use super::Cmd;
use base64::{decode, encode};
use clap::{value_parser, Arg, ArgAction, ArgMatches, Command};
use std::{
    error::Error,
    fs,
    io::{self, Read},
};

#[derive(Debug)]
pub struct Base64 {
    name: &'static str,
    path: Option<crate::Path>,
}

pub const BASE_64: Base64 = Base64 {
    name: "base64",
    path: Some(crate::Path::UsrBin),
};

impl Cmd for Base64 {
    fn name(&self) -> &str {
        self.name
    }

    fn cli(&self) -> Command {
        Command::new("base64")
            .author("Nathan Fisher")
            .about("Base64 encode/decode data and print to standard output")
            .args([
                Arg::new("INPUT")
                    .help("The input file to use")
                    .num_args(0..),
                Arg::new("DECODE")
                    .help("Decode rather than encode")
                    .short('d')
                    .long("decode")
                    .action(ArgAction::SetTrue),
                Arg::new("IGNORE")
                    .help("Ignore whitespace when decoding")
                    .short('i')
                    .long("ignore-space")
                    .action(ArgAction::SetTrue),
                Arg::new("WRAP")
                    .help("Wrap encoded lines after n characters")
                    .short('w')
                    .long("wrap")
                    .default_value("76")
                    .value_parser(value_parser!(usize)),
                Arg::new("VERBOSE")
                    .help("Display a header naming each file")
                    .short('v')
                    .long("verbose")
                    .action(ArgAction::SetTrue),
                Arg::new("QUIET")
                    .help("Do not display header, even with multiple files")
                    .short('q')
                    .long("quiet")
                    .action(ArgAction::SetTrue),
            ])
    }

    fn run(&self, matches: Option<&ArgMatches>) -> Result<(), Box<dyn Error>> {
        let Some(matches) = matches else {
            return Err(Box::new(io::Error::new(io::ErrorKind::Other, "No input")));
        };
        let files: Vec<_> = match matches.get_many::<String>("INPUT") {
            Some(c) => c.map(|x| x.clone()).collect(),
            None => vec![String::from("-")],
        };
        let len = files.len();
        for (index, file) in files.into_iter().enumerate() {
            if { len > 1 || matches.get_flag("VERBOSE") } && !matches.get_flag("QUIET") {
                match index {
                    0 => println!("===> {file} <==="),
                    _ => println!("\n===> {file} <==="),
                };
            } else if index > 0 {
                println!();
            }
            let contents = get_contents(&file)?;
            if matches.get_flag("DECODE") {
                decode_base64(contents, matches.get_flag("IGNORE"))?;
            } else {
                encode_base64(
                    &contents,
                    match matches.get_one("WRAP") {
                        Some(c) => *c,
                        None => 76,
                    },
                );
            }
        }
        Ok(())
    }

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

fn decode_base64(mut contents: String, ignore: bool) -> Result<(), Box<dyn Error>> {
    if ignore {
        contents.retain(|c| !c.is_whitespace());
    } else {
        contents = contents.replace('\n', "");
    }
    let decoded = decode(&contents)?.to_vec();
    let output = String::from_utf8(decoded)?;
    println!("{}", output.trim_end());
    Ok(())
}

fn encode_base64(contents: &str, wrap: usize) {
    let encoded = encode(contents.as_bytes())
        .chars()
        .collect::<Vec<char>>()
        .chunks(wrap)
        .map(|c| c.iter().collect::<String>())
        .collect::<Vec<String>>();
    for line in &encoded {
        println!("{line}");
    }
}

fn get_contents(file: &str) -> Result<String, Box<dyn Error>> {
    let mut contents = String::new();
    if file == "-" {
        io::stdin().read_to_string(&mut contents)?;
    } else {
        contents = fs::read_to_string(file)?;
    }
    Ok(contents)
}