#include "ImGuiWrapper.hpp"

#include <cstdio>
#include <vector>
#include <cmath>
#include <stdexcept>

#include <boost/format.hpp>
#include <boost/log/trivial.hpp>

#include <wx/string.h>
#include <wx/event.h>
#include <wx/debug.h>

#include <GL/glew.h>

#include <imgui/imgui_internal.h>

#include "libslic3r/libslic3r.h"
#include "libslic3r/Utils.hpp"
#include "GUI.hpp"

namespace Slic3r {
namespace GUI {


ImGuiWrapper::ImGuiWrapper()
    : m_font_texture(0)
    , m_style_scaling(1.0)
    , m_mouse_buttons(0)
    , m_disabled(false)
{
}

ImGuiWrapper::~ImGuiWrapper()
{
    destroy_device_objects();
    ImGui::DestroyContext();
}

bool ImGuiWrapper::init()
{
    ImGui::CreateContext();

    init_default_font(m_style_scaling);

    ImGui::GetIO().IniFilename = nullptr;

    return true;
}

void ImGuiWrapper::set_display_size(float w, float h)
{
    ImGuiIO& io = ImGui::GetIO();
    io.DisplaySize = ImVec2(w, h);
    io.DisplayFramebufferScale = ImVec2(1.0f, 1.0f);
}

void ImGuiWrapper::set_style_scaling(float scaling)
{
    if (!std::isnan(scaling) && !std::isinf(scaling) && scaling != m_style_scaling) {
        ImGui::GetStyle().ScaleAllSizes(scaling / m_style_scaling);
        init_default_font(scaling);
        m_style_scaling = scaling;
    }
}

bool ImGuiWrapper::update_mouse_data(wxMouseEvent& evt)
{
    ImGuiIO& io = ImGui::GetIO();
    io.MousePos = ImVec2((float)evt.GetX(), (float)evt.GetY());
    io.MouseDown[0] = evt.LeftDown();
    io.MouseDown[1] = evt.RightDown();
    io.MouseDown[2] = evt.MiddleDown();

    unsigned buttons = (evt.LeftDown() ? 1 : 0) | (evt.RightDown() ? 2 : 0) | (evt.MiddleDown() ? 4 : 0);
    bool res = buttons != m_mouse_buttons;
    m_mouse_buttons = buttons;
    return res;
}

void ImGuiWrapper::new_frame()
{
    if (m_font_texture == 0)
        create_device_objects();

    ImGui::NewFrame();
}

void ImGuiWrapper::render()
{
    ImGui::Render();
    render_draw_data(ImGui::GetDrawData());
}

void ImGuiWrapper::set_next_window_pos(float x, float y, int flag)
{
    ImGui::SetNextWindowPos(ImVec2(x, y), (ImGuiCond)flag);
    ImGui::SetNextWindowSize(ImVec2(0.0, 0.0));
}

void ImGuiWrapper::set_next_window_bg_alpha(float alpha)
{
    ImGui::SetNextWindowBgAlpha(alpha);
}

bool ImGuiWrapper::begin(const std::string &name, int flags)
{
    return ImGui::Begin(name.c_str(), nullptr, (ImGuiWindowFlags)flags);
}

bool ImGuiWrapper::begin(const wxString &name, int flags)
{
    return begin(into_u8(name), flags);
}

void ImGuiWrapper::end()
{
    ImGui::End();
}

bool ImGuiWrapper::button(const wxString &label)
{
    auto label_utf8 = into_u8(label);
    return ImGui::Button(label_utf8.c_str());
}

bool ImGuiWrapper::radio_button(const wxString &label, bool active)
{
    auto label_utf8 = into_u8(label);
    return ImGui::RadioButton(label_utf8.c_str(), active);
}

bool ImGuiWrapper::input_double(const std::string &label, const double &value, const std::string &format)
{
    return ImGui::InputDouble(label.c_str(), const_cast<double*>(&value), 0.0f, 0.0f, format.c_str());
}

bool ImGuiWrapper::input_vec3(const std::string &label, const Vec3d &value, float width, const std::string &format)
{
    bool value_changed = false;

    ImGui::BeginGroup();

    for (int i = 0; i < 3; ++i)
    {
        std::string item_label = (i == 0) ? "X" : ((i == 1) ? "Y" : "Z");
        ImGui::PushID(i);
        ImGui::PushItemWidth(width);
        value_changed |= ImGui::InputDouble(item_label.c_str(), const_cast<double*>(&value(i)), 0.0f, 0.0f, format.c_str());
        ImGui::PopID();
    }
    ImGui::EndGroup();

    return value_changed;
}

bool ImGuiWrapper::checkbox(const wxString &label, bool &value)
{
    auto label_utf8 = into_u8(label);
    return ImGui::Checkbox(label_utf8.c_str(), &value);
}

void ImGuiWrapper::text(const wxString &label)
{
    auto label_utf8 = into_u8(label);
    ImGui::Text(label_utf8.c_str(), NULL);
}


void ImGuiWrapper::combo(const wxString& label, const std::vector<wxString>& options, wxString& selection)
{
    const char* selection_u8 = into_u8(selection).c_str();

