#-----------------------------------------------------------
# 
# Generate Vector Grid
#
# A QGIS plugin for generating a line or polygon grid
#
# Copyright (C) 2008  Carson Farmer
#
# EMAIL: carson.farmer (at) gmail.com
# WEB  : www.geog.uvic.ca/spar/carson
#
#-----------------------------------------------------------
# 
# licensed under the terms of GNU GPL 2
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
# 
#---------------------------------------------------------------------

from PyQt4.QtCore import *
from PyQt4.QtGui import *
import ftools_utils
from qgis.core import *
from ui_frmVectorGrid import Ui_Dialog

class Dialog(QDialog, Ui_Dialog):
	def __init__(self, iface):
		QDialog.__init__(self)
		self.iface = iface
		self.setupUi(self)
		QObject.connect(self.toolOut, SIGNAL("clicked()"), self.outFile)
		QObject.connect(self.spnX, SIGNAL("valueChanged(double)"), self.offset)
		#QObject.connect(self.inShape, SIGNAL("currentIndexChanged(QString)"), self.updateInput)
		QObject.connect(self.btnUpdate, SIGNAL("clicked()"), self.updateLayer)
		QObject.connect(self.btnCanvas, SIGNAL("clicked()"), self.updateCanvas)
		self.setWindowTitle(self.tr("Vector grid"))
		self.xMin.setValidator(QDoubleValidator(self.xMin))
		self.xMax.setValidator(QDoubleValidator(self.xMax))
		self.yMin.setValidator(QDoubleValidator(self.yMin))
		self.yMax.setValidator(QDoubleValidator(self.yMax))
		layermap = QgsMapLayerRegistry.instance().mapLayers()
		for name, layer in layermap.iteritems():
			self.inShape.addItem( unicode( layer.name() ) )

	def offset(self, value):
		if self.chkLock.isChecked():
			self.spnY.setValue(value)

	def updateLayer( self ):
		mLayerName = self.inShape.currentText()
		if not mLayerName == "":
			mLayer = ftools_utils.getMapLayerByName( unicode( mLayerName ) )
			boundBox = mLayer.extent()
			self.updateExtents( boundBox )
			
	def updateCanvas( self ):
		canvas = self.iface.mapCanvas()
		boundBox = canvas.extent()
		self.updateExtents( boundBox )
		
	def updateExtents( self, boundBox ):
		self.xMin.setText( unicode( boundBox.xMinimum() ) )
		self.yMin.setText( unicode( boundBox.yMinimum() ) )
		self.xMax.setText( unicode( boundBox.xMaximum() ) )
		self.yMax.setText( unicode( boundBox.yMaximum() ) )

	def accept(self):
		if self.xMin.text() == "" or self.xMax.text() == "" or self.yMin.text() == "" or self.yMax.text() == "":
			QMessageBox.information(self, self.tr("Vector grid"), self.tr("Please specify valid extent coordinates"))
		elif self.outShape.text() == "":
			QMessageBox.information(self, self.tr("Vector grid"), self.tr("Please specify output shapefile"))
		else:
			try:
				boundBox = QgsRectangle( 
				float( self.xMin.text() ),
				float( self.yMin.text() ),
				float( self.xMax.text() ),
				float( self.yMax.text() ) )
			except:
				QMessageBox.information(self, self.tr("Vector grid"), self.tr("Invalid extent coordinates entered"))
			xSpace = self.spnX.value()
			ySpace = self.spnY.value()
			if self.rdoPolygons.isChecked(): polygon = True
			else: polygon = False
			self.outShape.clear()
			self.compute( boundBox, xSpace, ySpace, polygon )
			addToTOC = QMessageBox.question(self, self.tr("Generate Vector Grid"), self.tr("Created output shapefile:\n%1\n\nNote: Layer has no associated coordinate system, please use the Projection Management Tool to specify spatial reference system.\n\nWould you like to add the new layer to the TOC?").arg(unicode(self.shapefileName)), QMessageBox.Yes, QMessageBox.No, QMessageBox.NoButton)
			if addToTOC == QMessageBox.Yes:
				ftools_utils.addShapeToCanvas( self.shapefileName )
			self.progressBar.setValue( 0 )

