//===========================================
//  Lumina-DE source code
//  Copyright (c) 2015, Ken Moore
//  Available under the 3-clause BSD license
//  See the LICENSE file for full details
//===========================================
#include "TerminalWidget.h"

#include <QProcessEnvironment>
#include <QDebug>
#include <QApplication>
#include <QScrollBar>
#include <QTextBlock>

#include <LuminaXDG.h>

//Special control code ending symbols (aside from letters)
//QByteArray CC_END_SYMBOLS("@");

TerminalWidget::TerminalWidget(QWidget *parent, QString dir) : QTextEdit(parent){
  //Setup the text widget
  this->setLineWrapMode(QTextEdit::WidgetWidth);
  this->setAcceptRichText(false);
  this->setOverwriteMode(true);
  this->setFocusPolicy(Qt::StrongFocus);
  this->setWordWrapMode(QTextOption::NoWrap);
  this->setContextMenuPolicy(Qt::CustomContextMenu);
  DEFFMT = this->textCursor().charFormat(); //save the default structure for later
  CFMT = this->textCursor().charFormat(); //current format
  selCursor = this->textCursor(); //used for keeping track of selections
  lastCursor = this->textCursor();
  startrow = endrow = -1;
  altkeypad = false;
  QFontDatabase FDB;
  QStringList fonts = FDB.families(QFontDatabase::Latin);
  for(int i=0; i<fonts.length(); i++){
    if(FDB.isFixedPitch(fonts[i])){ this->setFont(QFont(fonts[i])); qDebug() << "Using Font:" << fonts[i]; break; }
  }
  //Create/open the TTY port
  PROC = new TTYProcess(this);
  qDebug() << "Open new TTY";
  //int fd;
  bool ok = PROC->startTTY( QProcessEnvironment::systemEnvironment().value("SHELL","/bin/sh"), QStringList(), dir);
  qDebug() << " - opened:" << ok;
  this->setEnabled(PROC->isOpen());
  contextMenu = new QMenu(this);
    copyA = contextMenu->addAction(LXDG::findIcon("edit-copy"), tr("Copy Selection"), this, SLOT(copySelection()) );
    pasteA = contextMenu->addAction(LXDG::findIcon("edit-paste"), tr("Paste"), this, SLOT(pasteSelection()) );
  //Connect the signals/slots
  connect(PROC, SIGNAL(readyRead()), this, SLOT(UpdateText()) );
  connect(PROC, SIGNAL(processClosed()), this, SLOT(ShellClosed()) );
  
}

TerminalWidget::~TerminalWidget(){
  aboutToClose();
}

void TerminalWidget::aboutToClose(){
  if(PROC->isOpen()){ PROC->closeTTY(); } //TTY PORT
}

// ==================
//          PRIVATE
// ==================
void TerminalWidget::InsertText(QString txt){
  if(txt.isEmpty()){ return; }
  //qDebug() << "Insert Text:" << txt << "Cursor Pos:" << this->textCursor().position() << "Column:" << this->textCursor().columnNumber();
  QTextCursor cur = this->textCursor();
  cur.setCharFormat(CFMT);
  cur.insertText( txt, CFMT);
  this->setTextCursor(cur);
}

void TerminalWidget::applyData(QByteArray data){
  //Make sure the current cursor is the right cursor
  if(this->textCursor()==selCursor){ this->setTextCursor(lastCursor); }
  //Iterate through the data and apply it when possible
  QByteArray chars;
  //qDebug() << "Data:" << data;
  for(int i=0; i<data.size(); i++){
    if( data.at(i)=='\b' ){
      //Flush current text buffer to widget
      //Simple cursor backward 1 (NOT backspace in this context!! - this widget should be in "insert" mode instead)
      InsertText(chars); chars.clear(); 
      this->moveCursor(QTextCursor::Left, QTextCursor::MoveAnchor);
    //}else if( data.at(i)=='\t' ){
       //chars.append("  ");
    }else if( data.at(i)=='\x1B' ){
      //Flush current text buffer to widget
      if(!chars.isEmpty()){ InsertText(chars); chars.clear(); }
      //ANSI Control Code start
      //Look for the end of the code
      int end = -1;
      for(int j=1; j<(data.size()-i) && end<0; j++){
        if(QChar(data.at(i+j)).isLetter() || (QChar(data.at(i+j)).isSymbol() && data.at(i+j)!=';') ){ end = j; }
	else if(data.at(i+j)=='\x1B'){ end = j-1; } //start of the next control code
      }
      if(end<0){ return; } //skip everything else - no end to code found
      applyANSI(data.mid(i+1, end));
      //qDebug() << "Code:" << data.mid(i+1, end) << "Next Char:" << data[i+end+2];
      i+=end; //move the final loop along - already handled these bytes
      
