use bevy::{asset::AssetEvents, gltf::Gltf, prelude::*, utils::HashMap};
use monologue_trees::debug::*;

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins.set(WindowPlugin {
                primary_window: Some(Window {
                    title: "GLTF Inspector".into(),
                    resolution: (640., 480.).into(),
                    ..default()
                }),
                ..default()
            }),
            DebugInfoPlugin,
        ))
        .add_event::<ResetScene>()
        .add_event::<SpawnScene>()
        .init_resource::<Current>()
        .add_systems(Startup, spawn_ui)
        .add_systems(
            Update,
            (
                drag_and_drop,
                loading,
                reset_scene.before(spawn_scene),
                spawn_scene.after(reset_scene),
                wire_up_scenes,
                control_scene,
                wire_up_animations,
                control_animation,
                wire_up_cameras,
                control_camera,
                control_default_camera,
            ),
        )
        .run();
}

#[derive(Component)]
struct SceneMarker;

#[derive(Component)]
struct MainCamera;

#[derive(Component)]
struct MainUi;

#[derive(Component)]
struct UiTitle;

#[derive(Component)]
struct InstructionsUi;

#[derive(Component)]
struct SceneSelectUi;

#[derive(Component, PartialEq, Debug)]
struct SceneButton(Handle<Scene>);

#[derive(Component)]
struct AnimationSelectUi;

#[derive(Component, PartialEq, Debug)]
struct AnimationButton(Handle<AnimationClip>);

#[derive(Component)]
struct CameraSelectUi;

#[derive(Component, PartialEq, Debug)]
struct CameraButton(Entity);

#[derive(Resource, Default)]
struct Current {
    gltf: Handle<Gltf>,
    scenes: HashMap<String, Handle<Scene>>,
    animations: HashMap<String, Handle<AnimationClip>>,
}

#[derive(Event)]
struct ResetScene;

#[derive(Event)]
struct SpawnScene(Handle<Scene>);

fn drag_and_drop(
    mut events: EventReader<FileDragAndDrop>,
    server: Res<AssetServer>,
    mut current: ResMut<Current>,
) {
    events
        .iter()
        .filter_map(|event| {
            if let FileDragAndDrop::DroppedFile { path_buf, .. } = event {
                info!("Drag+Drop file: {:?}", path_buf);
                Some(path_buf)
            } else {
                None
            }
        })
        .map(|path_buf| server.load(path_buf.to_str().expect("PathBuf to str")))
        .for_each(|handle| current.gltf = handle.clone());
}

fn spawn_ui(mut commands: Commands) {
    // TODO: Warn no camera (hidden)
    // TODO: Scene select container
    // TODO: Animation Play/Pause Placeholder
    commands.spawn((
        Camera3dBundle { ..default() },
        UiCameraConfig { show_ui: true },
        MainCamera,
    ));
    commands
        .spawn((
            NodeBundle {
                style: Style {
                    flex_wrap: FlexWrap::Wrap,
                    flex_direction: FlexDirection::Row,
                    justify_content: JustifyContent::SpaceAround,
                    width: Val::Percent(100.0),
                    height: Val::Percent(100.0),
                    ..default()
                },
                ..default()
            },
            MainUi,
        ))
        .with_children(|parent| {
            // TOOD: Prompt to drag+drop Gltf/Gltf file
            parent.spawn((
                TextBundle {
                    text: Text {
                        sections: vec![TextSection {
                            value: String::from("Drag and Drop .gltf/.glb file"),
                            style: TextStyle {
                                color: Color::WHITE,
                                ..default()
                            },
                        }],
                        ..default()
                    },
                    ..default()
                },
                InstructionsUi,
            ));
            parent
                .spawn((
                    NodeBundle {
                        style: Style {
                            flex_direction: FlexDirection::Column,
                            ..default()
                        },
                        ..default()
                    },
                    SceneSelectUi,
                ))
                .with_children(|parent| {
                    parent.spawn((
                        TextBundle::from_section("Scenes", TextStyle { ..default() }),
                        UiTitle,
                    ));
                });
            parent
                .spawn((
                    NodeBundle {
                        style: Style {
                            flex_direction: FlexDirection::Column,
                            ..default()
                        },
                        ..default()
                    },
                    AnimationSelectUi,
                ))
                .with_children(|parent| {
                    parent.spawn((
                        TextBundle::from_section("Animations", TextStyle { ..default() }),
                        UiTitle,
                    ));
                });
            parent
                .spawn((
                    NodeBundle {
                        style: Style {
                            flex_direction: FlexDirection::Column,
                            ..default()
                        },
                        ..default()
                    },
                    CameraSelectUi,
                ))
                .with_children(|parent| {
                    parent.spawn((
                        TextBundle::from_section("Cameras", TextStyle { ..default() }),
                        UiTitle,
                    ));
                });
        });
}

