//! Custom error type for `peach-stats`.

use probes::ProbeError;
use std::{error, fmt, io::Error as IoError, str::Utf8Error};

/// Custom error type encapsulating all possible errors when retrieving system
/// statistics.
#[derive(Debug)]
pub enum StatsError {
    /// Failed to retrieve CPU statistics.
    CpuStat(ProbeError),
    /// Failed to retrieve disk usage statistics.
    DiskUsage(ProbeError),
    /// Failed to retrieve load average statistics.
    LoadAvg(ProbeError),
    /// Failed to retrieve memory usage statistics.
    MemStat(ProbeError),
    /// Failed to retrieve system uptime.
    Uptime(IoError),
    /// Systemctl command returned an error.
    Systemctl(IoError),
    /// Failed to interpret sequence of `u8` as a string.
    Utf8String(Utf8Error),
}

impl error::Error for StatsError {}

impl fmt::Display for StatsError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            StatsError::CpuStat(ref source) => {
                write!(f, "Failed to retrieve CPU statistics: {}", source)
            }
            StatsError::DiskUsage(ref source) => {
                write!(f, "Failed to retrieve disk usage statistics: {}", source)
            }
            StatsError::LoadAvg(ref source) => {
                write!(f, "Failed to retrieve load average statistics: {}", source)
            }
            StatsError::MemStat(ref source) => {
                write!(f, "Failed to retrieve memory statistics: {}", source)
            }
            StatsError::Uptime(ref source) => {
                write!(f, "Failed to retrieve system uptime: {}", source)
            }
            StatsError::Systemctl(ref source) => {
                write!(f, "Systemctl command returned an error: {}", source)
            }
            StatsError::Utf8String(ref source) => {
                write!(f, "Failed to convert stdout to string: {}", source)
            }
        }
    }
}