#include <mbgl/annotation/point_annotation.hpp>
#include <mbgl/annotation/shape_annotation.hpp>
#include <mbgl/sprite/sprite_image.hpp>
#include <mbgl/platform/default/glfw_view.hpp>
#include <mbgl/platform/gl.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/util/gl_helper.hpp>
#include <mbgl/util/string.hpp>

#include <cassert>
#include <cstdlib>

void glfwError(int error, const char *description) {
    mbgl::Log::Error(mbgl::Event::OpenGL, "GLFW error (%i): %s", error, description);
    assert(false);
}

GLFWView::GLFWView(bool fullscreen_, bool benchmark_)
    : fullscreen(fullscreen_), benchmark(benchmark_) {
    glfwSetErrorCallback(glfwError);

    std::srand(std::time(0));

    if (!glfwInit()) {
        mbgl::Log::Error(mbgl::Event::OpenGL, "failed to initialize glfw");
        exit(1);
    }

    GLFWmonitor *monitor = nullptr;
    if (fullscreen) {
        monitor = glfwGetPrimaryMonitor();
        auto videoMode = glfwGetVideoMode(monitor);
        width = videoMode->width;
        height = videoMode->height;
    }

#ifdef DEBUG
    glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GL_TRUE);
#endif

#ifdef GL_ES_VERSION_2_0
    glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
#endif

    glfwWindowHint(GLFW_RED_BITS, 8);
    glfwWindowHint(GLFW_GREEN_BITS, 8);
    glfwWindowHint(GLFW_BLUE_BITS, 8);
    glfwWindowHint(GLFW_ALPHA_BITS, 8);
    glfwWindowHint(GLFW_STENCIL_BITS, 8);
    glfwWindowHint(GLFW_DEPTH_BITS, 16);

    window = glfwCreateWindow(width, height, "Mapbox GL", monitor, NULL);
    if (!window) {
        glfwTerminate();
        mbgl::Log::Error(mbgl::Event::OpenGL, "failed to initialize window");
        exit(1);
    }

    glfwSetWindowUserPointer(window, this);
    glfwMakeContextCurrent(window);
    if (benchmark) {
        // Disables vsync on platforms that support it.
        glfwSwapInterval(0);
    } else {
        glfwSwapInterval(1);
    }


    glfwSetCursorPosCallback(window, onMouseMove);
    glfwSetMouseButtonCallback(window, onMouseClick);
    glfwSetWindowSizeCallback(window, onWindowResize);
    glfwSetFramebufferSizeCallback(window, onFramebufferResize);
    glfwSetScrollCallback(window, onScroll);
    glfwSetKeyCallback(window, onKey);

    mbgl::gl::InitializeExtensions(glfwGetProcAddress);

    glfwGetWindowSize(window, &width, &height);
    glfwGetFramebufferSize(window, &fbWidth, &fbHeight);
    pixelRatio = static_cast<float>(fbWidth) / width;

    glfwMakeContextCurrent(nullptr);

    printf("\n");
    printf("================================================================================\n");
    printf("\n");
    printf("- Press `S` to cycle through bundled styles\n");
    printf("- Press `X` to reset the transform\n");
    printf("- Press `N` to reset north\n");
    printf("- Press `R` to toggle any available `night` style class\n");
    printf("\n");
    printf("- Press `1` through `6` to add increasing numbers of point annotations for testing\n");
    printf("- Press `7` through `0` to add increasing numbers of shape annotations for testing\n");
    printf("\n");
    printf("- Press `Q` to remove annotations\n");
    printf("- Press `P` to add a random custom runtime imagery annotation\n");
    printf("- Press `W` to pop the last-added annotation off\n");
    printf("\n");
    printf("- `Control` + mouse drag to rotate\n");
    printf("- `Shift` + mouse drag to tilt\n");
    printf("\n");
    printf("- Press `Tab` to cycle through the map debug options\n");
    printf("- Press `Esc` to quit\n");
    printf("\n");
    printf("================================================================================\n");
    printf("\n");
}

GLFWView::~GLFWView() {
    glfwDestroyWindow(window);
    glfwTerminate();
}

void GLFWView::initialize(mbgl::Map *map_) {
    View::initialize(map_);
    map->addAnnotationIcon("default_marker", makeSpriteImage(22, 22, 1));
}

void GLFWView::onKey(GLFWwindow *window, int key, int /*scancode*/, int action, int mods) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));

