#include <algorithm>
#include <wx/dcbuffer.h>

#include "RammingChart.hpp"
#include "GUI.hpp"


wxDEFINE_EVENT(EVT_WIPE_TOWER_CHART_CHANGED, wxCommandEvent);


void Chart::draw() {
    wxAutoBufferedPaintDC dc(this); // unbuffered DC caused flickering on win

    dc.SetBrush(GetBackgroundColour());
    dc.SetPen(GetBackgroundColour());
    dc.DrawRectangle(GetClientRect());  // otherwise the background would end up black on windows

    dc.SetPen(*wxBLACK_PEN);
    dc.SetBrush(*wxWHITE_BRUSH);
    dc.DrawRectangle(m_rect);
    
    if (visible_area.m_width < 0.499) {
        dc.DrawText(_(L("NO RAMMING AT ALL")),wxPoint(m_rect.GetLeft()+m_rect.GetWidth()/2-50,m_rect.GetBottom()-m_rect.GetHeight()/2));
        return;
    }
    
    
    if (!m_line_to_draw.empty()) {
        for (unsigned int i=0;i<m_line_to_draw.size()-2;++i) {
            int color = 510*((m_rect.GetBottom()-(m_line_to_draw)[i])/double(m_rect.GetHeight()));
            dc.SetPen( wxPen( wxColor(std::min(255,color),255-std::max(color-255,0),0), 1 ) );
            dc.DrawLine(m_rect.GetLeft()+1+i,(m_line_to_draw)[i],m_rect.GetLeft()+1+i,m_rect.GetBottom());        
        }
        dc.SetPen( wxPen( wxColor(0,0,0), 1 ) );
        for (unsigned int i=0;i<m_line_to_draw.size()-2;++i) {
            if (splines)
                dc.DrawLine(m_rect.GetLeft()+i,(m_line_to_draw)[i],m_rect.GetLeft()+i+1,(m_line_to_draw)[i+1]);
            else {
                dc.DrawLine(m_rect.GetLeft()+i,(m_line_to_draw)[i],m_rect.GetLeft()+i+1,(m_line_to_draw)[i]);
                dc.DrawLine(m_rect.GetLeft()+i+1,(m_line_to_draw)[i],m_rect.GetLeft()+i+1,(m_line_to_draw)[i+1]);
            }
        }
    }
    
    // draw draggable buttons
    dc.SetBrush(*wxBLUE_BRUSH);
    dc.SetPen( wxPen( wxColor(0,0,0), 1 ) );
    for (auto& button : m_buttons)
        //dc.DrawRectangle(math_to_screen(button.get_pos())-wxPoint(side/2.,side/2.), wxSize(side,side));
        dc.DrawCircle(math_to_screen(button.get_pos()),side/2.);
        //dc.DrawRectangle(math_to_screen(button.get_pos()-wxPoint2DDouble(0.125,0))-wxPoint(0,5),wxSize(50,10));

    // draw x-axis:
    float last_mark = -10000;
    for (float math_x=int(visible_area.m_x*10)/10 ; math_x < (visible_area.m_x+visible_area.m_width) ; math_x+=0.1) {
        int x = math_to_screen(wxPoint2DDouble(math_x,visible_area.m_y)).x;
        int y = m_rect.GetBottom();
        if (x-last_mark < 50) continue;
        dc.DrawLine(x,y+3,x,y-3);
        dc.DrawText(wxString().Format(wxT("%.1f"), math_x),wxPoint(x-10,y+7));
        last_mark = x;
    }
    
    // draw y-axis:
    last_mark=10000;
    for (int math_y=visible_area.m_y ; math_y < (visible_area.m_y+visible_area.m_height) ; math_y+=1) {
        int y = math_to_screen(wxPoint2DDouble(visible_area.m_x,math_y)).y;
        int x = m_rect.GetLeft();
        if (last_mark-y < 50) continue;    
        dc.DrawLine(x-3,y,x+3,y);
        dc.DrawText(wxString()<<math_y,wxPoint(x-25,y-2/*7*/));
        last_mark = y;
    }
    
