use clap::{Arg, ArgMatches, App, SubCommand};

use tag::Tag;

/// Generates a clap::SubCommand to be integrated in the commandline-ui builder for building a
/// "tags --add foo --remove bar" subcommand to do tagging action.
pub fn tag_subcommand<'a, 'b>() -> App<'a, 'b> {
    SubCommand::with_name("tags")
        .author("Matthias Beyer <mail@beyermatthias.de>")
        .version("0.1")
        .about("Add or remove tags")

        .arg(Arg::with_name("add-tags")
             .short("a")
             .long("add")
             .takes_value(true)
             .multiple(true)
             .help("Add tags, seperated by comma or by specifying multiple times"))

        .arg(Arg::with_name("remove-tags")
             .short("r")
             .long("remove")
             .takes_value(true)
             .multiple(true)
             .help("Remove tags, seperated by comma or by specifying multiple times"))
}

/// Generates a clap::Arg which can be integrated into the commandline-ui builder for building a
/// "-t" or "--tags" argument which takes values for tagging actions (add, remove)
pub fn tag_argument<'a, 'b>() -> Arg<'a, 'b> {
    Arg::with_name("specify-tags")
        .short("t")
        .long("tags")
        .takes_value(true)
        .multiple(true)
        .help("Add or remove tags, prefixed by '+' (for adding) or '-' (for removing)")
}

/// Get the tags which should be added from the commandline
///
/// Returns none if the argument was not specified
pub fn get_add_tags(matches: &ArgMatches) -> Option<Vec<Tag>> {
    extract_tags(matches, "add-tags", '+')
}

/// Get the tags which should be removed from the commandline
///
/// Returns none if the argument was not specified
pub fn get_remove_tags(matches: &ArgMatches) -> Option<Vec<Tag>> {
    extract_tags(matches, "remove-tags", '-')
}

fn extract_tags(matches: &ArgMatches, specifier: &str, specchar: char) -> Option<Vec<Tag>> {
    if let Some(submatch) = matches.subcommand_matches("tags") {
        submatch.values_of(specifier)
            .map(|values| values.map(String::from).collect())
    } else {
        matches.values_of("specify-tags")
            .map(|argmatches| {
                argmatches
                    .map(String::from)
                    .filter(|s| s.chars().next() == Some(specchar))
                    .map(|s| {
                        String::from(s.split_at(1).1)
                    })
                    .collect()
            })
    }
}