fn wire_up_scenes(
    mut events: EventReader<AssetEvent<Scene>>,
    root: Query<Entity, With<SceneSelectUi>>,
    root_children: Query<&Children, With<SceneSelectUi>>,
    mut commands: Commands,
    gltfs: Res<Assets<Gltf>>,
    current: Res<Current>,
    existing: Query<&SceneButton, Without<UiTitle>>,
) {
    events.iter().for_each(|event| {
        // Cleanup unused buttons
        root_children.iter().for_each(|children| {
            // Iterate over UI children elements
            children
                .iter()
                // Filter to just the buttons we want to despawn
                .filter(|&child| {
                    // Check each child entity against the currently loaded scenes
                    // Note: !(_.any(...)) (not-any)
                    !((*current).scenes.iter().any(|(_, handle)| {
                        // If the current entitie's scene button corresponds to one of the scenes
                        // loaded, continue, otherwise
                        existing.get(*child).map_or(false, |scene_button| {
                            *scene_button == SceneButton(handle.cast_weak::<Scene>())
                        })
                    }))
                })
                .for_each(|&e| {
                    commands.entity(e).despawn_recursive();
                });
        });

        // Add buttons
        match event {
            AssetEvent::Created { handle } | AssetEvent::Modified { handle } => {
                let (name, _) = gltfs
                    .get(&current.gltf)
                    .expect("Load current gltf")
                    .named_scenes
                    .iter()
                    .find(|(_, h)| h == &handle)
                    .expect("Find this scene");

                let mut ui = commands.entity(root.single());

                ui.with_children(|parent| {
                    parent
                        .spawn((
                            ButtonBundle {
                                background_color: BackgroundColor(Color::NONE),
                                ..default()
                            },
                            SceneButton(handle.clone()),
                        ))
                        .with_children(|parent| {
                            parent.spawn(TextBundle {
                                text: Text {
                                    sections: vec![TextSection {
                                        value: name.clone(),
                                        style: TextStyle {
                                            color: Color::WHITE,
                                            ..default()
                                        },
                                    }],
                                    ..default()
                                },
                                ..default()
                            });
                        });
                });
            }
            AssetEvent::Removed { .. } => warn!("IGNORED Remove scene in list"),
        }
    });
}

/// Translate UI button presses into scene spawn events
fn control_scene(
    mut events: EventWriter<SpawnScene>,
    interactions: Query<(&Interaction, &SceneButton), (Changed<Interaction>, With<Button>)>,
) {
    // Handle UI buttons
    interactions
        .iter()
        .for_each(|(interaction, SceneButton(handle))| match interaction {
            Interaction::Pressed => events.send(SpawnScene(handle.clone())),
            _ => (),
        });
}

fn wire_up_animations(
    mut events: EventReader<AssetEvent<AnimationClip>>,
    root: Query<Entity, With<AnimationSelectUi>>,
    root_children: Query<&Children, With<AnimationSelectUi>>,
    mut commands: Commands,
    gltfs: Res<Assets<Gltf>>,
    current: Res<Current>,
    existing: Query<&AnimationButton, Without<UiTitle>>,
) {
    events.iter().for_each(|event| {
        // Cleanup unused buttons
        root_children.iter().for_each(|children| {
            // Iterate over UI children elements
            children
                .iter()
                // Filter to just the buttons we want to despawn
                .filter(|&child| {
                    // Check each child entity against the currently loaded animations
                    // Note: !(_.any(...)) (not-any)
                    !((*current).animations.iter().any(|(_, handle)| {
                        // If the current entitie's animation button corresponds to one of
                        // the animations loaded, continue, otherwise
                        existing.get(*child).map_or(false, |scene_button| {
                            *scene_button == AnimationButton(handle.cast_weak::<AnimationClip>())
                        })
                    }))
                })
                .for_each(|&e| {
                    commands.entity(e).despawn_recursive();
                });
        });
        match event {
            AssetEvent::Created { handle } | AssetEvent::Modified { handle } => {
                let (name, _) = gltfs
                    .get(&current.gltf)
                    .expect("Load current gltf")
                    .named_animations
                    .iter()
                    .find(|(_, h)| h == &handle)
                    .expect("Find this animation");

                commands.entity(root.single()).with_children(|parent| {
                    parent
                        .spawn((
                            ButtonBundle {
                                background_color: BackgroundColor(Color::NONE),
                                ..default()
                            },
                            AnimationButton(handle.clone()),
                        ))
                        .with_children(|parent| {
                            parent.spawn(TextBundle {
                                text: Text {
                                    sections: vec![TextSection {
                                        value: name.clone(),
                                        style: TextStyle {
                                            color: Color::WHITE,
                                            ..default()
                                        },
                                    }],
                                    ..default()
                                },
                                ..default()
                            });
                        });
                });
            }
            AssetEvent::Removed { .. } => warn!("Ignoring asset removal"),
        }
    });
}

fn control_animation(
    interactions: Query<(&Interaction, &AnimationButton), (Changed<Interaction>, With<Button>)>,
) {
    interactions
        .iter()
        .for_each(|(interaction, AnimationButton(handle))| match interaction {
            Interaction::Pressed => {
                info!("TODO: Play animation {:?}", handle);
            }
            _ => (),
        })
}

