mod util;
mod command;
mod config;
mod api_types;
mod cache;

use crate::util::event::{Event, Events};
use crate::command::Command;
use crate::cache::Cache;
use std::{env, fs, error::Error, io};
use clap::{App as Clap, Arg, ArgMatches};
use termion::{event::Key, input::MouseTerminal, raw::IntoRawMode, screen::AlternateScreen};
use tui::{
    backend::TermionBackend,
    layout::{Constraint, Direction, Layout},
    style::{Color, Modifier, Style},
    text::{Span, Spans, Text},
    widgets::{Wrap, Block, Borders, Paragraph},
    Terminal,
};
use unicode_width::UnicodeWidthStr;

enum InputMode {
    Normal,
    Editing,
}

/// App holds the state of the application
struct App {
    /// Current value of the input box
    input: String,
    /// Current input mode
    input_mode: InputMode,
    /// History of recorded messages
    messages: Vec<Command>,
    cache: Cache
}

impl Default for App {
    fn default() -> App {
        App {
            input: String::new(),
            input_mode: InputMode::Normal,
            messages: Vec::new(),
            cache: Cache::default() // empty cache lad
        }
    }
}

fn get_args() -> ArgMatches<'static> {
    Clap::new("Freechat TUI")
        .version("v69.420")
        .author("Author: shockrah")
        .about("Description: A terminal based program for interacting with freechat servers")
        .arg(Arg::with_name("config")
            .short("c")
            .long("config")
            .value_name("CONFIG")
            .help("Specify path of config to use")
            .takes_value(true))
        .arg(Arg::with_name("no_login")
             .short("l")
             .long("no-login")
             .help("Don't automatically login on startup")).get_matches()
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // parameter things first
    let args = get_args();

    let (config_path, mut config): (String, config::Config) = if args.args.len() == 0 {
        let home = env::var("HOME").unwrap();
        let path = format!("{}/.config/freechat/config.json", home);
        match fs::read_to_string(&path) {
            Ok(data) => (path, serde_json::from_str(&data).unwrap()),
            Err(e) => panic!("Unable to parse config file @{} : {}", path, e)
        }
    } else{
        let path = args.value_of("config").unwrap();
        match fs::read_to_string(path) {
            Ok(data) => (path.into(), serde_json::from_str(&data).unwrap()),
            Err(e) => panic!("Unable to parse config @ {} : {}", path, e)
        }
    };

    // Terminal initialization
    let stdout = io::stdout().into_raw_mode()?;
    let stdout = MouseTerminal::from(stdout);
    let stdout = AlternateScreen::from(stdout);
    let backend = TermionBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    // Setup event handlers
    let mut events = Events::new();

    // Create default app state
    let mut app = App::default();

    loop {
        // Draw UI
        terminal.draw(|f| {
            let chunks = Layout::default()
                .direction(Direction::Vertical)
                .margin(2)
                .constraints(
                    [
                        Constraint::Length(1),
                        Constraint::Length(3),
                        Constraint::Min(1),
                    ]
                    .as_ref(),
                )
                .split(f.size());

            let (msg, style) = match app.input_mode {
                InputMode::Normal => (
                    vec![
                        Span::styled("I", Style::default().add_modifier(Modifier::BOLD)),
                        Span::raw(" for insert mode"),
                    ],
                    Style::default()
                ),
                InputMode::Editing => (
                    vec![
                        Span::raw("Keys: "),
                        Span::styled("Esc", Style::default().add_modifier(Modifier::BOLD)),
                        Span::styled(" Enter ", Style::default().add_modifier(Modifier::BOLD)),
                        Span::styled("/help", Style::default().add_modifier(Modifier::BOLD))
                    ],
                    Style::default(),
                ),
            };
            let mut text = Text::from(Spans::from(msg));
            text.patch_style(style);
            let help_message = Paragraph::new(text);
            f.render_widget(help_message, chunks[0]);

            let input = Paragraph::new(app.input.as_ref())
                .style(match app.input_mode {
                    InputMode::Normal => Style::default(),
                    InputMode::Editing => Style::default().fg(Color::Yellow),
                })
                .block(Block::default().borders(Borders::ALL));
            f.render_widget(input, chunks[1]);

            let mut lines: Vec<Spans> = Vec::new();
            for cmd in app.messages.iter() {
                &lines.push(cmd.styled());
            }

            let list = Paragraph::new(lines)
                .wrap(Wrap { trim: false })
                .block(Block::default()
                    .borders(Borders::ALL)
                    .title("Messages"));

            f.render_widget(list, chunks[2]);

            match app.input_mode {
                InputMode::Normal =>
                    // Hide the cursor. `Frame` does this by default, so we don't need to do anything here
                    {}

                InputMode::Editing => {
                    // Make the cursor visible and ask tui-rs to put it at the specified coordinates after rendering
                    f.set_cursor(
                        // Put cursor past the end of the input text
                        chunks[1].x + app.input.width() as u16 + 1,
                        // Move one line down, from the border to the input line
                        chunks[1].y + 1,
                    )
                }
            }
        })?;

        // Handle input
        if let Event::Input(input) = events.next()? {
            match app.input_mode {
                InputMode::Normal => match input {
                    Key::Char('i') => {
                        app.input_mode = InputMode::Editing;
                        events.disable_exit_key();
                    }
                    Key::Char('q') => {
                        // save the config as is then quit out
                        match config.save(config_path) {
                            Ok(_) => println!(":^)"),
                            Err(e) => eprintln!("Couldn't save config state: {}", e)
                        };
                        break;
                    }
                    _ => {}
                },
                InputMode::Editing => match input {
                    Key::Char('\n') => {
                        let cmd = Command::from(app.input.drain(..).collect());
                        app.messages.push(match cmd {
                            // only for networked commands do we need to touch cache
                            Command::Channel(id) => app.cache.switch_channel(id).await,
                            Command::Server(host) => app.cache.switch_server(&host).await,
                            Command::Message(msg) => app.cache.send_message(&msg).await,
                            _ => cmd
                        });
                    }
                    Key::Char(c) => {
                        app.input.push(c);
                    }
                    Key::Backspace => {
                        app.input.pop();
                    }
                    Key::Ctrl('c') | Key::Esc => {
                        app.input_mode = InputMode::Normal;
                        events.enable_exit_key();
                    }
                    _ => {}
                },
            }
        }
    }
    Ok(())
}