use bevy::ecs::schedule::ShouldRun;
use bevy::input::mouse::{MouseMotion, MouseWheel};
use bevy::math::Vec3Swizzles;
use bevy::{prelude::*, window::PresentMode, winit::WinitSettings};
use bevy_egui::{egui, EguiContext, EguiPlugin};
use bevy_prototype_lyon::prelude::*;

use shape_maker::*;

fn main() {
    let mut app = App::new();

    app
        .insert_resource(ClearColor(Color::rgb(0.1, 0.1, 0.12)))
        .insert_resource(Msaa { samples: 4 })
        // Optimal power saving and present mode settings for desktop apps.
        .insert_resource(WinitSettings::desktop_app())
        .insert_resource(WindowDescriptor {
            present_mode: PresentMode::Fifo,
            title: "Shape Maker".to_string(),
            ..Default::default()
        })
        .insert_resource(ButtonsColors::default())
        .insert_resource(UiState::default())
        .insert_resource(PointSize(6.0))
        .insert_resource(SnapGrid::default())
    ;

    app
        .add_plugins(DefaultPlugins)
        .add_plugin(EguiPlugin)
        .add_plugin(ShapePlugin)
    ;

    app
        .add_startup_system(configure_visuals)
        .add_startup_system(basic_setup_sys)
        .add_system(create_sys.with_run_criteria(|state: Res<UiState>, mut ec: ResMut<EguiContext>| 
            if !ec.ctx_mut().is_pointer_over_area() && state.current_action == Action::Create { ShouldRun::Yes } else { ShouldRun::No }
        ))
        .add_system(modify_sys.with_run_criteria(|state: Res<UiState>, mut ec: ResMut<EguiContext>| 
            if !ec.ctx_mut().is_pointer_over_area() && state.current_action == Action::Modify { ShouldRun::Yes } else { ShouldRun::No }
        ))
        .add_system(ui::action_bar_sys)
        .add_system(ui::shape_tree_sys)
        .add_system(show_hide_points)
        .add_system(color_points)
        .add_system(drag_camera_sys)
        .add_system(zoom_camera_sys)
        .add_system(scale_points)
        .add_system(ui::grid_window_sys)
    ;
    
    app.run();
}

fn basic_setup_sys(
    mut coms: Commands,
) {
    coms.spawn_bundle(Camera2dBundle::default())
        .insert(MainCamera);
}

fn configure_visuals(mut egui_ctx: ResMut<EguiContext>) {
    egui_ctx.ctx_mut().set_visuals(egui::Visuals {
        window_rounding: 0.0.into(),
        ..Default::default()
    });
}

fn zoom_camera_sys(
    mut mouse_scroll: EventReader<MouseWheel>,
    mut cam: Query<&mut OrthographicProjection, With<MainCamera>>,
) {
    let mut scroll = 0.0;

    for m in mouse_scroll.iter() {
        scroll += m.y * 0.1;
    }

    for mut op in cam.iter_mut() {
        op.scale += scroll ;
        if op.scale <= 0.05 {
            op.scale = 0.05;
        }
    }
}

fn scale_points(
    scale: Query<&OrthographicProjection, (With<MainCamera>, Changed<OrthographicProjection>)>,
    shapes: Query<&ShapeData>,
    p_size: Res<PointSize>,
    mut paths: Query<&mut Path, With<Path>>,
) {
    if let Ok(scale) = scale.get_single() {
        let scale = scale.scale;
        
        for sd in shapes.iter() {
            if let Ok(mut p) = paths.get_mut(sd.center.unwrap()) {
                let shape = shapes::Circle {
                    radius: p_size.0 * scale,
                    center: Vec2::ZERO,
                };
                *p = ShapePath::build_as(&shape);
            }
            for &edge in sd.edges.iter() {
                if let Ok(mut p) = paths.get_mut(edge) {
                    let shape = shapes::Circle {
                        radius: p_size.0 * scale,
                        center: Vec2::ZERO,
                    };
                    *p = ShapePath::build_as(&shape);
                }

