#include "unitrenderer.h"
#include <cmath>
#include <vector>

struct VertexPN {
    float x, y, z;
    float nx, ny, nz;
};

UnitRenderer::UnitRenderer()
    : m_program(nullptr), m_vertexCount(0), m_initialized(false)
{
}

UnitRenderer::~UnitRenderer()
{
    if (m_program) delete m_program;
}

void UnitRenderer::initialize()
{
    if (m_initialized) return;
    initializeOpenGLFunctions();

    m_program = new QOpenGLShaderProgram();
    m_program->addShaderFromSourceFile(QOpenGLShader::Vertex, "/home/bart/project/tiletest/shaders/unit.vert");
    m_program->addShaderFromSourceFile(QOpenGLShader::Fragment, "/home/bart/project/tiletest/shaders/unit.frag");
    m_program->link();

    buildCylinderMesh();
    m_initialized = true;
}

void UnitRenderer::buildCylinderMesh()
{
    std::vector<VertexPN> vertices;
    const int sectors = 24;
    const float pi = 3.14159265359f;

    for (int i = 0; i < sectors; ++i) {
        float a1 = 2.0f * pi * i / sectors;
        float a2 = 2.0f * pi * (i + 1) / sectors;

        float c1 = std::cos(a1), s1 = std::sin(a1);
        float c2 = std::cos(a2), s2 = std::sin(a2);

        // --- Side Quad (2 Triangles) ---
        // Tri 1
        vertices.push_back({c1, s1, 0.0f, c1, s1, 0.0f});
        vertices.push_back({c2, s2, 0.0f, c2, s2, 0.0f});
        vertices.push_back({c2, s2, 1.0f, c2, s2, 0.0f});
        // Tri 2
        vertices.push_back({c1, s1, 0.0f, c1, s1, 0.0f});
        vertices.push_back({c2, s2, 1.0f, c2, s2, 0.0f});
        vertices.push_back({c1, s1, 1.0f, c1, s1, 0.0f});

        // --- Top Cap ---
        vertices.push_back({0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f});
        vertices.push_back({c1, s1, 1.0f, 0.0f, 0.0f, 1.0f});
        vertices.push_back({c2, s2, 1.0f, 0.0f, 0.0f, 1.0f});

        // --- Bottom Cap ---
        vertices.push_back({0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f});
        vertices.push_back({c2, s2, 0.0f, 0.0f, 0.0f, -1.0f});
        vertices.push_back({c1, s1, 0.0f, 0.0f, 0.0f, -1.0f});
    }

    m_vertexCount = (int)vertices.size();

    m_vao.create();
    m_vao.bind();

    m_vbo.create();
    m_vbo.bind();
    m_vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
    m_vbo.allocate(vertices.data(), (int)(vertices.size() * sizeof(VertexPN)));

    m_program->enableAttributeArray(0);
    m_program->setAttributeBuffer(0, GL_FLOAT, 0, 3, sizeof(VertexPN));

    m_program->enableAttributeArray(1);
    m_program->setAttributeBuffer(1, GL_FLOAT, 3 * sizeof(float), 3, sizeof(VertexPN));

    m_vao.release();
    m_vbo.release();
}

void UnitRenderer::renderUnits(
    const std::vector<std::shared_ptr<Unit>> &units,
    const std::vector<City> &cities,
    const PlayerManager &players,
    const QMatrix4x4 &projection,
    const QMatrix4x4 &vMatrix,
    const QVector3D &lightDir,
    int selectedUnitId)
{
    if (!m_initialized || !m_program) return;

    glEnable(GL_DEPTH_TEST);
    m_program->bind();
    m_program->setUniformValue("u_lightDir", lightDir);
    m_vao.bind();

    // 1. Render Cities (as stylized hexagonal / cylindrical city bastions)
    for (const auto &c : cities) {
        const Player *p = players.getPlayer(c.playerId);
        QColor col = p ? p->primaryColor : QColor(100, 100, 100);

        QMatrix4x4 model;
        model.translate(c.worldPos.x(), c.worldPos.y(), c.worldPos.z());
        model.scale(0.30f, 0.30f, 0.45f);

        QMatrix4x4 mvp = projection * vMatrix * model;
        m_program->setUniformValue("modelMatrix", model);
        m_program->setUniformValue("MVP", mvp);
        m_program->setUniformValue("u_color", QVector4D(col.redF(), col.greenF(), col.blueF(), 1.0f));

        glDrawArrays(GL_TRIANGLES, 0, m_vertexCount);
    }

    // 2. Render Units (Cylinders in player primary color)
    const float unitRadius = 0.18f;
    const float unitHeight = 0.36f;

    for (const auto &unit : units) {
        if (unit->isDead()) continue;

        const Player *player = players.getPlayer(unit->playerId);
        QColor col = player ? player->primaryColor : QColor(200, 200, 200);

        // Flash white/red if attacked
        if (unit->attackFlashTimer > 0.0f) {
            float f = unit->attackFlashTimer / 0.5f;
            col = QColor(
                (int)(col.red() * (1.0f - f) + 255 * f),
                (int)(col.green() * (1.0f - f) + 255 * f),
                (int)(col.blue() * (1.0f - f) + 255 * f)
            );
        }

        QMatrix4x4 model;
        model.translate(unit->worldPos.x(), unit->worldPos.y(), unit->worldPos.z());
        model.scale(unitRadius, unitRadius, unitHeight);

        QMatrix4x4 mvp = projection * vMatrix * model;
        m_program->setUniformValue("modelMatrix", model);
        m_program->setUniformValue("MVP", mvp);
        m_program->setUniformValue("u_color", QVector4D(col.redF(), col.greenF(), col.blueF(), 1.0f));

        glDrawArrays(GL_TRIANGLES, 0, m_vertexCount);

        // Ground selection base disk if selected
        if (unit->id == selectedUnitId) {
            QMatrix4x4 selModel;
            selModel.translate(unit->worldPos.x(), unit->worldPos.y(), unit->worldPos.z());
            selModel.scale(unitRadius * 1.6f, unitRadius * 1.6f, 0.04f);

            QMatrix4x4 selMvp = projection * vMatrix * selModel;
            m_program->setUniformValue("modelMatrix", selModel);
            m_program->setUniformValue("MVP", selMvp);
            m_program->setUniformValue("u_color", QVector4D(1.0f, 0.9f, 0.2f, 0.9f));

            glDrawArrays(GL_TRIANGLES, 0, m_vertexCount);
        }
    }

    m_vao.release();
    m_program->release();
}

QPointF UnitRenderer::projectToScreen(
    const QVector3D &worldPoint,
    const QMatrix4x4 &projection,
    const QMatrix4x4 &vMatrix,
    int viewportW, int viewportH,
    bool &inFront)
{
    QMatrix4x4 vp = projection * vMatrix;
    QVector4D clip = vp.map(QVector4D(worldPoint, 1.0f));

    inFront = (clip.w() > 0.01f);
    if (!inFront) {
        return QPointF(-9999, -9999);
    }

    QVector3D ndc = clip.toVector3DAffine();
    float sx = (ndc.x() + 1.0f) * 0.5f * viewportW;
    float sy = (1.0f - (ndc.y() + 1.0f) * 0.5f) * viewportH;

    return QPointF(sx, sy);
}