#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);

    rendersystem = new RenderSystem();
    rendersystem->Initialize();
    physicsengine = new Physics();
    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* magic = new Texture("assets/itsmagicbitch.jpg");
    Texture* snowflake = new Texture("assets/snowflake.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({ 0.5f, 1.8f, 0.5f });
    testcharacter->body->t.TranslateTo({ 0.0f, 0.9f, 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({ 0.5f, 1.8f, 0.5f });
    npc->body->t.TranslateTo({ 3.0f, 0.9f, 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;
    };
    std::map<int, RemotePlayer> remotes;
    auto SpawnRemote = [&]() -> Character* {
        Character* c = new Character();
        c->name = "remote";
        c->castshadow = true;
        c->body->t.ScaleBy({ 0.5f, 1.8f, 0.5f });
        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), 0.9f, 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();

    TextBox* tb = new TextBox();
    tb->font = arial;
    tb->text = "ASDASD\nASDASD\nADSADSA";
    tb->fontsize = 0.5f;
    tb->Color = { 0.0f, 0.0f, 0.0f };
    tb->t2d.position = { 0.5f, 0.5f, 0.0f, 0.0f };
    tb->t2d.center = { 0.0f, 0.0f };
    tb->textCenter = { 0.0f, 0.5f };
    tb->t2d.size = { 0.2f, 0.1f, 0.0f, 0.0f };
    tb->BindToRenderSystem();

    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, 40.0f };
    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();

    TextBox* hpText = new TextBox();
    hpText->font = arial;
    hpText->text = "100/100 HP";
    hpText->fontsize = 0.7f;
    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, 220.0f, 50.0f };
    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, 300.0f, 40.0f };
    grappleText->BindToRenderSystem();

    ImageBox* testgui = new ImageBox();
    testgui->tex = magic;
    testgui->Color = { 1.0f, 1.0f, 1.0f };
    testgui->Opacity = 0.8f;
    testgui->rounding = 0.1f;
    testgui->t2d.center = { 0.0f, 1.0f };
    testgui->t2d.position = { 0.0f, 1.0f, 10.0f, -10.0f };
    testgui->t2d.size = { 0.0f, 0.0f, 744.0f / 2.0f, 914.0f / 2.0f };
    testgui->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 });
    debugcube->BindToRenderSystem();
    mainf->AddChild(debugcube);

    Mesh* floor = CreateCubeMesh();
    floor->name = "floor";
    floor->meshTexture = blanktex;
    floor->t.ScaleTo({ 100.0f, 2.0f, 100.0f });
    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);

    // Wall: frictionless (player friction is 0 too) so you slide along it
    Mesh* wall = CreateCubeMesh();
    wall->name = "wall";
    wall->meshTexture = blanktex;
    wall->t.ScaleTo({ 1.0f, 6.0f, 20.0f });
    wall->t.TranslateTo({ -8.0f, 3.0f, 0.0f });
    wall->BindToRenderSystem();
    mainf->AddChild(wall);
    p* wallBody = new p(wall);
    wallBody->velocity = false;
    wallBody->friction = 0.0f;
    physicsengine->AddObject(wallBody);

    Mesh* cube = CreateCubeMesh();
    cube->name = "cube";
    cube->meshTexture = blanktex;
    cube->t.ScaleTo({ 1.0f, 1.0f, 1.0f });
    cube->t.TranslateTo({ 5.0f, 4.0f, 6.5f });
    cube->BindToRenderSystem();
    mainf->AddChild(cube);

    Mesh* cube2 = CreateCubeMesh();
    cube2->name = "cubee";
    cube2->meshTexture = blanktex;
    cube2->t.ScaleTo({ 1.0f,  1.0f,  1.0f });
    cube2->t.TranslateTo({ 10.0f, 4.0f, 10.5f });
    cube2->BindToRenderSystem();
    mainf->AddChild(cube2);

    // 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 grappleRange = 4.0f;         // metres from the player
    const float grappleSpeed = 28.0f;        // launch speed toward the hit point
    const float grappleCooldownTime = 2.5f;  // seconds
    float       grappleCooldown = 0.0f;

    // Slide (key C): locked direction, committed for slideDuration, speed eases from
    // slideBoost x ground top speed down to 1x by slideFalloffTime.
    const float slideBoost = 2.0f;
    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 = 0.7f;   // eyes 0.7 above body centre (body centre 0.9, height 1.8)
    const float slideEyeOffset = 0.25f;  // lying down, eyes just above the floor
    float       eyeOffset = standEyeOffset;
    bool        sliding = false;
    float       slideTime = 0.0f;
    glm::vec3   slideDir(0.0f);

    const int   maxHealth = 100;
    const int   bodyDamage = 50;
    const float headFraction = 0.8f;
    auto Shoot = [&]() {
        Ray ray;
        ray.origin = camera->t.GetTranslation();
        ray.direction = glm::normalize(camera->t.GetFrontVector());

        auto targetHit = IsRayInT(ray, npc->body->t);
        if (!targetHit.has_value()) return;
        const float targetDist = glm::distance(ray.origin, targetHit.value());