    if (action == GLFW_RELEASE) {
        switch (key) {
        case GLFW_KEY_ESCAPE:
            glfwSetWindowShouldClose(window, true);
            break;
        case GLFW_KEY_TAB:
            view->map->cycleDebugOptions();
            break;
        case GLFW_KEY_X:
            if (!mods)
                view->map->resetPosition();
            break;
        case GLFW_KEY_S:
            if (view->changeStyleCallback)
                view->changeStyleCallback();
            break;
        case GLFW_KEY_R:
            if (!mods) {
                view->map->setDefaultTransitionDuration(std::chrono::milliseconds(300));
                if (view->map->hasClass("night")) {
                    view->map->removeClass("night");
                } else {
                    view->map->addClass("night");
                }
            }
            break;
        case GLFW_KEY_N:
            if (!mods)
                view->map->resetNorth();
            break;
        case GLFW_KEY_Q:
            view->clearAnnotations();
            break;
        case GLFW_KEY_P: {
            view->addRandomCustomPointAnnotations(1);
        } break;
        }
    }

    if (action == GLFW_RELEASE || action == GLFW_REPEAT) {
        switch (key) {
        case GLFW_KEY_W: view->popAnnotation(); break;
        case GLFW_KEY_1: view->addRandomPointAnnotations(1); break;
        case GLFW_KEY_2: view->addRandomPointAnnotations(10); break;
        case GLFW_KEY_3: view->addRandomPointAnnotations(100); break;
        case GLFW_KEY_4: view->addRandomPointAnnotations(1000); break;
        case GLFW_KEY_5: view->addRandomPointAnnotations(10000); break;
        case GLFW_KEY_6: view->addRandomPointAnnotations(100000); break;
        case GLFW_KEY_7: view->addRandomShapeAnnotations(1); break;
        case GLFW_KEY_8: view->addRandomShapeAnnotations(10); break;
        case GLFW_KEY_9: view->addRandomShapeAnnotations(100); break;
        case GLFW_KEY_0: view->addRandomShapeAnnotations(1000); break;
        }
    }
}

mbgl::LatLng GLFWView::makeRandomPoint() const {
    const auto sw = map->latLngForPixel({ 0, 0 });
    const auto ne = map->latLngForPixel({ double(width), double(height) });

    const double lon = sw.longitude + (ne.longitude - sw.longitude) * (double(std::rand()) / RAND_MAX);
    const double lat = sw.latitude + (ne.latitude - sw.latitude) * (double(std::rand()) / RAND_MAX);

    return { lat, lon };
}

std::shared_ptr<const mbgl::SpriteImage>
GLFWView::makeSpriteImage(int width, int height, float pixelRatio) {
    const int r = 255 * (double(std::rand()) / RAND_MAX);
    const int g = 255 * (double(std::rand()) / RAND_MAX);
    const int b = 255 * (double(std::rand()) / RAND_MAX);

    const int w = std::ceil(pixelRatio * width);
    const int h = std::ceil(pixelRatio * height);

    std::string pixels(w * h * 4, '\x00');
    auto data = reinterpret_cast<uint32_t*>(const_cast<char*>(pixels.data()));
    const int dist = (w / 2) * (w / 2);
    for (int y = 0; y < h; y++) {
        for (int x = 0; x < w; x++) {
            const int dx = x - w / 2;
            const int dy = y - h / 2;
            const int diff = dist - (dx * dx + dy * dy);
            if (diff > 0) {
                const int a = std::min(0xFF, diff) * 0xFF / dist;
                // Premultiply the rgb values with alpha
                data[w * y + x] =
                    (a << 24) | ((a * r / 0xFF) << 16) | ((a * g / 0xFF) << 8) | (a * b / 0xFF);
            }
        }
    }

    return std::make_shared<mbgl::SpriteImage>(width, height, pixelRatio, std::move(pixels));
}

void GLFWView::addRandomCustomPointAnnotations(int count) {
    std::vector<mbgl::PointAnnotation> points;

    for (int i = 0; i < count; i++) {
        static int spriteID = 1;
        const auto name = std::string{ "marker-" } + mbgl::util::toString(spriteID++);
        map->addAnnotationIcon(name, makeSpriteImage(22, 22, 1));
        spriteIDs.push_back(name);
        points.emplace_back(makeRandomPoint(), name);
    }

    auto newIDs = map->addPointAnnotations(points);
    annotationIDs.insert(annotationIDs.end(), newIDs.begin(), newIDs.end());
}

void GLFWView::addRandomPointAnnotations(int count) {
    std::vector<mbgl::PointAnnotation> points;

    for (int i = 0; i < count; i++) {
        points.emplace_back(makeRandomPoint(), "default_marker");
    }

    auto newIDs = map->addPointAnnotations(points);
    annotationIDs.insert(annotationIDs.end(), newIDs.begin(), newIDs.end());
}

void GLFWView::addRandomShapeAnnotations(int count) {
    std::vector<mbgl::ShapeAnnotation> shapes;

    mbgl::FillAnnotationProperties properties;
    properties.opacity = .1;

    for (int i = 0; i < count; i++) {
        mbgl::AnnotationSegment triangle;
        triangle.push_back(makeRandomPoint());
        triangle.push_back(makeRandomPoint());
        triangle.push_back(makeRandomPoint());

