extern crate regex;
use crate::{actor, nature};
use regex::Regex;
use bevy::prelude::*;
//use bevy::core_pipeline::Skybox;
//use bevy::asset::LoadState;
//use bevy::render::render_resource::{TextureViewDescriptor, TextureViewDimension};
use bevy::pbr::CascadeShadowConfigBuilder;
use bevy_xpbd_3d::prelude::*;
use std::f32::consts::PI;

const ASTEROID_SIZE: f32 = 100.0;
const STARS_MAX_MAGNITUDE: f32 = 5.5;

//const SKYBOX_BRIGHTNESS: f32 = 300.0;
//const SKYBOX_BRIGHTNESS_AR: f32 = 100.0;

//const ASSET_CUBEMAP: &str = "textures/cubemap-fs8.png";
//const ASSET_CUBEMAP_AR: &str = "textures/out.png";
const ASSET_ASTEROID1: &str = "models/asteroid.glb#Scene0";
const ASSET_ASTEROID2: &str = "models/asteroid2.glb#Scene0";
fn asset_name_to_path(name: &str) -> &'static str {
    match name {
        "suit" => "models/suit.glb#Scene0",
        "jupiter" => "models/jupiter.glb#Scene0",
        "asteroid1" => ASSET_ASTEROID1,
        "asteroid2" => ASSET_ASTEROID2,
        "moonlet" => "models/moonlet.glb#Scene0",
        "monolith" => "models/monolith_neon.glb#Scene0",
        "MeteorAceGT" => "models/MeteorAceGT.glb#Scene0",
        "pizzeria" => "models/pizzeria2.glb#Scene0",
        "pizzasign" => "models/pizzasign.glb#Scene0",
        _ => "models/error.glb#Scene0",
    }
}

pub struct WorldPlugin;
impl Plugin for WorldPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, (setup, load_defs));
        //app.add_systems(Update, asset_loaded.after(load_cubemap_asset));
        //app.add_systems(Update, swap_world_on_ar_toggle);
        app.add_plugins(PhysicsPlugins::default());
        //app.add_plugins(PhysicsDebugPlugin::default());
        app.insert_resource(ClearColor(Color::rgb(0.0, 0.0, 0.0)));
        app.insert_resource(Gravity(Vec3::splat(0.0)));
    }
}

#[derive(Component)]
pub struct Star;

//#[derive(Resource)]
//pub struct WorldState {
//    is_loaded: bool,
//    entities_viewn_through_ar: bool,
//    cubemap_handle: Handle<Image>,
//    cubemap_ar_handle: Handle<Image>,
//}
//impl WorldState {
//    pub fn get_cubemap_handle(&self) -> Handle<Image> {
//        if self.entities_viewn_through_ar {
//            self.cubemap_ar_handle.clone()
//        } else {
//            self.cubemap_handle.clone()
//        }
//    }
//}

pub fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    asset_server: Res<AssetServer>,
) {
//    let cubemap_handle = asset_server.load(ASSET_CUBEMAP);
//    commands.insert_resource(WorldState {
//        is_loaded: false,
//        entities_viewn_through_ar: settings.hud_active,
//        cubemap_handle: asset_server.load(ASSET_CUBEMAP),
//        cubemap_ar_handle: asset_server.load(ASSET_CUBEMAP_AR),
//    });

    // Generate a bunch of asteriods
    let maxdist = 10;
    for i in -maxdist..maxdist {
        for j in -maxdist..maxdist {
            for k in -maxdist..maxdist {
                let offset = 500.0;
                let dist = 8e3;
                let wobble = dist/2.0;
                let (i, j, k) = (i as f32, j as f32, k as f32);
                let asset = match ((i+j+k) as i32) % 2 {
                    0 => ASSET_ASTEROID1,
                    _ => ASSET_ASTEROID2,
                };
                commands.spawn((
                    actor::Actor {
                        v: Vec3::new(-0.00, 0.0, 0.35),
                        angular_momentum: Quat::from_euler(EulerRot::XYZ, 0.001, 0.001, 0.0003),
                        ..default()
                    },
                    SceneBundle {
                        transform: Transform {
                            translation: Vec3::new(
                                offset + dist * i + wobble * (j+k/PI).sin() * (k+j/PI).cos(),
                                offset + dist * j + wobble * (k+i/PI).sin() * (i+k/PI).cos(),
                                offset + dist * k + wobble * (i+j/PI).sin() * (j+i/PI).cos(),
                            ),
                            rotation: Quat::from_rotation_y(-PI / 3.),
                            scale: Vec3::splat(ASTEROID_SIZE),
                        },
                        scene: asset_server.load(asset),
                        ..default()
                    },
                ));
            }
        }
    }

