#ifdef _MSC_VER
#  include <winsock2.h>
#else
#  include <sys/time.h>
#endif

#include <algorithm>
#include <assert.h>
#include <limits>
#include <stdlib.h>

#include "../common/TracyProtocol.hpp"
#include "../common/TracySystem.hpp"
#include "../common/TracyQueue.hpp"
#include "TracyImGui.hpp"
#include "TracyView.hpp"

namespace tracy
{

static View* s_instance = nullptr;

View::View( const char* addr )
    : m_addr( addr )
    , m_shutdown( false )
    , m_connected( false )
    , m_mbps( 64 )
    , m_stream( LZ4_createStreamDecode() )
    , m_buffer( new char[TargetFrameSize*3] )
    , m_bufferOffset( 0 )
    , m_frameScale( 0 )
    , m_pause( false )
    , m_frameStart( 0 )
{
    assert( s_instance == nullptr );
    s_instance = this;

    m_thread = std::thread( [this] { Worker(); } );
    SetThreadName( m_thread, "Tracy View" );
}

View::~View()
{
    m_shutdown.store( true, std::memory_order_relaxed );
    m_thread.join();

    delete[] m_buffer;
    LZ4_freeStreamDecode( m_stream );

    assert( s_instance != nullptr );
    s_instance = nullptr;
}

bool View::ShouldExit()
{
    return s_instance->m_shutdown.load( std::memory_order_relaxed );
}

void View::Worker()
{
    timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec = 10000;

    for(;;)
    {
        if( m_shutdown.load( std::memory_order_relaxed ) ) return;
        if( !m_sock.Connect( m_addr.c_str(), "8086" ) ) continue;

        std::chrono::time_point<std::chrono::high_resolution_clock> t0;

        uint8_t lz4;
        uint64_t bytes = 0;
        uint64_t timeStart;

        if( !m_sock.Read( &timeStart, sizeof( timeStart ), &tv, ShouldExit ) ) goto close;
        if( !m_sock.Read( &lz4, sizeof( lz4 ), &tv, ShouldExit ) ) goto close;

        m_frames.push_back( timeStart );
        LZ4_setStreamDecode( m_stream, nullptr, 0 );

        m_connected.store( true, std::memory_order_relaxed );

        t0 = std::chrono::high_resolution_clock::now();

        for(;;)
        {
            if( m_shutdown.load( std::memory_order_relaxed ) ) return;

            if( lz4 )
            {
                auto buf = m_buffer + m_bufferOffset;
                char lz4buf[LZ4Size];
                lz4sz_t lz4sz;
                if( !m_sock.Read( &lz4sz, sizeof( lz4sz ), &tv, ShouldExit ) ) goto close;
                if( !m_sock.Read( lz4buf, lz4sz, &tv, ShouldExit ) ) goto close;
                bytes += sizeof( lz4sz ) + lz4sz;

                auto sz = LZ4_decompress_safe_continue( m_stream, lz4buf, buf, lz4sz, TargetFrameSize );
                assert( sz >= 0 );

                const char* ptr = buf;
                const char* end = buf + sz;
                while( ptr < end )
                {
                    auto ev = (QueueItem*)ptr;
                    DispatchProcess( *ev, ptr );
                }

                m_bufferOffset += sz;
                if( m_bufferOffset > TargetFrameSize * 2 ) m_bufferOffset = 0;
            }
            else
            {
                QueueItem ev;
                if( !m_sock.Read( &ev.hdr, sizeof( QueueHeader ), &tv, ShouldExit ) ) goto close;
                const auto payload = QueueDataSize[ev.hdr.idx] - sizeof( QueueHeader );
                if( payload > 0 )
                {
                    if( !m_sock.Read( ((char*)&ev) + sizeof( QueueHeader ), payload, &tv, ShouldExit ) ) goto close;
                }
                bytes += sizeof( QueueHeader ) + payload;   // ignores string transfer
                DispatchProcess( ev );
            }

            auto t1 = std::chrono::high_resolution_clock::now();
            auto td = std::chrono::duration_cast<std::chrono::milliseconds>( t1 - t0 ).count();
            enum { MbpsUpdateTime = 200 };
            if( td > MbpsUpdateTime )
            {
                std::lock_guard<std::mutex> lock( m_mbpslock );
                m_mbps.erase( m_mbps.begin() );
                m_mbps.emplace_back( bytes / ( td * 125.f ) );
                t0 = t1;
                bytes = 0;
            }
        }

