# -*- coding: utf-8 -*-
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *
from qgis.gui import *

from ui_extentSelector import Ui_GdalToolsExtentSelector as Ui_ExtentSelector
import GdalTools_utils as Utils

class GdalToolsExtentSelector(QWidget, Ui_ExtentSelector):

  def __init__(self, parent=None):
      QWidget.__init__(self, parent)
      self.canvas = None
      self.tool = None
      self.previousMapTool = None
      self.isStarted = False

      self.setupUi(self)

      self.connect(self.x1CoordEdit, SIGNAL("textChanged(const QString &)"), self.coordsChanged)
      self.connect(self.x2CoordEdit, SIGNAL("textChanged(const QString &)"), self.coordsChanged)
      self.connect(self.y1CoordEdit, SIGNAL("textChanged(const QString &)"), self.coordsChanged)
      self.connect(self.y2CoordEdit, SIGNAL("textChanged(const QString &)"), self.coordsChanged)
      self.connect(self.btnEnable, SIGNAL("clicked()"), self.start)

  def setCanvas(self, canvas):
      self.canvas = canvas
      self.tool = RectangleMapTool(self.canvas)
      self.previousMapTool = self.canvas.mapTool()
      self.connect(self.tool, SIGNAL("rectangleCreated()"), self.fillCoords)
      self.connect(self.tool, SIGNAL("deactivated()"), self.pause)

  def stop(self):
      if not self.isStarted:
        return
      self.isStarted = False
      self.btnEnable.setVisible(False)
      self.tool.reset()
      self.canvas.unsetMapTool(self.tool)
      if self.previousMapTool != self.tool:
        self.canvas.setMapTool(self.previousMapTool)
      #self.coordsChanged()
      self.emit( SIGNAL( "selectionStopped()" ) )

  def start(self):
      prevMapTool = self.canvas.mapTool()
      if prevMapTool != self.tool:
      	self.previousMapTool = prevMapTool
      self.canvas.setMapTool(self.tool)
      self.isStarted = True
      self.btnEnable.setVisible(False)
      self.coordsChanged()
      self.emit( SIGNAL( "selectionStarted()" ) )

  def pause(self):
      if not self.isStarted:
        return

      self.btnEnable.setVisible(True)
      self.emit( SIGNAL( "selectionPaused()" ) )

  def setExtent(self, rect):
      if self.tool.setRectangle(rect):
        self.emit( SIGNAL( "newExtentDefined()" ) )

  def getExtent(self):
      return self.tool.rectangle()

  def isCoordsValid(self):
      try:
        point1 = QgsPoint( float(self.x1CoordEdit.text()), float(self.y1CoordEdit.text()) )
        point2 = QgsPoint( float(self.x2CoordEdit.text()), float(self.y2CoordEdit.text()) )
      except ValueError:
        return False

      return True

  def coordsChanged(self):
      rect = None
      if self.isCoordsValid():
        point1 = QgsPoint( float(self.x1CoordEdit.text()), float(self.y1CoordEdit.text()) )
        point2 = QgsPoint( float(self.x2CoordEdit.text()), float(self.y2CoordEdit.text()) )
        rect = QgsRectangle(point1, point2)

      self.setExtent(rect)

  def fillCoords(self):
      rect = self.getExtent()
      self.blockSignals(True)
      if rect != None:
        self.x1CoordEdit.setText( str(rect.xMinimum()) )
        self.x2CoordEdit.setText( str(rect.xMaximum()) )
        self.y1CoordEdit.setText( str(rect.yMaximum()) )
        self.y2CoordEdit.setText( str(rect.yMinimum()) )
      else:
        self.x1CoordEdit.clear()
        self.x2CoordEdit.clear()
        self.y1CoordEdit.clear()
        self.y2CoordEdit.clear()
      self.blockSignals(False)
      self.emit( SIGNAL( "newExtentDefined()" ) )

class RectangleMapTool(QgsMapToolEmitPoint):
  def __init__(self, canvas):
      self.canvas = canvas
      QgsMapToolEmitPoint.__init__(self, self.canvas)

      self.rubberBand = QgsRubberBand( self.canvas, True )	# true, its a polygon
      self.rubberBand.setColor( Qt.red )
      self.rubberBand.setWidth( 1 )

      self.reset()

  def reset(self):
      self.startPoint = self.endPoint = None
      self.isEmittingPoint = False
      self.rubberBand.reset( True )	# true, its a polygon

  def canvasPressEvent(self, e):
      self.startPoint = self.toMapCoordinates( e.pos() )
      self.endPoint = self.startPoint
      self.isEmittingPoint = True

      self.showRect(self.startPoint, self.endPoint)

  def canvasReleaseEvent(self, e):
      self.isEmittingPoint = False
      if self.rectangle() != None:
        self.emit( SIGNAL("rectangleCreated()") )

  def canvasMoveEvent(self, e):
      if not self.isEmittingPoint:
        return

      self.endPoint = self.toMapCoordinates( e.pos() )
      self.showRect(self.startPoint, self.endPoint)

  def showRect(self, startPoint, endPoint):
      self.rubberBand.reset( True )	# true, it's a polygon
      if startPoint.x() == endPoint.x() or startPoint.y() == endPoint.y():
        return

      point1 = QgsPoint(startPoint.x(), startPoint.y())
      point2 = QgsPoint(startPoint.x(), endPoint.y())
      point3 = QgsPoint(endPoint.x(), endPoint.y())
      point4 = QgsPoint(endPoint.x(), startPoint.y())

      self.rubberBand.addPoint( point1, False )
      self.rubberBand.addPoint( point2, False )
      self.rubberBand.addPoint( point3, False )
      self.rubberBand.addPoint( point4, True )	# true to update canvas
      self.rubberBand.show()

  def rectangle(self):
      if self.startPoint == None or self.endPoint == None:
        return None
      elif self.startPoint.x() == self.endPoint.x() or self.startPoint.y() == self.endPoint.y():
        return None

      return QgsRectangle(self.startPoint, self.endPoint)

  def setRectangle(self, rect):
      if rect == self.rectangle():
        return False

      if rect == None:
        self.reset()
      else:
        self.startPoint = QgsPoint(rect.xMaximum(), rect.yMaximum())
        self.endPoint = QgsPoint(rect.xMinimum(), rect.yMinimum())
        self.showRect(self.startPoint, self.endPoint)
      return True

  def deactivate(self):
      QgsMapTool.deactivate(self)
      self.emit(SIGNAL("deactivated()"))