extern crate cursive;
extern crate pretty_bytes;

use std::io;

use cursive::traits::{Boxable, With};
use cursive::utils;
use cursive::views::{Canvas, Dialog, LinearLayout, ProgressBar};
use cursive::Cursive;
use pretty_bytes::converter::convert;
use std::thread;
use std::time;

// This example is a visual version of the `pv` tool.

fn main() {
    let mut siv = Cursive::default();

    // We'll use this channel to signal the end of the transfer
    let cb_sink = siv.cb_sink().clone();

    // Use a counter to track progress
    let counter = utils::Counter::new(0);
    let counter_copy = counter.clone();
    let start = time::Instant::now();

    // If an argument is given, it is the file we'll read from.
    // Else, read from stdin.
    let (source, len) = match std::env::args().nth(1) {
        Some(source) => {
            let meta = std::fs::metadata(&source).unwrap();
            // If possible, read the file size to have a progress bar.
            let len = meta.len();
            (Some(source), if len > 0 { Some(len) } else { None })
        }
        None => (None, None),
    };

    // Start the copy in a separate thread
    thread::spawn(move || {
        // Copy to stdout - lock it for better performance.
        let stdout = io::stdout();
        let mut stdout = stdout.lock();

        match source {
            None => {
                // Copy from stdin - lock it for better performance.
                let stdin = io::stdin();
                let stdin = stdin.lock();
                let mut reader =
                    utils::ProgressReader::new(counter_copy, stdin);

                // And copy!
                io::copy(&mut reader, &mut stdout).unwrap();
            }
            Some(source) => {
                // Copy from stdin - lock it for better performance.
                let input = std::fs::File::open(source).unwrap();
                let mut reader =
                    utils::ProgressReader::new(counter_copy, input);

                // And copy!
                io::copy(&mut reader, &mut stdout).unwrap();
            }
        }

        // When we're done, shut down the application
        cb_sink.send(Box::new(|s: &mut Cursive| s.quit())).unwrap();
    });

    // Add a single view: progress status
    siv.add_layer(
        Dialog::new().title("Copying...").content(
            LinearLayout::vertical()
                .child(
                    Canvas::new(counter.clone())
                        .with_draw(move |c, printer| {
                            let ticks = c.get() as f64;
                            let now = time::Instant::now();
                            let duration = now - start;

                            let seconds = duration.as_secs() as f64
                                + duration.subsec_nanos() as f64 * 1e-9;

                            let speed = ticks / seconds;

                            // Print ETA if we have a file size
                            // Otherwise prints elapsed time.
                            if let Some(len) = len {
                                let remaining = (len as f64 - ticks) / speed;
                                printer.print(
                                    (0, 0),
                                    &format!(
                                        "ETA:     {:.1} seconds",
                                        remaining
                                    ),
                                );
                            } else {
                                printer.print(
                                    (0, 0),
                                    &format!(
                                        "Elapsed: {:.1} seconds",
                                        seconds
                                    ),
                                );
                            }
                            printer.print(
                                (0, 1),
                                &format!("Copied:  {}", convert(ticks)),
                            );
                            printer.print(
                                (0, 2),
                                &format!("Speed:   {}/s", convert(speed)),
                            );
                        })
                        .fixed_size((25, 3)),
                )
                .with(|l| {
                    // If we have a file length, add a progress bar
                    if let Some(len) = len {
                        l.add_child(
                            ProgressBar::new()
                                .max(len as usize)
                                .with_value(counter.clone()),
                        );
                    }
                }),
        ),
    );

    siv.set_fps(10);

    siv.run();
}