors" = "0" ] && echo 1 || echo 0)

# Capabilities
lxc.cap.drop = sys_module mac_admin mac_override sys_rawio

# cgroups limits
lxc.cgroup2.memory.max = $mem_bytes

# Init
lxc.init.cmd = /opt/start-glances.sh

# Console
lxc.console.size = 1024
lxc.pty.max = 1024
EOF

	log_info "LXC config created at $LXC_CONFIG"
}

lxc_stop() {
	if lxc-info -n "$LXC_NAME" >/dev/null 2>&1; then
		lxc-stop -n "$LXC_NAME" -k >/dev/null 2>&1 || true
	fi
}

lxc_run() {
	load_config
	lxc_stop

	if [ ! -f "$LXC_CONFIG" ]; then
		log_error "LXC not configured. Run 'glancesctl install' first."
		return 1
	fi

	# Regenerate config to pick up any UCI changes
	lxc_create_config

	# Regenerate /etc/mtab from host mounts (psutil reads this)
	grep -E '^(/dev/|overlayfs:)' /proc/mounts | \
		grep -v '/srv/docker/overlay' > "$LXC_ROOTFS/etc/mtab" 2>/dev/null

	log_info "Starting Glances LXC container..."
	log_info "Web interface: http://0.0.0.0:$web_port"
	exec lxc-start -n "$LXC_NAME" -F -f "$LXC_CONFIG"
}

lxc_status() {
	load_config
	echo "=== Glances Status ==="
	echo ""

	if lxc-info -n "$LXC_NAME" >/dev/null 2>&1; then
		lxc-info -n "$LXC_NAME"
	else
		echo "LXC container '$LXC_NAME' not found or not configured"
	fi

	echo ""
	echo "=== Configuration ==="
	echo "Web port: $web_port"
	echo "Refresh rate: ${refresh_rate}s"
	echo "Memory limit: $memory_limit"
}

lxc_logs() {
	if [ "$1" = "-f" ]; then
		logread -f -e glances
	else
		logread -e glances | tail -100
	fi
}

lxc_shell() {
	lxc-attach -n "$LXC_NAME" -- /bin/sh
}

lxc_destroy() {
	lxc_stop
	if [ -d "$LXC_PATH/$LXC_NAME" ]; then
		rm -rf "$LXC_PATH/$LXC_NAME"
		log_info "LXC container destroyed"
	fi
}

# =============================================================================
# COMMANDS
# =============================================================================

cmd_install() {
	require_root
	load_config

	if ! has_lxc; then
		log_error "LXC not available. Install lxc packages first."
		exit 1
	fi

	log_info "Installing Glances..."

	lxc_check_prereqs || exit 1
	lxc_create_rootfs || exit 1

	uci_set main.enabled '1'
	/etc/init.d/glances enable

	log_info "Glances installed."
	log_info "Start with: /etc/init.d/glances start"
	log_info "Web interface: http://<router-ip>:$web_port"
}

cmd_check() {
	load_config

	log_info "Checking prerequisites..."
	if has_lxc; then
		log_info "LXC: available"
		lxc_check_prereqs
	else
		log_warn "LXC: not available"
	fi
}

cmd_update() {
	require_root
	load_config

	log_info "Updating Glances..."
	lxc_destroy
	lxc_create_rootfs || exit 1

	if /etc/init.d/glances enabled >/dev/null 2>&1; then
		/etc/init.d/glances restart
	else
		log_info "Update complete. Restart manually to apply."
	fi
}

cmd_status() {
	lxc_status
}

cmd_logs() {
	lxc_logs "$@"
}

cmd_shell() {
	lxc_shell
}

cmd_service_run() {
	require_root
	load_config

	if ! has_lxc; then
		log_error "LXC not available"
		exit 1
	fi

	lxc_check_prereqs || exit 1
	lxc_run
}

cmd_service_stop() {
	require_root
	lxc_stop
}

# Main Entry Point
case "${1:-}" in
	install) shift; cmd_install "$@" ;;
	check) shift; cmd_check "$@" ;;
	update) shift; cmd_update "$@" ;;
	status) shift; cmd_status "$@" ;;
	logs) shift; cmd_logs "$@" ;;
	shell) shift; cmd_shell "$@" ;;
	service-run) shift; cmd_service_run "$@" ;;
	service-stop) shift; cmd_service_stop "$@" ;;
	help|--help|-h|'') usage ;;
	*) echo "Unknown command: $1" >&2; usage >&2; exit 1 ;;
esac