/*
    Rust Arch Linux Updater
    Copyright (C) 2024 Luke Harding <luke@lukeh990.io>
    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/>.
*/

/*
    pacman_api.rs
    This module provides an api to make working with Pacman much easier.
*/

use std::{error, fmt};
use std::fmt::Formatter;
use std::path::Path;

use crate::shell_commands;

#[derive(Debug, Clone)]
pub enum PacmanError {
    InsufficientPrivilege,
    NotInstalled,
    Other(String),
}

impl fmt::Display for PacmanError {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        let output = match self {
            PacmanError::InsufficientPrivilege => "Failed to run pacman. Maybe try sudo?",
            PacmanError::NotInstalled => "Unable to find pacman. Is this system arch based?",
            PacmanError::Other(msg) => msg,
        };

        write!(f, "{}", output)
    }
}

impl error::Error for PacmanError {}

pub fn check() -> Result<(), PacmanError> {
    let out = match shell_commands::execute_quiet("which", ["pacman"]) {
        Ok(out) => out,
        Err(e) => return Err(PacmanError::Other(e.to_string())),
    };

    let path = if out.status.success() {
        let mut stdout = out.stdout;
        stdout.pop(); // Remove \n from stdout

        match String::from_utf8(stdout) {
            Ok(result) => result,
            Err(e) => return Err(PacmanError::Other(e.to_string())),
        }
    } else {
        String::from("/usr/bin/pacman")
    };

    let path = Path::new(&path);

    if !path.exists() {
        return Err(PacmanError::NotInstalled);
    }

    Ok(())
}

pub fn update_all() -> Result<(), PacmanError> {
    if let Err(e) = shell_commands::execute_in_sh("sudo pacman -Syu") {
        return Err(PacmanError::Other(e.to_string()));
    }

    Ok(())
}