use crate::cmd;
use clap::{value_parser, Arg, ArgAction, ArgMatches, Command};
use clap_complete::{generate_to, shells, Generator};
use clap_complete_nushell::Nushell;
use clap_mangen::Man;
use std::{
    fs, io,
    path::{Path, PathBuf},
    process,
};

const COMMANDS: [fn() -> clap::Command; 8] = [
    cmd::bootstrap::cli,
    cmd::echo::cli,
    cmd::r#false::cli,
    cmd::head::cli,
    cmd::hostname::cli,
    cmd::r#true::cli,
    cmd::sleep::cli,
    crate::cli::cli,
];

#[must_use]
pub fn cli() -> Command {
    Command::new("bootstrap")
        .version(env!("CARGO_PKG_VERSION"))
        .author("Nathan Fisher")
        .about("Install shitbox into the filesystem")
        .long_about("Install symlinks, manpages and shell completions")
        .args([
            Arg::new("prefix")
                .help("The directory path under which to install")
                .short('p')
                .long("prefix")
                .num_args(1)
                .default_value("/")
                .required(false),
            Arg::new("usr")
                .help("Use /usr")
                .long_help(
                    "Split the installation so that some applets go into /bin | /sbin\n\
                    while others are placed into /usr/bin | /usr/sbin",
                )
                .short('u')
                .long("usr")
                .default_value("true")
                .value_parser(value_parser!(bool)),
        ])
        .subcommands([
            Command::new("all").about("Install everything"),
            Command::new("links")
                .about("Install links for each applet")
                .arg(
                    Arg::new("soft")
                        .help("Install soft links instead of hardlinks")
                        .short('s')
                        .long("soft"),
                ),
            Command::new("manpages")
                .about("Install Unix man pages")
                .alias("man"),
            Command::new("completions")
                .about("Install shell completions")
                .alias("comp")
                .args([
                    Arg::new("all")
                        .help("Install completions for all supported shells")
                        .short('a')
                        .long("all")
                        .action(ArgAction::SetTrue),
                    Arg::new("bash")
                        .help("Bash shell completions")
                        .short('b')
                        .long("bash")
                        .action(ArgAction::SetTrue),
                    Arg::new("fish")
                        .help("Fish shell completions")
                        .short('f')
                        .long("fish")
                        .action(ArgAction::SetTrue),
                    Arg::new("nu")
                        .help("Nushell completions")
                        .short('n')
                        .long("nu")
                        .action(ArgAction::SetTrue),
                    Arg::new("pwsh")
                        .help("PowerShell completions")
                        .short('p')
                        .long("pwsh")
                        .action(ArgAction::SetTrue),
                ]),
        ])
}

fn manpage(prefix: &str, f: &dyn Fn() -> Command) -> Result<(), io::Error> {
    let cmd = f();
    let fname = match cmd.get_name() {
        "bootstrap" => "shitbox-bootstrap.1".to_string(),
        s => format!("{s}.1"),
    };
    let outdir: PathBuf = [prefix, "usr", "share", "man", "man1"].iter().collect();
    if !outdir.exists() {
        fs::create_dir_all(&outdir)?;
    }
    let mut outfile = outdir;
    outfile.push(fname);
    let man = Man::new(cmd);
    let mut buffer: Vec<u8> = vec![];
    man.render(&mut buffer)?;
    fs::write(&outfile, buffer)?;
    println!("    {}", outfile.display());
    Ok(())
}

fn manpages(prefix: &str) -> Result<(), io::Error> {
    println!("Generating Unix man pages:");
    COMMANDS.iter().try_for_each(|cmd| manpage(prefix, &cmd))?;
    Ok(())
}

fn generate_completions(
    outdir: &Path,
    f: &dyn Fn() -> Command,
    gen: impl Generator,
) -> Result<(), io::Error> {
    let cmd = f();
    let name = cmd.get_name();
    let mut cmd = cmd.clone();
    if !outdir.exists() {
        fs::create_dir_all(&outdir)?;
    }
    let path = generate_to(gen, &mut cmd, name, outdir)?;
    println!("    {}", path.display());
    Ok(())
}

fn completions(prefix: &str, matches: &ArgMatches) -> Result<(), io::Error> {
    println!("Generating completions:");
    if matches.get_flag("bash") || matches.get_flag("all") {
        let outdir: PathBuf = [prefix, "share", "bash-completion", "completion"]
            .iter()
            .collect();
        COMMANDS
            .iter()
            .try_for_each(|cmd| generate_completions(&outdir, &cmd, shells::Bash))?;
    }
    if matches.get_flag("fish") || matches.get_flag("all") {
        let outdir: PathBuf = [prefix, "share", "fish", "completions"].iter().collect();
        COMMANDS
            .iter()
            .try_for_each(|cmd| generate_completions(&outdir, &cmd, shells::Fish))?;
    }
    if matches.get_flag("nu") || matches.get_flag("all") {
        let outdir: PathBuf = [prefix, "share", "nu", "completions"].iter().collect();
        COMMANDS
            .iter()
            .try_for_each(|cmd| generate_completions(&outdir, &cmd, Nushell))?;
    }
    if matches.get_flag("pwsh") || matches.get_flag("all") {
        let outdir: PathBuf = [prefix, "share", "pwsh", "completions"].iter().collect();
        COMMANDS
            .iter()
            .try_for_each(|cmd| generate_completions(&outdir, &cmd, shells::PowerShell))?;
    }
    if matches.get_flag("zsh") || matches.get_flag("all") {
        let outdir: PathBuf = [prefix, "share", "zsh", "site-functions"].iter().collect();
        COMMANDS
            .iter()
            .try_for_each(|cmd| generate_completions(&outdir, &cmd, shells::Zsh))?;
    }
    Ok(())
}

pub fn run(matches: &ArgMatches) {
    if let Some(prefix) = matches.get_one::<String>("prefix") {
        match matches.subcommand() {
            Some(("manpages", _matches)) => {
                if let Err(e) = manpages(prefix) {
                    eprintln!("{e}");
                    process::exit(1);
                }
            }
            Some(("completions", matches)) => {
                if let Err(e) = completions(prefix, matches) {
                    eprintln!("{e}");
                    process::exit(1);
                }
            }
            Some(("all", _matches)) => {
                if let Err(e) = manpages(prefix) {
                    eprintln!("{e}");
                    process::exit(1);
                }
            }
            _ => {}
        }
    }
}