use std::cell::RefCell;
use std::thread;

use cairo;
use gtk;
use gtk::prelude::*;
use gtk::{Window, WindowType, DrawingArea, Grid, ToolButton, ButtonBox, Orientation, Image};
use neovim_lib::Neovim;

use ui_model::UiModel;
use nvim::RedrawEvents;

thread_local!(pub static UI: RefCell<Ui> = {
    let thread = thread::current();
    let current_thread_name = thread.name();
    if current_thread_name != Some("<main>") {
        panic!("Can create UI  only from main thread, {:?}", current_thread_name);
    }
    RefCell::new(Ui::new())
});

pub struct Ui {
    pub model: UiModel,
    nvim: Option<Neovim>,
    drawing_area: DrawingArea,
}

impl Ui {
    pub fn new() -> Ui {
        Ui {
            model: UiModel::empty(),
            drawing_area: DrawingArea::new(),
            nvim: None,
        }
    }

    pub fn set_nvim(&mut self, nvim: Neovim) {
        self.nvim = Some(nvim);
    }

    pub fn nvim(&mut self) -> &mut Neovim {
        self.nvim.as_mut().unwrap()
    }

    pub fn init(&mut self) {

        let window = Window::new(WindowType::Toplevel);

        let grid = Grid::new();

        let button_bar = ButtonBox::new(Orientation::Horizontal);
        button_bar.set_hexpand(true);
        button_bar.set_layout(gtk::ButtonBoxStyle::Start);

        let open_image = Image::new_from_icon_name("document-open", 50);
        let open_btn = ToolButton::new(Some(&open_image), None);
        button_bar.add(&open_btn);

        let save_image = Image::new_from_icon_name("document-save", 50);
        let save_btn = ToolButton::new(Some(&save_image), None);
        button_bar.add(&save_btn);

        let exit_image = Image::new_from_icon_name("application-exit", 50);
        let exit_btn = ToolButton::new(Some(&exit_image), None);
        button_bar.add(&exit_btn);

        grid.attach(&button_bar, 0, 0, 1, 1);

        self.drawing_area.set_size_request(500, 500);
        self.drawing_area.set_hexpand(true);
        self.drawing_area.set_vexpand(true);
        grid.attach(&self.drawing_area, 0, 1, 1, 1);
        self.drawing_area.connect_draw(gtk_draw);

        window.add(&grid);
        window.show_all();
        window.connect_delete_event(|_, _| {
            gtk::main_quit();
            Inhibit(false)
        });
    }
}

fn gtk_draw(drawing_area: &DrawingArea, ctx: &cairo::Context) -> Inhibit {
    let width = drawing_area.get_allocated_width() as f64;
    let height = drawing_area.get_allocated_height() as f64;

    let font_face = cairo::FontFace::toy_create("",
                                                cairo::enums::FontSlant::Normal,
                                                cairo::enums::FontWeight::Normal);
    ctx.set_font_face(font_face);
    UI.with(|ui_cell| {
        ctx.set_source_rgb(0.0, 0.0, 0.0);
        let ui = ui_cell.borrow();
        let mut line_y = 30.0;
        for line in ui.model.lines() {
            ctx.move_to(0.0, line_y);
            ctx.show_text(&line);
            line_y += 30.0;
        }
    });

    Inhibit(true)
}

impl RedrawEvents for Ui {
    fn on_cursor_goto(&mut self, row: u64, col: u64) {
        self.model.set_cursor(row, col);
    }

    fn on_put(&mut self, text: &str) {
        self.model.put(text);
    }

    fn on_clear(&mut self) {
        self.model.clear();
    }

    fn on_resize(&mut self, columns: u64, rows: u64) {
        self.model = UiModel::new(rows, columns);
    }
}