    // Generate starmap
    let sphere_handle = meshes.add(Sphere::new(1.0));
    let mut starcount = 0;
    for star in nature::STARS {
        let mag = star[3];
        if mag > STARS_MAX_MAGNITUDE {
            continue;
        }
        let scale_color = {|color: f32|
            if mag < -20.0 {
                color * 13.0f32 // Sun
            } else {
                color * (0.0659663 * mag * mag - 1.09862 * mag + 4.3)
            }
        };
        let scale_size = {|mag: f32|
            if mag < -20.0 {
                40000.0f32 // Sun
            } else {
                1000.0 * (0.230299 * mag * mag - 3.09013 * mag + 15.1782)
            }
        };
        let (r, g, b) = nature::star_color_index_to_rgb(star[4]);
        let star_color_handle = materials.add(StandardMaterial {
            base_color: Color::rgb(scale_color(r), scale_color(g), scale_color(b)),
            unlit: true,
            ..default()
        });
        let dist = 1e7;
        commands.spawn((
            Star,
            PbrBundle {
                mesh: sphere_handle.clone(),
                material: star_color_handle.clone(),
                transform: Transform::from_xyz(
                        dist * star[0],
                        dist * star[1],
                        dist * star[2],
                    )
                    .with_scale(Vec3::splat(scale_size(mag))),
                ..default()
            }
        ));
        starcount += 1;
    }
    info!("Generated {starcount} stars");

    // Add Light from the Sun
    commands.spawn(DirectionalLightBundle {
        directional_light: DirectionalLight {
            illuminance: 1000.0,
            shadows_enabled: false,
            ..default()
        },
        transform: Transform::from_rotation(Quat::from_rotation_y(PI/2.0)),
        cascade_shadow_config: CascadeShadowConfigBuilder {
            first_cascade_far_bound: 7.0,
            maximum_distance: 25.0,
            ..default()
        }
        .into(),
        ..default()
    });
}

enum DefClass {
    Actor,
    Chat,
    None,
}

struct ParserState {
    class: DefClass,

    // Generic fields
    name: String,
    chat: String,

    // Actor fields
    id: String,
    pos: Vec3,
    model: String,
    model_scale: f32,
    rotation: Quat,
    angular_momentum: Quat,
    pronoun: String,
    is_player: bool,
    is_lifeform: bool,
    is_alive: bool,
    is_suited: bool,
    is_vehicle: bool,
    thrust_forward: f32,
    thrust_sideways: f32,
    thrust_back: f32,
    reaction_wheels: f32,
    warmup_seconds: f32,
    engine_type: actor::EngineType,
    oxygen: f32,
    mass: f32,
    collider: Collider,
    camdistance: f32,

    // Chat fields
    delay: f64,
    text: String,
    level: String,
    label: String,
    goto: String,
    is_choice: bool,
    stores_item: bool,
    script: String,
    script_parameter: String,
    script_parameter2: String,
}
impl Default for ParserState {
    fn default() -> Self {
        let default_actor = actor::Actor::default();
        let default_engine = actor::Engine::default();
        Self {
            class: DefClass::None,
            name: "NONAME".to_string(),
            chat: "".to_string(),

            id: "".to_string(),
            pos: Vec3::new(0.0, 0.0, 0.0),
            model: "".to_string(),
            model_scale: 1.0,
            rotation: Quat::IDENTITY,
            angular_momentum: default_actor.angular_momentum,
            pronoun: "they/them".to_string(),
            is_player: false,
            is_lifeform: false,
            is_alive: false,
            is_suited: false,
            is_vehicle: false,
            thrust_forward: default_engine.thrust_forward,
            thrust_sideways: default_engine.thrust_forward,
            thrust_back: default_engine.thrust_back,
            reaction_wheels: default_engine.reaction_wheels,
            warmup_seconds: default_engine.warmup_seconds,
            engine_type: default_engine.engine_type,
            oxygen: nature::OXY_D,
            mass: 1.0,
            collider: Collider::sphere(1.0),
            camdistance: default_actor.camdistance,

