#include "Engine.h"

// ============================================================================
// Standard library
// ============================================================================
#include <iostream>
#include <vector>
#include <random>
#include <map>
#include <string>
#include <memory>
#include <type_traits>

// ============================================================================
// OpenGL
// ============================================================================
#include <glad/glad.h>
#include <GLFW/glfw3.h>

// ============================================================================
// Math
// ============================================================================
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/quaternion.hpp>

// ============================================================================
// Third party
// ============================================================================
#include <ft2build.h>
#include FT_FREETYPE_H

// ============================================================================
// Engine � core
// ============================================================================
#include "common.h"
#include "Window.h"
#include "Camera.h"
#include "Keyboard.h"
#include "Mouse.h"
#include "Physics.h"
#include "RenderSystem.h"
#include "SoundSystem.h"
#include "ResourceManager.h"
#include "tFunctions.h"
#include "Debug.h"

// Rendering
#include "shaderClass.h"
#include "VBO.h"
#include "VAO.h"
#include "EBO.h"
#include "FBO.h"
#include "texture.h"
#include "Material.h"
#include "Mesh.h"
#include "Model.h"
#include "Cubemap.h"
#include "QuadVertices.h"
#include "Particle.h"
#include "Lighting.h"
#include "DirLight.h"

// Scene
#include "Folder.h"
#include "Sound.h"
#include "Gui.h"
#include "Net.h"
#include "font.h"

// Character / animation
#include "Rig.h"
#include "Animator.h"
#include "Character.h"
#include "DefaultBodyComponents.h"
#include "BodyComponentActions.h"

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

// ============================================================================
// Constructor � window, callbacks, systems, shaders
// ============================================================================
Engine::Engine()
{
    engine = this;

    glfwSetFramebufferSizeCallback(window->handle, framebuffer_size_callback);
    glfwSetCursorPosCallback(window->handle, mouse_callback);
    glfwSetScrollCallback(window->handle, scroll_callback);
    glfwSetKeyCallback(window->handle, key_callback);
    glfwSetMouseButtonCallback(window->handle, mouse_button_callback);
    glfwSwapInterval(1);

    // Start from the real framebuffer size (can differ from the requested size under DPI scaling)
    int fbw, fbh;
    glfwGetFramebufferSize(window->handle, &fbw, &fbh);
    framebuffer_size_callback(window->handle, fbw, fbh);

    rendersystem = new RenderSystem();
    rendersystem->Initialize();
    physicsengine = new Physics();
    physicsengine->SetGravity(physicsengine->GetGravity() * 1.25f);  // slightly stronger gravity to suit the larger map
    mainf = new Folder();
    camera = new Camera();
    camera->t.TranslateTo({ 0.0f, 5.0f, 0.0f });

    rendersystem->RigShader = new Shader("shaders/rig.vert", "shaders/default.frag");
    rendersystem->MeshShader = new Shader("shaders/default.vert", "shaders/default.frag");
    rendersystem->MeshShadowShader = new Shader("shaders/meshshadow.vert", "shaders/shadow.frag");
    rendersystem->RigShadowShader = new Shader("shaders/rigshadow.vert", "shaders/shadow.frag");
    rendersystem->SkyboxShader = new Shader("shaders/skybox.vert", "shaders/skybox.frag");
    rendersystem->ScreenShader = new Shader("shaders/ScreenShader.vert", "shaders/ScreenShader.frag");
    rendersystem->ImageBoxShader = new Shader("shaders/ImageBox.vert", "shaders/ImageBox.frag");
    rendersystem->BoxShader = new Shader("shaders/Box.vert", "shaders/Box.frag");
    rendersystem->Text2DShader = new Shader("shaders/2DText.vert", "shaders/2DText.frag");
    rendersystem->ParticleShader = new Shader("shaders/Particle.vert", "shaders/Particle.frag");
}

// ============================================================================
// Initiate � scene setup + game loop
// ============================================================================
void Engine::Initiate()
{
    // ------------------------------------------------------------------------
    // Assets
    // ------------------------------------------------------------------------
    Font* arial = new Font("assets/ft/arial.ttf");
    Texture* blanktex = new Texture("assets/blanktexture.png");
    Texture* blacktex = new Texture("assets/blacktexture.png");
    Texture* magic = new Texture("assets/itsmagicbitch.jpg");
    Texture* snowflake = new Texture("assets/snowflake.png");
    Texture* shockwavetex = new Texture("assets/shockwave.png");
    Texture* leontex = new Texture("assets/revolvertex.png");

    // ------------------------------------------------------------------------
    // Shared rig + animations
    // ------------------------------------------------------------------------
    Rig* testrig = new Rig("assets/rig.glb");
    Animation* testanimation = new Animation("assets/walkanim.glb");
    Animation* punchanim = new Animation("assets/punchanim.glb");

    // ------------------------------------------------------------------------
    // Player character
    // ------------------------------------------------------------------------
    Character* testcharacter = new Character();
    testcharacter->name = "character";
    testcharacter->castshadow = true;
    testcharacter->body->t.ScaleBy({ 0.7f, 2.5f, 0.7f });
    testcharacter->body->t.TranslateTo({ 0.0f, 10.0f, 0.0f });
    testcharacter->body->SetRig(testrig);

    // Base animator (weight 0) � walk, looped
    testcharacter->body->SetAnimation(testanimation);
    testcharacter->body->animator->loops = true;

    // Punch animator (weight 1) � one-shot, starts stopped
    Animator* punchAnimator = testcharacter->body->AddAnimator(1);
    punchAnimator->loops = false;
    punchAnimator->SetAnimation(punchanim);
    punchAnimator->StopAnimation();

    // First person: don't draw our own model (other players still see it via the network)
    p* characterBody = new p(testcharacter->body);
    characterBody->mass = 80.0f;
    characterBody->lockRotation = true;
    characterBody->friction = 0.0f;
    physicsengine->AddObject(characterBody);

    // ------------------------------------------------------------------------
    // NPC
    // ------------------------------------------------------------------------
    Character* npc = new Character();
    npc->name = "npc";
    npc->castshadow = true;
    npc->body->t.ScaleBy({ 0.7f, 2.5f, 0.7f });
    npc->body->t.TranslateTo({ 3.0f, 1.25f, 3.0f });
    npc->body->SetRig(testrig);
    npc->body->SetAnimation(testanimation);
    npc->BindToRenderSystem();

    p* npcBody = new p(npc->body);
    npcBody->mass = 80.0f;
    npcBody->lockRotation = true;
    npcBody->friction = 0.0f;
    physicsengine->AddObject(npcBody);

    // ------------------------------------------------------------------------
    // Remote players (other PCs), keyed by network id. Not in physics: their transform
    // comes from the network. Created on first packet, removed when packets stop.
    // ------------------------------------------------------------------------
    struct RemotePlayer {
        Character* character = nullptr;
        double     lastSeen = 0.0;
        p*         body = nullptr;  // host only: lets the host's cubes collide with this player
        glm::vec3  targetPos = glm::vec3(0.0f);  // latest pose received; the model eases toward it every frame
        glm::quat  targetRot = glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
    };
    std::map<int, RemotePlayer> remotes;
    auto SpawnRemote = [&]() -> Character* {
        Character* c = new Character();
        c->name = "remote";
        c->colorOverride = glm::vec4(0.02f, 0.08f, 0.5f, 1.0f);  // dark blue
        c->castshadow = true;
        c->body->t.ScaleBy({ 0.7f, 2.5f, 0.7f });
        c->body->SetRig(testrig);
        c->body->SetAnimation(testanimation);
        c->BindToRenderSystem();
        return c;
        };

    // In a LAN game, start at a random spot so players don't all spawn inside each other
    if (lan && lan->IsActive()) {
        std::mt19937 rng(std::random_device{}());
        std::uniform_real_distribution<float> spread(-8.0f, 8.0f);
        testcharacter->body->t.TranslateTo({ spread(rng), 10.0f, spread(rng) });
    }

