//use chrono::Utc;
use nvml_wrapper::Nvml;
use reqwest::{Client, StatusCode};
use serde::{Deserialize, Serialize};
use std::{error::Error, fs, process::Command, time::Duration};
use sysinfo::{CpuExt, DiskExt, System, SystemExt};
use tokio::time::{interval, sleep};

// Data structures matching the C# DTOs
#[derive(Serialize, Debug)]
struct RegistrationDto {
    #[serde(rename = "id")]
    id: i32,
    #[serde(rename = "ipAddress")]
    ip_address: String,
    #[serde(rename = "cpuType")]
    cpu_type: String,
    #[serde(rename = "cpuCores")]
    cpu_cores: i32,
    #[serde(rename = "gpuType")]
    gpu_type: String,
    #[serde(rename = "ramSize")]
    ram_size: f64,
}

#[derive(Serialize, Debug)]
struct MetricDto {
    #[serde(rename = "serverId")]
    server_id: i32,
    #[serde(rename = "ipAddress")]
    ip_address: String,
    #[serde(rename = "cpu_Load")]
    cpu_load: f64,
    #[serde(rename = "cpu_Temp")]
    cpu_temp: f64,
    #[serde(rename = "gpu_Load")]
    gpu_load: f64,
    #[serde(rename = "gpu_Temp")]
    gpu_temp: f64,
    #[serde(rename = "gpu_Vram_Size")]
    gpu_vram_size: f64,
    #[serde(rename = "gpu_Vram_Usage")]
    gpu_vram_usage: f64,
    #[serde(rename = "ram_Load")]
    ram_load: f64,
    #[serde(rename = "ram_Size")]
    ram_size: f64,
    #[serde(rename = "disk_Size")]
    disk_size: f64,
    #[serde(rename = "disk_Usage")]
    disk_usage: f64,
    #[serde(rename = "disk_Temp")]
    disk_temp: f64,
    #[serde(rename = "net_In")]
    net_in: f64,
    #[serde(rename = "net_Out")]
    net_out: f64,
}

#[derive(Deserialize)]
struct IdResponse {
    id: i32,
    #[serde(rename = "ipAddress")]
    ip_address: String,
}

#[derive(Serialize)]
struct HeartbeatPayload {
    #[serde(rename = "IpAddress")]
    ip_address: String,
}

struct HardwareInfo {
    cpu_type: String,
    cpu_cores: i32,
    gpu_type: String,
    ram_size: f64,
    ip_address: String,
}

impl HardwareInfo {
    async fn collect() -> Result<Self, Box<dyn Error>> {
        let mut sys = System::new();
        sys.refresh_cpu();
        sys.refresh_memory();

        let cpus = sys.cpus();
        let cpu_type = cpus
            .get(0)
            .map(|c| c.brand().to_string())
            .unwrap_or("Unknown CPU".to_string());
        let cpu_cores = cpus.len() as i32;
        let ram_gb = (sys.total_memory() as f64) / 1024.0 / 1024.0;
        let gpu_type = Self::detect_gpu_name();
        let ip_address = local_ip_address::local_ip()?.to_string();

        Ok(Self {
            cpu_type,
            cpu_cores,
            gpu_type,
            ram_size: ram_gb,
            ip_address,
        })
    }

    fn detect_gpu_name() -> String {
        Self::try_nvml_gpu_name()
            .or_else(Self::fallback_gpu_name)
            .unwrap_or_else(|| "Unknown GPU".to_string())
    }

    fn try_nvml_gpu_name() -> Option<String> {
        let nvml = Nvml::init().ok()?;
        let device = nvml.device_by_index(0).ok()?;
        device.name().ok().map(|s| s.to_string())
    }

    fn fallback_gpu_name() -> Option<String> {
        #[cfg(target_os = "linux")]
        {
            let output = std::process::Command::new("lshw")
                .args(&["-C", "display"])
                .output()
                .ok()?;
            Some(
                String::from_utf8_lossy(&output.stdout)
                    .lines()
                    .find(|l| l.contains("product:"))
                    .map(|l| l.trim().replace("product:", "").trim().to_string())
                    .unwrap_or("Unknown GPU".to_string()),
            )
        }

