#!/bin/bash
# System Compatibility Check for ZMB Webui Backend
# Run before installation to verify system meets requirements

set -e

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

echo -e "${BLUE}╔═══════════════════════════════════════════════════════════╗${NC}"
echo -e "${BLUE}║  ZMB Webui Backend – System Compatibility Check       ║${NC}"
echo -e "${BLUE}╚═══════════════════════════════════════════════════════════╝${NC}"
echo ""

ISSUES=0
WARNINGS=0

# ============== ARCHITECTURE ==============
echo -e "${YELLOW}Architecture${NC}"
ARCH=$(uname -m)
case $ARCH in
    aarch64)
        echo -e "  ${GREEN}✓${NC} $ARCH (ARM64 - Raspberry Pi)"
        ;;
    x86_64 | x86-64)
        echo -e "  ${GREEN}✓${NC} $ARCH (AMD64 - 64-bit x86)"
        ;;
    i686 | i386)
        echo -e "  ${YELLOW}⚠${NC} $ARCH (32-bit x86 - may be slow)"
        ((WARNINGS++))
        ;;
    *)
        echo -e "  ${RED}✗${NC} $ARCH (unknown/unsupported)"
        ((ISSUES++))
        ;;
esac
echo ""

# ============== OS ==============
echo -e "${YELLOW}Operating System${NC}"
if [ -f /etc/os-release ]; then
    . /etc/os-release
    OS_NAME="${NAME:-Unknown}"
    OS_VERSION="${VERSION_ID:-unknown}"

    if [[ "$ID" == "debian" ]] || [[ "$ID_LIKE" == *"debian"* ]]; then
        echo -e "  ${GREEN}✓${NC} $OS_NAME ($OS_VERSION) - Debian-based"
        PKG_MANAGER="apt"
    elif [[ "$ID" == "ubuntu" ]]; then
        echo -e "  ${GREEN}✓${NC} Ubuntu ($OS_VERSION) - Debian-based"
        PKG_MANAGER="apt"
    elif [[ "$ID" == "rhel" ]] || [[ "$ID" == "centos" ]] || [[ "$ID" == "fedora" ]]; then
        echo -e "  ${YELLOW}⚠${NC} $OS_NAME ($OS_VERSION) - RHEL-based (use install-rhel.sh)"
        ((WARNINGS++))
        PKG_MANAGER="dnf"
    else
        echo -e "  ${RED}✗${NC} $OS_NAME - not tested"
        ((ISSUES++))
    fi
else
    echo -e "  ${RED}✗${NC} Could not detect OS"
    ((ISSUES++))
fi
echo ""

# ============== PYTHON ==============
echo -e "${YELLOW}Python${NC}"
if command -v python3 &> /dev/null; then
    PYTHON_VERSION=$(python3 -c 'import sys; print(".".join(map(str, sys.version_info[:2])))')
    PYTHON_MAJOR=$(echo $PYTHON_VERSION | cut -d. -f1)
    PYTHON_MINOR=$(echo $PYTHON_VERSION | cut -d. -f2)

    if [ "$PYTHON_MAJOR" -ge 3 ] && [ "$PYTHON_MINOR" -ge 8 ]; then
        echo -e "  ${GREEN}✓${NC} Python $PYTHON_VERSION"
    else
        echo -e "  ${RED}✗${NC} Python $PYTHON_VERSION (need 3.8+)"
        ((ISSUES++))
    fi
else
    echo -e "  ${RED}✗${NC} Python 3 not found"
    ((ISSUES++))
fi
echo ""

# ============== PIP ==============
echo -e "${YELLOW}pip${NC}"
if python3 -m pip --version &> /dev/null; then
    echo -e "  ${GREEN}✓${NC} pip available"
else
    echo -e "  ${RED}✗${NC} pip not found"
    ((ISSUES++))
fi
echo ""