    // axis labels:
    wxString label = _(L("Time")) + " ("+_(L("s"))+")";
    int text_width = 0;
    int text_height = 0;
    dc.GetTextExtent(label,&text_width,&text_height);
    dc.DrawText(label,wxPoint(0.5*(m_rect.GetRight()+m_rect.GetLeft())-text_width/2.f, m_rect.GetBottom()+25));
    label = _(L("Volumetric speed")) + " (" + _(L("mm")) + wxString("³/", wxConvUTF8) + _(L("s")) + ")";
    dc.GetTextExtent(label,&text_width,&text_height);
    dc.DrawRotatedText(label,wxPoint(0,0.5*(m_rect.GetBottom()+m_rect.GetTop())+text_width/2.f),90);
}

void Chart::mouse_right_button_clicked(wxMouseEvent& event) {
    if (!manual_points_manipulation)
        return;
    wxPoint point = event.GetPosition();
    int button_index = which_button_is_clicked(point);
    if (button_index != -1 && m_buttons.size()>2) {
        m_buttons.erase(m_buttons.begin()+button_index);
        recalculate_line();
    }
}
    


void Chart::mouse_clicked(wxMouseEvent& event) {
    wxPoint point = event.GetPosition();
    int button_index = which_button_is_clicked(point);
    if ( button_index != -1) {
        m_dragged = &m_buttons[button_index];
        m_previous_mouse = point;            
    }
}
    
    
    
void Chart::mouse_moved(wxMouseEvent& event) {
    if (!event.Dragging() || !m_dragged) return;
    wxPoint pos = event.GetPosition();    
    wxRect rect = m_rect;
    rect.Deflate(side/2.);
    if (!(rect.Contains(pos))) {  // the mouse left chart area
        mouse_left_window(event);
        return;
    }    
    int delta_x = pos.x - m_previous_mouse.x;
    int delta_y = pos.y - m_previous_mouse.y;
    m_dragged->move(fixed_x?0:double(delta_x)/m_rect.GetWidth() * visible_area.m_width,-double(delta_y)/m_rect.GetHeight() * visible_area.m_height); 
    m_previous_mouse = pos;
    recalculate_line();
}



void Chart::mouse_double_clicked(wxMouseEvent& event) {
    if (!manual_points_manipulation)
        return;
    wxPoint point = event.GetPosition();
    if (!m_rect.Contains(point))     // the click is outside the chart
        return;
    m_buttons.push_back(screen_to_math(point));
    std::sort(m_buttons.begin(),m_buttons.end());
    recalculate_line();
    return;
}




void Chart::recalculate_line() {
    std::vector<wxPoint> points;
    for (auto& but : m_buttons) {
        points.push_back(wxPoint(math_to_screen(but.get_pos())));
        if (points.size()>1 && points.back().x==points[points.size()-2].x) points.pop_back();
        if (points.size()>1 && points.back().x > m_rect.GetRight()) {
            points.pop_back();
            break;
        }
    }
    std::sort(points.begin(),points.end(),[](wxPoint& a,wxPoint& b) { return a.x < b.x; });
    
    m_line_to_draw.clear();
    m_total_volume = 0.f;
   
   
    // Cubic spline interpolation: see https://en.wikiversity.org/wiki/Cubic_Spline_Interpolation#Methods
    const bool boundary_first_derivative = true; // true - first derivative is 0 at the leftmost and rightmost point
                                                 // false - second ---- || -------
    const int N = points.size()-1; // last point can be accessed as N, we have N+1 total points
    std::vector<float> diag(N+1);
    std::vector<float> mu(N+1);
    std::vector<float> lambda(N+1);
    std::vector<float> h(N+1);
    std::vector<float> rhs(N+1);
    
    // let's fill in inner equations
    for (int i=1;i<=N;++i) h[i] = points[i].x-points[i-1].x;
    std::fill(diag.begin(),diag.end(),2.f);
    for (int i=1;i<=N-1;++i) {
        mu[i] = h[i]/(h[i]+h[i+1]);
        lambda[i] = 1.f - mu[i];
        rhs[i] = 6 * ( float(points[i+1].y-points[i].y  )/(h[i+1]*(points[i+1].x-points[i-1].x)) -  
                       float(points[i].y  -points[i-1].y)/(h[i]  *(points[i+1].x-points[i-1].x))   );                       
    }
    
