#!/bin/bash
# System preflight checks.
set -euo pipefail

detect_system_arch() {
	local raw
	raw="$(uname -m)"
	case "$raw" in
		aarch64|arm64|armv7l|armv8*)
			SYSTEM_ARCH="arm"
			USE_ARM_POSTGIS=true
			POSTGIS_IMAGE="imresamu/postgis:16-3.5-alpine"
			;;
		x86_64|amd64)
			SYSTEM_ARCH="amd64"
			USE_ARM_POSTGIS=false
			POSTGIS_IMAGE="postgis/postgis:16-3.5"
			;;
		*)
			SYSTEM_ARCH="$raw"
			USE_ARM_POSTGIS=false
			POSTGIS_IMAGE="postgis/postgis:16-3.5"
			;;
	esac
}

verify_postgis_image() {
	local image="$1"
	if docker manifest inspect "$image" &>/dev/null; then
		return 0
	fi
	log_warning "Could not verify manifest for $image"
	return 1
}

write_postgis_override() {
	local target="${1:-docker-compose.override.yml}"
	if [[ "$USE_ARM_POSTGIS" != true ]]; then
		return 0
	fi
	log_info "ARM architecture detected — using PostGIS image: $POSTGIS_IMAGE"
	cat > "$target" << EOF
# Auto-generated by AdventureLog installer for ARM hosts
services:
  db:
    image: ${POSTGIS_IMAGE}
EOF
	log_success "Wrote $target"
}

check_dependencies() {
	print_section "Dependencies"
	local missing=()
	command -v curl &>/dev/null || missing+=("curl")
	command -v docker &>/dev/null || missing+=("docker")
	if ! docker compose version &>/dev/null 2>&1 && ! command -v docker-compose &>/dev/null; then
		missing+=("docker-compose")
	fi
	if [[ ${#missing[@]} -gt 0 ]]; then
		log_error "Missing required tools: ${missing[*]}"
		log_muted "Install Docker: https://docs.docker.com/get-docker/"
		exit 1
	fi
	log_success "Docker, Compose, and curl are available"
}

check_docker_status() {
	if [[ "${DRY_RUN:-false}" == true ]]; then
		log_muted "[dry-run] Skipping Docker daemon check"
		return 0
	fi
	log_info "Checking Docker daemon"
	if ! docker info &>/dev/null; then
		log_error "Docker is not running — start Docker and try again"
		exit 1
	fi
	if ! docker info 2>/dev/null | grep -q "Username:" && [[ "$(id -u)" -ne 0 ]]; then
		if ! groups 2>/dev/null | grep -q docker; then
			log_warning "Your user is not in the docker group — you may need sudo"
		fi
	fi
	log_success "Docker daemon is running"
}

check_memory() {
	local avail_kb avail_mb
	if [[ -r /proc/meminfo ]]; then
		avail_kb="$(awk '/MemAvailable/ {print $2}' /proc/meminfo)"
		if [[ -n "$avail_kb" && "$avail_kb" =~ ^[0-9]+$ ]]; then
			avail_mb=$((avail_kb / 1024))
			if (( avail_mb < 2048 )); then
				log_warning "Available RAM is ~${avail_mb}MB — first boot needs ~2GB for world data import"
				if tui_confirm "Enable SKIP_WORLD_DATA=1 to skip geography import on first boot?" "y"; then
					SKIP_WORLD_DATA="1"
					append_env_line "SKIP_WORLD_DATA=1"
				fi
			fi
		fi
	elif [[ "$OSTYPE" == "darwin"* ]]; then
		log_info "Could not auto-detect RAM on macOS — ensure at least 2GB is allocated to Docker"
	fi
}

check_disk_space() {
	local target="${1:-.}"
	local check_path="$target"
	if [[ ! -e "$check_path" ]]; then
		check_path="."
	fi
	local avail
	if command -v df &>/dev/null; then
		avail="$(df -BG "$check_path" 2>/dev/null | awk 'NR==2 {gsub(/G/,"",$4); print $4}')" || avail=""
		if [[ -n "$avail" && "$avail" =~ ^[0-9]+$ ]] && (( avail < 5 )); then
			log_warning "Less than 5GB free disk space in $check_path"
		fi
	fi
}

check_port_in_use() {
	local port="$1"
	local name="$2"
	local in_use=false
	if command -v ss &>/dev/null; then
		ss -ln 2>/dev/null | grep -q ":${port} " && in_use=true
	elif command -v netstat &>/dev/null; then
		netstat -ln 2>/dev/null | grep -q ":${port} " && in_use=true
	fi
	if [[ "$in_use" == true ]]; then
		log_warning "Port $port ($name) appears to be in use"
		tui_confirm "Continue anyway?" "n" || exit 0
	fi
}

detect_existing_install() {
	local dir="${1:-$INSTALL_DIR}"
	if [[ -f "$dir/.env" ]] || [[ -f "$dir/.env.advanced" ]] || [[ -f "$dir/.env.aio" ]]; then
		return 0
	fi
	if docker ps -a --format '{{.Names}}' 2>/dev/null | grep -qE '^(adventurelog|adventurelog-aio|adventurelog-frontend|adventurelog-backend)$'; then
		return 0
	fi
	return 1
}

detect_setup_type_from_install() {
	local dir="${1:-$INSTALL_DIR}"
	if [[ -f "$dir/.env.aio" ]]; then
		SETUP_TYPE="standard"
	elif [[ -f "$dir/.env.advanced" ]]; then
		SETUP_TYPE="advanced"
	elif [[ -f "$dir/.env" ]]; then
		if grep -qE '^(ORIGIN|PUBLIC_URL|FRONTEND_URL)=' "$dir/.env" 2>/dev/null; then
			SETUP_TYPE="advanced"
		else
			SETUP_TYPE="standard"
		fi
	fi
	resolve_compose_settings
}

run_preflight() {
	print_step_header 1 "$WIZARD_TOTAL" "System checks"
	check_dependencies
	check_docker_status
	detect_system_arch
	log_success "Architecture: $SYSTEM_ARCH"
	log_muted "PostGIS image: $POSTGIS_IMAGE"
	check_memory
	check_disk_space "$INSTALL_DIR"
}

run_port_checks() {
	if [[ "$SETUP_TYPE" == "standard" ]]; then
		check_port_in_use "$HOST_PORT" "AdventureLog"
	else
		check_port_in_use "$FRONTEND_PORT" "frontend"
		check_port_in_use "$BACKEND_PORT" "backend"
	fi
}

prompt_postgis_override() {
	if [[ "$USE_ARM_POSTGIS" == true ]]; then
		return 0
	fi
	if tui_confirm "Use custom PostGIS image? (default: $POSTGIS_IMAGE)" "n"; then
		POSTGIS_IMAGE="$(prompt_with_default "PostGIS image" "$POSTGIS_IMAGE")"
		USE_ARM_POSTGIS=true
	fi
}