    }else if( data.at(i) != '\r' ){
      //Special Check: if inserting text within a line, clear the rest of this line first
      if(i==0 && this->textCursor().position() < this->document()->characterCount()-1){
        applyANSI("[K");
      }
      chars.append(data.at(i));
      //Plaintext character - just add it here
      //qDebug() << "Insert Text:" << data.at(i) << CFMT.foreground().color() << CFMT.background().color();
      //qDebug() << "  " << this->currentCharFormat().foreground().color() << this->currentCharFormat().background().color();
      //this->textCursor().insertText( QChar(data.at(i)), CFMT );
    }
  } //end loop over data
  if(!chars.isEmpty()){ InsertText(chars); }
}

void TerminalWidget::applyANSI(QByteArray code){
  //Note: the first byte is often the "[" character
  qDebug() << "Handle ANSI:" << code;
  if(code.length()==1){
    //KEYPAD MODES
    if(code.at(0)=='='){ altkeypad = true; }
    else if(code.at(0)=='>'){ altkeypad = false; }
    else{
      qDebug() << "Unhandled ANSI Code:" << code;
    }
  }else if(code.startsWith("[")){
    // VT100 ESCAPE CODES
  //CURSOR MOVEMENT
  if( code.endsWith("A") ){ //Move Up
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::Up, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("B")){ //Move Down
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
        QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::Down, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("C")){ //Move Forward
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::Right, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("D")){ //Move Back
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::Left, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("E")){ //Move Next/down Lines (go toward end)
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::NextRow, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("F")){ //Move Previous/up Lines (go to beginning)
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.movePosition(QTextCursor::PreviousRow, QTextCursor::MoveAnchor, num);
    this->setTextCursor(cur);
  }else if(code.endsWith("G")){ //Move to specific column
    int num = 1;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    QTextCursor cur = this->textCursor();
    cur.setPosition(num);
    this->setTextCursor(cur);
  }else if(code.endsWith("H") || code.endsWith("f") ){ //Move to specific position (row/column)
    int mid = code.indexOf(";");
    if(mid>1){
      int numR, numC; numR = numC = 1;
      if(mid >=2){ numR = code.mid(1,mid-1).toInt(); }
      if(mid < code.size()-1){ numC = code.mid(mid+1,code.size()-mid-2).toInt(); }
      
      if(startrow>=0 && endrow>=0){
	if(numR == startrow){ numR = 0;}
	else if(numR==endrow){ numR = this->document()->lineCount()-1; }
      }
      qDebug() << "Set Text Position (absolute):" << "Code:" << code << "Row:" << numR << "Col:" << numC;
      //qDebug() << " - Current Pos:" << this->textCursor().position() << "Line Count:" << this->document()->lineCount();
      //if(!this->textCursor().movePosition(QTextCursor::Start, QTextCursor::MoveAnchor,1) ){ qDebug() << "Could not go to start"; }
      QTextCursor cur(this->textCursor());
      cur.setPosition(QTextCursor::Start, QTextCursor::MoveAnchor); //go to start of document
       //qDebug() << " - Pos After Start Move:" << cur.position();
      if( !cur.movePosition(QTextCursor::Down, QTextCursor::MoveAnchor, numR) ){ qDebug() << "Could not go to row:" << numR; }
       //qDebug() << " - Pos After Down Move:" << cur.position();
      if( !cur.movePosition(QTextCursor::Right, QTextCursor::MoveAnchor, numC) ){ qDebug() << "Could not go to col:" << numC; }
      /*this->textCursor().setPosition( this->document()->findBlockByLineNumber(numR).position() );
      qDebug() << " - Pos After Row Move:" << this->textCursor().position();
      if( !this->textCursor().movePosition(QTextCursor::Right, QTextCursor::MoveAnchor, numC) ){ qDebug() << "Could not go to col:" << numC; }*/
      //qDebug() << " - Ending Pos:" << cur.position();
      this->setTextCursor(cur);
    }else{
      //Go to home position
      this->moveCursor(QTextCursor::Start);
    }