        #[cfg(target_os = "windows")]
        {
            let output = std::process::Command::new("wmic")
                .args(&["path", "win32_VideoController", "get", "name"])
                .output()
                .ok()?;
            Some(
                String::from_utf8_lossy(&output.stdout)
                    .lines()
                    .nth(1)
                    .map(|s| s.trim().to_string())
                    .unwrap_or("Unknown GPU".to_string()),
            )
        }
    }
}

async fn get_server_id_by_ip(base_url: &str, ip: &str) -> Result<(i32, String), Box<dyn Error>> {
    let client = Client::builder()
        .danger_accept_invalid_certs(true)
        .build()?;

    let url = format!("{}/monitoring/server-id-by-ip?ipAddress={}", base_url, ip);

    loop {
        println!("Attempting to fetch server ID for IP {}...", ip);
        match client.get(&url).send().await {
            Ok(resp) if resp.status().is_success() => {
                let text = resp.text().await?;
                println!("Raw response: {}", text); // Debug output

                let id_resp: IdResponse = serde_json::from_str(&text).map_err(|e| {
                    println!("Failed to parse response: {}", e);
                    e
                })?;

                println!(
                    "✅ Received ID {} for IP {}",
                    id_resp.id, id_resp.ip_address
                );
                return Ok((id_resp.id, id_resp.ip_address));
            }
            Ok(resp) if resp.status() == StatusCode::NOT_FOUND => {
                println!(
                    "❌ Server with IP {} not found in database (will retry in 10 seconds)",
                    ip
                );
                sleep(Duration::from_secs(10)).await;
            }
            Ok(resp) => {
                println!(
                    "⚠️ Server responded with status: {} - {}",
                    resp.status(),
                    resp.text().await?
                );
                sleep(Duration::from_secs(10)).await;
            }
            Err(err) => {
                println!("⚠️ Request failed: {} (will retry in 10 seconds)", err);
                sleep(Duration::from_secs(10)).await;
            }
        }
    }
}

async fn register_with_server(base_url: &str) -> Result<(i32, String), Box<dyn Error>> {
    // First get local IP
    let ip = local_ip_address::local_ip()?.to_string();
    println!("Local IP address detected: {}", ip);

    // Get server ID from backend (this will retry until successful)
    let (server_id, registered_ip) = get_server_id_by_ip(base_url, &ip).await?;

    // Create HTTP client for registration
    let client = Client::builder()
        .danger_accept_invalid_certs(true)
        .build()?;

    // Collect hardware info
    let hardware = HardwareInfo::collect().await?;

    // Prepare registration data
    let registration = RegistrationDto {
        id: server_id,
        ip_address: registered_ip.clone(),
        cpu_type: hardware.cpu_type,
        cpu_cores: hardware.cpu_cores,
        gpu_type: hardware.gpu_type,
        ram_size: hardware.ram_size,
    };

    // Try to register (will retry on failure)
    loop {
        println!("Attempting to register with server...");
        let url = format!("{}/monitoring/register-agent-by-id", base_url);
        match client.post(&url).json(&registration).send().await {
            Ok(resp) if resp.status().is_success() => {
                println!("✅ Successfully registered with server.");
                return Ok((server_id, registered_ip));
            }
            Ok(resp) => {
                let status = resp.status();
                let text = resp.text().await.unwrap_or_default();
                println!(
                    "⚠️ Registration failed ({}): {} (will retry in 10 seconds)",
                    status, text
                );
            }
            Err(err) => {
                println!("⚠️ Registration error: {} (will retry in 10 seconds)", err);
            }
        }
        sleep(Duration::from_secs(10)).await;
    }
}

async fn heartbeat_loop(base_url: &str, ip: &str) -> Result<(), Box<dyn Error>> {
    let client = Client::builder()
        .danger_accept_invalid_certs(true)
        .build()?;
    let url = format!("{}/heartbeat/receive", base_url);

    loop {
        let payload = HeartbeatPayload {
            ip_address: ip.to_string(),
        };

        match client.post(&url).json(&payload).send().await {
            Ok(res) if res.status().is_success() => {
                println!("Heartbeat sent successfully.");
            }
            Ok(res) => eprintln!("Server responded with status: {}", res.status()),
            Err(e) => eprintln!("Heartbeat error: {}", e),
        }