/// Wire up the camera UI
fn wire_up_cameras(
    added_cam: Query<(Entity, &Name), (Without<MainCamera>, Added<Camera>)>,
    mut removed_cam: RemovedComponents<Camera>,
    mut commands: Commands,
    root: Query<Entity, With<CameraSelectUi>>,
    root_children: Query<&Children, With<CameraSelectUi>>,
    existing: Query<&CameraButton, Without<UiTitle>>,
) {
    // Add new camera buttons
    added_cam.iter().for_each(|(entity, name)| {
        info!("Adding camera button");
        commands.entity(root.single()).with_children(|parent| {
            parent
                .spawn((
                    ButtonBundle {
                        background_color: BackgroundColor(Color::NONE),
                        ..default()
                    },
                    CameraButton(entity),
                ))
                .with_children(|parent| {
                    parent.spawn(TextBundle {
                        text: Text {
                            sections: vec![TextSection {
                                value: name.as_str().into(),
                                style: TextStyle {
                                    color: Color::WHITE,
                                    ..default()
                                },
                            }],
                            ..default()
                        },
                        ..default()
                    });
                });
        });
    });

    // Remove deleted cameras
    removed_cam.iter().for_each(|entity| {
        info!("Removing camera button");
        root_children
            .single()
            .iter()
            .filter(|&child| {
                if let Ok(button) = existing.get(*child) {
                    *button == CameraButton(entity)
                } else {
                    false
                }
            })
            .for_each(|child| commands.entity(*child).despawn_recursive());
    })
}

fn control_camera(
    interactions: Query<(&Interaction, &CameraButton), (Changed<Interaction>, With<Button>)>,
    mut cameras: Query<(Entity, &mut Camera), Without<MainCamera>>,
) {
    interactions
        .iter()
        .for_each(|(interaction, CameraButton(entity))| match interaction {
            Interaction::Pressed => cameras
                .iter_mut()
                .for_each(|(e, mut camera)| camera.is_active = e == *entity),
            _ => (),
        })
}

fn control_default_camera(
    mut main_camera: Query<&mut Camera, With<MainCamera>>,
    other_cameras: Query<&mut Camera, Without<MainCamera>>,
) {
    // PERF: Probably don't need to do this every frame
    main_camera.single_mut().is_active = other_cameras.is_empty();
}

/// Load gltfs and spawn default scene
fn loading(
    mut events: EventReader<AssetEvent<Gltf>>,
    gltfs: Res<Assets<Gltf>>,
    mut spawn: EventWriter<SpawnScene>,
    mut current: ResMut<Current>,
) {
    events.iter().for_each(|event| {
        info!("Event!: {:?}", event);
        if let AssetEvent::<Gltf>::Created { handle, .. } = event {
            // Despawn existing scene
            let gltf = gltfs.get(handle).expect("Loaded Gltf");
            let default_scene = gltf.default_scene.clone().expect("Default scene");
            spawn.send(SpawnScene(default_scene));

            // Save active scenes
            current.scenes = gltf.named_scenes.clone();
            current.animations = gltf.named_animations.clone();

            // TOOD: Spawn default camera
            // TODO: Handle multiple cameras
            // TODO: Scene Selection scenes in one Gltf
            // TODO: Handle animation
        }
    });
}

/// Reset the current scene
fn reset_scene(
    mut events: EventReader<ResetScene>,
    mut commands: Commands,
    current: Query<Entity, With<SceneMarker>>,
) {
    events.iter().for_each(|_| {
        info!("Reset scene");

        current
            .iter()
            .for_each(|e| commands.entity(e).despawn_recursive())
    });
}

/// Spawn a desired scene
fn spawn_scene(
    mut events: EventReader<SpawnScene>,
    mut commands: Commands,
    current: Query<Entity, With<SceneMarker>>,
) {
    // Handle SpawnScene events
    events.iter().for_each(|SpawnScene(handle)| {
        info!("Reset scene (inline)");
        current
            .iter()
            .for_each(|e| commands.entity(e).despawn_recursive());

        info!("Spawning scene {:?}", handle);
        commands.spawn((
            SceneBundle {
                scene: handle.clone(),
                ..default()
            },
            SceneMarker,
        ));
    });
}