use super::Cmd;
use clap::{value_parser, Arg, ArgAction, Command};
use data_encoding::BASE32;
use std::{
    fs,
    io::{self, Read, Write},
    process,
};
use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};

#[derive(Debug)]
pub struct Base32 {
    name: &'static str,
    path: Option<crate::Path>,
}

pub const BASE_32: Base32 = Base32 {
    name: "base32",
    path: Some(crate::Path::UsrBin),
};

impl Cmd for Base32 {
    fn name(&self) -> &str {
        self.name
    }

    fn cli(&self) -> clap::Command {
        Command::new("base32")
            .author("Nathan Fisher")
            .about("Base32 encode/decode data and print to standard output")
            .args([
                Arg::new("INPUT")
                    .help("The input file to use")
                    .num_args(1..),
                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")
                    .value_parser(value_parser!(usize))
                    .default_value("76"),
                Arg::new("color")
                    .short('c')
                    .long("color")
                    .value_parser(["always", "ansi", "auto", "never"]),
                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<&clap::ArgMatches>) -> Result<(), Box<dyn std::error::Error>> {
        let Some(matches) = matches else {
            return Err(io::Error::new(io::ErrorKind::Other, "No input").into());
        };
        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();
        let color = match matches.get_one::<String>("color").map(|x| x.as_str()) {
            Some("always") => ColorChoice::Always,
            Some("ansi") => ColorChoice::AlwaysAnsi,
            Some("auto") => {
                if atty::is(atty::Stream::Stdout) {
                    ColorChoice::Auto
                } else {
                    ColorChoice::Never
                }
            }
            _ => ColorChoice::Never,
        };
        for (index, file) in files.into_iter().enumerate() {
            if { len > 1 || matches.get_flag("VERBOSE") } && !matches.get_flag("QUIET") {
                let mut stdout = StandardStream::stdout(color);
                stdout.set_color(ColorSpec::new().set_fg(Some(Color::Green)))?;
                match index {
                    0 => writeln!(stdout, "===> {file} <==="),
                    _ => writeln!(stdout, "\n===> {file} <==="),
                }?;
                stdout.reset()?;
            } else if index > 0 {
                println!();
            }
            let contents = get_contents(&file);
            if matches.get_flag("DECODE") {
                decode_base32(contents, matches.get_flag("IGNORE"));
            } else {
                encode_base32(
                    &contents,
                    match matches.get_one::<usize>("WRAP") {
                        Some(c) => *c,
                        None => {
                            return Err(io::Error::new(io::ErrorKind::Other, "Invalid wrap").into())
                        }
                    },
                );
            }
        }
        Ok(())
    }

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

fn decode_base32(mut contents: String, ignore: bool) {
    if ignore {
        contents.retain(|c| !c.is_whitespace());
    } else {
        contents = contents.replace('\n', "");
    }
    let decoded = match BASE32.decode(contents.as_bytes()) {
        Ok(c) => c,
        Err(e) => {
            eprintln!("base32: {e}");
            process::exit(1);
        }
    };
    let output = match String::from_utf8(decoded) {
        Ok(c) => c,
        Err(e) => {
            eprintln!("base32: {e}");
            process::exit(1);
        }
    };
    println!("{}", output.trim_end());
}

fn encode_base32(contents: &str, wrap: usize) {
    let encoded = BASE32
        .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) -> String {
    let mut contents = String::new();
    if file == "-" {
        match io::stdin().read_to_string(&mut contents) {
            Ok(_) => true,
            Err(e) => {
                eprintln!("base32: {e}");
                process::exit(1);
            }
        };
    } else {
        contents = match fs::read_to_string(file) {
            Ok(c) => c,
            Err(e) => {
                eprintln!("base32: {e}");
                process::exit(1);
            }
        };
    }
    contents
}