#include "CRainSplashGenerator.hpp"
#include "CStateManager.hpp"
#include "World/CWorld.hpp"

namespace urde
{

CRainSplashGenerator::CRainSplashGenerator(const zeus::CVector3f& scale, u32 maxSplashes,
                                           u32 genRate, float minZ, float alpha)
: x14_scale(scale), x2c_minZ(minZ)
{
    x30_alpha = std::min(1.f, alpha);
    x44_genRate = std::min(maxSplashes, genRate);
    x48_24 = false;
    x48_25_raining = true;
    x0_rainSplashes.reserve(maxSplashes);
    m_gfxTok = CGraphics::CommitResources([&](boo::IGraphicsDataFactory::Context& ctx)
    {
        for (int i=0 ; i<maxSplashes ; ++i)
            x0_rainSplashes.emplace_back(ctx);
        return true;
    });
}

void CRainSplashGenerator::SSplashLine::Draw(float alpha, float dt, const zeus::CVector3f& pos) const
{
    if (x0_t > 0.f)
    {
        float delta = dt * xc_speed;
        float vt = std::max(0.f, x0_t - delta * x15_length);
        auto vertCount = u32((x0_t - vt) / delta + 1.f);
        m_renderer.Reset();
        for (u32 i=0 ; i<vertCount ; ++i)
        {
            float vertAlpha = vt * alpha;
            zeus::CVector3f vec(vt * x4_xEnd, vt * x8_yEnd, -4.f * vt * (vt - 1.f) * x10_zParabolaHeight);
            vec += pos;
            vt += delta;
            m_renderer.AddVertex(vec, zeus::CColor(1.f, vertAlpha), 1);
        }
        m_renderer.Render();
    }
}

void CRainSplashGenerator::SRainSplash::Draw(float alpha, float dt, const zeus::CVector3f& pos) const
{
    for (const SSplashLine& line : x0_lines)
        line.Draw(alpha, dt, pos);
}

void CRainSplashGenerator::DoDraw(const zeus::CTransform& xf) const
{
    CGraphics::SetModelMatrix(xf);
    if (x40_queueSize > 0)
    {
        if (x38_queueTail <= x3c_queueHead)
        {
            for (int i=x3c_queueHead ; i<x0_rainSplashes.size() ; ++i)
            {
                const SRainSplash& splash = x0_rainSplashes[i];
                splash.Draw(x30_alpha, x28_dt, splash.x64_pos);
            }
            for (int i=0 ; i<x38_queueTail ; ++i)
            {
                const SRainSplash& splash = x0_rainSplashes[i];
                splash.Draw(x30_alpha, x28_dt, splash.x64_pos);
            }
        }
        else
        {
            for (int i=x3c_queueHead ; i<x38_queueTail ; ++i)
            {
                const SRainSplash& splash = x0_rainSplashes[i];
                splash.Draw(x30_alpha, x28_dt, splash.x64_pos);
            }
        }
    }
}

void CRainSplashGenerator::Draw(const zeus::CTransform& xf) const
{
    if (x48_25_raining)
        DoDraw(xf);
}

CRainSplashGenerator::SSplashLine::SSplashLine(boo::IGraphicsDataFactory::Context& ctx)
: m_renderer(ctx, CLineRenderer::EPrimitiveMode::LineStrip, 3, nullptr, false)
{}

CRainSplashGenerator::SRainSplash::SRainSplash(boo::IGraphicsDataFactory::Context& ctx)
{
    for (int i=0 ; i<4 ; ++i)
        x0_lines.emplace_back(ctx);
}

void CRainSplashGenerator::SSplashLine::Update(float dt, CStateManager& mgr)
{
    if (!x16_active)
        return;
    if (x0_t <= 0.8f)
    {
        x14_ = u8(5.f * (1.f - x0_t) + 3.f * x0_t);
        x0_t += dt * xc_speed;
    }
    else if (x15_length != 0)
    {
        x15_length -= 1;
    }
    else
    {
        x16_active = false;
        xc_speed = mgr.GetActiveRandom()->Range(0.015625f, 8.f);
        x10_zParabolaHeight = mgr.GetActiveRandom()->Range(0.015625f, 0.03125f);
        x4_xEnd = mgr.GetActiveRandom()->Range(-0.125f, 0.125f);
        x8_yEnd = mgr.GetActiveRandom()->Range(-0.125f, 0.125f);
        x15_length = u8(mgr.GetActiveRandom()->Range(1, 2));
    }
}

