use super::Cmd;
use clap::{Arg, ArgAction, Command};
use std::{error::Error, ffi::CString, io};

#[derive(Debug, Default)]
pub struct Sync;

impl Cmd for Sync {
    fn cli(&self) -> clap::Command {
        Command::new("sync")
            .about("force completion of pending disk writes (flush cache)")
            .author("Nathan Fisher")
            .version(env!("CARGO_PKG_VERSION"))
            .args([
                Arg::new("data")
                    .short('d')
                    .long("data")
                    .help("sync only file data, no unneeded metadata")
                    .conflicts_with("fs")
                    .action(ArgAction::SetTrue),
                Arg::new("fs")
                    .short('f')
                    .long("file-system")
                    .help("sync the file systems that contain the files")
                    .action(ArgAction::SetTrue),
                Arg::new("FILE")
                    .help(
                        "If one or more files are specified, sync only them, or \
                        their containing file systems.",
                    )
                    .num_args(0..),
            ])
    }

    fn run(&self, matches: Option<&clap::ArgMatches>) -> Result<(), Box<dyn Error>> {
        let Some(matches) = matches else {
            return Err(Box::new(io::Error::new(io::ErrorKind::Other, "no input")));
        };
        if let Some(files) = matches.get_many::<String>("FILE") {
            for f in files {
                let file = CString::new(f.as_bytes())?;
                if matches.get_flag("data") {
                    let rc = unsafe {
                        let fd = libc::open(file.as_ptr(), libc::O_RDWR | libc::O_NOATIME);
                        libc::fdatasync(fd)
                    };
                    if rc != 0 {
                        return Err(Box::new(io::Error::last_os_error()));
                    }
                } else if matches.get_flag("fs") {
                    let rc = unsafe {
                        let fd = libc::open(file.as_ptr(), libc::O_RDWR | libc::O_NOATIME);
                        libc::syncfs(fd)
                    };
                    if rc != 0 {
                        return Err(Box::new(io::Error::last_os_error()));
                    }
                } else {
                    let rc = unsafe {
                        let fd = libc::open(file.as_ptr(), libc::O_RDWR | libc::O_NOATIME);
                        libc::fsync(fd)
                    };
                    if rc != 0 {
                        return Err(Box::new(io::Error::last_os_error()));
                    }
                }
            }
        } else {
            unsafe {
                libc::sync();
            }
        }
        Ok(())
    }

    fn path(&self) -> Option<crate::Path> {
        Some(crate::Path::Bin)
    }
}