        mbgl::AnnotationSegments segments;
        segments.push_back(triangle);

        shapes.emplace_back(segments, properties);
    }

    auto newIDs = map->addShapeAnnotations(shapes);
    annotationIDs.insert(annotationIDs.end(), newIDs.begin(), newIDs.end());
}

void GLFWView::clearAnnotations() {
    if (annotationIDs.empty()) {
        return;
    }

    map->removeAnnotations(annotationIDs);
    annotationIDs.clear();
}

void GLFWView::popAnnotation() {
    if (annotationIDs.empty()) {
        return;
    }

    map->removeAnnotation(annotationIDs.back());
    annotationIDs.pop_back();
}

void GLFWView::onScroll(GLFWwindow *window, double /*xOffset*/, double yOffset) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));
    double delta = yOffset * 40;

    bool isWheel = delta != 0 && std::fmod(delta, 4.000244140625) == 0;

    double absDelta = delta < 0 ? -delta : delta;
    double scale = 2.0 / (1.0 + std::exp(-absDelta / 100.0));

    // Make the scroll wheel a bit slower.
    if (!isWheel) {
        scale = (scale - 1.0) / 2.0 + 1.0;
    }

    // Zooming out.
    if (delta < 0 && scale != 0) {
        scale = 1.0 / scale;
    }

    view->map->scaleBy(scale, { view->lastX, view->lastY });
}

void GLFWView::onWindowResize(GLFWwindow *window, int width, int height) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));
    view->width = width;
    view->height = height;

    view->map->update(mbgl::Update::Dimensions);
}

void GLFWView::onFramebufferResize(GLFWwindow *window, int width, int height) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));
    view->fbWidth = width;
    view->fbHeight = height;

    view->map->update(mbgl::Update::Repaint);
}

void GLFWView::onMouseClick(GLFWwindow *window, int button, int action, int modifiers) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));

    if (button == GLFW_MOUSE_BUTTON_RIGHT ||
        (button == GLFW_MOUSE_BUTTON_LEFT && modifiers & GLFW_MOD_CONTROL)) {
        view->rotating = action == GLFW_PRESS;
        view->map->setGestureInProgress(view->rotating);
    } else if (button == GLFW_MOUSE_BUTTON_LEFT && (modifiers & GLFW_MOD_SHIFT)) {
        view->pitching = action == GLFW_PRESS;
        view->map->setGestureInProgress(view->pitching);
    } else if (button == GLFW_MOUSE_BUTTON_LEFT) {
        view->tracking = action == GLFW_PRESS;
        view->map->setGestureInProgress(view->tracking);

        if (action == GLFW_RELEASE) {
            double now = glfwGetTime();
            if (now - view->lastClick < 0.4 /* ms */) {
                if (modifiers & GLFW_MOD_SHIFT) {
                    view->map->scaleBy(0.5, { view->lastX, view->lastY }, std::chrono::milliseconds(500));
                } else {
                    view->map->scaleBy(2.0, { view->lastX, view->lastY }, std::chrono::milliseconds(500));
                }
            }
            view->lastClick = now;
        }
    }
}

void GLFWView::onMouseMove(GLFWwindow *window, double x, double y) {
    GLFWView *view = reinterpret_cast<GLFWView *>(glfwGetWindowUserPointer(window));
    if (view->tracking) {
        double dx = x - view->lastX;
        double dy = y - view->lastY;
        if (dx || dy) {
            double flippedY = view->height - y;
            view->map->setLatLng(
                    view->map->latLngForPixel(mbgl::PrecisionPoint(x - dx, flippedY + dy)),
                    mbgl::PrecisionPoint(x, flippedY));
        }
    } else if (view->rotating) {
        view->map->rotateBy({ view->lastX, view->lastY }, { x, y });
    } else if (view->pitching) {
        const double dy = y - view->lastY;
        if (dy) {
            view->map->setPitch(view->map->getPitch() - dy / 2);
        }
    }
    view->lastX = x;
    view->lastY = y;
}

void GLFWView::run() {
    while (!glfwWindowShouldClose(window)) {
        glfwWaitEvents();
        const bool dirty = !clean.test_and_set();
        if (dirty) {
            const double started = glfwGetTime();
            map->renderSync();
            report(1000 * (glfwGetTime() - started));
            if (benchmark) {
                map->update(mbgl::Update::Repaint);
            }
        }
    }
}

float GLFWView::getPixelRatio() const {
    return pixelRatio;
}

std::array<uint16_t, 2> GLFWView::getSize() const {
    return {{ static_cast<uint16_t>(width), static_cast<uint16_t>(height) }};
}

std::array<uint16_t, 2> GLFWView::getFramebufferSize() const {
    return {{ static_cast<uint16_t>(fbWidth), static_cast<uint16_t>(fbHeight) }};
}

