#include <cmath>

#include "client/Game.h"
#include "client/utils/Utils.h"
#include "rendering/Renderer.h"
#include "common/utils/String.h"
#include "common/utils/Random.h"

Game::Game(const Control& control, const Camera& camera, Ray& ray, const Clock& fps, const Clock& tps,
        RenderSettings& renderSettings) :
control(control), camera(camera), ray(ray), fps(fps), tps(tps), renderSettings(renderSettings), lengthAngle(240.0f),
widthAngle(20.0f), world(blockRegistry), worldRenderer(world), pointIndex(0), moveSpeed(0.25f), movedLength(0.0f),
mode(Mode::AUTO) {
    Random r(0);
    float h = World::WORLD_SIZE * 0.75f;
    float mid = World::WORLD_SIZE * 0.5f;
    float randLength = World::WORLD_SIZE * 0.125f;
    pos.set(0, h, 0);

    for(uint i = 0; i < cameraPoints.getCapacity(); i++) {
        Vector offset(mid, h, mid);
        offset.add(Vector(r.nextFloat(randLength), r.nextFloat(randLength), r.nextFloat(randLength)));
        Vector v;
        v.setAngles(i * 360.0f / cameraPoints.getCapacity(), 0.0f).mul(mid * 0.5f).add(offset);
        cameraPoints.add( {v, 0.0f});
    }
    for(uint i = 0; i < cameraPoints.getLength(); i++) {
        cameraPoints[i].distance = distance(i, 20);
    }
}

void Game::tick() {
    if(mode == Mode::PLAYER) {
        const float speed = 0.25f;
        if(control.keys.down.isDown()) {
            pos.addMul(camera.getFlatBack(), speed);
        }
        if(control.keys.up.isDown()) {
            pos.addMul(camera.getFlatBack(), -speed);
        }
        if(control.keys.left.isDown()) {
            pos.addMul(camera.getFlatRight(), -speed);
        }
        if(control.keys.right.isDown()) {
            pos.addMul(camera.getFlatRight(), speed);
        }
        if(control.keys.jump.isDown()) {
            pos.addMul(camera.getFlatUp(), speed);
        }
        if(control.keys.sneak.isDown()) {
            pos.addMul(camera.getFlatUp(), -speed);
        }

        const float rotation = 5.0f;
        if(control.keys.camLeft.isDown()) {
            lengthAngle += rotation;
        }
        if(control.keys.camRight.isDown()) {
            lengthAngle -= rotation;
        }
        if(control.keys.camUp.isDown() && widthAngle - rotation > -90.0f) {
            widthAngle -= rotation;
        }
        if(control.keys.camDown.isDown() && widthAngle + rotation < 90.0f) {
            widthAngle += rotation;
        }

        ray.store();
        ray.set(pos, lengthAngle, widthAngle);
    } else if(mode == Mode::AUTO) {
        movedLength += moveSpeed;
    }

    if(control.keys.test.getDownTime() == 1) {
        mode = Mode::PLAYER;
    }
    if(control.keys.test2.getDownTime() == 1) {
        mode = Mode::AUTO;
    }
    if(control.keys.test5.getDownTime() == 1) {
        renderSettings.ssao = !renderSettings.ssao;
    }
}

void Game::renderWorld(float lag, Renderer& renderer) const {
    if(mode == Mode::AUTO) {
        float leftLength = (movedLength - moveSpeed) + moveSpeed * lag;
        uint index = 0;
        while(leftLength >= cameraPoints[index].distance) {
            leftLength -= cameraPoints[index].distance;
            index = (index + 1) % cameraPoints.getLength();
        }

        uint prev = index;
        float t = leftLength / cameraPoints[index].distance;
        if(prev == 0) {
            prev = cameraPoints.getLength() - 1;
        } else {
            prev = (prev - 1) % cameraPoints.getLength();
        }
        uint currentA = (prev + 1) % cameraPoints.getLength();
        uint currentB = (prev + 2) % cameraPoints.getLength();
        uint next = (prev + 3) % cameraPoints.getLength();

        Vector tangentA = splineTangent(cameraPoints[prev].pos, cameraPoints[currentA].pos, cameraPoints[currentB].pos);
        Vector tangentB = splineTangent(cameraPoints[currentA].pos, cameraPoints[currentB].pos, cameraPoints[next].pos);

        Vector interpolatedPos = interpolate(cameraPoints[currentA].pos, cameraPoints[currentB].pos, tangentA, tangentB, t);

        pos.set(interpolatedPos);
        ray.set(interpolatedPos, lengthAngle, widthAngle);
        ray.store();
    }
    worldRenderer.render(lag, renderer);
}

void Game::renderTextOverlay(float lag, Renderer& renderer, FontRenderer& fr) const {
    (void) lag;
    renderer.scale(1.0f).update();

    String s;
    fr.drawString(10, 10, s.append("FPS: ").append(fps.getUpdatesPerSecond()));
    fr.drawString(10, 19, s.clear().append("TPS: ").append(tps.getUpdatesPerSecond()));
    s.clear();
    pos.toString(s);
    fr.drawString(10, 28, s);
    for(uint i = 0; i < cameraPoints.getLength(); i++) {
        s.clear().append(i + 1).append(": ");
        cameraPoints[i].pos.toString(s);
        fr.drawString(10, i * 9 + 37, s);
    }
}

bool Game::isRunning() const {
    return true;
}

Vector Game::splineTangent(const Vector& prev, const Vector& current, const Vector& next) const {
    Vector v(current);
    v.sub(prev).mul(0.5f).addMul(next, 0.5f).addMul(current, -0.5f);
    return v;
}

Vector Game::interpolate(const Vector& a, const Vector& b, const Vector& tanA, const Vector& tanB, float t) const {
    float t2 = t * t;
    float t3 = t2 * t;
    Vector v;
    v.addMul(a, 2.0f * t3 - 3.0f * t2 + 1.0f).addMul(b, -2.0f * t3 + 3.0f * t2)
            .addMul(tanA, t3 - 2.0f * t2 + t).addMul(tanB, t3 - t2);
    return v;
}

float Game::distance(uint index, uint splits) const {
    uint prev = index == 0 ? cameraPoints.getLength() - 1 : index - 1;
    uint currentA = (prev + 1) % cameraPoints.getLength();
    uint currentB = (prev + 2) % cameraPoints.getLength();
    uint next = (prev + 3) % cameraPoints.getLength();

    Vector tangentA = splineTangent(cameraPoints[prev].pos, cameraPoints[currentA].pos, cameraPoints[currentB].pos);
    Vector tangentB = splineTangent(cameraPoints[currentA].pos, cameraPoints[currentB].pos, cameraPoints[next].pos);

    Vector currentPos;
    Vector currentNext = interpolate(cameraPoints[currentA].pos, cameraPoints[currentB].pos, tangentA, tangentB, 0.0f);

    float sum = 0.0f;
    for(uint i = 0; i <= splits; i++) {
        currentPos = currentNext;
        float t = (i + 1.0f) / (splits + 1.0f);
        currentNext = interpolate(cameraPoints[currentA].pos, cameraPoints[currentB].pos, tangentA, tangentB, t);
        sum += currentPos.sub(currentNext).length();
    }
    return sum;
}