    // this is to force the label to the left of the widget:
    text(label);
    ImGui::SameLine();
    
    if (ImGui::BeginCombo("", selection_u8)) {
        for (const wxString& option : options) {
            const char* option_u8 = into_u8(option).c_str();
            bool is_selected = (selection_u8 == nullptr) ? false : strcmp(option_u8, selection_u8) == 0;
            if (ImGui::Selectable(option_u8, is_selected))
                selection = option_u8;
        }
        ImGui::EndCombo();
    }
}

void ImGuiWrapper::disabled_begin(bool disabled)
{
    wxCHECK_RET(!m_disabled, "ImGUI: Unbalanced disabled_begin() call");

    if (disabled) {
        ImGui::PushItemFlag(ImGuiItemFlags_Disabled, true);
        ImGui::PushStyleVar(ImGuiStyleVar_Alpha, ImGui::GetStyle().Alpha * 0.5f);
        m_disabled = true;
    }
}

void ImGuiWrapper::disabled_end()
{
    if (m_disabled) {
        ImGui::PopItemFlag();
        ImGui::PopStyleVar();
        m_disabled = false;
    }
}

bool ImGuiWrapper::want_mouse() const
{
    return ImGui::GetIO().WantCaptureMouse;
}

bool ImGuiWrapper::want_keyboard() const
{
    return ImGui::GetIO().WantCaptureKeyboard;
}

bool ImGuiWrapper::want_text_input() const
{
    return ImGui::GetIO().WantTextInput;
}

bool ImGuiWrapper::want_any_input() const
{
    const auto io = ImGui::GetIO();
    return io.WantCaptureMouse || io.WantCaptureKeyboard || io.WantTextInput;
}

void ImGuiWrapper::init_default_font(float scaling)
{
    static const float font_size = 18.0f;

    destroy_fonts_texture();

    ImGuiIO& io = ImGui::GetIO();
    io.Fonts->Clear();
    ImFont* font = io.Fonts->AddFontFromFileTTF((Slic3r::resources_dir() + "/fonts/NotoSans-Regular.ttf").c_str(), font_size * scaling);
    if (font == nullptr) {
        font = io.Fonts->AddFontDefault();
        if (font == nullptr) {
            throw std::runtime_error("ImGui: Could not load deafult font");
        }
    }
}

void ImGuiWrapper::create_device_objects()
{
    create_fonts_texture();
}

void ImGuiWrapper::create_fonts_texture()
{
    // Build texture atlas
    ImGuiIO& io = ImGui::GetIO();
    unsigned char* pixels;
    int width, height;
    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.

    // Upload texture to graphics system
    GLint last_texture;
    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
    glGenTextures(1, &m_font_texture);
    glBindTexture(GL_TEXTURE_2D, m_font_texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);

    // Store our identifier
    io.Fonts->TexID = (ImTextureID)(intptr_t)m_font_texture;

    // Restore state
    glBindTexture(GL_TEXTURE_2D, last_texture);
}

void ImGuiWrapper::render_draw_data(ImDrawData *draw_data)
{
    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
    ImGuiIO& io = ImGui::GetIO();
    int fb_width = (int)(draw_data->DisplaySize.x * io.DisplayFramebufferScale.x);
    int fb_height = (int)(draw_data->DisplaySize.y * io.DisplayFramebufferScale.y);
    if (fb_width == 0 || fb_height == 0)
        return;
    draw_data->ScaleClipRects(io.DisplayFramebufferScale);

    // We are using the OpenGL fixed pipeline to make the example code simpler to read!
    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill.
    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
    GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
    GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box); 
    glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glDisable(GL_CULL_FACE);
    glDisable(GL_DEPTH_TEST);
    glDisable(GL_LIGHTING);
    glDisable(GL_COLOR_MATERIAL);
    glEnable(GL_SCISSOR_TEST);
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glEnable(GL_TEXTURE_2D);
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    GLint texture_env_mode = GL_MODULATE;
    glGetTexEnviv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, &texture_env_mode);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound

    // Setup viewport, orthographic projection matrix
    // Our visible imgui space lies from draw_data->DisplayPps (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
    glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    glOrtho(draw_data->DisplayPos.x, draw_data->DisplayPos.x + draw_data->DisplaySize.x, draw_data->DisplayPos.y + draw_data->DisplaySize.y, draw_data->DisplayPos.y, -1.0f, +1.0f);
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    // Render command lists
    ImVec2 pos = draw_data->DisplayPos;
    for (int n = 0; n < draw_data->CmdListsCount; n++)
    {
        const ImDrawList* cmd_list = draw_data->CmdLists[n];
        const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
        const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
        glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos)));
        glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv)));
        glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col)));

        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
        {
            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
            if (pcmd->UserCallback)
            {
                // User callback (registered via ImDrawList::AddCallback)
                pcmd->UserCallback(cmd_list, pcmd);
            }
            else
            {
                ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - pos.x, pcmd->ClipRect.y - pos.y, pcmd->ClipRect.z - pos.x, pcmd->ClipRect.w - pos.y);
                if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
                {
                    // Apply scissor/clipping rectangle
                    glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));

                    // Bind texture, Draw
                    glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer);
                }
            }
            idx_buffer += pcmd->ElemCount;
        }
    }

    // Restore modified state
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, texture_env_mode);
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisableClientState(GL_VERTEX_ARRAY);
    glBindTexture(GL_TEXTURE_2D, (GLuint)last_texture);
    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glPopAttrib();
    glPolygonMode(GL_FRONT, (GLenum)last_polygon_mode[0]); glPolygonMode(GL_BACK, (GLenum)last_polygon_mode[1]);
    glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
    glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
}

void ImGuiWrapper::destroy_device_objects()
{
    destroy_fonts_texture();
}

void ImGuiWrapper::destroy_fonts_texture()
{
    if (m_font_texture) {
        ImGuiIO& io = ImGui::GetIO();
        io.Fonts->TexID = 0;
        glDeleteTextures(1, &m_font_texture);
        m_font_texture = 0;
    }
}


} // namespace GUI
} // namespace Slic3r