extern crate log;
extern crate rustyline;

use log::{Level, LevelFilter, Metadata, Record, SetLoggerError};
use std::borrow::Cow::{self, Borrowed, Owned};

use rustyline::completion::{Completer, FilenameCompleter, Pair};
use rustyline::error::ReadlineError;
use rustyline::highlight::Highlighter;
use rustyline::hint::Hinter;
use rustyline::{Cmd, CompletionType, Config, EditMode, Editor, Helper, KeyPress};

static COLORED_PROMPT: &'static str = "\x1b[1;32m>>\x1b[0m ";

static PROMPT: &'static str = ">> ";

struct MyHelper(FilenameCompleter);

impl Completer for MyHelper {
    type Candidate = Pair;

    fn complete(&self, line: &str, pos: usize) -> Result<(usize, Vec<Pair>), ReadlineError> {
        self.0.complete(line, pos)
    }
}

impl Hinter for MyHelper {
    fn hint(&self, line: &str, _pos: usize) -> Option<String> {
        if line == "hello" {
            Some(" World".to_owned())
        } else {
            None
        }
    }
}

impl Highlighter for MyHelper {
    fn highlight_prompt<'p>(&self, _: &str) -> Cow<'static, str> {
        Borrowed(COLORED_PROMPT)
    }

    fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
        Owned("\x1b[1m".to_owned() + hint + "\x1b[m")
    }
}

impl Helper for MyHelper {}

fn main() {
    init_logger().is_ok();
    let config = Config::builder()
        .history_ignore_space(true)
        .completion_type(CompletionType::List)
        .edit_mode(EditMode::Emacs)
        .build();
    let h = MyHelper(FilenameCompleter::new());
    let mut rl = Editor::with_config(config);
    rl.set_helper(Some(h));
    rl.bind_sequence(KeyPress::Meta('N'), Cmd::HistorySearchForward);
    rl.bind_sequence(KeyPress::Meta('P'), Cmd::HistorySearchBackward);
    if rl.load_history("history.txt").is_err() {
        println!("No previous history.");
    }
    loop {
        let readline = rl.readline(PROMPT);
        match readline {
            Ok(line) => {
                rl.add_history_entry(line.as_ref());
                println!("Line: {}", line);
            }
            Err(ReadlineError::Interrupted) => {
                println!("CTRL-C");
                break;
            }
            Err(ReadlineError::Eof) => {
                println!("CTRL-D");
                break;
            }
            Err(err) => {
                println!("Error: {:?}", err);
                break;
            }
        }
    }
    rl.save_history("history.txt").unwrap();
}

static LOGGER: Logger = Logger;
struct Logger;

impl log::Log for Logger {
    fn enabled(&self, metadata: &Metadata) -> bool {
        metadata.level() <= Level::Debug
    }

    fn log(&self, record: &Record) {
        if self.enabled(record.metadata()) {
            eprintln!("{} - {}", record.level(), record.args());
        }
    }

    fn flush(&self) {}
}

fn init_logger() -> Result<(), SetLoggerError> {
    try!(log::set_logger(&LOGGER));
    log::set_max_level(LevelFilter::Info);
    Ok(())
}