//------------------------------------------------------------------------------
// VERSION 0.9.1
//
// LICENSE
//   This software is dual-licensed to the public domain and under the following
//   license: you are granted a perpetual, irrevocable license to copy, modify,
//   publish, and distribute this file as you see fit.
//
// CREDITS
//   Written by Michal Cichon
//------------------------------------------------------------------------------

# include "imgui_node_editor_internal.h"
# include <cstdio> 
# include <string>
# include <fstream>
# include <bitset>
# include <climits>
# include <algorithm>
# include <sstream>
# include <streambuf>
# include <type_traits>
# include <cstdarg>
# include <vector>

namespace ed = ax::NodeEditor::Detail;

//------------------------------------------------------------------------------
// In-App Logger (similar to ImGui demo's ExampleAppLog)
//------------------------------------------------------------------------------
class InAppLogger
{
public:
    ImGuiTextBuffer     Buf;
    ImGuiTextFilter     Filter;
    ImVector<int>       LineOffsets; // Index to lines offset. We maintain this with AddLog() calls.
    bool                AutoScroll;  // Keep scrolling if already at the bottom.
    int                 MaxLines;    // Maximum number of lines to keep

    InAppLogger()
    {
        AutoScroll = true;
        MaxLines = 1000; // Keep last 1000 lines
        Clear();
    }

    void Clear()
    {
        Buf.clear();
        LineOffsets.clear();
        LineOffsets.push_back(0);
    }

    void AddLog(const char* fmt, ...) IM_FMTARGS(2)
    {
        int old_size = Buf.size();
        va_list args;
        va_start(args, fmt);
        Buf.appendfv(fmt, args);
        va_end(args);
        UpdateLineOffsets(old_size);
    }
    
    void AddLogV(const char* fmt, va_list args)
    {
        int old_size = Buf.size();
        Buf.appendfv(fmt, args);
        UpdateLineOffsets(old_size);
    }

    void DrawInline(float height);
    
private:
    void UpdateLineOffsets(int old_size)
    {
        for (int new_size = Buf.size(); old_size < new_size; old_size++)
            if (Buf[old_size] == '\n')
                LineOffsets.push_back(old_size + 1);
        
        // Trim to MaxLines if needed
        if (LineOffsets.Size > MaxLines)
        {
            int linesToRemove = LineOffsets.Size - MaxLines;
            int bytesToRemove = LineOffsets[linesToRemove];
            Buf.Buf.erase(Buf.Buf.Data, Buf.Buf.Data + bytesToRemove);
            LineOffsets.erase(LineOffsets.Data, LineOffsets.Data + linesToRemove);
            // Adjust remaining offsets
            for (int i = 0; i < LineOffsets.Size; i++)
                LineOffsets[i] -= bytesToRemove;
        }
    }
};

//------------------------------------------------------------------------------
void InAppLogger::DrawInline(float height)
{
    // Header
    ImGui::GetWindowDrawList()->AddRectFilled(
        ImGui::GetCursorScreenPos(),
        ImGui::GetCursorScreenPos() + ImVec2(ImGui::GetContentRegionAvail().x, ImGui::GetTextLineHeight()),
        ImColor(ImGui::GetStyle().Colors[ImGuiCol_HeaderActive]), ImGui::GetTextLineHeight() * 0.25f);
    ImGui::Spacing(); ImGui::SameLine();
    ImGui::TextUnformatted("Log");
    ImGui::SameLine();
    ImGui::TextDisabled("(%d)", LineOffsets.Size > 0 ? LineOffsets.Size - 1 : 0);
    
    // Options menu
    ImGui::SameLine();
    if (ImGui::SmallButton("Clear"))
        Clear();
    ImGui::SameLine();
    bool copy = ImGui::SmallButton("Copy");
    ImGui::SameLine();
    Filter.Draw("Filter", -60.0f);
    
    ImGui::Separator();
    
    // Scrolling region
    ImGui::BeginChild("scrolling_log", ImVec2(0, height), false, ImGuiWindowFlags_HorizontalScrollbar);
    
    if (copy)
        ImGui::LogToClipboard();

    ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
    const char* buf = Buf.begin();
    const char* buf_end = Buf.end();
    
    if (Filter.IsActive())
    {
        // Filter is active - show filtered lines
        for (int line_no = 0; line_no < LineOffsets.Size; line_no++)
        {
            const char* line_start = buf + LineOffsets[line_no];
            const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end;
            if (Filter.PassFilter(line_start, line_end))
                ImGui::TextUnformatted(line_start, line_end);
        }
    }
    else
    {
        // No filter - use clipper for performance
        ImGuiListClipper clipper;
        clipper.Begin(LineOffsets.Size);
        while (clipper.Step())
        {
            for (int line_no = clipper.DisplayStart; line_no < clipper.DisplayEnd; line_no++)
            {
                const char* line_start = buf + LineOffsets[line_no];
                const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end;
                ImGui::TextUnformatted(line_start, line_end);
            }
        }
        clipper.End();
    }
    ImGui::PopStyleVar();

    // Keep up at the bottom of the scroll region if we were already at the bottom
    if (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY())
        ImGui::SetScrollHereY(1.0f);
        
    ImGui::EndChild();
    
    if (copy)
        ImGui::LogFinish();
}

static InAppLogger g_InAppLogger;

//------------------------------------------------------------------------------
// Function to add log message from external code (like LogV)
//------------------------------------------------------------------------------
void ed::AddInAppLog(const char* fmt, ...)
{
    va_list args;
    va_start(args, fmt);
    g_InAppLogger.AddLogV(fmt, args);
    va_end(args);
}

//------------------------------------------------------------------------------
// Function to draw the in-app logger inline (for use in panels)
//------------------------------------------------------------------------------
void ed::DrawInAppLogger(float height)
{
    g_InAppLogger.DrawInline(height);
}