        sleep(Duration::from_secs(20)).await;
    }
}

struct MetricsCollector {
    sys: System,
    nvml: Option<Nvml>,
    server_id: i32,
    ip_address: String,
}

impl MetricsCollector {
    fn new(server_id: i32, ip_address: String) -> Self {
        Self {
            sys: System::new(),
            nvml: Nvml::init().ok(),
            server_id,
            ip_address,
        }
    }

    async fn collect_and_send_loop(&mut self, base_url: &str) -> Result<(), Box<dyn Error>> {
        let client = Client::new();
        let url = format!("{}/monitoring/metric", base_url);
        let mut interval = interval(Duration::from_secs(20));

        loop {
            interval.tick().await;
            let metric = self.collect_metrics();
            println!("Collected metrics: {:?}", metric);

            match client.post(&url).json(&metric).send().await {
                Ok(res) => println!(
                    "✅ Sent metrics for server {} | Status: {}",
                    metric.server_id,
                    res.status()
                ),
                Err(err) => eprintln!("❌ Failed to send metrics: {}", err),
            }
        }
    }

    fn collect_metrics(&mut self) -> MetricDto {
        self.sys.refresh_all();

        // CPU
        let cpu_load = self.sys.global_cpu_info().cpu_usage() as f64;
        let cpu_temp = get_cpu_temp().unwrap_or(0.0) as f64;

        // RAM
        let total_memory = self.sys.total_memory();
        let used_memory = self.sys.used_memory();
        let ram_load = (used_memory as f64 / total_memory as f64) * 100.0;
        let ram_size = (total_memory as f64) / 1024.0 / 1024.0;

        // Disk
        let disk = self.sys.disks().first();
        // In collect_metrics():
        let (disk_size, disk_usage, disk_temp) = {
            let mut total_size = 0u64;
            let mut total_used = 0u64;
            let mut temp = 0.0;
            let mut count = 0;

            for disk in self.sys.disks() {
                total_size += disk.total_space();
                total_used += disk.total_space() - disk.available_space();
                count += 1;
            }

            // Disk temperature (Linux only)
            #[cfg(target_os = "linux")]
            {
                if let Ok(dir) = fs::read_dir("/sys/block") {
                    for entry in dir.flatten() {
                        if let Some(disk_name) = entry.file_name().to_str() {
                            if disk_name.starts_with("sd") || disk_name.starts_with("nvme") {
                                let temp_path = format!(
                                    "/sys/block/{}/device/hwmon/hwmon*/temp1_input",
                                    disk_name
                                );
                                if let Ok(paths) = glob::glob(&temp_path) {
                                    for path in paths.flatten() {
                                        if let Ok(content) = fs::read_to_string(path) {
                                            if let Ok(t) = content.trim().parse::<f32>() {
                                                temp += t / 1000.0; // Convert millidegrees
                                                break;
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

            let size_gb = if count > 0 {
                (total_size as f64) / 1024.0 / 1024.0 / 1024.0
            } else {
                0.0
            };

            let usage = if total_size > 0 {
                (total_used as f64 / total_size as f64) * 100.0
            } else {
                0.0
            };

            let avg_temp = if count > 0 { temp / count as f32 } else { 0.0 };

            (size_gb, usage, avg_temp)
        };
        // GPU (NVIDIA)
        let (gpu_temp, gpu_load, vram_used, vram_total) = if let Some(nvml) = &self.nvml {
            if let Ok(device) = nvml.device_by_index(0) {
                let temp = device
                    .temperature(nvml_wrapper::enum_wrappers::device::TemperatureSensor::Gpu)
                    .unwrap_or(0) as f64;
                let load = device
                    .utilization_rates()
                    .map(|u| u.gpu as f64)
                    .unwrap_or(0.0);
                let mem = device.memory_info().ok();
                let used = mem
                    .clone()
                    .map(|m| (m.used as f64) / 1024.0 / 1024.0 / 1024.0)
                    .unwrap_or(0.0); // GB
                let total = mem
                    .map(|m| (m.total as f64) / 1024.0 / 1024.0 / 1024.0)
                    .unwrap_or(0.0); // GB
                (temp, load, used, total)
            } else {
                (0.0, 0.0, 0.0, 0.0)
            }
        } else {
            (0.0, 0.0, 0.0, 0.0)
        };