            }
        }
    }
}

fn drag_camera_sys(
    mut mouse_move: EventReader<MouseMotion>,
    mouse_input: Res<Input<MouseButton>>,
    mut cam: Query<(&mut Transform, &OrthographicProjection), With<MainCamera>>,
) {
    if mouse_input.pressed(MouseButton::Middle) {
        let mut delta = Vec2::ZERO;
        for m in mouse_move.iter() {
            delta -= Vec2::new(m.delta.x, -m.delta.y) * 2.0;
        }
        for (mut t, op) in cam.iter_mut() {
            t.translation += delta.extend(0.0) * op.scale;
        }
    }
}

fn show_hide_points(
    state: Res<UiState>,
    shapes: Query<&ShapeData>,
    mut dots: Query<&mut Visibility, (With<Transform>, With<Path>)>,
) {
    let (center, edge) = match state.current_action {
        Action::Create => (false, false),
        Action::Modify => (true, true),
    };

    for sd in shapes.iter() {
        // center
        if let Ok(mut v) = dots.get_mut(sd.center.unwrap()) {
            if v.is_visible != center {
                v.is_visible = center;
            }
        }
        for e in sd.edges.iter() {
            if let Ok(mut v) = dots.get_mut(*e) {
                if v.is_visible != edge {
                    v.is_visible = edge;
                }
            }
        }
    }
}

fn color_points(
    mut current: Local<Option<Entity>>,
    scale: Query<&OrthographicProjection, With<MainCamera>>,
    wnds: Res<Windows>,
    p_size: Res<PointSize>,
    q_cam: Query<(&Camera, &GlobalTransform), With<MainCamera>>,
    shapes: Query<&ShapeData>,
    global_transforms: Query<&GlobalTransform, With<Path>>,
    mut dots: Query<&mut DrawMode, With<Path>>,
) {
    let scale = scale.get_single().map(|s| s.scale).unwrap_or(1.0);

    let normal = DrawMode::Outlined { fill_mode: FillMode::color(Color::RED), outline_mode: StrokeMode::new(Color::rgb(0.9,0.0,0.0), 0.0) };
    let hover = DrawMode::Outlined { fill_mode: FillMode::color(Color::RED), outline_mode: StrokeMode::new(Color::ORANGE, 3.0 * scale) };

    let mouse_pos = get_mouse_pos(&q_cam, &wnds);
    if let Some(mpos) = mouse_pos {
        let mut hovering = false;
        'shapes: for sd in shapes.iter() {
            let e = sd.center.unwrap();
            let p = global_transforms.get(e).unwrap().translation().xy();
            if (mpos - p).length_squared() < (p_size.0 * scale).powi(2) {
                if Some(e) != *current {
                    if let Some(c) = &*current {
                        if let Ok(mut md) = dots.get_mut(*c) {
                            *md = normal;
                        }
                    }
                    *current = Some(e);
                    if let Ok(mut md) = dots.get_mut(e) {
                        *md = hover;
                    }
                }
                hovering = true;
                break;
            }
            for edge in sd.edges.iter() {
                let p = global_transforms.get(*edge).unwrap().translation().xy();
                if (mpos - p).length_squared() < (p_size.0 * scale).powi(2) {
                    if Some(*edge) != *current {
                        if let Some(c) = &*current {
                            if let Ok(mut md) = dots.get_mut(*c) {
                                *md = normal;
                            }
                        }
                        *current = Some(*edge);
                        if let Ok(mut md) = dots.get_mut(*edge) {
                            *md = hover;
                        }
                    }
                    hovering = true;
                    break 'shapes;
                }
            }
        }
        if !hovering {
            if let Some(c) = &*current {
                if let Ok(mut md) = dots.get_mut(*c) {
                    *md = normal;
                }
                *current = None;
            }
        }
    }
}