use lighthouse_network::{NetworkGlobals, types::SyncState};
use parking_lot::RwLock;
use serde::{Deserialize, Serialize};
use std::path::{Path, PathBuf};
use std::sync::Arc;
use sysinfo::{CpuExt, DiskExt, NetworkExt, NetworksExt, System, SystemExt};
use types::EthSpec;

#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct SystemHealth {
    /// Total memory of the system.
    pub total_memory: u64,
    /// Total free memory available to the system.
    pub free_memory: u64,
    /// Total used memory.
    pub used_memory: u64,

    /// System load average over 1 minute.
    pub sys_loadavg_1: f64,
    /// System load average over 5 minutes.
    pub sys_loadavg_5: f64,
    /// System load average over 15 minutes.
    pub sys_loadavg_15: f64,

    /// Total cpu cores.
    pub cpu_cores: usize,
    /// Total cpu threads.
    pub cpu_threads: usize,
    /// The global cpu frequency.
    pub global_cpu_frequency: f32,

    /// Total capacity of disk.
    pub disk_bytes_total: u64,
    /// Free space in disk.
    pub disk_bytes_free: u64,

    /// System uptime.
    pub system_uptime: u64,
    /// Application uptime.
    pub app_uptime: u64,
    /// The System name
    pub system_name: String,
    /// Kernel version
    pub kernel_version: String,
    /// OS version
    pub os_version: String,
    /// Hostname
    pub host_name: String,
}

/// System related health, specific to the UI for the validator client.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct SystemHealthVC {
    #[serde(flatten)]
    pub system_health: SystemHealth,
}

/// System related health, specific to the UI for the Beacon Node.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct SystemHealthBN {
    #[serde(flatten)]
    pub system_health: SystemHealth,
    /// The name of the network that uses the most traffic.
    pub network_name: String,
    /// Total bytes received over the main interface.
    pub network_bytes_total_received: u64,
    /// Total bytes sent over the main interface.
    pub network_bytes_total_transmit: u64,

    /// The current NAT status.
    pub nat_open: bool,
    /// The current number of connected peers.
    pub connected_peers: usize,
    /// The current syncing state of the consensus node.
    pub sync_state: SyncState,
}

/// Populates the system health.
fn observe_system_health(
    sysinfo: Arc<RwLock<System>>,
    data_dir: PathBuf,
    app_uptime: u64,
) -> SystemHealth {
    let sysinfo = sysinfo.read();
    let loadavg = sysinfo.load_average();

    let cpus = sysinfo.cpus();

    let disks = sysinfo.disks();

    let system_uptime = sysinfo.uptime();

    // Helper functions to extract specific data

    // Find fs associated with the data dir location and report this
    let (disk_bytes_total, disk_bytes_free) = {
        // There is no clean way to find this in an OS-agnostic way. We take a simple approach,
        // which is attempt to match the mount_point to the data_dir. If this cannot be done, we
        // just fallback to the root fs.

        let mut root_fs_disk = None;
        let mut other_matching_fs = None;

        for disk in disks.iter() {
            if disk.mount_point() == Path::new("/")
                || disk.mount_point() == Path::new("C:\\")
                || disk.mount_point() == Path::new("/System/Volumes/Data")
            {
                // Found the usual default root_fs
                root_fs_disk = Some(disk);
                continue;
            }

            // If we have other file systems, compare these to the data_dir of Lighthouse and
            // prioritize these.
            if data_dir
                .to_str()
                .map(|path| {
                    if let Some(mount_str) = disk.mount_point().to_str() {
                        path.contains(mount_str)
                    } else {
                        false
                    }
                })
                .unwrap_or(false)
            {
                other_matching_fs = Some(disk);
                break; // Don't bother finding other competing fs.
            }
        }

        // If we found a file system other than the root, report this, otherwise just report the
        // root fs
        let fs = other_matching_fs.or(root_fs_disk);

        // If the root fs is not known, just add up the total of all known partitions
        match fs {
            Some(fs) => (fs.total_space(), fs.available_space()),
            None => {
                // If we can't find a known partition, just add them all up
                disks.iter().fold((0, 0), |mut current_sizes, disk| {
                    current_sizes.0 += disk.total_space();
                    current_sizes.1 += disk.available_space();
                    current_sizes
                })
            }
        }
    };

    // Attempt to get the clock speed from the name of the CPU
    let cpu_frequency_from_name = cpus.iter().next().and_then(|cpu| {
        cpu.brand()
            .split_once("GHz")
            .and_then(|(result, _)| result.trim().rsplit_once(' '))
            .and_then(|(_, result)| result.parse::<f32>().ok())
    });

    let global_cpu_frequency = match cpu_frequency_from_name {
        Some(freq) => freq,
        None => {
            // Get the frequency from average measured frequencies
            let global_cpu_frequency: f32 =
                cpus.iter().map(|cpu| cpu.frequency()).sum::<u64>() as f32 / cpus.len() as f32;
            // Shift to ghz to 1dp
            (global_cpu_frequency / 100.0).round() / 10.0
        }
    };

