/*
 * This file is part of laurelin_client
 * Copyright (C) 2023 Jonni Liljamo <jonni@liljamo.com>
 *
 * Licensed under GPL-3.0-only.
 * See LICENSE for licensing information.
 */

use bevy::{prelude::*, input::mouse::{MouseScrollUnit, MouseWheel}, a11y::{AccessibilityNode, accesskit::NodeBuilder}};

use crate::AppState;

pub struct LogPlugin;

impl Plugin for LogPlugin {
    fn build(&self, app: &mut App) {
        app.add_event::<ToggleLogEvent>()
            .add_event::<UpdateLogEvent>()
            .add_system(setup_log.in_schedule(OnEnter(AppState::InGame)))
            .add_system(update_log_button)
            .add_system(toggle_log.run_if(on_event::<ToggleLogEvent>()))
            .add_system(update_log.run_if(on_event::<UpdateLogEvent>()))
            .add_system(log_mouse_scroll);
    }
}

pub struct ToggleLogEvent;
pub struct UpdateLogEvent;

const NORMAL_BUTTON: Color = Color::rgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::rgb(0.25, 0.25, 0.25);
const PRESSED_BUTTON: Color = Color::rgb(0.35, 0.75, 0.35);

#[derive(Component)]
struct LogButton;
#[derive(Component)]
struct LogList;

fn setup_log(mut commands: Commands, asset_server: Res<AssetServer>) {
    // setup a button for log toggle
    // setup the log ui itself, with hidden visibility

    let font = asset_server.load("fonts/FiraMono-Bold.ttf");

    // log toggle button
    commands
        .spawn(NodeBundle {
            style: Style {
                position_type: PositionType::Absolute,
                position: UiRect {
                    top: Val::Px(20.),
                    right: Val::Px(20.),
                    ..Default::default()
                },
                ..Default::default()
            },
            ..Default::default()
        })
        .with_children(|parent| {
            parent
                .spawn((
                    ButtonBundle {
                        style: Style {
                            size: Size::new(Val::Px(75.), Val::Px(35.)),
                            // center child text
                            justify_content: JustifyContent::Center,
                            align_items: AlignItems::Center,
                            ..Default::default()
                        },
                        background_color: NORMAL_BUTTON.into(),
                        ..Default::default()
                    },
                    LogButton,
                ))
                .with_children(|parent| {
                    parent.spawn((
                        TextBundle::from_section(
                            "Log",
                            TextStyle {
                                font: font.clone(),
                                font_size: 20.,
                                color: Color::WHITE,
                            },
                        ),
                    ));
                });
        });

    // log window
    commands
        .spawn(NodeBundle {
            style: Style {
                flex_direction: FlexDirection::Column,
                justify_content: JustifyContent::Center,
                align_items: AlignItems::Center,
                size: Size {
                    width: Val::Px(300.),
                    height: Val::Px(300.),
                },
                position_type: PositionType::Absolute,
                position: UiRect {
                    bottom: Val::Percent(12.5),
                    right: Val::Px(100.),
                    ..Default::default()
                },
                ..Default::default()
            },
            background_color: Color::rgb(0.15, 0.15, 0.15).into(),
            ..Default::default()
        })
        .with_children(|parent| {
            parent
                .spawn(NodeBundle {
                    style: Style {
                        flex_direction: FlexDirection::Column,
                        align_self: AlignSelf::Stretch,
                        size: Size::all(Val::Percent(95.)),
                        overflow: Overflow::Hidden,
                        ..Default::default()
                    },
                    ..Default::default()
                })
                .with_children(|parent| {
                    parent
                        .spawn((
                            NodeBundle {
                                style: Style {
                                    flex_direction: FlexDirection::Column,
                                    max_size: Size::UNDEFINED,
                                    ..Default::default()
                                },
                                ..Default::default()
                            },
                            AccessibilityNode(NodeBuilder::new(bevy::a11y::accesskit::Role::List)),
                            ScrollingList::default(),
                            LogList,
                        ))
                        .with_children(|parent| {
                            for i in 0..30 {
                                parent.spawn((
                                    TextBundle::from_section(
                                        format!("Item {i}"),
                                        TextStyle {
                                            font: font.clone(),
                                            font_size: 20.,
                                            color: Color::WHITE,
                                        },
                                    ),
                                    AccessibilityNode(NodeBuilder::new(bevy::a11y::accesskit::Role::ListItem)),
                                ));
                            }
                        });
                });
        });
}

fn update_log_button(
    mut interaction_query: Query<
        (&Interaction, &mut BackgroundColor),
        (Changed<Interaction>, With<LogButton>),
    >,
    mut ul_ev_w: EventWriter<UpdateLogEvent>,
) {
    for (interaction, mut color) in &mut interaction_query {
        match interaction {
            Interaction::Clicked => {
                *color = PRESSED_BUTTON.into();
                ul_ev_w.send(UpdateLogEvent);
            }
            Interaction::Hovered => {
                *color = HOVERED_BUTTON.into();
            }
            Interaction::None => {
                *color = NORMAL_BUTTON.into();
            }
        }
    }
}

fn toggle_log() {
    // toggle the node visibility, see the state button for e.g
}

fn update_log() {
    // despawn the children ui nodes, and create new ones.
    // update log ui scrolling items with... log items
}

#[derive(Component, Default)]
struct ScrollingList {
    position: f32,
}

fn log_mouse_scroll(
    mut mouse_wheel_events: EventReader<MouseWheel>,
    mut query_list: Query<(&mut ScrollingList, &mut Style, &Parent, &Node)>,
    query_node: Query<&Node>,
) {
    for mouse_wheel_event in mouse_wheel_events.iter() {
        for (mut scrolling_list, mut style, parent, list_node) in &mut query_list {
            let items_height = list_node.size().y;
            let container_height = query_node.get(parent.get()).unwrap().size().y;

            let max_scroll = (items_height - container_height).max(0.);

            let dy = match mouse_wheel_event.unit {
                MouseScrollUnit::Line => mouse_wheel_event.y * 20.,
                MouseScrollUnit::Pixel => mouse_wheel_event.y,
            };

            scrolling_list.position += dy;
            scrolling_list.position = scrolling_list.position.clamp(-max_scroll, 0.);
            style.position.top = Val::Px(scrolling_list.position);
        }
    }
}