    // ------------------------------------------------------------------------
    // Rain particles
    // ------------------------------------------------------------------------
    ParticleEmitter* rain = new ParticleEmitter();
    rain->name = "rain";
    rain->tex = snowflake;
    rain->opaque = false;
    rain->speed = 35.0f;
    rain->lifespan = 0.6f;
    rain->angularvelocity = { 0.0f, 0.0f, glm::radians(10.0f) };
    rain->size = { 0.04f, 0.4f, 0.0f };
    rain->emitangle = { glm::radians(60.0f), glm::radians(360.0f), glm::radians(60.0f) };
    rain->facecamera = false;
    rain->color = { 1.0f, 1.0f, 1.0f, 1.0f };
    rain->emitdirection = ParticleEmitter::EmitDirection::Perpendicular;
    rain->t.TranslateTo({ 0.0f, 10.0f, 0.0f });
    rain->t.RotateToQuaternion(glm::quat(glm::vec3(glm::radians(85.0f), 0.0f, 0.0f)));
    rain->BindToRenderSystem();
    mainf->AddChild(rain);

    // ------------------------------------------------------------------------
    // 3D audio
    // ------------------------------------------------------------------------
    Sound* music = new Sound();
    music->name = "music";
    music->LoadSound("assets/fs.wav", true);
    music->Update3DPosition(0.0f, 0.0f, 0.0f);
    music->PlayTrack(true);
    mainf->AddChild(music);

    // ------------------------------------------------------------------------
    // GUI
    // ------------------------------------------------------------------------
    Crosshair* crosshair = new Crosshair();
    crosshair->Color = { 0.0f, 0.0f, 0.0f };
    crosshair->Dot = true;
    crosshair->Apply();

    // Hit marker: an X around the crosshair built from small squares (Box has no rotation),
    // white for a normal hit and red for a headshot / kill. Fades out after each hit.
    std::vector<Box*> hitMarker;
    for (int corner = 0; corner < 4; ++corner) {
        const float sx = (corner & 1) ? 1.0f : -1.0f, sy = (corner & 2) ? 1.0f : -1.0f;
        for (int step = 0; step < 3; ++step) {
            const float d = 7.0f + step * 3.5f;
            Box* b = new Box();
            b->Opacity = 0.0f;
            b->t2d.center = { 0.5f, 0.5f };
            b->t2d.position = { 0.5f, 0.5f, sx * d, sy * d };
            b->t2d.size = { 0.0f, 0.0f, 3.5f, 3.5f };
            b->BindToRenderSystem();
            hitMarker.push_back(b);
        }
    }
    float hitMarkerTime = 0.0f;
    const float hitMarkerDuration = 0.25f;
    auto ShowHitMarker = [&](bool strong) {
        hitMarkerTime = hitMarkerDuration;
        for (Box* b : hitMarker) b->Color = strong ? glm::vec3(1.0f, 0.15f, 0.15f) : glm::vec3(1.0f);
        };

    TextBox* fpsCounter = new TextBox();
    fpsCounter->font = arial;
    fpsCounter->text = "TEST1231231123";
    fpsCounter->fontsize = 0.5f;
    fpsCounter->Color = { 0.0f, 0.0f, 0.0f };
    fpsCounter->t2d.position = { 1.0f, 0.0f, 0.0f, 0.0f };
    fpsCounter->t2d.center = { 1.0f, 0.0f };
    fpsCounter->textCenter = { 0.0f, 0.5f };
    fpsCounter->t2d.size = { 0.1f, 0.1f, 0.0f, 0.0f };
    fpsCounter->BindToRenderSystem();

    TextBox* netText = new TextBox();
    netText->font = arial;
    netText->text = "";
    netText->fontsize = 0.5f;
    netText->Color = { 1.0f, 1.0f, 1.0f };
    netText->t2d.position = { 1.0f, 0.0f, 0.0f, 110.0f };
    netText->t2d.center = { 1.0f, 0.0f };
    netText->textCenter = { 1.0f, 0.5f };
    netText->t2d.size = { 0.0f, 0.0f, 360.0f, 40.0f };
    netText->BindToRenderSystem();

    // Full-screen green flash when the player takes damage (drawn before the HUD text)
    Box* damageFlash = new Box();
    damageFlash->Color = { 0.0f, 1.0f, 0.2f };
    damageFlash->Opacity = 0.0f;
    damageFlash->t2d.position = { 0.0f, 0.0f, 0.0f, 0.0f };
    damageFlash->t2d.center = { 0.0f, 0.0f };
    damageFlash->t2d.size = { 1.0f, 1.0f, 0.0f, 0.0f };
    damageFlash->BindToRenderSystem();
    int   lastPlayerHealth = 100;
    float damageFlashTime = 0.0f;
    const float damageFlashDuration = 0.35f;

    TextBox* hpText = new TextBox();
    hpText->font = arial;
    hpText->text = "100/100 HP";
    hpText->fontsize = 0.6f;
    hpText->Color = { 1.0f, 1.0f, 1.0f };
    hpText->t2d.position = { 0.0f, 1.0f, 20.0f, -20.0f };
    hpText->t2d.center = { 0.0f, 1.0f };
    hpText->textCenter = { 0.0f, 0.5f };
    hpText->t2d.size = { 0.0f, 0.0f, 400.0f, 90.0f };
    hpText->BindToRenderSystem();

    TextBox* grappleText = new TextBox();
    grappleText->font = arial;
    grappleText->text = "GRAPPLE READY";
    grappleText->fontsize = 0.5f;
    grappleText->Color = { 1.0f, 1.0f, 1.0f };
    grappleText->t2d.position = { 0.5f, 1.0f, 0.0f, -20.0f };
    grappleText->t2d.center = { 0.5f, 1.0f };
    grappleText->textCenter = { 0.5f, 0.5f };
    grappleText->t2d.size = { 0.0f, 0.0f, 560.0f, 40.0f };
    grappleText->BindToRenderSystem();

    // Shot cooldown bar at the bottom of the screen: full and white when ready, empties on a shot
    // and refills as the cooldown runs down.
    const float shotBarWidth = 300.0f, shotBarHeight = 8.0f;
    Box* shotBarBack = new Box();
    shotBarBack->Color = { 0.0f, 0.0f, 0.0f };
    shotBarBack->Opacity = 0.45f;
    shotBarBack->t2d.position = { 0.5f, 1.0f, 0.0f, -30.0f };
    shotBarBack->t2d.center = { 0.5f, 1.0f };
    shotBarBack->t2d.size = { 0.0f, 0.0f, shotBarWidth + 4.0f, shotBarHeight + 4.0f };
    shotBarBack->BindToRenderSystem();
    Box* shotBar = new Box();
    shotBar->Color = { 1.0f, 1.0f, 1.0f };
    shotBar->t2d.position = { 0.5f, 1.0f, -shotBarWidth * 0.5f, -32.0f };
    shotBar->t2d.center = { 0.0f, 1.0f };
    shotBar->t2d.size = { 0.0f, 0.0f, shotBarWidth, shotBarHeight };
    shotBar->BindToRenderSystem();

    // ------------------------------------------------------------------------
    // World meshes
    // ------------------------------------------------------------------------
    Model leonrevolver("assets/leonrevolver.obj");
    for (Mesh* mesh : leonrevolver.meshes) {
        auto newmesh = mesh->Clone();
        newmesh->name = "revolver";
        newmesh->castshadow = true;
        newmesh->meshTexture = leontex;
        newmesh->t.TranslateBy({ 4.0f, 4.0f, 4.0f });
        newmesh->BindToRenderSystem();
        mainf->AddChild(newmesh);
    }