	def compute( self, bound, xOffset, yOffset, polygon ):
		if polygon:
			fields = {0:QgsField("ID", QVariant.Int), 1:QgsField("XMIN", QVariant.Double), 2:QgsField("XMAX", QVariant.Double),
			3:QgsField("YMIN", QVariant.Double), 4:QgsField("YMAX", QVariant.Double)}
			check = QFile(self.shapefileName)
			if check.exists():
				if not QgsVectorFileWriter.deleteShapeFile(self.shapefileName):
					return
			writer = QgsVectorFileWriter(self.shapefileName, self.encoding, fields, QGis.WKBPolygon, None)
			#writer = QgsVectorFileWriter(outPath, "CP1250", fields, QGis.WKBPolygon, None)
		else:
			fields = {0:QgsField("ID", QVariant.Int), 1:QgsField("COORD", QVariant.Double)}
			check = QFile(self.shapefileName)
			if check.exists():
				if not QgsVectorFileWriter.deleteShapeFile(self.shapefileName):
					return
			writer = QgsVectorFileWriter(self.shapefileName, self.encoding, fields, QGis.WKBLineString, None)
			#writer = QgsVectorFileWriter(unicode(outPath), "CP1250", fields, QGis.WKBLineString, None)
		outFeat = QgsFeature()
		outGeom = QgsGeometry()
		idVar = 0
		self.progressBar.setRange( 0, 0 )
		if not polygon:
			y = bound.yMaximum()
			while y >= bound.yMinimum():
				pt1 = QgsPoint(bound.xMinimum(), y)
				pt2 = QgsPoint(bound.xMaximum(), y)
				line = [pt1, pt2]
				outFeat.setGeometry(outGeom.fromPolyline(line))
				outFeat.addAttribute(0, QVariant(idVar))
				outFeat.addAttribute(1, QVariant(y))
				writer.addFeature(outFeat)
				y = y - yOffset
				idVar = idVar + 1
			x = bound.xMinimum()
			while x <= bound.xMaximum():
				pt1 = QgsPoint(x, bound.yMaximum())
				pt2 = QgsPoint(x, bound.yMinimum())
				line = [pt1, pt2]
				outFeat.setGeometry(outGeom.fromPolyline(line))
				outFeat.addAttribute(0, QVariant(idVar))
				outFeat.addAttribute(1, QVariant(x))
				writer.addFeature(outFeat)
				x = x + xOffset
				idVar = idVar + 1
		else:
			y = bound.yMaximum()
			while y >= bound.yMinimum():
				x = bound.xMinimum()
				while x <= bound.xMaximum():
					pt1 = QgsPoint(x, y)
					pt2 = QgsPoint(x + xOffset, y)
					pt3 = QgsPoint(x + xOffset, y - yOffset)
					pt4 = QgsPoint(x, y - yOffset)
					pt5 = QgsPoint(x, y)
					polygon = [[pt1, pt2, pt3, pt4, pt5]]
					outFeat.setGeometry(outGeom.fromPolygon(polygon))
					outFeat.addAttribute(0, QVariant(idVar))
					outFeat.addAttribute(1, QVariant(x))
					outFeat.addAttribute(2, QVariant(x + xOffset))
					outFeat.addAttribute(3, QVariant(y - yOffset))
					outFeat.addAttribute(4, QVariant(y))
					writer.addFeature(outFeat)
					idVar = idVar + 1
					x = x + xOffset
				y = y - yOffset
		self.progressBar.setRange( 0, 100 )
		del writer

	def outFile(self):
		self.outShape.clear()
		( self.shapefileName, self.encoding ) = ftools_utils.saveDialog( self )
		if self.shapefileName is None or self.encoding is None:
			return
		self.outShape.setText( QString( self.shapefileName ) )

	def getVectorLayerByName(self, myName):
		mc = self.iface.mapCanvas()
		nLayers = mc.layerCount()
		for l in range(nLayers):
			layer = mc.layer(l)
			if unicode(layer.name()) == unicode(myName):
				vlayer = QgsVectorLayer(unicode(layer.source()),  unicode(myName),  unicode(layer.dataProvider().name()))
				if vlayer.isValid():
					return vlayer

	def getMapLayerByName(self, myName):
		mc = self.iface.mapCanvas()
		nLayers = mc.layerCount()
		for l in range(nLayers):
			layer = mc.layer(l)
			if unicode(layer.name()) == unicode(myName):
				if layer.isValid():
					return layer