use crate::Cmd;
use clap::{Arg, ArgAction, ArgMatches, Command, ValueHint};
use std::{fs, path::PathBuf};

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

impl Cmd for Readlink {
    fn cli(&self) -> clap::Command {
        Command::new("readlink")
            .about("Print symbolic link target or canonical file name")
            .version(env!("CARGO_PKG_VERSION"))
            .author("Nathan Fisher")
            .args([
                Arg::new("path")
                    .value_name("PATH")
                    .value_hint(ValueHint::AnyPath)
                    .num_args(1..)
                    .required(true),
                Arg::new("canon")
                    .help("Canonicalize path")
                    .short('f')
                    .visible_short_alias('c')
                    .long("canonicalize")
                    .action(ArgAction::SetTrue),
                Arg::new("newline")
                    .help("Do not print the terminating newline.")
                    .short('n')
                    .long("no-newline")
                    .action(ArgAction::SetTrue),
            ])
    }

    fn run(&self, matches: &ArgMatches) -> Result<(), Box<dyn std::error::Error>> {
        if let Some(paths) = matches.get_many::<String>("path") {
            let paths: Vec<_> = paths.collect();
            let len = paths.len();
            if matches.get_flag("newline") && len > 1 {
                eprintln!("readlink: ignoring --no-newline with multiple arguments");
            }
            for p in paths {
                let path = if matches.get_flag("canon") {
                    PathBuf::from(p).canonicalize()?
                } else {
                    fs::read_link(p)?
                };
                print!("{}", path.display());
                if !matches.get_flag("newline") || len > 1 {
                    println!();
                }
            }
        }
        Ok(())
    }

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