    Mesh* debugcube = CreateCubeMesh();
    debugcube->name = "debugcube";
    debugcube->t.ScaleTo({ 0.8f, 0.8f, 0.8f });
    // Punch hitbox only: intentionally not bound to the render system, so it isn't drawn
    mainf->AddChild(debugcube);

    const float mapScale = 1.5f;  // uniform scale applied to the floor and every map prop
    Mesh* floor = CreateCubeMesh();
    floor->name = "floor";
    floor->meshTexture = blanktex;
    floor->t.ScaleTo({ 80.0f * mapScale, 2.0f, 40.0f * mapScale });
    floor->t.TranslateTo({ 0.0f, -1.0f, 0.0f });
    floor->BindToRenderSystem();
    mainf->AddChild(floor);
    p* floorBody = new p(floor);
    floorBody->velocity = false;
    physicsengine->AddObject(floorBody);

    // Static map props: axis-aligned blocks (collision is AABB-based, so dome/cones/ramp are
    // built from stacked tiers and stairs). Footprints are recorded so respawns avoid them.
    struct Footprint { float minX, maxX, minZ, maxZ; };
    std::vector<Footprint> propFootprints;
    // pos = centre of the block's footprint on the floor; it sits on y = 0 and is `size.y` tall.
    // Walls are frictionless (player friction is 0 too) so you slide along them.
    auto AddBlock = [&](const char* name, glm::vec3 pos, glm::vec3 size, bool slippery = false) {
        pos *= mapScale;
        size *= mapScale;
        Mesh* m = CreateCubeMesh();
        m->name = name;
        m->meshTexture = blanktex;
        m->t.ScaleTo(size);
        m->t.TranslateTo({ pos.x, pos.y + size.y * 0.5f, pos.z });
        m->BindToRenderSystem();
        mainf->AddChild(m);
        p* body = new p(m);
        body->velocity = false;
        if (slippery) body->friction = 0.0f;
        physicsengine->AddObject(body);
        propFootprints.push_back({ pos.x - size.x * 0.5f, pos.x + size.x * 0.5f,
                                   pos.z - size.z * 0.5f, pos.z + size.z * 0.5f });
    };
    // Concentric stack of square tiers, widest at the bottom (stands in for dome / cone)
    // xStretch scales the stack along x only (left/right); height and depth are unchanged
    auto AddTiers = [&](const char* name, glm::vec2 pos, float baseWidth, float tierHeight, int tiers, float xStretch = 1.0f) {
        for (int i = 0; i < tiers; ++i) {
            const float w = baseWidth * (1.0f - float(i) / float(tiers));
            AddBlock(name, { pos.x, tierHeight * i, pos.y }, { w * xStretch, tierHeight, w });
        }
    };

    // Map is a rectangle: x in [-60, 60], z in [-30, 30] (authored at 1x, scaled by mapScale)
    // Centre dome
    AddTiers("dome", { 0.0f, 0.0f }, 18.0f, 2.0f, 5, 0.5f);
    // Cones, opposite corners of the dome
    AddTiers("cone", { -12.0f, -13.0f }, 6.0f, 1.0f, 5);
    AddTiers("cone", { 12.0f, 13.0f }, 6.0f, 1.0f, 5);
    // Big cubes either side of the dome
    AddBlock("cube", { -24.0f, 0.0f, 0.0f }, { 7.0f, 8.4f, 7.0f });
    AddBlock("cube", { 24.0f, 0.0f, 0.0f }, { 7.0f, 8.4f, 7.0f });
    // Stairs climbing to a tall back wall (the ramp), back right
    AddBlock("stair", { 29.0f, 0.0f, -12.0f }, { 2.5f, 1.0f, 10.0f });
    AddBlock("stair", { 31.5f, 0.0f, -12.0f }, { 2.5f, 2.0f, 10.0f });
    AddBlock("stair", { 34.0f, 0.0f, -12.0f }, { 2.5f, 3.0f, 10.0f });
    AddBlock("wall", { 36.5f, 0.0f, -12.0f }, { 1.0f, 9.0f, 10.0f }, true);
    // Stacked boxes, front right
    AddBlock("box", { 30.0f, 0.0f, 12.0f }, { 6.0f, 2.5f, 6.0f });
    AddBlock("box", { 34.5f, 0.0f, 15.0f }, { 5.0f, 5.0f, 5.0f });
    // Long wall with a small block at its end, left front
    AddBlock("wall", { -33.0f, 0.0f, 9.0f }, { 1.0f, 7.0f, 18.0f }, true);
    AddBlock("box", { -30.0f, 0.0f, 17.5f }, { 3.0f, 2.0f, 3.0f });
    // Small box cluster, back left
    AddBlock("box", { -26.0f, 0.0f, -12.0f }, { 6.0f, 2.0f, 6.0f });
    AddBlock("box", { -22.0f, 0.0f, -15.5f }, { 6.0f, 1.0f, 4.0f });

    // Ground check
    auto IsGrounded = [&]() -> bool {
        Ray downRay;
        downRay.origin = testcharacter->body->t.GetTranslation();
        downRay.direction = glm::vec3(0.0f, -1.0f, 0.0f);
        const float halfHeight = testcharacter->body->t.GetScale().y * 0.5f;
        for (p* obj : physicsengine->GetObjects()) {
            if (obj->pointer == testcharacter->body) continue;
            if (!obj->collision) continue;
            auto hit = IsRayInT(downRay, obj->pointer->t);
            if (hit.has_value()) {
                if (glm::distance(downRay.origin, hit.value()) < halfHeight + 0.15f)
                    return true;
            }
        }
        return false;
        };

    // Hitscan shot from the camera. Head = top 20% of the target's box = instant kill,
    // body = 50 damage (two shots). Respawns the target when it dies.
    // Movement tuning
    const float airControl = 0.5f;           // fraction of ground acceleration available in the air
    const float shockedAirControl = 0.1f;    // air control after being hit by another player's shockwave
    const float shockedDuration = 2.0f;      // seconds the reduced air control lasts
    float       shockedTime = 0.0f;
    const float grappleRange = 30.0f;        // metres from the player
    const float grappleSpeed = 28.0f;        // launch speed toward the hit point
    // Visible grapple rope: a thin black box stretched from the hand to the latch point
    const float grappleLineShowTime = 0.5f;
    float       grappleLineTime = 0.0f;
    glm::vec3   grappleLineEnd(0.0f);
    Mesh* grappleLine = CreateCubeMesh();
    grappleLine->name = "grappleline";
    grappleLine->meshTexture = blacktex;
    grappleLine->t.TranslateTo({ 0.0f, -1000.0f, 0.0f });  // hidden until a grapple latches
    grappleLine->BindToRenderSystem();
    mainf->AddChild(grappleLine);
    const float grappleLift = 10.0f;         // extra upward speed added on top of the pull
    const float grappleCooldownTime = 2.5f;  // seconds
    float       grappleCooldown = 0.0f;

    // Slide (key Left Ctrl): locked direction, committed for slideDuration, speed eases from
    // slideBoost x ground top speed down to 1x by slideFalloffTime.
    const float slideBoost = 1.5f;
    const float slideDuration = 0.8f;
    const float slideFalloffTime = 0.7f;
    const float slideDropY = 0.65f;  // standing centre height (0.9) minus lying (0.25)
    const float standEyeOffset = 1.05f;  // eyes 1.05 above body centre (body centre 1.25, height 2.5)
    const float slideEyeOffset = 0.25f;  // lying down, eyes just above the floor
    float       eyeOffset = standEyeOffset;
    bool        sliding = false;
    float       slideTime = 0.0f;
    const float slideCooldownTime = 1.0f;  // seconds after a slide ends before the next
    float       slideCooldown = 0.0f;
    const float dashCooldownTime = 1.5f;  // seconds between dashes
    float       dashCooldown = 0.0f;
    const float shootCooldownTime = 0.5f;  // seconds between shots
    float       shootCooldown = 0.0f;

