//
// Sysinfo
//
// Copyright (c) 2019 Guillaume Gomez
//

use std::fs::File;
use std::io::Read;
use std::path::Path;

use crate::{NetworkExt, NetworksExt, NetworksIter};
use std::collections::HashMap;

/// Network interfaces.
///
/// ```no_run
/// use sysinfo::{NetworksExt, System, SystemExt};
///
/// let s = System::new_all();
/// let networks = s.get_networks();
/// ```
pub struct Networks {
    interfaces: HashMap<String, NetworkData>,
}

macro_rules! old_and_new {
    ($ty_:expr, $name:ident, $old:ident) => {{
        $ty_.$old = $ty_.$name;
        $ty_.$name = $name;
    }};
    ($ty_:expr, $name:ident, $old:ident, $path:expr) => {{
        let _tmp = $path;
        $ty_.$old = $ty_.$name;
        $ty_.$name = _tmp;
    }};
}

fn read<P: AsRef<Path>>(parent: P, path: &str, data: &mut Vec<u8>) -> u64 {
    if let Ok(mut f) = File::open(parent.as_ref().join(path)) {
        if let Ok(size) = f.read(data) {
            let mut i = 0;
            let mut ret = 0;

            while i < size && i < data.len() && data[i] >= b'0' && data[i] <= b'9' {
                ret *= 10;
                ret += (data[i] - b'0') as u64;
                i += 1;
            }
            return ret;
        }
    }
    0
}

impl Networks {
    pub(crate) fn new() -> Self {
        Networks {
            interfaces: HashMap::new(),
        }
    }
}

impl NetworksExt for Networks {
    fn iter(&self) -> NetworksIter {
        NetworksIter::new(self.interfaces.iter())
    }

    fn refresh(&mut self) {
        let mut v = vec![0; 30];

        for (interface_name, data) in self.interfaces.iter_mut() {
            data.update(interface_name, &mut v);
        }
    }

    fn refresh_networks_list(&mut self) {
        if let Ok(dir) = std::fs::read_dir("/sys/class/net/") {
            let mut data = vec![0; 30];
            for entry in dir.flatten() {
                let parent = &entry.path().join("statistics");
                let entry = match entry.file_name().into_string() {
                    Ok(entry) => entry,
                    Err(_) => continue,
                };
                let rx_bytes = read(parent, "rx_bytes", &mut data);
                let tx_bytes = read(parent, "tx_bytes", &mut data);
                let rx_packets = read(parent, "rx_packets", &mut data);
                let tx_packets = read(parent, "tx_packets", &mut data);
                let rx_errors = read(parent, "rx_errors", &mut data);
                let tx_errors = read(parent, "tx_errors", &mut data);
                // let rx_compressed = read(parent, "rx_compressed", &mut data);
                // let tx_compressed = read(parent, "tx_compressed", &mut data);
                let interface = self.interfaces.entry(entry).or_insert_with(|| NetworkData {
                    rx_bytes,
                    old_rx_bytes: rx_bytes,
                    tx_bytes,
                    old_tx_bytes: tx_bytes,
                    rx_packets,
                    old_rx_packets: rx_packets,
                    tx_packets,
                    old_tx_packets: tx_packets,
                    rx_errors,
                    old_rx_errors: rx_errors,
                    tx_errors,
                    old_tx_errors: tx_errors,
                    // rx_compressed,
                    // old_rx_compressed: rx_compressed,
                    // tx_compressed,
                    // old_tx_compressed: tx_compressed,
                });
                old_and_new!(interface, rx_bytes, old_rx_bytes);
                old_and_new!(interface, tx_bytes, old_tx_bytes);
                old_and_new!(interface, rx_packets, old_rx_packets);
                old_and_new!(interface, tx_packets, old_tx_packets);
                old_and_new!(interface, rx_errors, old_rx_errors);
                old_and_new!(interface, tx_errors, old_tx_errors);
                // old_and_new!(interface, rx_compressed, old_rx_compressed);
                // old_and_new!(interface, tx_compressed, old_tx_compressed);
            }
        }
    }
}

