using System;
using System.Diagnostics;
using System.Management;
using System.Threading.Tasks;

namespace PCMonitor {

    /// <summary>
    /// Monitor Informasi Sistem PC
    /// </summary>
    public class SystemInfoMonitor : IDisposable {
        private readonly ApiClient apiClient;
        private readonly ILog logger = new FileLogger();

        public SystemInfoMonitor(ApiClient client) {
            apiClient = client;
        }

        public async Task CollectAsync() {
            try {
                var systemInfo = GetSystemInfo();
                await apiClient.SendAsync("system-info", "POST", systemInfo);
            } catch (Exception ex) {
                logger.Error($"Error collecting system info: {ex.Message}");
            }
        }

        private dynamic GetSystemInfo() {
            var totalVisibleMemory = GetTotalMemory();
            var availableMemory = GetAvailableMemory();
            var usedMemory = totalVisibleMemory - availableMemory;

            var driveInfo = new System.IO.DriveInfo("C");

            return new {
                cpu_name = GetCpuName(),
                cpu_cores = Environment.ProcessorCount,
                cpu_usage = GetCpuUsage(),
                memory_total = totalVisibleMemory,
                memory_used = usedMemory,
                disk_total = driveInfo.TotalSize / 1024 / 1024 / 1024, // GB
                disk_used = (driveInfo.TotalSize - driveInfo.AvailableFreeSpace) / 1024 / 1024 / 1024, // GB
                os_name = Environment.OSVersion.Platform.ToString(),
                os_version = Environment.OSVersion.VersionString,
                last_boot = DateTime.UtcNow.AddMilliseconds(-Environment.TickCount),
                updated_at = DateTime.Now
            };
        }

        private string GetCpuName() {
            try {
                var searcher = new System.Management.ManagementObjectSearcher("SELECT Name FROM Win32_Processor");
                foreach (var obj in searcher.Get()) {
                    return obj["Name"].ToString();
                }
            } catch { }
            return "Unknown CPU";
        }

        private double GetCpuUsage() {
            try {
                var cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total", true);
                cpuCounter.NextValue();
                return Math.Round(cpuCounter.NextValue(), 2);
            } catch {
                return 0;
            }
        }

        private long GetTotalMemory() {
            try {
                var wmiObject = new System.Management.ManagementObject("Win32_ComputerSystem");
                return long.Parse(wmiObject["TotalPhysicalMemory"].ToString()) / 1024 / 1024; // MB
            } catch {
                return 0;
            }
        }

        private long GetAvailableMemory() {
            try {
                var wmiObject = new System.Management.ManagementClass("Win32_OperatingSystem");
                var instances = wmiObject.GetInstances();
                foreach (var instance in instances) {
                    return long.Parse(instance["FreePhysicalMemory"].ToString()) / 1024; // MB
                }
            } catch { }
            return 0;
        }

        public void Dispose() { }
    }
}