close:
        m_sock.Close();
        m_connected.store( false, std::memory_order_relaxed );
    }
}

void View::DispatchProcess( const QueueItem& ev )
{
    if( ev.hdr.type == QueueType::StringData )
    {
        timeval tv;
        tv.tv_sec = 0;
        tv.tv_usec = 10000;

        char buf[TargetFrameSize];
        uint16_t sz;
        m_sock.Read( &sz, sizeof( sz ), &tv, ShouldExit );
        m_sock.Read( buf, sz, &tv, ShouldExit );
        AddString( ev.hdr.id, std::string( buf, buf+sz ) );
    }
    else
    {
        Process( ev );
    }
}

void View::DispatchProcess( const QueueItem& ev, const char*& ptr )
{
    ptr += QueueDataSize[ev.hdr.idx];
    if( ev.hdr.type == QueueType::StringData )
    {
        uint16_t sz;
        memcpy( &sz, ptr, sizeof( sz ) );
        ptr += sizeof( sz );
        AddString( ev.hdr.id, std::string( ptr, ptr+sz ) );
        ptr += sz;
    }
    else
    {
        Process( ev );
    }
}

void View::Process( const QueueItem& ev )
{
    switch( ev.hdr.type )
    {
    case QueueType::ZoneBegin:
        ProcessZoneBegin( ev.hdr.id, ev.zoneBegin );
        break;
    case QueueType::ZoneEnd:
        ProcessZoneEnd( ev.hdr.id, ev.zoneEnd );
        break;
    case QueueType::FrameMark:
        ProcessFrameMark( ev.hdr.id );
        break;
    default:
        assert( false );
        break;
    }
}

void View::ProcessZoneBegin( uint64_t id, const QueueZoneBegin& ev )
{
    auto it = m_pendingEndZone.find( id );
    auto zone = m_slab.Alloc<Event>();
    CheckString( ev.filename );
    CheckString( ev.function );
    zone->start = ev.time;
    std::unique_lock<std::mutex> lock( m_lock );
    if( it == m_pendingEndZone.end() )
    {
        zone->end = -1;
        NewZone( zone );
        lock.unlock();
        m_openZones.emplace( id, zone );
    }
    else
    {
        assert( ev.time <= it->second.time );
        zone->end = it->second.time;
        NewZone( zone );
        lock.unlock();
        m_pendingEndZone.erase( it );
    }
}

void View::ProcessZoneEnd( uint64_t id, const QueueZoneEnd& ev )
{
    auto it = m_openZones.find( id );
    if( it == m_openZones.end() )
    {
        m_pendingEndZone.emplace( id, ev );
    }
    else
    {
        auto zone = it->second;
        std::unique_lock<std::mutex> lock( m_lock );
        assert( ev.time >= zone->start );
        zone->end = ev.time;
        UpdateZone( zone );
        lock.unlock();
        m_openZones.erase( it );
    }
}

void View::ProcessFrameMark( uint64_t id )
{
    assert( !m_frames.empty() );
    const auto lastframe = m_frames.back();
    if( lastframe < id )
    {
        std::unique_lock<std::mutex> lock( m_lock );
        m_frames.push_back( id );
    }
    else
    {
        auto it = std::lower_bound( m_frames.begin(), m_frames.end(), id );
        std::unique_lock<std::mutex> lock( m_lock );
        m_frames.insert( it, id );
    }
}

void View::CheckString( uint64_t ptr )
{
    if( m_strings.find( ptr ) != m_strings.end() ) return;
    if( m_pendingStrings.find( ptr ) != m_pendingStrings.end() ) return;

    m_pendingStrings.emplace( ptr );
    m_sock.Send( &ptr, sizeof( ptr ) );
}

void View::AddString( uint64_t ptr, std::string&& str )
{
    assert( m_strings.find( ptr ) == m_strings.end( ptr ) );
    auto it = m_pendingStrings.find( ptr );
    assert( it != m_pendingStrings.end() );
    m_pendingStrings.erase( it );
    std::lock_guard<std::mutex> lock( m_lock );
    m_strings.emplace( ptr, std::move( str ) );
}

void View::NewZone( Event* zone )
{
    if( !m_timeline.empty() )
    {
        const auto lastend = m_timeline.back()->end;
        if( lastend != -1 && lastend < zone->start )
        {
            m_timeline.push_back( zone );
        }
        else
        {