    // Cubes (E). Whoever hosts (or an offline player) owns and simulates them and decides when they
    // despawn; LAN clients only ask the host for one and draw the poses it streams back.
    const float  cubeCooldownTime = 0.1f;  // seconds between cubes per player
    const double cubeLifetime = 30.0;      // seconds before a cube despawns
    float        cubeCooldown = 0.0f;
    // Cubes also rain from the sky on their own (host / offline only; clients see them via the stream)
    const float  cubeRainInterval = 0.5f;  // seconds between rain cubes
    const float  cubeRainHeight = 45.0f;
    const size_t cubeRainMax = 200;        // stop raining while this many cubes exist
    float        cubeRainTimer = 0.0f;
    struct HostCube { uint32_t id; Mesh* mesh; double spawnTime; };
    std::vector<HostCube> hostCubes;
    uint32_t              nextCubeId = 0;
    std::map<uint8_t, double> lastCubeSpawn;  // host: when each client last spawned one (rate limit)
    struct PuppetCube { Mesh* mesh; double lastSeen; };
    std::map<uint32_t, PuppetCube> puppetCubes;  // client: the host's cubes, keyed by host id
    auto SpawnCube = [&](const glm::vec3& at) {
        Mesh* nc = CreateCubeMesh();
        nc->name = "cube!";
        nc->t.ScaleTo(1.0f);
        nc->t.TranslateTo(at);
        nc->BindToRenderSystem();
        mainf->AddChild(nc);
        physicsengine->AddObject(new p(nc));
        hostCubes.push_back({ ++nextCubeId, nc, glfwGetTime() });
        };
    glm::vec3   slideDir(0.0f);

    // Shockwave (key Q): projectile that explodes on the first surface it touches. The blast
    // launches the player, the NPC and loose props away from the impact point. No damage.
    const float shockSpeed = 30.0f;
    const float shockGravity = 6.0f;
    const float shockLifetime = 3.0f;
    const float shockRadius = 7.0f;
    const float shockPower = 26.0f;       // launch speed at the centre of the blast
    const float shockCooldownTime = 6.0f;
    const float blastShowTime = 0.25f;
    const glm::vec3 hiddenPos(0.0f, -1000.0f, 0.0f);
    float       shockCooldown = 0.0f;
    bool        shockActive = false;
    float       shockAge = 0.0f;
    float       blastTime = 0.0f;
    glm::vec3   shockVel(0.0f);

    Mesh* shockMesh = CreateCubeMesh();
    shockMesh->name = "shockwave";
    shockMesh->meshTexture = blanktex;
    shockMesh->t.ScaleTo({ 0.3f, 0.3f, 0.3f });
    shockMesh->t.TranslateTo(hiddenPos);
    shockMesh->BindToRenderSystem();
    mainf->AddChild(shockMesh);

    Mesh* blastMesh = CreateCubeMesh();
    blastMesh->name = "shockblast";
    blastMesh->meshTexture = shockwavetex;
    blastMesh->t.TranslateTo(hiddenPos);
    blastMesh->BindToRenderSystem();
    mainf->AddChild(blastMesh);

    // fromNet = another player's blast: we only launch ourselves (the other machines launch
    // themselves the same way, since remote players are just puppets on this machine).
    // (Lambda default arguments can't reference locals, so callers pass radius/power explicitly.)
    auto Explode = [&](const glm::vec3& center, bool fromNet, float radius, float power) {
        auto launch = [&](const glm::vec3& pos, p* body) {
            const glm::vec3 offset = pos - center;
            const float dist = glm::length(offset);
            if (dist >= radius) return;
            // Away from the blast, biased upward so grounded targets actually lift off
            glm::vec3 dir = dist > 0.001f ? offset / dist : glm::vec3(0.0f, 1.0f, 0.0f);
            dir.y = std::max(dir.y, 0.0f) + 0.6f;
            dir = glm::normalize(dir);
            const float falloff = 1.0f - 0.7f * (dist / radius);  // 100% at centre, 30% at the edge
            body->linearvelocity += dir * power * falloff;
            body->WakeUp();

            // Another player's blast (not our own) takes away most of our air control for a while
            if (body == characterBody && fromNet) shockedTime = shockedDuration;

            if (body == characterBody && sliding) {
                // The slide overrides horizontal velocity every frame, so end it and stand back up
                sliding = false;
                glm::vec3 p0 = testcharacter->body->t.GetTranslation();
                p0.y += slideDropY + 0.02f;
                testcharacter->body->t.TranslateTo(p0);
            }
        };
        launch(testcharacter->body->t.GetTranslation(), characterBody);
        if (!fromNet) {
            launch(npc->body->t.GetTranslation(), npcBody);
            for (p* obj : physicsengine->GetObjects()) {
                if (!obj->velocity || obj == characterBody || obj == npcBody) continue;
                launch(obj->pointer->t.GetTranslation(), obj);
            }

            NetBlast nb;
            nb.center = center;
            nb.radius = radius;
            nb.power = power;
            if (lan && lan->IsActive()) lan->SendBlast(nb);

            shockActive = false;
            shockMesh->t.TranslateTo(hiddenPos);
        }
        else if (lan && lan->IsActive()) {
            // Another player's blast: launch the cubes (host: the real ones; client: its local copies)
            for (p* obj : physicsengine->GetObjects()) {
                bool isCube = false;
                for (const HostCube& hc : hostCubes) if (obj->pointer == hc.mesh) isCube = true;
                for (auto& kv : puppetCubes) if (obj->pointer == kv.second.mesh) isCube = true;
                if (isCube) launch(obj->pointer->t.GetTranslation(), obj);
            }
        }
        blastMesh->t.TranslateTo(center);
        blastMesh->t.ScaleTo(glm::vec3(0.5f));
        blastTime = blastShowTime;
        camera->AddScreenshake(0.25f);
        };

    const int   maxHealth = 100;
    const int   bodyDamage = 50;
    const int   punchDamage = 25;
    const float headFraction = 0.8f;  // top 20% of the hitbox counts as the head

    // Random respawn spot on the floor (NPC and player), kept clear of every map prop
    std::mt19937 respawnRng(std::random_device{}());
    const float respawnHeight = 15.0f;  // respawn in the air and drop to the floor
    auto RandomSpawn = [&]() -> glm::vec3 {
        std::uniform_real_distribution<float> spreadX(-37.0f * mapScale, 37.0f * mapScale), spreadZ(-17.0f * mapScale, 17.0f * mapScale);
        const float margin = 1.5f;
        for (;;) {
            const float x = spreadX(respawnRng), z = spreadZ(respawnRng);
            bool blocked = false;
            for (const Footprint& f : propFootprints) {
                if (x > f.minX - margin && x < f.maxX + margin &&
                    z > f.minZ - margin && z < f.maxZ + margin) { blocked = true; break; }
            }
            if (blocked) continue;
            return { x, respawnHeight, z };
        }
        };

    auto Shoot = [&]() {
        Ray ray;
        ray.origin = camera->t.GetTranslation();
        ray.direction = glm::normalize(camera->t.GetFrontVector());

        // Nearest shootable target along the ray: the NPC or any remote (LAN) player
        float     targetDist = 1e9f;
        glm::vec3 targetPoint(0.0f);
        t*        targetT = nullptr;
        int       targetRemoteId = -1;  // -1 = the NPC
        auto consider = [&](t& tr, int remoteId) {
            auto h = IsRayInT(ray, tr);
            if (!h.has_value()) return;
            const float d = glm::distance(ray.origin, h.value());
            if (d < targetDist) { targetDist = d; targetPoint = h.value(); targetT = &tr; targetRemoteId = remoteId; }
        };
        consider(npc->body->t, -1);
        for (auto& kv : remotes) consider(kv.second.character->body->t, kv.first);
        if (!targetT) return;