   // CURSOR MANAGEMENT
  }else if(code.endsWith("r")){ //Tag top/bottom lines as perticular numbers
    int mid = code.indexOf(";");
    qDebug() << "New Row Codes:" << code << "midpoint:" << mid;
    if(mid>1){
      if(mid >=2){ startrow = code.mid(1,mid-1).toInt(); }
      if(mid < code.size()-1){ endrow = code.mid(mid+1,code.size()-mid-2).toInt(); }
    }
    qDebug() << "New Row Codes:" << startrow << endrow;
   // DISPLAY CLEAR CODES
  }else if(code.endsWith("J")){ //ED - Erase Display
    int num = 0;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    //qDebug() << "Erase Display:" << num;
    if(num==1){
      //Clear from cursor to beginning of screen
      QTextCursor cur = this->textCursor();
	cur.movePosition(QTextCursor::Start, QTextCursor::KeepAnchor, 1);
	cur.removeSelectedText();
      this->setTextCursor(cur);
    }else if(num==2){
      //Clear the whole screen
      qDebug() << "Clear Screen:" << this->document()->lineCount();
      this->clear();
    }else{
      //Clear from cursor to end of screen
      QTextCursor cur = this->textCursor();
	cur.movePosition(QTextCursor::End, QTextCursor::KeepAnchor, 1);
	cur.removeSelectedText();
      this->setTextCursor(cur);
    }	    
  }else if(code.endsWith("K")){ //EL - Erase in Line
    int num = 0;
    if(code.size()>2){ num = code.mid(1, code.size()-2).toInt(); } //everything in the middle
    //qDebug() << "Erase Number" << num;
    //Now determine what should be cleared based on code
    if(num==1){
      //Clear from current cursor to beginning of line
      QTextCursor cur = this->textCursor();
	cur.movePosition(QTextCursor::StartOfLine, QTextCursor::KeepAnchor, 1);
	cur.removeSelectedText();
      this->setTextCursor(cur);
    }else if(num==2){
      //Clear the entire line
      QTextCursor cur = this->textCursor();
	cur.movePosition(QTextCursor::StartOfLine, QTextCursor::MoveAnchor, 1);
	cur.movePosition(QTextCursor::EndOfLine, QTextCursor::KeepAnchor, 1);
      cur.removeSelectedText();
      this->setTextCursor(cur);
    }else{
      //Clear from current cursor to end of line
      QTextCursor cur = this->textCursor();
	cur.movePosition(QTextCursor::EndOfLine, QTextCursor::KeepAnchor, 1);
	cur.removeSelectedText();
      this->setTextCursor(cur);
    }
    
   //SCROLL MOVEMENT CODES 
  //}else if(code.endsWith("S")){ // SU - Scroll Up
    //qDebug() << "Scroll Up:" << code;
  //}else if(code.endsWith("T")){ // SD - Scroll Down
    //qDebug() << "Scroll Down:" << code;
	  
  // GRAPHICS RENDERING
  }else if(code.endsWith("m")){
    //Format: "[<number>;<number>m" (no limit to sections separated by ";")
    int start = 1;
    int end = code.indexOf(";");
    while(end>start){
      applyANSIColor(code.mid(start, end-start).toInt());
      //Now update the iterators and try again
      start = end;
      end = code.indexOf(";",start+1); //go to the next one
    }
    //Need the last section as well
    end = code.size()-1;
    if(end>start){ applyANSIColor(code.mid(start, end-start).toInt());}
    else{ applyANSIColor(0); }
    