        // 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 = (targetHit->y - npc->body->t.GetTranslation().y)
            / npc->body->t.GetScale().y + 0.5f;
        const bool headshot = heightFrac >= headFraction;
        npc->body->Health -= headshot ? maxHealth : bodyDamage;
        std::cout << (headshot ? "HEADSHOT" : "BODY SHOT") << " - NPC HP " << npc->body->Health << "\n";
        camera->AddScreenshake(0.05f);

        if (npc->body->Health <= 0) {
            npc->body->Health = maxHealth;
            npc->body->t.TranslateTo({ 3.0f, 0.9f, 3.0f });
            npcBody->linearvelocity = glm::vec3(0.0f);
            npcBody->WakeUp();
        }
        };

    // ========================================================================
    // Game loop
    // ========================================================================
    while (!glfwWindowShouldClose(window->handle))
    {
        frame++;
        const float deltatime = 1.0f / float(fps);

        const glm::vec3 camFront = camera->t.GetFrontVector();
        const glm::vec3 camRight = camera->t.GetRightVector();
        const float     movespeed = 3.0f * 1.3f;

        // --------------------------------------------------------------------
        // 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) {
                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()) {
                Mesh* nc = CreateCubeMesh();
                nc->name = "cube!";
                nc->t.ScaleTo(1.0f);
                nc->t.TranslateTo(camera->t.GetTranslation());
                nc->t.RotateByEulerAngles({ 0.0f, 0.0f, 0.0f });
                nc->BindToRenderSystem();
                mainf->AddChild(nc);
                physicsengine->AddObject(new p(nc));
            }
            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
                }
                else {
                    std::cout << "MISSED\n";
                }
            }
            if (buffer.GetCode() == GLFW_KEY_LEFT_SHIFT && buffer.IsPress() && !sliding) {
                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() == 'C' && buffer.IsPress() && !sliding && 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;

                    // 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;
                    characterBody->WakeUp();
                    grappleCooldown = grappleCooldownTime;
                    camera->AddScreenshake(0.1f);
                }
            }
            if (buffer.GetCode() == 'G' && buffer.IsPress()) {
                camera->AddScreenshake(0.2f);
            }
            if (buffer.GetCode() == GLFW_KEY_SPACE && buffer.IsPress()) {
                if (!sliding && IsGrounded())
                    characterBody->linearvelocity.y = 5.0f;
            }
        }

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

        // Movement + damping
        grappleCooldown = std::max(grappleCooldown - deltatime, 0.0f);
        const float accel = 40.0f;
        const float damp = 0.75f;
        const float groundTopSpeed = movespeed * accel * deltatime * 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 * (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()) {
            characterBody->linearvelocity.x *= damp;
            characterBody->linearvelocity.z *= damp;
            characterBody->linearvelocity.x += inputVel.x * accel * deltatime;
            characterBody->linearvelocity.z += inputVel.z * accel * deltatime;
        }
        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 * 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));
        }

        rain->t.TranslateTo(camera->t.GetTranslation() + glm::vec3(0.0f, 20.0f, 0.0f));
        for (int i = 0; i < 30; i++) rain->Emit();

        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) * 0.3f;
        camera->t.TranslateTo(testcharacter->body->t.GetTranslation() + glm::vec3(0.0f, eyeOffset, 0.0f));

        Sound* music = static_cast<Sound*>(mainf->GetFirstChildOfName("music"));
        Mesh* cube = static_cast<Mesh*>(mainf->GetFirstChildOfName("cube"));
        music->Update3DPosition(cube->t.GetTranslation());

        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";
        }
        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";

        // --------------------------------------------------------------------
        // Step systems
        // --------------------------------------------------------------------
        camera->Step(deltatime);
        rain->Step(deltatime);
        testcharacter->Step(deltatime);
        npc->Step(deltatime);
        soundsystem->Update();
        physicsengine->Step(deltatime);

        // --------------------------------------------------------------------
        // LAN: send our transform, apply the other player's
        // --------------------------------------------------------------------
        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;
            lan->Receive(updates);
            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);
                    it = remotes.emplace(u.id, rp).first;
                }
                else {
                    // Smooth over the 60 Hz updates
                    t& rt = it->second.character->body->t;
                    rt.TranslateTo(glm::mix(rt.GetTranslation(), u.state.position, 0.5f));
                    rt.RotateToQuaternion(glm::slerp(rt.GetRotationQuaternion(), u.state.rotation, 0.5f));
                }
                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);
                    delete it->second.character;
                    it = remotes.erase(it);
                }
                else {
                    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)
{
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    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);
    glfwSetCursorPos(window, ::window->width / 2, ::window->height / 2);
    mouse->OnMouseMove(::window->width / 2.0f, ::window->height / 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();
    }
}