        // Walls/props in front of the target block the shot
        for (p* obj : physicsengine->GetObjects()) {
            if (obj->pointer == testcharacter->body || obj->pointer == npc->body) continue;
            if (!obj->collision) continue;
            auto blocked = IsRayInT(ray, obj->pointer->t);
            if (blocked.has_value() && glm::distance(ray.origin, blocked.value()) < targetDist)
                return;
        }

        const float heightFrac = (targetPoint.y - targetT->GetTranslation().y)
            / targetT->GetScale().y + 0.5f;
        const bool headshot = heightFrac >= headFraction;
        const int  damage = headshot ? maxHealth : bodyDamage;
        camera->AddScreenshake(0.05f);
        ShowHitMarker(headshot);

        if (targetRemoteId >= 0) {
            // Another player: their machine owns their health, so tell it
            NetHit hit;
            hit.damage = damage;
            if (lan && lan->IsActive()) lan->SendHit((uint8_t)targetRemoteId, hit);
            std::cout << (headshot ? "HEADSHOT" : "BODY SHOT") << " - player " << targetRemoteId << "\n";
            return;
        }

        npc->body->Health -= damage;
        std::cout << (headshot ? "HEADSHOT" : "BODY SHOT") << " - NPC HP " << npc->body->Health << "\n";

        if (npc->body->Health <= 0) {
            npc->body->Health = maxHealth;
            npc->body->t.TranslateTo(RandomSpawn());
            npcBody->linearvelocity = glm::vec3(0.0f);
            npcBody->WakeUp();
        }
        };

    // ========================================================================
    // Game loop
    // ========================================================================
    while (!glfwWindowShouldClose(window->handle))
    {
        frame++;
        // Real frame time (clamped so a hitch can't tunnel through colliders), scaled so the game
        // plays at the speed it had when it ran one 1/fps step per frame on a 144 Hz display.
        // refDt is the step the movement constants were tuned at.
        static double prevFrameTime = glfwGetTime();
        const double  frameNow = glfwGetTime();
        const float   deltatime = glm::clamp(float(frameNow - prevFrameTime), 0.001f, 1.0f / 60.0f) * (144.0f / float(fps));
        prevFrameTime = frameNow;
        const float   refDt = 1.0f / float(fps);

        const glm::vec3 camFront = camera->t.GetFrontVector();
        const glm::vec3 camRight = camera->t.GetRightVector();
        const float     walkScale = 0.6f;  // WASD speed relative to the original 3.9
        const float     movespeed = 3.0f * 1.3f * walkScale;

        // --------------------------------------------------------------------
        // Input � mouse
        // --------------------------------------------------------------------
        while (Mouse::Event buffer = mouse->Read()) {
            if (buffer.GetType() == Mouse::Event::Type::Move) {
                float xoffset = mouse->GetX() - mouse->GetLastX();
                float yoffset = mouse->GetLastY() - mouse->GetY();
                camera->ProcessMouseMovement(xoffset, yoffset);
            }
            else if (buffer.GetType() == Mouse::Event::Type::LPress) {
                if (shootCooldown <= 0.0f) {
                    shootCooldown = shootCooldownTime;
                    Shoot();
                }
            }
            else if (buffer.GetType() == Mouse::Event::Type::RPress) {
                camera->lockedcursor = !camera->lockedcursor;
            }
        }

        // --------------------------------------------------------------------
        // Input � held movement
        // --------------------------------------------------------------------
        glm::vec3 inputVel = glm::vec3(0.0f);
        if (keyboard->IsKeyDown('W')) inputVel += glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z));
        if (keyboard->IsKeyDown('S')) inputVel -= glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z));
        if (keyboard->IsKeyDown('A')) inputVel += glm::normalize(glm::vec3(camRight.x, 0.0f, camRight.z));
        if (keyboard->IsKeyDown('D')) inputVel -= glm::normalize(glm::vec3(camRight.x, 0.0f, camRight.z));
        if (glm::length(inputVel) > 0.0f)
            inputVel = glm::normalize(inputVel) * movespeed;

        // --------------------------------------------------------------------
        // Input � keyboard events
        // --------------------------------------------------------------------
        while (Keyboard::Event buffer = keyboard->ReadKey()) {
            if (buffer.GetCode() == 'E' && buffer.IsPress() && cubeCooldown <= 0.0f) {
                cubeCooldown = cubeCooldownTime;
                if (lan && lan->IsActive() && lan->GetMode() == Lan::Mode::Client)
                    lan->SendCubeSpawn(camera->t.GetTranslation());  // the host spawns it
                else
                    SpawnCube(camera->t.GetTranslation());
            }
            if (buffer.GetCode() == 'F' && buffer.IsPress()) {
                const glm::vec3 playerPos = testcharacter->body->t.GetTranslation();
                const glm::vec3 playerFront = glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z));

                // Restart punch on high-priority animator
                punchAnimator->m_CurrentTime = 0.0f;
                punchAnimator->PlayAnimation();

                debugcube->t.TranslateTo(playerPos + playerFront * 0.8f);
                debugcube->t.ScaleTo({ 0.8f, 0.8f, 0.8f });
                debugcube->t.RotateToQuaternion(LookAt(-playerFront));

                std::optional<TInTInfo> hit = TInT(debugcube->t, npc->body->t);
                if (hit.has_value()) {
                    std::cout << "HIT NPC\n";
                    npcBody->WakeUp();
                    npcBody->linearvelocity += playerFront * 5.0f + glm::vec3(0.0f, 3.0f, 0.0f);
                    camera->AddScreenshake(0.15f);  // landing a punch feels impactful
                    ShowHitMarker(false);

                    npc->body->Health -= punchDamage;
                    std::cout << "PUNCH - NPC HP " << npc->body->Health << "\n";
                    if (npc->body->Health <= 0) {
                        npc->body->Health = maxHealth;
                        npc->body->t.TranslateTo(RandomSpawn());
                        npcBody->linearvelocity = glm::vec3(0.0f);
                        npcBody->WakeUp();
                    }
                }
                else {
                    std::cout << "MISSED\n";
                }

                // Punch LAN players too: their machine applies the damage and knockback
                for (auto& kv : remotes) {
                    if (!TInT(debugcube->t, kv.second.character->body->t).has_value()) continue;
                    NetHit ph;
                    ph.damage = punchDamage;
                    ph.knockback = playerFront * 5.0f + glm::vec3(0.0f, 3.0f, 0.0f);
                    if (lan && lan->IsActive()) lan->SendHit((uint8_t)kv.first, ph);
                    camera->AddScreenshake(0.15f);
                    ShowHitMarker(false);
                    std::cout << "PUNCH - player " << kv.first << "\n";
                }
            }
            if (buffer.GetCode() == GLFW_KEY_LEFT_SHIFT && buffer.IsPress() && !sliding && dashCooldown <= 0.0f) {
                dashCooldown = dashCooldownTime;
                glm::vec3 dashDir = glm::length(inputVel) > 0.0f
                    ? glm::normalize(inputVel)
                    : glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z));
                characterBody->linearvelocity.x += dashDir.x * 18.0f;
                characterBody->linearvelocity.z += dashDir.z * 18.0f;
                camera->AddScreenshake(0.04f);
            }
            if (buffer.GetCode() == GLFW_KEY_LEFT_CONTROL && buffer.IsPress() && !sliding && slideCooldown <= 0.0f && IsGrounded()) {
                const glm::vec3 horizVel(characterBody->linearvelocity.x, 0.0f, characterBody->linearvelocity.z);
                if (glm::length(inputVel) > 0.0f || glm::length(horizVel) > 1.0f) {
                    slideDir = glm::length(inputVel) > 0.0f ? glm::normalize(inputVel) : glm::normalize(horizVel);
                    sliding = true;
                    slideTime = 0.0f;
                    slideCooldown = slideDuration + slideCooldownTime;