    // now fill in the first and last equations, according to boundary conditions:
    if (boundary_first_derivative) {
        const float endpoints_derivative = 0;
        lambda[0] = 1;
        mu[N]     = 1;
        rhs[0] = (6.f/h[1]) * (float(points[0].y-points[1].y)/(points[0].x-points[1].x) - endpoints_derivative);
        rhs[N] = (6.f/h[N]) * (endpoints_derivative - float(points[N-1].y-points[N].y)/(points[N-1].x-points[N].x));        
    }
    else {
        lambda[0] = 0;
        mu[N]     = 0;
        rhs[0]    = 0;
        rhs[N]    = 0;
    }
        
    // the trilinear system is ready to be solved:
    for (int i=1;i<=N;++i) {
        float multiple = mu[i]/diag[i-1];    // let's subtract proper multiple of above equation
        diag[i]-= multiple * lambda[i-1];
        rhs[i] -= multiple * rhs[i-1];        
    }
    // now the back substitution (vector mu contains invalid values from now on):
    rhs[N] = rhs[N]/diag[N];
    for (int i=N-1;i>=0;--i)
        rhs[i] = (rhs[i]-lambda[i]*rhs[i+1])/diag[i];
    
    
    
    
    unsigned int i=1;
    float y=0.f;
    for (int x=m_rect.GetLeft(); x<=m_rect.GetRight() ; ++x) {        
        if (splines) {
            if (i<points.size()-1 && points[i].x < x ) {
                ++i; 
            }
            if (points[0].x > x)
                y = points[0].y;
            else
                if (points[N].x < x)
                    y = points[N].y;
                else 
                    y = (rhs[i-1]*pow(points[i].x-x,3)+rhs[i]*pow(x-points[i-1].x,3)) / (6*h[i]) +
                        (points[i-1].y-rhs[i-1]*h[i]*h[i]/6.f) * (points[i].x-x)/h[i] +
                        (points[i].y  -rhs[i]  *h[i]*h[i]/6.f) * (x-points[i-1].x)/h[i];
            m_line_to_draw.push_back(y);
        }
        else {            
            float x_math = screen_to_math(wxPoint(x,0)).m_x;
            if (i+2<=points.size() && m_buttons[i+1].get_pos().m_x-0.125 < x_math)
                ++i;
            m_line_to_draw.push_back(math_to_screen(wxPoint2DDouble(x_math,m_buttons[i].get_pos().m_y)).y);
        }
            
                    
        m_line_to_draw.back() = std::max(m_line_to_draw.back(), m_rect.GetTop()-1);
        m_line_to_draw.back() = std::min(m_line_to_draw.back(), m_rect.GetBottom()-1);
        m_total_volume += (m_rect.GetBottom() - m_line_to_draw.back()) * (visible_area.m_width / m_rect.GetWidth()) * (visible_area.m_height / m_rect.GetHeight());
    }
    
    wxPostEvent(this->GetParent(), wxCommandEvent(EVT_WIPE_TOWER_CHART_CHANGED));
    Refresh();
}



std::vector<float> Chart::get_ramming_speed(float sampling) const {
    std::vector<float> speeds_out;
    
    const int number_of_samples = std::round( visible_area.m_width / sampling);
    if (number_of_samples>0) {
        const int dx = (m_line_to_draw.size()-1) / number_of_samples;
        for (int j=0;j<number_of_samples;++j) {
            float left =  screen_to_math(wxPoint(0,m_line_to_draw[j*dx])).m_y;
            float right = screen_to_math(wxPoint(0,m_line_to_draw[(j+1)*dx])).m_y;
            speeds_out.push_back((left+right)/2.f);            
        }
    }
    return speeds_out;
}


std::vector<std::pair<float,float>> Chart::get_buttons() const {
    std::vector<std::pair<float, float>> buttons_out;
    for (const auto& button : m_buttons)
        buttons_out.push_back(std::make_pair(button.get_pos().m_x,button.get_pos().m_y));            
    return buttons_out;
}
    
    
    

BEGIN_EVENT_TABLE(Chart, wxWindow)
EVT_MOTION(Chart::mouse_moved)
EVT_LEFT_DOWN(Chart::mouse_clicked)
EVT_LEFT_UP(Chart::mouse_released)
EVT_LEFT_DCLICK(Chart::mouse_double_clicked)
EVT_RIGHT_DOWN(Chart::mouse_right_button_clicked)
EVT_LEAVE_WINDOW(Chart::mouse_left_window)
EVT_PAINT(Chart::paint_event)
END_EVENT_TABLE()