# ============== ZFS TOOLS ==============
echo -e "${YELLOW}ZFS Tools${NC}"
ZFS_OK=true

if command -v zpool &> /dev/null; then
    ZPOOL_VERSION=$(zpool --version 2>/dev/null | head -1)
    echo -e "  ${GREEN}✓${NC} zpool - $ZPOOL_VERSION"
else
    echo -e "  ${RED}✗${NC} zpool not found"
    ZFS_OK=false
    ((ISSUES++))
fi

if command -v zfs &> /dev/null; then
    ZFS_VERSION=$(zfs --version 2>/dev/null | head -1)
    echo -e "  ${GREEN}✓${NC} zfs - $ZFS_VERSION"
else
    echo -e "  ${RED}✗${NC} zfs not found"
    ZFS_OK=false
    ((ISSUES++))
fi

if [ "$ZFS_OK" = true ]; then
    # Try to list pools to verify ZFS is working
    if zpool list &> /dev/null; then
        echo -e "  ${GREEN}✓${NC} ZFS is functional (can list pools)"
    fi
else
    echo -e "  ${YELLOW}ℹ${NC} ZFS not installed - install with: $PKG_MANAGER install zfsutils-linux"
    ((WARNINGS++))
fi
echo ""

# ============== SYSTEMD ==============
echo -e "${YELLOW}systemd${NC}"
if command -v systemctl &> /dev/null; then
    echo -e "  ${GREEN}✓${NC} systemd available"
else
    echo -e "  ${YELLOW}⚠${NC} systemd not found (required for service installation)"
    ((WARNINGS++))
fi
echo ""

# ============== DISK SPACE ==============
echo -e "${YELLOW}Disk Space${NC}"
AVAILABLE=$(df /opt 2>/dev/null | tail -1 | awk '{print $4}')
if [ -z "$AVAILABLE" ]; then
    AVAILABLE=$(df / 2>/dev/null | tail -1 | awk '{print $4}')
fi

if [ ! -z "$AVAILABLE" ] && [ "$AVAILABLE" -gt 500000 ]; then
    AVAILABLE_MB=$((AVAILABLE / 1024))
    echo -e "  ${GREEN}✓${NC} ~${AVAILABLE_MB}MB available"
else
    echo -e "  ${RED}✗${NC} Less than 500MB available"
    ((ISSUES++))
fi
echo ""

# ============== MEMORY ==============
echo -e "${YELLOW}Memory${NC}"
if [ -f /proc/meminfo ]; then
    TOTAL_MEM=$(grep MemTotal /proc/meminfo | awk '{print $2}')
    TOTAL_MB=$((TOTAL_MEM / 1024))

    if [ "$TOTAL_MB" -ge 512 ]; then
        echo -e "  ${GREEN}✓${NC} ${TOTAL_MB}MB available"
        if [ "$TOTAL_MB" -lt 1024 ]; then
            echo -e "  ${YELLOW}⚠${NC} Less than 1GB - performance may be limited"
            ((WARNINGS++))
        fi
    else
        echo -e "  ${RED}✗${NC} Only ${TOTAL_MB}MB - too little memory"
        ((ISSUES++))
    fi
else
    echo -e "  ${YELLOW}⚠${NC} Could not determine memory"
    ((WARNINGS++))
fi
echo ""

# ============== NETWORK ==============
echo -e "${YELLOW}Network${NC}"
if ping -c 1 8.8.8.8 &> /dev/null; then
    echo -e "  ${GREEN}✓${NC} Internet connectivity OK"
else
    echo -e "  ${YELLOW}⚠${NC} No internet connectivity (needed for apt)"
    ((WARNINGS++))
fi
echo ""

# ============== SUMMARY ==============
echo -e "${BLUE}═══════════════════════════════════════════════════════════${NC}"

if [ $ISSUES -eq 0 ]; then
    echo -e "${GREEN}✓ System is compatible - ready for installation${NC}"
    if [ $WARNINGS -gt 0 ]; then
        echo -e "${YELLOW}⚠ $WARNINGS warning(s) - review above${NC}"
    fi
    echo ""
    echo -e "Next step: ${BLUE}sudo bash install.sh${NC}"
    exit 0
else
    echo -e "${RED}✗ $ISSUES issue(s) found - cannot proceed${NC}"
    echo ""
    echo "Fix the issues above and try again."
    exit 1
fi