                    // Lie down feet-first: tilt the model's up axis to point back along the slide.
                    // Hitbox is the same box, rotated with it; drop it so the feet stay on the floor.
                    const glm::vec3 tiltAxis = glm::normalize(glm::cross(slideDir, glm::vec3(0.0f, 1.0f, 0.0f)));
                    testcharacter->body->t.RotateToQuaternion(
                        glm::angleAxis(glm::radians(90.0f), tiltAxis) * LookAt(-slideDir));
                    glm::vec3 pos = testcharacter->body->t.GetTranslation();
                    pos.y -= slideDropY;
                    testcharacter->body->t.TranslateTo(pos);
                    camera->AddScreenshake(0.06f);
                }
            }
            if (buffer.GetCode() == 'R' && buffer.IsPress() && !sliding && grappleCooldown <= 0.0f) {
                // Short-range grapple: aim with the camera, latch onto a surface within range
                Ray ray;
                ray.origin = camera->t.GetTranslation();
                ray.direction = glm::normalize(camFront);
                float bestDist = grappleRange;
                glm::vec3 bestPoint(0.0f);
                bool found = false;
                for (p* obj : physicsengine->GetObjects()) {
                    if (obj->pointer == testcharacter->body || obj->pointer == npc->body) continue;
                    if (!obj->collision) continue;
                    auto hit = IsRayInT(ray, obj->pointer->t);
                    if (!hit.has_value()) continue;
                    const float d = glm::distance(ray.origin, hit.value());
                    if (d < bestDist) { bestDist = d; bestPoint = hit.value(); found = true; }
                }
                if (found) {
                    characterBody->linearvelocity = glm::normalize(bestPoint - ray.origin) * grappleSpeed;
                    // Extra upward fling so the grapple gains height instead of just pulling sideways
                    characterBody->linearvelocity.y = std::max(characterBody->linearvelocity.y, 0.0f) + grappleLift;
                    characterBody->WakeUp();
                    grappleCooldown = grappleCooldownTime;
                    grappleLineTime = grappleLineShowTime;
                    grappleLineEnd = bestPoint;
                    camera->AddScreenshake(0.1f);
                }
            }
            if (buffer.GetCode() == 'Q' && buffer.IsPress() && !shockActive && shockCooldown <= 0.0f) {
                const glm::vec3 front = glm::normalize(camFront);
                shockMesh->t.TranslateTo(camera->t.GetTranslation() + front * 0.6f);
                shockVel = front * shockSpeed;
                shockActive = true;
                shockAge = 0.0f;
                shockCooldown = shockCooldownTime;
                camera->AddScreenshake(0.05f);
            }
            if (buffer.GetCode() == 'G' && buffer.IsPress()) {
                camera->AddScreenshake(0.2f);
            }
            if (buffer.GetCode() == GLFW_KEY_SPACE && buffer.IsPress()) {
                if (!sliding && IsGrounded())
                    characterBody->linearvelocity.y = 11.0f;
            }
        }

        // --------------------------------------------------------------------
        // Input � held keys
        // --------------------------------------------------------------------
        if (keyboard->IsKeyDown(GLFW_KEY_ESCAPE))
            glfwSetWindowShouldClose(window->handle, 1);

        // Movement + damping
        grappleCooldown = std::max(grappleCooldown - deltatime, 0.0f);
        slideCooldown = std::max(slideCooldown - deltatime, 0.0f);
        dashCooldown = std::max(dashCooldown - deltatime, 0.0f);
        shootCooldown = std::max(shootCooldown - deltatime, 0.0f);
        cubeCooldown = std::max(cubeCooldown - deltatime, 0.0f);
        const float accel = 40.0f;
        const float damp = 0.75f;
        const float groundTopSpeed = movespeed * accel * refDt * damp / (1.0f - damp);
        if (sliding) {
            // Direction is locked; speed eases from boost x down to 1x (quadratic: drops fastest early)
            slideTime += deltatime;
            const float u = glm::clamp(slideTime / slideFalloffTime, 0.0f, 1.0f);
            const float speed = (groundTopSpeed / walkScale) * (1.0f + (slideBoost - 1.0f) * (1.0f - u) * (1.0f - u));
            characterBody->linearvelocity.x = slideDir.x * speed;
            characterBody->linearvelocity.z = slideDir.z * speed;

            if (slideTime >= slideDuration) {
                sliding = false;
                glm::vec3 pos = testcharacter->body->t.GetTranslation();
                pos.y += slideDropY + 0.02f;  // stand back up (rotation is reset below)
                testcharacter->body->t.TranslateTo(pos);
            }
        }
        else if (IsGrounded()) {
            // Drag and acceleration rescaled so the top speed is the same at any frame rate
            const float dampStep = std::pow(damp, deltatime / refDt);
            const float accelScale = refDt * damp * (1.0f - dampStep) / (deltatime * dampStep * (1.0f - damp));
            characterBody->linearvelocity.x *= dampStep;
            characterBody->linearvelocity.z *= dampStep;
            characterBody->linearvelocity.x += inputVel.x * accel * deltatime * accelScale;
            characterBody->linearvelocity.z += inputVel.z * accel * deltatime * accelScale;
        }
        else if (glm::length(inputVel) > 0.0f) {
            // Air: no ground drag so momentum (grapple, dash) carries. Input only adds
            // speed along the wish direction up to movespeed, at airControl of ground accel.
            const glm::vec3 wishDir = glm::normalize(inputVel);
            const float current = glm::dot(glm::vec3(characterBody->linearvelocity.x, 0.0f,
                characterBody->linearvelocity.z), wishDir);
            const float add = glm::clamp(groundTopSpeed - current, 0.0f,
                accel * (shockedTime > 0.0f ? shockedAirControl : airControl) * movespeed * deltatime);
            characterBody->linearvelocity.x += wishDir.x * add;
            characterBody->linearvelocity.z += wishDir.z * add;
        }

        // --------------------------------------------------------------------
        // Scene updates
        // --------------------------------------------------------------------
        {
            const glm::vec3 playerPos = testcharacter->body->t.GetTranslation();
            const glm::vec3 playerFront = glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z));
            debugcube->t.TranslateTo(playerPos + playerFront * 0.8f);
            debugcube->t.ScaleTo({ 0.8f, 0.8f, 0.8f });
            debugcube->t.RotateToQuaternion(LookAt(-playerFront));
        }

        // Shockwave projectile: arc forward, explode on the first collider along this frame's path
        shockCooldown = std::max(shockCooldown - deltatime, 0.0f);
        shockedTime = std::max(shockedTime - deltatime, 0.0f);
        if (shockActive) {
            shockVel.y -= shockGravity * deltatime;
            shockAge += deltatime;
            const glm::vec3 from = shockMesh->t.GetTranslation();
            const glm::vec3 step = shockVel * deltatime;
            const float stepLen = glm::length(step);

