use std::{fs::metadata, path::PathBuf, str::FromStr};

use crate::error::ShellError;

use super::{Builtin, BuiltinConfig};

pub struct Ls;

impl Builtin for Ls {
    fn execute(&mut self, _: &mut BuiltinConfig, _: Vec<String>) -> Result<(), ShellError> {
        let dir = std::env::current_dir().unwrap_or(PathBuf::from_str("/").unwrap());
        let entries = match std::fs::read_dir(dir) {
            Ok(e) => e,
            Err(e) => return Err(ShellError::ExecuteFailure(e.to_string())),
        };
        //for entry in entries.by_ref().into_iter() {}

        for entry in entries {
            let Ok(entry) = entry else {
                eprintln!("Couldn't get directory entry");
                continue;
            };
            let metadata = match metadata(entry.path()) {
                Ok(m) => m,
                Err(_) => {
                    continue;
                }
            };

            let file_name = entry.file_name().to_string_lossy().to_string();
            let mut file_type = "unknown";
            if metadata.file_type().is_dir() {
                file_type = "dir"
            } else if metadata.file_type().is_file() {
                file_type = "file"
            } else if metadata.file_type().is_symlink() {
                file_type = "link"
            }
            println!("{}", format_line(20, &file_name, file_type, metadata.len()));
        }
        Ok(())
    }
}

fn format_filesize(filesize: u64) -> String {
    if filesize > 9_999 && filesize <= 999_999 {
        return format!("{}KB", filesize / 1_000);
    } else if filesize > 999_999 && filesize <= 999_999_999 {
        return format!("{}MB", filesize / 1_000_000);
    } else if filesize > 999_999_999 {
        return format!("{}MB", filesize / 1_000_000_000);
    } else {
        format!("{}B", filesize)
    }
}

fn format_line(max_name_len: usize, file_name: &str, file_type: &str, file_size: u64) -> String {
    format!(
        "{} | {:4} | {:6}",
        right_padding(file_name, max_name_len),
        file_type,
        format_filesize(file_size),
    )
}

fn right_padding(s: &str, max: usize) -> String {
    let mut tmp = String::from_str(s).unwrap();
    for _ in tmp.len()..max {
        tmp.push(' ');
    }
    tmp
}