    
  // GRAPHICS MODES
  //}else if(code.endsWith("h")){
	  
  //}else if(code.endsWith("l")){
	  
  }else{
    qDebug() << "Unhandled Control Code:" << code;
  }
  
  } //End VT100 control codes
  else{
    qDebug() << "Unhandled Control Code:" << code;
  }
}

void TerminalWidget::applyANSIColor(int code){
  //qDebug() << "Apply Color code:" << code;
  if(code <=0){ CFMT = DEFFMT; } //Reset back to default
  else if(code==1){  CFMT.setFontWeight(75); } //BOLD font
  else if(code==2){ CFMT.setFontWeight(25); } //Faint font (smaller than normal by a bit)
  else if(code==3){ CFMT.setFontWeight(75); } //Italic font
  else if(code==4){ CFMT.setFontUnderline(true); } //Underline
  //5-6: Blink text (unsupported)
  //7: Reverse foreground/background (unsupported)
  //8: Conceal (unsupported)
  else if(code==9){ CFMT.setFontStrikeOut(true); } //Crossed out
  //10-19: Change font family (unsupported)
  //20: Fraktur Font (unsupported)
  //21: Bold:off or Underline:Double (unsupported)
  else if(code==22){ CFMT.setFontWeight(50); } //Normal weight
  //23: Reset font (unsupported)
  else if(code==24){ CFMT.setFontUnderline(false); } //disable underline
  //25: Disable blinking (unsupported)
  //26: Reserved
  //27: Reset reversal (7) (unsupported)
  //28: Reveal (cancel 8) (unsupported)
  else if(code==29){ CFMT.setFontStrikeOut(false); } //Not Crossed out
  else if(code>=30 && code<=39){
    //Set the font color
   QColor color;
    if(code==30){color=QColor(Qt::black); }
    else if(code==31){ color=QColor(Qt::red); }
    else if(code==32){ color=QColor(Qt::green); }
    else if(code==33){ color=QColor(Qt::yellow); }
    else if(code==34){ color=QColor(Qt::blue); }
    else if(code==35){ color=QColor(Qt::magenta); }
    else if(code==36){ color=QColor(Qt::cyan); }
    else if(code==37){ color=QColor(Qt::white); }
    //48: Special extended color setting (unsupported)
    else if(code==39){ color= DEFFMT.foreground().color(); } //reset to default color
QBrush brush = CFMT.background();
    color.setAlpha(255); //fully opaque
    brush.setColor(color);
    CFMT.setForeground( brush );
    this->setTextColor(color); //just in case the format is not used
  }
  else if(code>=40 && code<=49){
    //Set the font color
   QColor color;
    if(code==40){color=QColor(Qt::black); }
    else if(code==41){ color=QColor(Qt::red); }
    else if(code==42){ color=QColor(Qt::green); }
    else if(code==43){ color=QColor(Qt::yellow); }
    else if(code==44){ color=QColor(Qt::blue); }
    else if(code==45){ color=QColor(Qt::magenta); }
    else if(code==46){ color=QColor(Qt::cyan); }
    else if(code==47){ color=QColor(Qt::white); }
    //48: Special extended color setting (unsupported)
    else if(code==49){ color= DEFFMT.background().color(); } //reset to default color
    QBrush brush = CFMT.background();
    color.setAlpha(255); //fully opaque
    brush.setColor(color);
    CFMT.setBackground( brush );
  }
  //50: Reserved
  //51: Framed
  //52: Encircled
  else if(code==53){ CFMT.setFontOverline(true); } //enable overline
  //54: Not framed/circled (51/52)
  else if(code==55){ CFMT.setFontOverline(false); } //disable overline
  //56-59: Reserved
  //60+: Not generally supported (special code for particular terminals such as aixterm)
}

//Outgoing Data parsing
void TerminalWidget::sendKeyPress(int key){
  QByteArray ba;
  //if(this->textCursor()==selCursor){ this->setTextCursor(lastCursor); }
  //int fromEnd = this->document()->characterCount() - this->textCursor().position();
  //Check for special keys
  switch(key){
    case Qt::Key_Delete:
	ba.append("\x7F");
        break;
    case Qt::Key_Backspace:
	ba.append("\x08");    
        break;
    case Qt::Key_Left:
	if(altkeypad){ ba.append("^[D"); }
	else{ ba.append("\x1b[D"); }
        break;
    case Qt::Key_Right:
	if(altkeypad){ ba.append("^[C"); }
	else{ ba.append("\x1b[C"); }
        break;
    case Qt::Key_Up:
        if(altkeypad){ ba.append("^[A"); }
	else{ ba.append("\x1b[A"); }
        break;
    case Qt::Key_Down:
        if(altkeypad){ ba.append("^[B"); }
	else{ ba.append("\x1b[B"); }
        break;
    case Qt::Key_Home:
        ba.append("\x1b[H");
        break;	    
    case Qt::Key_End:
	ba.append("\x1b[F");
        break;	    
  }
   qDebug() << "Forward Input:" << ba;
  if(!ba.isEmpty()){ PROC->writeTTY(ba); }
}