            Ray ray;
            ray.origin = from;
            ray.direction = step / stepLen;
            float bestDist = stepLen;
            glm::vec3 bestPoint(0.0f);
            bool found = false;
            for (p* obj : physicsengine->GetObjects()) {
                if (obj == characterBody || !obj->collision) continue;
                auto hit = IsRayInT(ray, obj->pointer->t);
                if (!hit.has_value()) continue;
                const float d = glm::distance(from, hit.value());
                if (d <= bestDist) { bestDist = d; bestPoint = hit.value(); found = true; }
            }

            if (found) Explode(bestPoint, false, shockRadius, shockPower);
            else if (shockAge >= shockLifetime) {
                shockActive = false;
                shockMesh->t.TranslateTo(hiddenPos);
            }
            else shockMesh->t.TranslateTo(from + step);
        }
        if (blastTime > 0.0f) {
            blastTime -= deltatime;
            if (blastTime <= 0.0f) {
                blastMesh->t.TranslateTo(hiddenPos);
            }
            else {
                // Expand to the full blast radius over its lifetime
                const float u = 1.0f - blastTime / blastShowTime;
                blastMesh->t.ScaleTo(glm::vec3(0.5f + (shockRadius * 2.0f - 0.5f) * u));
            }
        }

        rain->t.TranslateTo(camera->t.GetTranslation() + glm::vec3(0.0f, 20.0f, 0.0f));

        if (!sliding) {
            testcharacter->body->t.RotateToQuaternion(
                LookAt(-glm::normalize(glm::vec3(camFront.x, 0.0f, camFront.z)))
            );
        }
        // First person: camera at the eyes (eased down while sliding)
        eyeOffset += ((sliding ? slideEyeOffset : standEyeOffset) - eyeOffset) * (1.0f - std::pow(0.7f, deltatime / refDt));
        camera->t.TranslateTo(testcharacter->body->t.GetTranslation() + glm::vec3(0.0f, eyeOffset, 0.0f));

        Sound* music = static_cast<Sound*>(mainf->GetFirstChildOfName("music"));
        music->Update3DPosition(5.0f, 4.0f, 6.5f);  // where the old floating cube was

        soundsystem->SetListenerPosition(
            camera->t.GetTranslation(),
            camera->t.GetFrontVector(),
            camera->t.GetUpVector()
        );

        // --------------------------------------------------------------------
        // FPS counter
        // --------------------------------------------------------------------
        {
            static double lastTime = glfwGetTime();
            static int    frameCount = 0;
            static int    measuredFps = 0;
            static float  accumulator = 0.0f;
            double now = glfwGetTime();
            accumulator += (float)(now - lastTime);
            lastTime = now;
            frameCount++;
            if (accumulator >= 0.25f) {
                measuredFps = (int)(frameCount / accumulator);
                frameCount = 0;
                accumulator = 0.0f;
            }
            fpsCounter->text = std::to_string(measuredFps) + " FPS";
        }
        {
            const float ready = 1.0f - glm::clamp(shootCooldown / shootCooldownTime, 0.0f, 1.0f);
            shotBar->t2d.size = { 0.0f, 0.0f, shotBarWidth * ready, shotBarHeight };
            shotBar->Opacity = ready > 0.0f ? 1.0f : 0.0f;
        }
        // Grapple rope: starts at the hand (follows the camera), ends on the latch point
        grappleLineTime = std::max(grappleLineTime - deltatime, 0.0f);
        if (grappleLineTime > 0.0f) {
            const glm::vec3 handPos = camera->t.GetTranslation() + camera->t.GetFrontVector() * 0.6f
                + camera->t.GetRightVector() * 0.3f - camera->t.GetUpVector() * 0.3f;
            const glm::vec3 delta = grappleLineEnd - handPos;
            const float len = glm::length(delta);
            if (len > 0.01f) {
                grappleLine->t.TranslateTo(handPos + delta * 0.5f);
                grappleLine->t.ScaleTo({ 0.05f, 0.05f, len });
                grappleLine->t.RotateToQuaternion(LookAt(delta));
            }
        }
        else grappleLine->t.TranslateTo(hiddenPos);
        hitMarkerTime = std::max(hitMarkerTime - deltatime, 0.0f);
        for (Box* b : hitMarker) b->Opacity = hitMarkerTime / hitMarkerDuration;
        // Damage flash: any HP loss restarts a short green fade-out
        if (testcharacter->body->Health < lastPlayerHealth)
            damageFlashTime = damageFlashDuration;
        lastPlayerHealth = testcharacter->body->Health;
        damageFlashTime = std::max(damageFlashTime - deltatime, 0.0f);
        damageFlash->Opacity = 0.45f * (damageFlashTime / damageFlashDuration);
        // Player respawn: at 0 HP or after falling off the map, teleport to a random spot
        if (testcharacter->body->Health <= 0 || testcharacter->body->t.GetTranslation().y < -20.0f) {
            testcharacter->body->Health = maxHealth;
            testcharacter->body->t.TranslateTo(RandomSpawn());
            characterBody->linearvelocity = glm::vec3(0.0f);
            characterBody->WakeUp();
            sliding = false;
        }
        hpText->text = std::to_string(std::max(testcharacter->body->Health, 0)) + "/100 HP";
        grappleText->text = grappleCooldown > 0.0f
            ? "GRAPPLE " + std::to_string(grappleCooldown).substr(0, 3) + "s"
            : "GRAPPLE READY";
        grappleText->text += shockCooldown > 0.0f
            ? "  |  SHOCKWAVE " + std::to_string(shockCooldown).substr(0, 3) + "s"
            : "  |  SHOCKWAVE READY (Q)";

        // --------------------------------------------------------------------
        // Step systems
        // --------------------------------------------------------------------
        camera->Step(deltatime);
        rain->Step(deltatime);
        testcharacter->Step(deltatime);
        npc->Step(deltatime);
        soundsystem->Update();
        // Split into equal substeps of at most 1/120 s so jump arcs, falling and collisions
        // come out the same whatever the frame rate
        {
            const int   substeps = std::max(1, (int)std::ceil(deltatime * 120.0f));
            const float subDt = deltatime / float(substeps);
            for (int i = 0; i < substeps; i++) physicsengine->Step(subDt);
        }

        // --------------------------------------------------------------------
        // LAN: send our transform, apply the other player's
        // --------------------------------------------------------------------
        // Rain cubes from the sky at random spots over the map (host / offline)
        if (!lan || !lan->IsActive() || lan->GetMode() == Lan::Mode::Host) {
            cubeRainTimer -= deltatime;
            if (cubeRainTimer <= 0.0f) {
                cubeRainTimer += cubeRainInterval;
                if (hostCubes.size() < cubeRainMax) {
                    glm::vec3 at = RandomSpawn();
                    at.y = cubeRainHeight;
                    SpawnCube(at);
                    std::uniform_real_distribution<float> spin(0.0f, 6.28318f);
                    hostCubes.back().mesh->t.RotateToEulerAngles({ spin(respawnRng), spin(respawnRng), spin(respawnRng) });
                }
            }
        }

        // Despawn cubes that have lived long enough (host / offline)
        {
            const double cubeNow = glfwGetTime();
            for (size_t i = 0; i < hostCubes.size();) {
                if (cubeNow - hostCubes[i].spawnTime > cubeLifetime) {
                    Mesh* m = hostCubes[i].mesh;
                    rendersystem->RemoveRenderable(m);
                    physicsengine->RemoveObject(m);
                    m->Delete();
                    hostCubes.erase(hostCubes.begin() + i);
                }
                else ++i;
            }
        }

        if (lan && lan->IsActive()) {
            NetState mine;
            mine.position = testcharacter->body->t.GetTranslation();
            mine.rotation = testcharacter->body->t.GetRotationQuaternion();
            mine.sliding = sliding;
            lan->Send(mine);

            const double now = glfwGetTime();
            std::vector<NetUpdate> updates;
            std::vector<NetBlast> blasts;
            std::vector<NetHit> hits;
            std::vector<NetCubeRequest> cubeRequests;
            std::vector<NetCube> cubeStates;
            lan->Receive(updates, &blasts, &hits, &cubeRequests, &cubeStates);

            // Host: spawn the cubes clients asked for (rate limited per client), then stream every cube's pose
            for (const NetCubeRequest& rq : cubeRequests) {
                double& last = lastCubeSpawn[rq.sender];
                if (now - last < cubeCooldownTime * 0.9) continue;
                last = now;
                SpawnCube(glm::clamp(rq.position, glm::vec3(-200.0f), glm::vec3(200.0f)));
            }
            if (lan->GetMode() == Lan::Mode::Host) {
                std::vector<NetCube> snapshot;
                snapshot.reserve(hostCubes.size());
                for (const HostCube& hc : hostCubes) {
                    NetCube nc;
                    nc.id = hc.id;
                    nc.position = hc.mesh->t.GetTranslation();
                    nc.rotation = hc.mesh->t.GetRotationQuaternion();
                    snapshot.push_back(nc);
                }
                lan->SendCubes(snapshot);
            }