        // Network (convert bytes to bits)
        let (net_in, net_out) = get_network_traffic().unwrap_or((0, 0));
        let net_in_bits = (net_in as f64) * 8.0;
        let net_out_bits = (net_out as f64) * 8.0;

        MetricDto {
            server_id: self.server_id,
            ip_address: self.ip_address.clone(),
            cpu_load,
            cpu_temp,
            gpu_load,
            gpu_temp,
            gpu_vram_size: vram_total,
            gpu_vram_usage: if vram_total > 0.0 {
                (vram_used / vram_total) * 100.0
            } else {
                0.0
            },
            ram_load,
            ram_size,
            disk_size,
            disk_usage: disk_usage,
            disk_temp: 0.0, // not supported
            net_in: net_in_bits,
            net_out: net_out_bits,
        }
    }
}

fn get_cpu_temp() -> Option<f32> {
    #[cfg(target_os = "linux")]
    {
        // Versuche mehrere Methoden der Reihe nach
        // 1. sensors-Befehl
        if let Ok(output) = Command::new("sensors").output() {
            let stdout = String::from_utf8_lossy(&output.stdout);
            for line in stdout.lines() {
                if line.contains("Package id") || line.contains("Tdie") || line.contains("CPU Temp")
                {
                    if let Some(temp_str) = line
                        .split('+')
                        .nth(1)
                        .and_then(|s| s.split_whitespace().next())
                    {
                        if let Ok(temp) = temp_str.replace("°C", "").parse::<f32>() {
                            return Some(temp);
                        }
                    }
                }
            }
        }

        // 2. Sysfs (Intel/AMD)
        if let Ok(content) = fs::read_to_string("/sys/class/thermal/thermal_zone0/temp") {
            if let Ok(temp) = content.trim().parse::<f32>() {
                return Some(temp / 1000.0);
            }
        }

        // 3. Alternative Sysfs-Pfade
        let paths = [
            "/sys/class/hwmon/hwmon*/temp1_input",
            "/sys/class/hwmon/hwmon*/device/temp1_input",
        ];

        for path_pattern in &paths {
            if let Ok(paths) = glob::glob(path_pattern) {
                for path in paths.flatten() {
                    if let Ok(content) = fs::read_to_string(&path) {
                        if let Ok(temp) = content.trim().parse::<f32>() {
                            return Some(temp / 1000.0);
                        }
                    }
                }
            }
        }
    }

    #[cfg(target_os = "windows")]
    {
        // Windows: OpenHardwareMonitor über WMI abfragen
        let output = Command::new("wmic")
            .args(&[
                "/namespace:\\root\\OpenHardwareMonitor",
                "path",
                "Sensor",
                "get",
                "Value,Name",
                "/format:list",
            ])
            .output()
            .ok()?;

        let stdout = String::from_utf8_lossy(&output.stdout);
        for line in stdout.lines() {
            if line.contains("Name=CPU Package") && line.contains("Value=") {
                if let Some(value) = line.split("Value=").nth(1) {
                    return value.trim().parse::<f32>().ok();
                }
            }
        }

        // Fallback: Standard WMI
        let output = Command::new("wmic")
            .args(&["cpu", "get", "Temperature", "/Value"])
            .output()
            .ok()?;

        let stdout = String::from_utf8_lossy(&output.stdout);
        for line in stdout.lines() {
            if line.starts_with("Temperature=") {
                return line.replace("Temperature=", "").trim().parse::<f32>().ok();
            }
        }
    }

    None
}

fn get_disk_info() -> (f64, f64, f64) {
    let mut sys = System::new();
    sys.refresh_disks();
    sys.refresh_disks_list();

    let mut total_size = 0u64;
    let mut total_used = 0u64;
    let mut count = 0;

    for disk in sys.disks() {
        // Ignoriere CD-ROMs und kleine Systempartitionen
        if disk.total_space() > 100 * 1024 * 1024 {
            // > 100MB
            total_size += disk.total_space();
            total_used += disk.total_space() - disk.available_space();
            count += 1;
        }
    }

