#include "AudioDevice.hpp"
#include "Color.hpp"
#include "Keyboard.hpp"
#include "Matrix.hpp"
#include "Mesh.hpp"
#include "Model.hpp"
#include "RadiansDegrees.hpp"
#include "Vector3.hpp"
#include "raylib.h"
#include <concepts>
#include <functional>
#include <memory>
#include <optional>
#include <raylib-cpp.hpp>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <vector>

#define SKYBOX_IMPLEMENTATION
#include "skybox.hpp"

void DrawBoundedModel(raylib::Model &model, auto transformer) {
    // store the original transform to apply a different transform to the
    // model without affecting the next time we draw
    raylib::Matrix oldTransform = model.GetTransform();

    // apply the transform that we get from whatever the transformer callback
    // gives us
    raylib::Matrix transform = transformer(model.GetTransform());

    // apply the transform that we got from the transformer to the model
    model.SetTransform(transform);

    // draw the model, passing the origin and default scale as arguments since
    // the transform is already applied to the model
    model.Draw({ 0, 0, 0 }, 1.0f, raylib::Color::White());

    // get the bounding box of the model after applying the transform
    auto box = model.GetTransformedBoundingBox();

    // draw the bounding box of the model using raylib's built in function
    DrawBoundingBox(box, raylib::Color::White());

    // restore the model's transform to its original state so that the next time we
    // draw the model, it doesn't have the previous transform applied to it
    model.SetTransform(oldTransform);
}

struct Entity {
    raylib::Vector3 position = raylib::Vector3::Zero();
    float speed = 0;
    raylib::Degree heading = 0;
    raylib::Model *model;
};

raylib::Degree angle_normalize(raylib::Degree angle) {
    float decimal = float(angle) - int(angle);
    int normalized = (int(angle) % 360 + 360) % 360;
    return raylib::Degree(normalized + decimal);
}

raylib::Vector3 from_magnitude_and_heading(
    float magnitude,
    raylib::Degree heading
) {
    return raylib::Vector3 {
        magnitude * std::sin(heading.RadianValue()),
        0,
        magnitude * std::cos(heading.RadianValue())
    };
}

// units/s
const float ACCELERATION = 100.0f;

// in radians
const raylib::Degree ANGULAR_VELOCITY = raylib::Degree(180.0f);

int main() {
    raylib::Window window(800, 600, "CS381 - Assignment 3");
    window.SetState(FLAG_WINDOW_RESIZABLE);
    raylib::AudioDevice audio;

    raylib::Model penguin("models/penguin.glb");
    raylib::Model eagle("models/eagle.glb");

    // behind and above the penguin (in penguin-local space)
    const float CAM_DIST = 512.0f;
    const float CAM_HEIGHT = 256.0f;
    const float CAM_ANGULAR_VELOCITY = 2.0f;
    const float CAM_PITCH_MIN = -0.5f;
    const float CAM_PITCH_MAX = 1.5f;

    float camYaw = 3.14f; // offset by 90 deg so it faces in the proper direction
    float camPitch = 0;

    raylib::Camera3D camera(
        { 0, CAM_DIST * std::sin(camPitch), CAM_DIST * std::cos(camPitch) },
        { 0, 0, 0 },
        { 0, 1, 0 },
        45.0f);

    raylib::Model ground = raylib::Mesh::Plane(10000, 10000, 50, 50, 25);

    raylib::Texture snowTexture("textures/snow.jpg");
    ground.GetMaterials()[0].maps[MATERIAL_MAP_DIFFUSE].texture = snowTexture;

    cs381::SkyBox skybox("textures/skybox.png");

    std::vector<Entity> entities;

    Entity &ePenguin = entities.emplace_back();
    ePenguin.model = &penguin;

    Entity &eEagle = entities.emplace_back();
    eEagle.model = &eagle;

    // penguin physics
    raylib::Vector3 position = { 0, 0, 0 };
    raylib::Vector3 velocity = { 0, 0, 0 };
    float heading = 0.0f;
    float speed = 0.0f;

    int selectedIdx = 0;

    window.SetTargetFPS(60); // save cpu cycles

    while (!window.ShouldClose()) {
        window.BeginDrawing();
        window.ClearBackground(raylib::Color::Gray());

        float dt = window.GetFrameTime();

        position += velocity * dt * 0.5f;

        if (IsKeyPressed(KEY_TAB)) {
            selectedIdx = (selectedIdx + 1) % entities.size();
        }

        Entity &selected = entities[selectedIdx];

        if (IsKeyDown(KEY_W)) {
            selected.speed += ACCELERATION * dt;
        }

        if (IsKeyDown(KEY_S)) {
            selected.speed -= ACCELERATION * dt;
        }

        if (IsKeyDown(KEY_A)) {
            selected.heading += dt * ANGULAR_VELOCITY;
        }

        if (IsKeyDown(KEY_D)) {
            selected.heading -= dt * ANGULAR_VELOCITY;
        }

        if (IsKeyDown(KEY_SPACE)) {
            selected.speed = 0.0f;
        }

        for (Entity &e : entities) {
            e.heading = angle_normalize(e.heading);
        }

        // ds = 1/2 * (v0 + v1) * dt
        position += velocity * dt * 0.5f;

        // movement for camera
        if (IsKeyDown(KEY_LEFT)) {
            camYaw += CAM_ANGULAR_VELOCITY * dt;
        }
        if (IsKeyDown(KEY_RIGHT)) {
            camYaw -= CAM_ANGULAR_VELOCITY * dt;
        }
        if (IsKeyDown(KEY_UP)) {
            camPitch += CAM_ANGULAR_VELOCITY * dt;
        }
        if (IsKeyDown(KEY_DOWN)) {
            camPitch -= CAM_ANGULAR_VELOCITY * dt;
        }

        // clamp the angle between
        camPitch = std::clamp(camPitch, CAM_PITCH_MIN, CAM_PITCH_MAX);

        // x = cos(pitch) * sin(yaw)
        // y = sin(pitch)
        // z = cos(pitch) * cos(yaw)
        float yaw = camYaw + heading; // follow penguin
        raylib::Vector3 camOffset = {
            CAM_DIST * std::cos(camPitch) * std::sin(yaw),
            CAM_DIST * std::sin(camPitch) + CAM_HEIGHT,
            CAM_DIST * std::cos(camPitch) * std::cos(yaw)
        };
        camera.SetPosition(position + camOffset);
        camera.SetTarget(position);

        camera.BeginMode();
        skybox.Draw();

        ground.Draw({ 0, 0, 0 }, 1.0f, raylib::Color::White());

        for (Entity &e : entities) {
            e.position += from_magnitude_and_heading(e.speed, e.heading) * dt;

            DrawBoundedModel(*e.model, [&e](raylib::Matrix transform) {
                return transform
                    .RotateY(e.heading)
                    .Scale(40, 40, 40)
                    .Translate(e.position);
            });
        }

        camera.EndMode();
        window.EndDrawing();
    }

    return 0;
}