        }
    }
    else
    {
        m_timeline.push_back( zone );
    }
}

void View::UpdateZone( Event* zone )
{
    assert( zone->end != -1 );
}

uint64_t View::GetFrameTime( size_t idx ) const
{
    if( idx < m_frames.size() - 1 )
    {
        return m_frames[idx+1] - m_frames[idx];
    }
    else
    {
        const auto last = GetLastTime();
        return last == 0 ? 0 : last - m_frames.back();
    }
}

uint64_t View::GetLastTime() const
{
    uint64_t last = 0;
    if( !m_frames.empty() ) last = m_frames.back();
    if( !m_timeline.empty() )
    {
        auto ev = m_timeline.back();
        if( ev->end > (int64_t)last ) last = ev->end;
    }
    return last;
}

const char* View::TimeToString( uint64_t ns ) const
{
    static char buf[64];
    if( ns < 1000 )
    {
        sprintf( buf, "%i ns", ns );
    }
    else if( ns < 1000ull * 1000 )
    {
        sprintf( buf, "%.2f us", ns / 1000. );
    }
    else if( ns < 1000ull * 1000 * 1000 )
    {
        sprintf( buf, "%.2f ms", ns / ( 1000. * 1000. ) );
    }
    else if( ns < 1000ull * 1000 * 1000 * 60 )
    {
        sprintf( buf, "%.2f s", ns / ( 1000. * 1000. * 1000. ) );
    }
    else
    {
        const auto m = ns / ( 1000ull * 1000 * 1000 * 60 );
        const auto s = ns - m * ( 1000ull * 1000 * 1000 * 60 );
        sprintf( buf, "%i:%04.1f", m, s / ( 1000. * 1000. * 1000. ) );
    }
    return buf;
}

void View::Draw()
{
    s_instance->DrawImpl();
}

void View::DrawImpl()
{
    // Connection window
    ImGui::Begin( m_addr.c_str(), nullptr, ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_ShowBorders );
    {
        std::lock_guard<std::mutex> lock( m_mbpslock );
        const auto mbps = m_mbps.back();
        char buf[64];
        if( mbps < 0.1f )
        {
            sprintf( buf, "%6.2f Kbps", mbps * 1000.f );
        }
        else
        {
            sprintf( buf, "%6.2f Mbps", mbps );
        }
        ImGui::Dummy( ImVec2( 10, 0 ) );
        ImGui::SameLine();
        ImGui::PlotLines( buf, m_mbps.data(), m_mbps.size(), 0, nullptr, 0, std::numeric_limits<float>::max(), ImVec2( 150, 0 ) );
    }

    ImGui::Text( "Memory usage: %.2f MB", memUsage.load( std::memory_order_relaxed ) / ( 1024.f * 1024.f ) );

    const auto wpos = ImGui::GetWindowPos() + ImGui::GetWindowContentRegionMin();
    ImGui::GetWindowDrawList()->AddCircleFilled( wpos + ImVec2( 6, 9 ), 5.f, m_connected.load( std::memory_order_relaxed ) ? 0xFF2222CC : 0xFF444444, 10 );

    std::lock_guard<std::mutex> lock( m_lock );
    {
        const auto sz = m_frames.size();
        if( sz > 1 )
        {
            const auto dt = m_frames[sz-1] - m_frames[sz-2];
            const auto dtm = dt / 1000000.f;
            const auto fps = 1000.f / dtm;
            ImGui::Text( "FPS: %6.1f  Frame time: %.2f ms", fps, dtm );
        }
    }

    ImGui::End();

    // Profiler window
    ImGui::Begin( "Profiler", nullptr, ImGuiWindowFlags_ShowBorders );
    if( ImGui::Button( m_pause ? "Resume" : "Pause", ImVec2( 80, 0 ) ) ) m_pause = !m_pause;
    ImGui::SameLine();
    ImGui::Text( "Frames: %-7i Time span: %s", m_frames.size(), TimeToString( GetLastTime() - m_frames[0] ) );
    DrawFrames();
    ImGui::End();

