//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 30 seconds)",
                    ip
                );
                sleep(Duration::from_secs(10)).await;
            }
            Ok(resp) => {
                //let text = resp.text().await?;
                println!(
                    "⚠️ Server responded with status: {} - {}",
                    resp.status(),
                    resp.text().await?
                );
                sleep(Duration::from_secs(10)).await;
            }
            Err(err) => {
                println!("⚠️ Request failed: {} (will retry in 30 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();

    // 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", 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 30 seconds)",
                    status, text
                );
            }
            Err(err) => {
                println!("⚠️ Registration error: {} (will retry in 30 seconds)", err);
            }
        }
        sleep(Duration::from_secs(30)).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(30));

        loop {
            interval.tick().await;
            let metric = self.collect_metrics();

            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();
        let (disk_size, disk_used) = if let Some(d) = disk {
            let total = d.total_space();
            let available = d.available_space();
            (
                (total as f64) / 1024.0 / 1024.0 / 1024.0, // Convert to GB
                (total - available) as f64 / total as f64 * 100.0,
            )
        } else {
            (0.0, 0.0)
        };

        // 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_used,
            disk_temp: 0.0, // not supported
            net_in: net_in_bits,
            net_out: net_out_bits,
        }
    }
}

fn get_cpu_temp() -> Option<f32> {
    let output = Command::new("sensors").output().ok()?;
    let stdout = String::from_utf8_lossy(&output.stdout);
    for line in stdout.lines() {
        if line.to_lowercase().contains("package id") || line.to_lowercase().contains("cpu temp") {
            if let Some(temp_str) = line.split_whitespace().find(|s| s.contains("°C")) {
                let number: String = temp_str
                    .chars()
                    .filter(|c| c.is_digit(10) || *c == '.')
                    .collect();
                return number.parse::<f32>().ok();
            }
        }
    }
    None
}

fn get_network_traffic() -> Option<(u64, u64)> {
    let content = fs::read_to_string("/proc/net/dev").ok()?;
    let mut rx_total = 0u64;
    let mut tx_total = 0u64;

    for line in content.lines().skip(2) {
        let parts: Vec<&str> = line.split_whitespace().collect();
        if parts.len() < 17 {
            continue;
        }
        if parts[0].contains("lo:") {
            continue;
        }
        rx_total += parts[1].parse::<u64>().ok()?;
        tx_total += parts[9].parse::<u64>().ok()?;
    }
    Some((rx_total, tx_total))
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let server_base_url = "http://localhost:5258";

    // 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(())
}