// ==================
//    PRIVATE SLOTS
// ==================
void TerminalWidget::UpdateText(){
  //read the data from the process
  //qDebug() << "UpdateText";
  if(!PROC->isOpen()){ return; }
  applyData(PROC->readTTY());
  //adjust the scrollbar as needed
  this->ensureCursorVisible();
  //this->verticalScrollBar()->setValue(this->verticalScrollBar()->maximum());
}

void TerminalWidget::ShellClosed(){
  emit ProcessClosed(this->whatsThis());
}

void TerminalWidget::copySelection(){
  QApplication::clipboard()->setText( selCursor.selectedText() );
}

void TerminalWidget::pasteSelection(){
  QString text = QApplication::clipboard()->text();
  if(!text.isEmpty()){ 
    QByteArray ba; ba.append(text); //avoid any byte conversions
    PROC->writeTTY(ba); 
  }
}

// ==================
//       PROTECTED
// ==================
void TerminalWidget::keyPressEvent(QKeyEvent *ev){
	
  if(ev->text().isEmpty() || ev->text()=="\b" ){
    sendKeyPress(ev->key());
  }else{
    if( (ev->key()==Qt::Key_Enter || ev->key()==Qt::Key_Return) && !this->textCursor().atEnd() ){
      sendKeyPress(Qt::Key_End); //just in case the cursor is not at the end (TTY will split lines and such - ugly)
    }
    QByteArray ba; ba.append(ev->text()); //avoid any byte conversions
    //qDebug() << "Forward Input:" << ba;
    PROC->writeTTY(ba);
  }
  
  ev->ignore();
}

void TerminalWidget::mousePressEvent(QMouseEvent *ev){
  this->setFocus();
  if(ev->button()==Qt::RightButton){
    QTextEdit::mousePressEvent(ev);	  
  }else if(ev->button()==Qt::MiddleButton){
    pasteSelection();
  }else if(ev->button()==Qt::LeftButton){
    if(this->textCursor()!=selCursor){ lastCursor = this->textCursor(); }
    selCursor = this->cursorForPosition(ev->pos());
  }
  Q_UNUSED(ev);
}

void TerminalWidget::mouseMoveEvent(QMouseEvent *ev){
  if(ev->button()==Qt::LeftButton){
    selCursor.setPosition(this->cursorForPosition(ev->pos()).position(), QTextCursor::KeepAnchor);
    if(selCursor.hasSelection()){ this->setTextCursor(selCursor); }
  }else{
    QTextEdit::mouseMoveEvent(ev);
  }
}

void TerminalWidget::mouseReleaseEvent(QMouseEvent *ev){
  if(ev->button()==Qt::LeftButton){
    selCursor.setPosition(this->cursorForPosition(ev->pos()).position(), QTextCursor::KeepAnchor);
    if(selCursor.hasSelection()){ this->setTextCursor(selCursor); }
    else{ this->setTextCursor(lastCursor); }
  }else if(ev->button()==Qt::RightButton){
    copyA->setEnabled( selCursor.hasSelection() );
    pasteA->setEnabled( !QApplication::clipboard()->text().isEmpty() );
    contextMenu->popup( this->mapToGlobal(ev->pos()) );	  
  }
  Q_UNUSED(ev);
}

void TerminalWidget::mouseDoubleClickEvent(QMouseEvent *ev){
  Q_UNUSED(ev);	
}

void TerminalWidget::resizeEvent(QResizeEvent *ev){
  if(!PROC->isOpen()){ return; }
  QSize pix = ev->size(); //pixels
  QSize chars; 
    chars.setWidth( pix.width()/this->fontMetrics().width("W") );
    chars.setHeight( pix.height()/this->fontMetrics().lineSpacing() );
  
  PROC->setTerminalSize(chars,pix);
  QTextEdit::resizeEvent(ev);
}