    ImGui::ShowTestWindow();
}

static ImU32 GetFrameColor( uint64_t frameTime )
{
    enum { BestTime = 1000 * 1000 * 1000 / 143 };
    enum { GoodTime = 1000 * 1000 * 1000 / 59 };
    enum { BadTime = 1000 * 1000 * 1000 / 29 };

    return frameTime > BadTime  ? 0xFF2222DD :
           frameTime > GoodTime ? 0xFF22DDDD :
           frameTime > BestTime ? 0xFF22DD22 : 0xFFDD9900;
}

void View::DrawFrames()
{
    enum { Offset = 25 };
    enum { Height = 40 };
    enum { MaxFrameTime = 50 * 1000 * 1000 };  // 50ms

    ImGuiWindow* window = ImGui::GetCurrentWindow();
    if( window->SkipItems ) return;

    auto& io = ImGui::GetIO();

    const auto wpos = ImGui::GetWindowPos() + ImGui::GetWindowContentRegionMin() + ImVec2( 0, Offset );
    const auto wspace = ImGui::GetWindowContentRegionMax() - ImGui::GetWindowContentRegionMin();
    const auto w = wspace.x;
    auto draw = ImGui::GetWindowDrawList();

    draw->AddRectFilled( wpos, wpos + ImVec2( w, Height ), 0x33FFFFFF );
    bool hover = ImGui::IsMouseHoveringRect( wpos, wpos + ImVec2( w, 60 ) );
    if( hover )
    {
        const auto wheel = io.MouseWheel;
        if( wheel > 0 )
        {
            if( m_frameScale > -1 ) m_frameScale--;
        }
        else if( wheel < 0 )
        {
            if( m_frameScale < 10 ) m_frameScale++;
        }
    }

    const int fwidth = m_frameScale == 0 ? 4 : ( m_frameScale == -1 ? 6 : 1 );
    const int group = m_frameScale < 2 ? 1 : ( 1 << ( m_frameScale - 1 ) );
    const int total = m_frames.size();
    const int onScreen = ( w - 2 ) / fwidth;
    if( !m_pause ) m_frameStart = ( total < onScreen * group ) ? 0 : total - onScreen * group;

    if( hover && ImGui::IsMouseDragging( 1, 0 ) )
    {
        m_pause = true;
        const auto delta = ImGui::GetMouseDragDelta( 1, 0 ).x;
        if( abs( delta ) >= fwidth )
        {
            const auto d = (int)delta / fwidth;
            m_frameStart = std::max( 0, m_frameStart - d * group );
            io.MouseClickedPos[1].x = io.MousePos.x + d * fwidth - delta;
        }
    }

    int i = 0, idx = 0;
    while( i < onScreen && m_frameStart + idx < total )
    {
        uint64_t f = GetFrameTime( m_frameStart + idx );
        int g;
        if( group > 1 )
        {
            g = std::min( group, total - ( m_frameStart + idx ) );
            for( int j=1; j<g; j++ )
            {
                f = std::max( f, GetFrameTime( m_frameStart + idx + j ) );
            }
        }

        bool fhover = false;
        const auto h = float( std::min<uint64_t>( MaxFrameTime, f ) ) / MaxFrameTime * ( Height - 2 );
        if( fwidth != 1 )
        {
            draw->AddRectFilled( wpos + ImVec2( 1 + i*4, Height-1-h ), wpos + ImVec2( 4 + i*4, Height-1 ), GetFrameColor( f ) );
            if( hover ) fhover = ImGui::IsMouseHoveringRect( wpos + ImVec2( 1 + i*4, 1 ), wpos + ImVec2( 5 + i*4, Height - 1 ) );
        }
        else
        {
            draw->AddLine( wpos + ImVec2( 1+i, Height-2-h ), wpos + ImVec2( 1+i, Height-2 ), GetFrameColor( f ) );
            if( hover ) fhover = ImGui::IsMouseHoveringRect( wpos + ImVec2( 1+i, 1 ), wpos + ImVec2( 2+i, Height - 1 ) );
        }
        if( fhover )
        {
            hover = false;
            ImGui::BeginTooltip();
            if( group > 1 )
            {
                ImGui::Text( "Frames: %i - %i (%i)", m_frameStart + idx, m_frameStart + idx + g - 1, g );
                ImGui::Text( "Max frame time: %s", TimeToString( f ) );
            }
            else
            {
                ImGui::Text( "Frame: %i", m_frameStart + idx );
                ImGui::Text( "Frame time: %s", TimeToString( f ) );
            }
            ImGui::EndTooltip();
        }
        i++;
        idx += group;
    }
}

}