    SystemHealth {
        total_memory: sysinfo.total_memory(),
        free_memory: sysinfo.free_memory(),
        used_memory: sysinfo.used_memory(),
        sys_loadavg_1: loadavg.one,
        sys_loadavg_5: loadavg.five,
        sys_loadavg_15: loadavg.fifteen,
        cpu_cores: sysinfo.physical_core_count().unwrap_or(0),
        cpu_threads: cpus.len(),
        global_cpu_frequency,
        disk_bytes_total,
        disk_bytes_free,
        system_uptime,
        app_uptime,
        system_name: sysinfo.name().unwrap_or_else(|| String::from("")),
        kernel_version: sysinfo.kernel_version().unwrap_or_else(|| "".into()),
        os_version: sysinfo.long_os_version().unwrap_or_else(|| "".into()),
        host_name: sysinfo.host_name().unwrap_or_else(|| "".into()),
    }
}

/// Observes the Validator client system health.
pub fn observe_system_health_vc(
    sysinfo: Arc<RwLock<System>>,
    data_dir: PathBuf,
    app_uptime: u64,
) -> SystemHealthVC {
    SystemHealthVC {
        system_health: observe_system_health(sysinfo, data_dir, app_uptime),
    }
}

/// The current state of Lighthouse NAT/connectivity.
#[derive(Serialize, Deserialize)]
pub struct NatState {
    /// Contactable on discovery ipv4.
    discv5_ipv4: bool,
    /// Contactable on discovery ipv6.
    discv5_ipv6: bool,
    /// Contactable on libp2p ipv4.
    libp2p_ipv4: bool,
    /// Contactable on libp2p ipv6.
    libp2p_ipv6: bool,
}

impl NatState {
    pub fn is_anything_open(&self) -> bool {
        self.discv5_ipv4 || self.discv5_ipv6 || self.libp2p_ipv4 || self.libp2p_ipv6
    }
}

/// Observes if NAT traversal is possible.
pub fn observe_nat() -> NatState {
    let discv5_ipv4 = lighthouse_network::metrics::get_int_gauge(
        &lighthouse_network::metrics::NAT_OPEN,
        &["discv5_ipv4"],
    )
    .map(|g| g.get() == 1)
    .unwrap_or_default();

    let discv5_ipv6 = lighthouse_network::metrics::get_int_gauge(
        &lighthouse_network::metrics::NAT_OPEN,
        &["discv5_ipv6"],
    )
    .map(|g| g.get() == 1)
    .unwrap_or_default();

    let libp2p_ipv4 = lighthouse_network::metrics::get_int_gauge(
        &lighthouse_network::metrics::NAT_OPEN,
        &["libp2p_ipv4"],
    )
    .map(|g| g.get() == 1)
    .unwrap_or_default();

    let libp2p_ipv6 = lighthouse_network::metrics::get_int_gauge(
        &lighthouse_network::metrics::NAT_OPEN,
        &["libp2p_ipv6"],
    )
    .map(|g| g.get() == 1)
    .unwrap_or_default();

    NatState {
        discv5_ipv4,
        discv5_ipv6,
        libp2p_ipv4,
        libp2p_ipv6,
    }
}

/// Observes the Beacon Node system health.
pub fn observe_system_health_bn<E: EthSpec>(
    sysinfo: Arc<RwLock<System>>,
    data_dir: PathBuf,
    app_uptime: u64,
    network_globals: Arc<NetworkGlobals<E>>,
) -> SystemHealthBN {
    let system_health = observe_system_health(sysinfo.clone(), data_dir, app_uptime);

    // Find the network with the most traffic and assume this is the main network
    let sysinfo = sysinfo.read();
    let networks = sysinfo.networks();
    let (network_name, network_bytes_total_received, network_bytes_total_transmit) = networks
        .iter()
        .max_by_key(|(_name, network)| network.total_received())
        .map(|(name, network)| {
            (
                name.clone(),
                network.total_received(),
                network.total_transmitted(),
            )
        })
        .unwrap_or_else(|| (String::from("None"), 0, 0));

    // Determine if the NAT is open or not.
    let nat_open = observe_nat().is_anything_open();

    SystemHealthBN {
        system_health,
        network_name,
        network_bytes_total_received,
        network_bytes_total_transmit,
        nat_open,
        connected_peers: network_globals.connected_peers(),
        sync_state: network_globals.sync_state(),
    }
}