    // Berechnungen
    let size_gb = if count > 0 {
        total_size as f64 / (1024.0 * 1024.0 * 1024.0)
    } else {
        // Fallback: Versuche df unter Linux
        #[cfg(target_os = "linux")]
        {
            if let Ok(output) = Command::new("df")
                .arg("-B1")
                .arg("--output=size,used")
                .output()
            {
                let stdout = String::from_utf8_lossy(&output.stdout);
                for line in stdout.lines().skip(1) {
                    let parts: Vec<&str> = line.split_whitespace().collect();
                    if parts.len() == 2 {
                        if let (Ok(size), Ok(used)) =
                            (parts[0].parse::<u64>(), parts[1].parse::<u64>())
                        {
                            total_size += size;
                            total_used += used;
                            count += 1;
                        }
                    }
                }
                total_size as f64 / (1024.0 * 1024.0 * 1024.0)
            } else {
                0.0
            }
        }
        #[cfg(not(target_os = "linux"))]
        {
            0.0
        }
    };

    let usage = if total_size > 0 {
        (total_used as f64 / total_size as f64) * 100.0
    } else {
        0.0
    };

    (size_gb, usage, 0.0) // Disk-Temp bleibt 0.0 ohne spezielle Hardware
}

#[cfg(target_os = "windows")]
fn get_network_traffic() -> Option<(u64, u64)> {
    use std::mem::size_of;
    use std::ptr::null_mut;
    use winapi::shared::ifmib::{MIB_IFROW, MIB_IFTABLE};
    use winapi::um::iphlpapi::GetIfTable;

    unsafe {
        // Erste Abfrage zur Bestimmung der benötigten Puffergröße
        let mut buffer_size = 0u32;
        if GetIfTable(null_mut(), &mut buffer_size, 0)
            != winapi::shared::winerror::ERROR_INSUFFICIENT_BUFFER
        {
            return None;
        }

        // Puffer allozieren
        let mut buffer = vec![0u8; buffer_size as usize];
        let if_table = buffer.as_mut_ptr() as *mut MIB_IFTABLE;

        // Tatsächliche Daten abrufen
        if GetIfTable(if_table, &mut buffer_size, 0) != 0 {
            return None;
        }

        // Daten auswerten
        let mut rx_total = 0u64;
        let mut tx_total = 0u64;

        for i in 0..(*if_table).dwNumEntries {
            let row = &*((*if_table).table.as_ptr().offset(i as isize));
            rx_total += row.dwInOctets as u64;
            tx_total += row.dwOutOctets as u64;
        }

        Some((rx_total, tx_total))
    }
}

#[cfg(target_os = "linux")]
fn get_network_traffic() -> Option<(u64, u64)> {
    // Bessere Methode mit sysfs
    let mut rx_total = 0u64;
    let mut tx_total = 0u64;

    if let Ok(dir) = fs::read_dir("/sys/class/net") {
        for entry in dir.flatten() {
            let iface = entry.file_name();
            let iface_name = iface.to_string_lossy();

            // Ignoriere virtuelle Interfaces
            if !iface_name.starts_with("lo") && !iface_name.starts_with("virbr") {
                if let (Ok(rx), Ok(tx)) = (
                    fs::read_to_string(entry.path().join("statistics/rx_bytes")),
                    fs::read_to_string(entry.path().join("statistics/tx_bytes")),
                ) {
                    rx_total += rx.trim().parse::<u64>().unwrap_or(0);
                    tx_total += tx.trim().parse::<u64>().unwrap_or(0);
                }
            }
        }
    }

    Some((rx_total, tx_total))
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let server_base_url = "http://localhost:5000";

    // Registration phase
    println!("Starting registration process...");
    let (server_id, ip_address) = register_with_server(server_base_url).await?;

    // Start heartbeat in background
    let heartbeat_handle = tokio::spawn({
        let ip = ip_address.clone();
        async move {
            if let Err(e) = heartbeat_loop(server_base_url, &ip).await {
                eprintln!("Heartbeat loop failed: {}", e);
            }
        }
    });

    // Start metrics collection
    println!("Starting metrics collection...");
    let mut metrics_collector = MetricsCollector::new(server_id, ip_address);
    metrics_collector
        .collect_and_send_loop(server_base_url)
        .await?;

    heartbeat_handle.await?;
    Ok(())
}

#[tokio::test]
async fn test_metrics() {
    println!("CPU Temp: {:?}", get_cpu_temp());
    println!("Disk Info: {:?}", get_disk_info());
    println!("Network: {:?}", get_network_traffic());
}