            delay: 0.0,
            text: "".to_string(),
            level: "chat".to_string(),
            label: "".to_string(),
            goto: "".to_string(),
            is_choice: false,
            stores_item: false,
            script: "".to_string(),
            script_parameter: "".to_string(),
            script_parameter2: "".to_string(),
        }
    }
}
impl ParserState {
    fn reset_message(&mut self) {
        let default = ParserState::default();
        self.label = default.label;
        self.delay = default.delay;
        self.goto = default.goto;
        self.level = default.level;
        self.text = default.text;
        self.is_choice = default.is_choice;
    }
    fn reset_chat(&mut self) {
        let default = ParserState::default();
        self.reset_message();
        self.stores_item = default.stores_item;
    }
    fn reset(&mut self) {
        *self = Self::default();
    }
    fn as_chatbranch(&self) -> actor::ChatBranch {
        return actor::ChatBranch {
            id: self.chat.clone(),
            name: self.name.clone(),
            label: self.label.clone(),
            delay: self.delay.clone(),
            sound: if self.is_choice { "".to_string() } else { "chat".to_string() },
            level: self.level.clone(),
            reply: if self.is_choice { "".to_string() } else { self.text.clone() },
            choice: if self.is_choice { self.text.clone() } else { "".to_string() },
            goto: self.goto.clone(),
            script: self.script.clone(),
            script_parameter: self.script_parameter.clone(),
            script_parameter2: self.script_parameter2.clone(),
        }
    }
    fn spawn_chat(&mut self, commands: &mut Commands) {
        if self.stores_item {
            debug!("{:#?}", self.as_chatbranch());
            commands.spawn(self.as_chatbranch());
        }
        self.reset_message();
    }
    fn spawn_actor(&mut self, commands: &mut Commands, asset_server: &Res<AssetServer>) {
        let mut actor = commands.spawn_empty();
        actor.insert(actor::Actor {
            angular_momentum: self.angular_momentum,
            id: self.id.clone(),
            camdistance: self.camdistance,
            ..default()
        });
        actor.insert(SceneBundle {
            transform: Transform {
                translation: self.pos,
                scale: Vec3::splat(self.model_scale),
                rotation: self.rotation,
            },
            scene: asset_server.load(asset_name_to_path(self.model.as_str())),
            ..default()
        });

        // Physics Parameters
        let fix_scale = 1.0 / self.model_scale.powf(3.0);
        actor.insert(RigidBody::Dynamic);
        actor.insert(self.collider.clone());
        actor.insert(ColliderDensity(self.mass * fix_scale));

        // Optional Components
        if self.is_player {
            actor.insert(actor::Player);
            actor.insert(actor::PlayerCamera);
        }
        if self.is_lifeform {
            actor.insert(actor::LifeForm::default());
            actor.insert(actor::Suit {
                oxygen: self.oxygen,
                oxygen_max: nature::OXY_D,
                ..default()
            });
        }
        if !self.chat.is_empty() {
            actor.insert(actor::Talker {
                conv_id: self.chat.clone(),
                ..default()
            });
        }
        if self.is_vehicle {
            actor.insert(actor::Vehicle);
        }
        if self.is_vehicle || self.is_suited {
            actor.insert(actor::Engine {
                thrust_forward: self.thrust_forward,
                thrust_back: self.thrust_back,
                thrust_sideways: self.thrust_sideways,
                reaction_wheels: self.reaction_wheels,
                warmup_seconds: self.warmup_seconds,
                engine_type: self.engine_type,
                ..default()
            });
        }

        //info!("Spawning actor {} with model {} at {}/{}/{}",
        //      self.name, self.model, self.pos.x, self.pos.y, self.pos.z);
        self.reset();
    }
    fn spawn_entities(&mut self, commands: &mut Commands, asset_server: &Res<AssetServer>) {
        match self.class {
            DefClass::Actor => { self.spawn_actor(commands, asset_server); }
            DefClass::Chat => { self.spawn_chat(commands); }
            DefClass::None => {}
        }
    }
}

pub fn load_defs(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
) {
    let re1 = Regex::new(r"^\s*([a-z_-]+)\s+(.*)$").unwrap();
    let re2 = Regex::new("\"([^\"]*)\"|(-?[0-9]+(?:\\.[0-9]+)?)|([a-zA-Z_-][a-zA-Z0-9_-]*)").unwrap();
    let defs_string = include_str!("defs.txt");
    let mut lines = defs_string.lines();
    let mut state = ParserState::default();
    let mut command;
    let mut parameters;

    let mut line_nr = -1;
    while let Some(line) = lines.next() {
        line_nr += 1;
        let caps = re1.captures(line);
        if caps.is_none() {
            if line.trim() != "" {
                error!("Syntax Error in definitions line {}: `{}`", line_nr, line);
            }
            continue;
        }
        if let Some(caps) = caps {
            command = caps.get(1).unwrap().as_str();
            parameters = caps.get(2).unwrap().as_str();
        }
        else {
            error!("Failed to read regex captures in line {}: `{}`", line_nr, line);
            continue;
        }