void CRainSplashGenerator::SRainSplash::Update(float dt, CStateManager& mgr)
{
    for (SSplashLine& point : x0_lines)
        point.Update(dt, mgr);
}

bool CRainSplashGenerator::SRainSplash::IsActive() const
{
    bool ret = false;
    for (const SSplashLine& line : x0_lines)
        ret |= line.x16_active;
    return ret;
}

void CRainSplashGenerator::UpdateRainSplashRange(CStateManager& mgr, int start, int end, float dt)
{
    for (int i=start ; i<end ; ++i)
    {
        SRainSplash& set = x0_rainSplashes[i];
        set.Update(dt, mgr);
        if (!set.IsActive())
        {
            x40_queueSize -= 1;
            x3c_queueHead += 1;
            if (x3c_queueHead >= x0_rainSplashes.size())
                x3c_queueHead = 0;
        }
    }
}

void CRainSplashGenerator::UpdateRainSplashes(CStateManager& mgr, float magnitude, float dt)
{
    x20_generateTimer += dt;
    x24_generateInterval = 1.f / (70.f * magnitude);
    if (x40_queueSize > 0)
    {
        if (x38_queueTail <= x3c_queueHead)
        {
            UpdateRainSplashRange(mgr, x3c_queueHead, int(x0_rainSplashes.size()), dt);
            UpdateRainSplashRange(mgr, 0, x38_queueTail, dt);
        }
        else
        {
            UpdateRainSplashRange(mgr, x3c_queueHead, x38_queueTail, dt);
        }
    }
}

void CRainSplashGenerator::Update(float dt, CStateManager& mgr)
{
    EEnvFxType neededFx = mgr.GetWorld()->GetNeededEnvFx();
    x28_dt = dt;
    x48_25_raining = false;
    if (neededFx != EEnvFxType::None && mgr.GetEnvFxManager()->GetX24() &&
        mgr.GetEnvFxManager()->GetRainMagnitude() != 0.f && neededFx == EEnvFxType::Rain)
    {
        UpdateRainSplashes(mgr, mgr.GetEnvFxManager()->GetRainMagnitude(), dt);
        x48_25_raining = true;
    }
}

u32 CRainSplashGenerator::GetNextBestPt(u32 pt, const std::vector<std::pair<zeus::CVector3f, zeus::CVector3f>>& vn,
                                        CRandom16& rand, float minZ)
{
    auto& refVert = vn[pt];
    float maxDist = 0.f;
    u32 nextPt = pt;
    for (int i=0 ; i<3 ; ++i)
    {
        auto idx = u32(rand.Range(0, int(vn.size() - 1)));
        auto& vert = vn[idx];
        float distSq = (refVert.first - vert.first).magSquared();
        if (distSq > maxDist &&
            vert.second.dot(zeus::CVector3f::skUp) >= 0.f &&
            (vert.first.z <= 0.f || vert.first.z > minZ))
        {
            nextPt = idx;
            maxDist = distSq;
        }
    }
    return nextPt;
}

void CRainSplashGenerator::SRainSplash::SetPoint(const zeus::CVector3f& pos)
{
    for (SSplashLine& line : x0_lines)
        line.SetActive();
    x64_pos = pos;
}

void CRainSplashGenerator::AddPoint(const zeus::CVector3f& pos)
{
    if (x38_queueTail >= x0_rainSplashes.size())
        x38_queueTail = 0;
    x0_rainSplashes[x38_queueTail].SetPoint(pos);
    x40_queueSize += 1;
    x38_queueTail += 1;
}

void CRainSplashGenerator::GeneratePoints(const std::vector<std::pair<zeus::CVector3f, zeus::CVector3f>>& vn)
{
    if (!x48_25_raining)
        return;

    if (x20_generateTimer > x24_generateInterval)
    {
        for (int i=0 ; i<x44_genRate ; ++i)
        {
            if (x40_queueSize >= x0_rainSplashes.size())
                break;
            x34_curPoint = GetNextBestPt(x34_curPoint, vn, x10_random, x2c_minZ);
            AddPoint(x14_scale * vn[x34_curPoint].first);
        }
        x20_generateTimer = 0.f;
    }
}

}