void GLFWView::activate() {
    glfwMakeContextCurrent(window);
}

void GLFWView::deactivate() {
    glfwMakeContextCurrent(nullptr);
}

void GLFWView::notify() {
    glfwPostEmptyEvent();
}

void GLFWView::invalidate() {
    clean.clear();
    glfwPostEmptyEvent();
}

void GLFWView::beforeRender() {
    // no-op
}

void GLFWView::afterRender() {
    glfwSwapBuffers(window);
}

void GLFWView::report(float duration) {
    frames++;
    frameTime += duration;

    const double currentTime = glfwGetTime();
    if (currentTime - lastReported >= 1) {
        frameTime /= frames;
        mbgl::Log::Info(mbgl::Event::OpenGL, "Frame time: %6.2fms (%6.2f fps)", frameTime,
            1000 / frameTime);
        frames = 0;
        frameTime = 0;
        lastReported = currentTime;
    }
}

void GLFWView::setChangeStyleCallback(std::function<void()> callback) {
    changeStyleCallback = callback;
}

void GLFWView::setShouldClose() {
    glfwSetWindowShouldClose(window, true);
    glfwPostEmptyEvent();
}

void GLFWView::setWindowTitle(const std::string& title) {
    glfwSetWindowTitle(window, (std::string { "Mapbox GL: " } + title).c_str());
}

namespace mbgl {
namespace platform {

#ifndef GL_ES_VERSION_2_0
void showDebugImage(std::string name, const char *data, size_t width, size_t height) {
    glfwInit();

    static GLFWwindow *debugWindow = nullptr;
    if (!debugWindow) {
        debugWindow = glfwCreateWindow(width, height, name.c_str(), nullptr, nullptr);
        if (!debugWindow) {
            glfwTerminate();
            fprintf(stderr, "Failed to initialize window\n");
            exit(1);
        }
    }

    GLFWwindow *currentWindow = glfwGetCurrentContext();

    glfwSetWindowSize(debugWindow, width, height);
    glfwMakeContextCurrent(debugWindow);

    int fbWidth, fbHeight;
    glfwGetFramebufferSize(debugWindow, &fbWidth, &fbHeight);
    float scale = static_cast<float>(fbWidth) / static_cast<float>(width);

    {
        gl::PreservePixelZoom pixelZoom;
        gl::PreserveRasterPos rasterPos;

        MBGL_CHECK_ERROR(glPixelZoom(scale, -scale));
        MBGL_CHECK_ERROR(glRasterPos2f(-1.0f, 1.0f));
        MBGL_CHECK_ERROR(glDrawPixels(width, height, GL_LUMINANCE, GL_UNSIGNED_BYTE, data));
    }

    glfwSwapBuffers(debugWindow);

    glfwMakeContextCurrent(currentWindow);
}

void showColorDebugImage(std::string name, const char *data, size_t logicalWidth, size_t logicalHeight, size_t width, size_t height) {
    glfwInit();

    static GLFWwindow *debugWindow = nullptr;
    if (!debugWindow) {
        debugWindow = glfwCreateWindow(logicalWidth, logicalHeight, name.c_str(), nullptr, nullptr);
        if (!debugWindow) {
            glfwTerminate();
            fprintf(stderr, "Failed to initialize window\n");
            exit(1);
        }
    }

    GLFWwindow *currentWindow = glfwGetCurrentContext();

    glfwSetWindowSize(debugWindow, logicalWidth, logicalHeight);
    glfwMakeContextCurrent(debugWindow);

    int fbWidth, fbHeight;
    glfwGetFramebufferSize(debugWindow, &fbWidth, &fbHeight);
    float xScale = static_cast<float>(fbWidth) / static_cast<float>(width);
    float yScale = static_cast<float>(fbHeight) / static_cast<float>(height);

    {
        gl::PreserveClearColor clearColor;
        gl::PreserveBlend blend;
        gl::PreserveBlendFunc blendFunc;
        gl::PreservePixelZoom pixelZoom;
        gl::PreserveRasterPos rasterPos;

        MBGL_CHECK_ERROR(glClearColor(0.8, 0.8, 0.8, 1));
        MBGL_CHECK_ERROR(glClear(GL_COLOR_BUFFER_BIT));
        MBGL_CHECK_ERROR(glEnable(GL_BLEND));
        MBGL_CHECK_ERROR(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
        MBGL_CHECK_ERROR(glPixelZoom(xScale, -yScale));
        MBGL_CHECK_ERROR(glRasterPos2f(-1.0f, 1.0f));
        MBGL_CHECK_ERROR(glDrawPixels(width, height, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, data));
    }

    glfwSwapBuffers(debugWindow);

    glfwMakeContextCurrent(currentWindow);
}
#endif

}
}