        let mut parts: Vec<&str> = Vec::new();
        parts.push(command);
        for caps in re2.captures_iter(parameters) {
            if let Some(part) = caps.get(1) {
                parts.push(&part.as_str());
            }
            if let Some(part) = caps.get(2) {
                parts.push(&part.as_str());
            }
            if let Some(part) = caps.get(3) {
                parts.push(&part.as_str());
            }
        }

        match parts.as_slice() {
            // Parsing actors
            ["actor", x, y, z, model] => {
                state.spawn_entities(&mut commands, &asset_server);
                state.reset();
                state.class = DefClass::Actor;
                state.model = model.to_string();
                if let (Ok(x_float), Ok(y_float), Ok(z_float)) =
                        (x.parse::<f32>(), y.parse::<f32>(), z.parse::<f32>()) {
                    state.pos = Vec3::new(x_float, y_float, z_float);
                }
                else {
                    error!("Can't parse coordinates as floats in def: {line}");
                    state.reset();
                    continue;
                }
            }
            ["id", id] => {
                state.id = id.to_string();
            }
            ["alive", "yes"] => {
                state.is_alive = true;
                state.is_lifeform = true;
                state.is_suited = true;
            }
            ["vehicle", "yes"] => {
                state.is_vehicle = true;
            }
            ["oxygen", amount] => {
                if let Ok(amount) = amount.parse::<f32>() {
                    state.is_lifeform = true;
                    state.is_suited = true;
                    state.oxygen = amount;
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["pronoun", pronoun] => {
                state.pronoun = pronoun.to_string();
            }
            ["chatid", chat] => {
                state.chat = chat.to_string();
            }
            ["scale", scale] => {
                if let Ok(scale_float) = scale.parse::<f32>() {
                    state.model_scale = scale_float;
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["rotationx", rotation_x] => {
                if let Ok(rotation_x_float) = rotation_x.parse::<f32>() {
                    state.rotation = Quat::from_rotation_x(PI * rotation_x_float);
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["rotationy", rotation_y] => {
                if let Ok(rotation_y_float) = rotation_y.parse::<f32>() {
                    state.rotation = Quat::from_rotation_y(PI * rotation_y_float);
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["angularmomentum", x, y, z] => {
                if let (Ok(x_float), Ok(y_float), Ok(z_float)) =
                        (x.parse::<f32>(), y.parse::<f32>(), z.parse::<f32>()) {
                    state.angular_momentum = Quat::from_euler(EulerRot::XYZ, x_float, y_float, z_float);
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["thrust", forward, back, sideways, reaction_wheels, warmup_time] => {
                if let (Ok(forward_float), Ok(back_float), Ok(sideways_float), Ok(reaction_wheels_float), Ok(warmup_time_float)) = (forward.parse::<f32>(), back.parse::<f32>(), sideways.parse::<f32>(), reaction_wheels.parse::<f32>(), warmup_time.parse::<f32>()) {
                    state.thrust_forward = forward_float;
                    state.thrust_back = back_float;
                    state.thrust_sideways = sideways_float;
                    state.reaction_wheels = reaction_wheels_float;
                    state.warmup_seconds = warmup_time_float;
                }
            }
            ["engine", "rocket"] => {
                state.engine_type = actor::EngineType::Rocket;
            }
            ["engine", "ion"] => {
                state.engine_type = actor::EngineType::Ion;
            }
            ["mass", value] => {
                if let Ok(value_float) = value.parse::<f32>() {
                    state.mass = value_float;
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["collider", "sphere", radius] => {
                if let Ok(radius_float) = radius.parse::<f32>() {
                    state.collider = Collider::sphere(radius_float);
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["collider", "capsule", height, radius] => {
                if let (Ok(height_float), Ok(radius_float)) = (height.parse::<f32>(), radius.parse::<f32>()) {
                    state.collider = Collider::capsule(height_float, radius_float);
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }
            ["player", "yes"] => {
                state.is_player = true;
                state.is_alive = true;
            }
            ["camdistance", value] => {
                if let Ok(value_float) = value.parse::<f32>() {
                    state.camdistance = value_float;
                }
                else {
                    error!("Can't parse float: {line}");
                    continue;
                }
            }