            // Client: show the host's cubes, and drop the ones it stopped sending (despawned)
            for (const NetCube& nc : cubeStates) {
                auto it = puppetCubes.find(nc.id);
                if (it == puppetCubes.end()) {
                    Mesh* m = CreateCubeMesh();
                    m->name = "cube!";
                    m->t.ScaleTo(1.0f);
                    m->BindToRenderSystem();
                    mainf->AddChild(m);
                    // Simulated locally exactly like the host's cubes (so the local player pushes them with
                    // no lag); the host's stream below only corrects drift.
                    physicsengine->AddObject(new p(m));
                    m->t.TranslateTo(nc.position);
                    m->t.RotateToQuaternion(nc.rotation);
                    it = puppetCubes.emplace(nc.id, PuppetCube{ m, now }).first;
                }
                else {
                    t& ct = it->second.mesh->t;
                    const glm::vec3 err = nc.position - ct.GetTranslation();
                    if (glm::length(err) > 3.0f) {
                        ct.TranslateTo(nc.position);
                        ct.RotateToQuaternion(nc.rotation);
                    }
                    else {
                        ct.TranslateBy(err * 0.35f);
                        ct.RotateToQuaternion(glm::slerp(ct.GetRotationQuaternion(), nc.rotation, 0.35f));
                    }
                }
                it->second.lastSeen = now;
            }
            for (auto it = puppetCubes.begin(); it != puppetCubes.end();) {
                if (now - it->second.lastSeen > 1.5) {
                    rendersystem->RemoveRenderable(it->second.mesh);
                    physicsengine->RemoveObject(it->second.mesh);
                    it->second.mesh->Delete();
                    it = puppetCubes.erase(it);
                }
                else ++it;
            }
            for (const NetBlast& b : blasts)
                Explode(b.center, true, b.radius, b.power);
            // Damage from other players (respawn handles dying, see the player respawn check)
            for (const NetHit& h : hits) {
                testcharacter->body->Health -= h.damage;
                characterBody->linearvelocity += h.knockback;
                characterBody->WakeUp();
                camera->AddScreenshake(0.15f);
                std::cout << "HIT by player " << (int)h.sender << " for " << h.damage
                          << " - HP " << testcharacter->body->Health << "\n";
            }
            for (const NetUpdate& u : updates) {
                auto it = remotes.find(u.id);
                if (it == remotes.end()) {
                    // First packet from this player: spawn them exactly at their pose
                    RemotePlayer rp;
                    rp.character = SpawnRemote();
                    rp.character->body->t.TranslateTo(u.state.position);
                    rp.character->body->t.RotateToQuaternion(u.state.rotation);
                    rp.targetPos = u.state.position;
                    rp.targetRot = u.state.rotation;
                    if (lan->GetMode() == Lan::Mode::Host) {
                        // Solid for the host's cubes (kinematic: moved by the client's stream only)
                        rp.body = new p(rp.character->body);
                        rp.body->velocity = false;
                        physicsengine->AddObject(rp.body);
                    }
                    it = remotes.emplace(u.id, rp).first;
                }
                else {
                    // Packets arrive in bursts (several in one frame, then none), so just remember the
                    // newest pose here; the per-frame smoothing below does the actual moving.
                    it->second.targetPos = u.state.position;
                    it->second.targetRot = u.state.rotation;
                }
                it->second.lastSeen = now;
            }

            // Drop players we haven't heard from in 2 s, animate the rest
            for (auto it = remotes.begin(); it != remotes.end();) {
                if (now - it->second.lastSeen > 2.0) {
                    rendersystem->RemoveRenderable(it->second.character);
                    if (it->second.body) physicsengine->RemoveObject(it->second.character->body);
                    delete it->second.character;
                    it = remotes.erase(it);
                }
                else {
                    // Frame-rate independent ease toward the latest pose (no matter how packets were batched)
                    t& rt = it->second.character->body->t;
                    const glm::vec3 before = rt.GetTranslation();
                    if (glm::distance(before, it->second.targetPos) > 6.0f)
                        rt.TranslateTo(it->second.targetPos);  // respawn / big jump: snap
                    else {
                        const float k = 1.0f - std::exp(-deltatime * 25.0f);
                        rt.TranslateTo(glm::mix(before, it->second.targetPos, k));
                    }
                    rt.RotateToQuaternion(glm::slerp(rt.GetRotationQuaternion(), it->second.targetRot,
                        1.0f - std::exp(-deltatime * 25.0f)));
                    // Kinematic body: its velocity makes cubes get pushed like the client's own body does there
                    if (it->second.body && deltatime > 0.0f)
                        it->second.body->linearvelocity = (rt.GetTranslation() - before) / deltatime;
                    it->second.character->Step(deltatime);
                    ++it;
                }
            }

            if (lan->GetMode() == Lan::Mode::Host)
                netText->text = "LAN: hosting - " + std::to_string(lan->PeerCount() + 1) + "/"
                    + std::to_string(Lan::MaxPlayers) + " players";
            else
                netText->text = lan->IsConnected() ? "LAN: connected - " + std::to_string(remotes.size() + 1) + " players"
                                                   : "LAN: joining...";
        }

        // --------------------------------------------------------------------
        // Render
        // --------------------------------------------------------------------
        rendersystem->Render(*camera);

        glfwPollEvents();
    }
}

// ============================================================================
// GLFW callbacks
// ============================================================================
void framebuffer_size_callback(GLFWwindow* window, int w, int h)
{
    if (w <= 0 || h <= 0) return;  // minimised
    // Everything pixel-based (viewport, projection aspect, GUI layout, scissor) reads these
    ::window->width = w;
    ::window->height = h;
    glViewport(0, 0, w, h);
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    // F11: toggle fullscreen on the primary monitor, restoring the old window rect on exit
    if (key == GLFW_KEY_F11 && action == GLFW_PRESS) {
        static int wx = 100, wy = 100, ww = 1920, wh = 1080;
        if (glfwGetWindowMonitor(window)) {
            glfwSetWindowMonitor(window, nullptr, wx, wy, ww, wh, 0);
        }
        else {
            glfwGetWindowPos(window, &wx, &wy);
            glfwGetWindowSize(window, &ww, &wh);
            GLFWmonitor* monitor = glfwGetPrimaryMonitor();
            const GLFWvidmode* mode = glfwGetVideoMode(monitor);
            glfwSetWindowMonitor(window, monitor, 0, 0, mode->width, mode->height, mode->refreshRate);
        }
        glfwSwapInterval(1);
    }

    if (action == GLFW_PRESS)   keyboard->KeyDown(key);
    else if (action == GLFW_RELEASE) keyboard->KeyUp(key);
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
}

void mouse_callback(GLFWwindow* window, double xposIn, double yposIn)
{
    mouse->OnMouseMove(static_cast<float>(xposIn), static_cast<float>(yposIn));
    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    // Cursor coordinates are in window units, which can differ from framebuffer pixels (DPI scaling)
    int ww, wh;
    glfwGetWindowSize(window, &ww, &wh);
    glfwSetCursorPos(window, ww / 2.0, wh / 2.0);
    mouse->OnMouseMove(ww / 2.0f, wh / 2.0f);
}

void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
{
    if (button == GLFW_MOUSE_BUTTON_RIGHT) {
        if (action == GLFW_PRESS) mouse->RightDown();
        else                      mouse->RightUp();
    }
    else if (button == GLFW_MOUSE_BUTTON_LEFT) {
        if (action == GLFW_PRESS) mouse->LeftDown();
        else                      mouse->LeftUp();
    }
}