/// Contains network information.
pub struct NetworkData {
    /// Total number of bytes received over interface.
    rx_bytes: u64,
    old_rx_bytes: u64,
    /// Total number of bytes transmitted over interface.
    tx_bytes: u64,
    old_tx_bytes: u64,
    /// Total number of packets received.
    rx_packets: u64,
    old_rx_packets: u64,
    /// Total number of packets transmitted.
    tx_packets: u64,
    old_tx_packets: u64,
    /// Shows the total number of packets received with error. This includes
    /// too-long-frames errors, ring-buffer overflow errors, CRC errors,
    /// frame alignment errors, fifo overruns, and missed packets.
    rx_errors: u64,
    old_rx_errors: u64,
    /// similar to `rx_errors`
    tx_errors: u64,
    old_tx_errors: u64,
    // /// Indicates the number of compressed packets received by this
    // /// network device. This value might only be relevant for interfaces
    // /// that support packet compression (e.g: PPP).
    // rx_compressed: usize,
    // old_rx_compressed: usize,
    // /// Indicates the number of transmitted compressed packets. Note
    // /// this might only be relevant for devices that support
    // /// compression (e.g: PPP).
    // tx_compressed: usize,
    // old_tx_compressed: usize,
}

impl NetworkData {
    fn update(&mut self, path: &str, data: &mut Vec<u8>) {
        let path = &Path::new("/sys/class/net/").join(path).join("statistics");
        old_and_new!(self, rx_bytes, old_rx_bytes, read(path, "rx_bytes", data));
        old_and_new!(self, tx_bytes, old_tx_bytes, read(path, "tx_bytes", data));
        old_and_new!(
            self,
            rx_packets,
            old_rx_packets,
            read(path, "rx_packets", data)
        );
        old_and_new!(
            self,
            tx_packets,
            old_tx_packets,
            read(path, "tx_packets", data)
        );
        old_and_new!(
            self,
            rx_errors,
            old_rx_errors,
            read(path, "rx_errors", data)
        );
        old_and_new!(
            self,
            tx_errors,
            old_tx_errors,
            read(path, "tx_errors", data)
        );
        // old_and_new!(
        //     self,
        //     rx_compressed,
        //     old_rx_compressed,
        //     read(path, "rx_compressed", data)
        // );
        // old_and_new!(
        //     self,
        //     tx_compressed,
        //     old_tx_compressed,
        //     read(path, "tx_compressed", data)
        // );
    }
}

impl NetworkExt for NetworkData {
    fn get_received(&self) -> u64 {
        self.rx_bytes.saturating_sub(self.old_rx_bytes)
    }

    fn get_total_received(&self) -> u64 {
        self.rx_bytes
    }

    fn get_transmitted(&self) -> u64 {
        self.tx_bytes.saturating_sub(self.old_tx_bytes)
    }

    fn get_total_transmitted(&self) -> u64 {
        self.tx_bytes
    }

    fn get_packets_received(&self) -> u64 {
        self.rx_packets.saturating_sub(self.old_rx_packets)
    }

    fn get_total_packets_received(&self) -> u64 {
        self.rx_packets
    }

    fn get_packets_transmitted(&self) -> u64 {
        self.tx_packets.saturating_sub(self.old_tx_packets)
    }

    fn get_total_packets_transmitted(&self) -> u64 {
        self.tx_packets
    }

    fn get_errors_on_received(&self) -> u64 {
        self.rx_errors.saturating_sub(self.old_rx_errors)
    }

    fn get_total_errors_on_received(&self) -> u64 {
        self.rx_errors
    }

    fn get_errors_on_transmitted(&self) -> u64 {
        self.tx_errors.saturating_sub(self.old_tx_errors)
    }

    fn get_total_errors_on_transmitted(&self) -> u64 {
        self.tx_errors
    }
}