// Gather and display system information
// Copyright (C) 2021 Lucien Cartier-Tilet <lucien@phundrak.com>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

use serde::Serialize;
use sysinfo::{DiskExt, System, SystemExt};

#[derive(Debug, Serialize)]
pub struct Memory {
    pub name: String,
    pub size: u64,
    pub available: u64,
}

impl Memory {
    pub fn new(name: String, size: u64, available: u64) -> Self {
        Self {
            name,
            size,
            available,
        }
    }

    pub fn used(&self) -> u64 {
        self.size - self.available
    }

    pub fn percentage(&self) -> f32 {
        self.used() as f32 / self.size as f32
    }
}

#[derive(Debug, Serialize)]
pub struct Machine {
    pub os: String,
    pub kernel: String,
    pub hostname: String,
    pub uptime: u64,
    pub ram: Memory,
    pub swap: Memory,
    pub disks: Vec<Memory>,
}

impl Machine {
    pub fn new() -> Self {
        let mut sys = System::new_all();
        sys.refresh_all();
        let disks = sys
            .disks()
            .iter()
            .map(|x| {
                Memory::new(
                    x.mount_point().to_str().unwrap().to_string(),
                    x.total_space(),
                    x.available_space(),
                )
            })
            .collect::<Vec<Memory>>();
        // Size of RAM and Swap is returned in KB, unlike the drives’
        // size which is in byte
        let ram = Memory::new(
            "RAM".into(),
            sys.total_memory() * 1000,
            sys.available_memory() * 1000,
        );
        let swap = Memory::new(
            "Swap".into(),
            sys.total_swap() * 1000,
            sys.free_swap() * 1000,
        );
        Self {
            os: sys.name().unwrap(),
            kernel: sys.kernel_version().unwrap(),
            hostname: sys.host_name().unwrap(),
            uptime: sys.uptime(),
            ram,
            swap,
            disks,
        }
    }
}

impl Default for Machine {
    fn default() -> Self {
        Self::new()
    }
}