            // Parsing chats
            ["chat", chat_name] => {
                debug!("Registering chat: {}", chat_name);
                state.spawn_entities(&mut commands, &asset_server);
                state.reset_chat();
                state.class = DefClass::Chat;
                state.chat = chat_name.to_string();
            }
            ["name", name] => {
                debug!("Registering name: {}", name);
                state.name = name.to_string();
            }
            ["msg", sleep, text] => {
                debug!("Registering message (sleep={}): {}", sleep, text);
                state.spawn_entities(&mut commands, &asset_server);
                if let Ok(sleep_float) = sleep.parse::<f64>() {
                    state.delay = sleep_float;
                    state.text = text.to_string();
                    state.stores_item = true;
                    state.is_choice = false;
                } else {
                    error!("The 'sleep' value for this message is not a float: {}", line);
                    continue;
                }
            }
            ["msg", sleep, label, goto, text] => {
                debug!("Registering message (sleep={}): {}", sleep, text);
                state.spawn_entities(&mut commands, &asset_server);
                if let Ok(sleep_float) = sleep.parse::<f64>() {
                    state.delay = sleep_float;
                    state.text = text.to_string();
                    state.stores_item = true;
                    state.is_choice = false;
                    state.goto = goto.to_string();
                    state.label = label.to_string();
                } else {
                    error!("The 'sleep' value for this message is not a float: {}", line);
                    continue;
                }
            }
            ["choice", sleep, text] => {
                debug!("Registering choice (sleep={}): {}", sleep, text);
                state.spawn_entities(&mut commands, &asset_server);
                if let Ok(sleep_float) = sleep.parse::<f64>() {
                    state.delay = sleep_float;
                    state.text = text.to_string();
                    state.stores_item = true;
                    state.is_choice = true;
                } else {
                    error!("The 'sleep' value for this message is not a float: {}", line);
                    continue;
                }
            }
            ["choice", sleep, label, goto, text] => {
                debug!("Registering choice (sleep={}): {}", sleep, text);
                state.spawn_entities(&mut commands, &asset_server);
                if let Ok(sleep_float) = sleep.parse::<f64>() {
                    state.delay = sleep_float;
                    state.text = text.to_string();
                    state.stores_item = true;
                    state.is_choice = true;
                    state.goto = goto.to_string();
                    state.label = label.to_string();
                } else {
                    error!("The 'sleep' value for this message is not a float: {}", line);
                    continue;
                }
            }
            ["goto", label] => {
                debug!("Registering goto: {}", label);
                state.goto = label.to_string();
            }
            ["label", label] => {
                debug!("Registering label: {}", label);
                state.label = label.to_string();
            }
            ["lvl", level] => {
                debug!("Registering level: {}", level);
                state.level = level.to_string();
            }
            ["script", scriptname, parameter] => {
                state.script = scriptname.to_string();
                state.script_parameter = parameter.to_string();
                state.script_parameter2 = "".to_string();
            }
            ["script", scriptname, parameter, parameter2] => {
                state.script = scriptname.to_string();
                state.script_parameter = parameter.to_string();
                state.script_parameter2 = parameter2.to_string();
            }
            _ => {
                error!("No match for [{}]", parts.join(","));
            }
        }
    }
    state.spawn_entities(&mut commands, &asset_server);
}

//pub fn swap_world_on_ar_toggle(
//    asset_server: Res<AssetServer>,
//    mut images: ResMut<Assets<Image>>,
//    mut worldstate: ResMut<WorldState>,
//    mut skyboxes: Query<&mut Skybox>,
//    settings: Res<settings::Settings>,
//) {
//    if settings.hud_active != worldstate.entities_viewn_through_ar {
//        worldstate.is_loaded = false;
//        worldstate.entities_viewn_through_ar = settings.hud_active;
//    }
//    if !worldstate.is_loaded && asset_server.load_state(&worldstate.get_cubemap_handle()) == LoadState::Loaded {
//        let cubemap_handle = &worldstate.get_cubemap_handle();
//        let image = images.get_mut(cubemap_handle).unwrap();
//        if image.texture_descriptor.array_layer_count() == 1 {
//            image.reinterpret_stacked_2d_as_array(image.height() / image.width());
//            image.texture_view_descriptor = Some(TextureViewDescriptor {
//                dimension: Some(TextureViewDimension::Cube),
//                ..default()
//            });
//        }
//
//        for mut skybox in &mut skyboxes {
//            skybox.image = cubemap_handle.clone();
//            skybox.brightness = if settings.hud_active {
//                SKYBOX_BRIGHTNESS_AR
//            } else {
//                SKYBOX_BRIGHTNESS
//            }
//        }
//
//        worldstate.is_loaded = true;
//    }
//}