// Library
use vek::*;
use image;
use conrod_core::widget::image::Image as ImageWidget;
use conrod_core::{Positionable, Sizeable, Widget};

// Crate
use crate::{
    PlayState,
    PlayStateResult,
    GlobalState,
    window::Event,
    session::SessionState,
    render::{
        Consts,
        UiLocals,
        Renderer,
    },
    ui::{
        Ui
    },
};

pub struct TitleState {
    ui: Ui
}

impl TitleState {
    /// Create a new `TitleState`
    pub fn new(renderer: &mut Renderer) -> Self {
        let mut ui = Ui::new(renderer, [500.0, 500.0]).unwrap();
        let widget_id = ui.new_widget();
        let image = image::open(concat!(env!("CARGO_MANIFEST_DIR"), "/test_assets/test.png")).unwrap();
        let title_img = ui.new_image(renderer, &image).unwrap();
        ui.set_widgets(|ui_cell| {
            ImageWidget::new(title_img)
                .x_y(0.0, 0.0)
                .w_h(500.0,500.0)
                .set(widget_id, ui_cell);
        });
        Self {
            ui
        }
    }
}

// The background colour
const BG_COLOR: Rgba<f32> = Rgba { r: 0.0, g: 0.3, b: 1.0, a: 1.0 };

impl PlayState for TitleState {
    fn play(&mut self, global_state: &mut GlobalState) -> PlayStateResult {
        loop {
            // Handle window events
            for event in global_state.window.fetch_events() {
                match event {
                    Event::Close => return PlayStateResult::Shutdown,
                    // When space is pressed, start a session
                    Event::Char(' ') => return PlayStateResult::Push(
                        Box::new(SessionState::new(global_state.window.renderer_mut()).unwrap()), // TODO: Handle this error
                    ),
                    // Ignore all other events
                    _ => {},
                }
            }


            global_state.window.renderer_mut().clear(BG_COLOR);

            // Maintain the UI
            //self.ui.maintain(global_state.window.renderer_mut());

            // Draw the UI to the screen
            self.ui.render(global_state.window.renderer_mut());

            // Finish the frame
            global_state.window.renderer_mut().flush();
            global_state.window
            .swap_buffers()
            .expect("Failed to swap window buffers");

        }
    }

    fn name(&self) -> &'static str { "Title" }
}