widgets.cpp

#include "widgets.hpp"
#include <imgui.h>
#include <iostream>

static inline ImVec2 operator+(const ImVec2& lhs, const ImVec2& rhs)            { return ImVec2(lhs.x+rhs.x, lhs.y+rhs.y); }
static inline ImVec2 operator-(const ImVec2& lhs, const ImVec2& rhs)            { return ImVec2(lhs.x-rhs.x, lhs.y-rhs.y); }

static const ImU32 ITEM_WIDGET_HOVERED_BG = IM_COL32(0, 103, 199, 255);
static const ImU32 ITEM_WIDGET_ACTIVE_BG = IM_COL32(0, 59, 115, 255);
static const ImU32 ITEM_WIDGET_NORMAL_BG = IM_COL32(0, 14, 28, 255);

/*
 * Help wanted: Improve colors
 */


ItemWidgetAction ItemWidget(int index, Item &item, bool is_focused, bool is_hovered) {

    bool is_item_updated = false;

    ImGui::PushID(index);
    auto drawlist = ImGui::GetWindowDrawList();
    drawlist->ChannelsSplit(2);
    // Split channels to foreground and background

    drawlist->ChannelsSetCurrent(1);
    // Switch to foreground channel

    auto initial_cursor = ImGui::GetCursorScreenPos();
    ImGui::BeginGroup();
        ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(10.0, 10.0));
        // Increase space between checkbox and text

            if(ImGui::Checkbox("##CHECK_BOX", &item.is_done)) {
                is_item_updated = true;
            }

            ImGui::SameLine();

            ImU32 text_color = ImGui::GetColorU32(ImGuiCol_Text);
            if(item.is_done) {
                text_color = IM_COL32(100, 100, 100, 255);
            }

            ImGui::PushStyleColor(ImGuiCol_Text, text_color);
                ImGui::TextWrapped("%s", item.text.c_str());
            ImGui::PopStyleColor();

        ImGui::PopStyleVar();
        
        ImGui::SameLine();
        ImGui::Dummy(ImVec2(ImGui::GetWindowContentRegionWidth() - ImGui::GetCursorPosX(), 0));

        ImGui::NewLine();
    ImGui::EndGroup();

    drawlist->ChannelsSetCurrent(0);
    // Switch to background channel

    auto final_cursor = initial_cursor + ImGui::GetItemRectSize();
    auto bg_start = initial_cursor; 
    auto bg_end = final_cursor - ImVec2(0, 1);

    drawlist->AddRectFilled(bg_start, bg_end, 
                            is_focused?ITEM_WIDGET_ACTIVE_BG:
                            is_hovered?ITEM_WIDGET_HOVERED_BG:
                                       ITEM_WIDGET_NORMAL_BG);
    // Draw background color

    auto line_start = ImVec2(0, final_cursor.y-1);
    auto line_end = ImVec2(final_cursor.x, final_cursor.y-1);
    drawlist->AddLine(line_start, line_end, IM_COL32_WHITE);

    drawlist->ChannelsMerge();
    ImGui::PopID();

    if(is_item_updated) return ItemWidgetAction::ItemUpdated;
    // ItemUpdated action triggers saving to disk. It has highest priority.

    if(is_focused) {
    // Process keyboard events only if focused

        if(ImGui::IsKeyReleased(ImGuiKey_Space)) {
            item.is_done = !item.is_done;
        }
        if(ImGui::IsKeyReleased(ImGuiKey_Enter)) {
            return ItemWidgetAction::RequestEdit;
        }
    }

    if(ImGui::IsItemHovered()) {
    // Process mouse events only if hovered

        if(ImGui::IsMouseDoubleClicked(0)) {
            return ItemWidgetAction::RequestEdit;
        } 
        if(ImGui::IsMouseClicked(0)) {
           return ItemWidgetAction::RequestFocus; 
        }
        if(ImGui::IsMouseClicked(1)) {
            return ItemWidgetAction::RequestContextMenu;
        }
    }

    if(  ImGui::IsItemHovered() && !is_hovered ) return ItemWidgetAction::HoverEnter;
    if( !ImGui::IsItemHovered() &&  is_hovered ) return ItemWidgetAction::HoverExit;
    // is_hovered will be passed in by the parent. 
    // It holds the hovered state in previous frame.

    return ItemWidgetAction::None;
}