package inventory

import (
	"os"
	"os/exec"
	"runtime"
	"strings"

	"github.com/fleetforge/forge-agent/internal/pkgmanager"
	"github.com/fleetforge/forge-agent/internal/svcmgr"
	"github.com/shirou/gopsutil/v3/cpu"
	"github.com/shirou/gopsutil/v3/disk"
	"github.com/shirou/gopsutil/v3/mem"
	"github.com/shirou/gopsutil/v3/net"
)

func execCmd(name string, args ...string) (string, error) {
	cmd := exec.Command(name, args...)
	out, err := cmd.Output()
	return string(out), err
}

type NetworkInterface struct {
	Name    string   `json:"name"`
	Addresses []string `json:"addresses"`
	MAC     string   `json:"mac_address,omitempty"`
}

type SystemInfo struct {
	Hostname          string
	Platform          string
	OSName            string
	OSVersion         string
	Architecture      string
	KernelVersion     string
	CPUModel          string
	CPUCores          int
	TotalMemory       uint64
	TotalDisk         uint64
	IPAddress         string
	NetworkInterfaces []NetworkInterface
	Packages          []pkgmanager.PackageInfo
	Services          []svcmgr.ServiceInfo
}

func CollectSystemInfo() (*SystemInfo, error) {
	hostname, _ := os.Hostname()

	info := &SystemInfo{
		Hostname:     hostname,
		Platform:     runtime.GOOS,
		Architecture: runtime.GOARCH,
	}

	switch runtime.GOOS {
	case "linux":
		info.OSName = "Linux"
		if data, err := os.ReadFile("/etc/os-release"); err == nil {
			lines := strings.Split(string(data), "\n")
			for _, line := range lines {
				if strings.HasPrefix(line, "PRETTY_NAME=") {
					info.OSName = strings.Trim(strings.TrimPrefix(line, "PRETTY_NAME="), "\"")
				}
				if strings.HasPrefix(line, "VERSION_ID=") {
					info.OSVersion = strings.Trim(strings.TrimPrefix(line, "VERSION_ID="), "\"")
				}
			}
		}
		if data, err := os.ReadFile("/proc/version"); err == nil {
			parts := strings.Fields(string(data))
			if len(parts) >= 3 {
				info.KernelVersion = parts[2]
			}
		}
	case "darwin":
		info.OSName = "macOS"
		if out, err := execCmd("sw_vers", "-productVersion"); err == nil {
			info.OSVersion = strings.TrimSpace(out)
		}
		if out, err := execCmd("uname", "-r"); err == nil {
			info.KernelVersion = strings.TrimSpace(out)
		}
	case "windows":
		info.OSName = "Windows"
		if out, err := execCmd("cmd", "/c", "ver"); err == nil {
			out = strings.TrimSpace(out)
			if start := strings.Index(out, "[Version "); start != -1 {
				ver := out[start+len("[Version "):]
				if end := strings.Index(ver, "]"); end != -1 {
					info.OSVersion = ver[:end]
				}
			}
			if info.OSVersion == "" {
				info.OSVersion = out
			}
		}
		if out, err := execCmd("cmd", "/c", "ver"); err == nil {
			_ = out
		}
		if out, err := execCmd("powershell", "-NoProfile", "-NonInteractive", "-Command",
			"(Get-CimInstance Win32_OperatingSystem).Caption"); err == nil {
			caption := strings.TrimSpace(out)
			if caption != "" {
				info.OSName = caption
			}
		}
		if out, err := execCmd("powershell", "-NoProfile", "-NonInteractive", "-Command",
			"$k = (Get-CimInstance Win32_OperatingSystem).Version; $b = (Get-CimInstance Win32_ComputerSystem).BuildNumber; $k"); err == nil {
			if kb := strings.TrimSpace(out); kb != "" {
				info.KernelVersion = kb
			}
		}
	}

	if cpuInfo, err := cpu.Info(); err == nil && len(cpuInfo) > 0 {
		info.CPUModel = cpuInfo[0].ModelName
		info.CPUCores = len(cpuInfo)
	}

	if v, err := mem.VirtualMemory(); err == nil {
		info.TotalMemory = v.Total
	}

	if d, err := disk.Usage("/"); err == nil {
		info.TotalDisk = d.Total
	}

	populateNetwork(info)

	if info.OSVersion == "" {
		info.OSVersion = "unknown"
	}

	if pkgs, err := pkgmanager.ListPackages(); err == nil {
		info.Packages = pkgs
	}

	if svcs, err := svcmgr.ListServices(); err == nil {
		info.Services = svcs
	}

	return info, nil
}

func populateNetwork(info *SystemInfo) {
	ifs, err := net.Interfaces()
	if err != nil {
		return
	}

	var primaryIP string
	for _, ifc := range ifs {
		if !containsFlag(ifc.Flags, "up") || containsFlag(ifc.Flags, "loopback") {
			continue
		}
		ni := NetworkInterface{
			Name:      ifc.Name,
			Addresses: []string{},
			MAC:       ifc.HardwareAddr,
		}
		for _, addr := range ifc.Addrs {
			if addr.Addr == "" {
				continue
			}
			ip := strings.TrimSpace(addr.Addr)
			ni.Addresses = append(ni.Addresses, ip)
			if primaryIP == "" && !strings.Contains(ip, ":") {
				primaryIP = strings.Split(ip, "/")[0]
			}
		}
		if len(ni.Addresses) > 0 {
			info.NetworkInterfaces = append(info.NetworkInterfaces, ni)
		}
	}

	if primaryIP != "" {
		info.IPAddress = primaryIP
	}
}

func containsFlag(flags []string, flag string) bool {
	for _, f := range flags {
		if strings.EqualFold(f, flag) {
			return true
		}
	}
	return false
}