#!/usr/bin/env python
###############################################################################
#
# Purpose:  Module for retiling (merging) tiles and building tiled pyramids
# Author:   Christian Meuller, christian.mueller@nvoe.at
#
###############################################################################
# Copyright (c) 2007, Christian Mueller
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
###############################################################################


try:
    from osgeo import gdal
    from osgeo import ogr
    from osgeo import osr
    from osgeo.gdalconst import *
except:
    import gdal
    import ogr
    import osr
    from gdalconst import *

import sys
import os
import math

class AffineTransformDecorator:
    """ A class providing some usefull methods for affine Transformations """
    def __init__(self, transform ):
        self.geotransform=transform
        self.scaleX=self.geotransform[1]
        self.scaleY=self.geotransform[5]
        if self.scaleY > 0:
            self.scaleY*=-1
        self.ulx = self.geotransform[0]
        self.uly = self.geotransform[3]

    def pointsFor(self,width,height):
        xlist=[]
        ylist=[]
        w=self.scaleX * width;
        h=self.scaleY * height;

        xlist.append(self.ulx)
        ylist.append(self.uly)
        xlist.append(self.ulx+w)
        ylist.append(self.uly)
        xlist.append(self.ulx+w)
        ylist.append(self.uly+h)
        xlist.append(self.ulx)
        ylist.append(self.uly+h)
        return [ xlist, ylist]


class DataSetCache:
    """ A class for caching source tiles """
    def __init__(self ):
        self.cacheSize=8
        self.queue=[]
        self.dict={}
    def get(self,name ):

        if self.dict.has_key(name):
            return self.dict[name]
        result = gdal.Open(name)
        if result is None:
            print "Error openenig:",NameError
            sys.exit(1)
        if len(self.queue)==self.cacheSize:
            toRemove = self.queue.pop(0)
            del self.dict[toRemove]
        self.queue.append(name)
        self.dict[name]=result
        return result
    def __del__(self):
        for name, dataset in self.dict.iteritems():
            del dataset
        del self.queue
        del self.dict



class tile_info:
    """ A class holding info how to tile """
    def __init__(self,xsize,ysize,tileWidth,tileHeight):
        self.tileWidth=tileWidth
        self.tileHeight=tileHeight
        self.countTilesX= xsize / tileWidth
        self.countTilesY= ysize / tileHeight
        self.lastTileWidth = xsize - self.countTilesX *  tileWidth
        self.lastTileHeight = ysize - self.countTilesY *  tileHeight

        if (self.lastTileWidth > 0 ):
            self.countTilesX=self.countTilesX+1
        else:
            self.lastTileWidth=tileWidth

        if (self.lastTileHeight > 0 ):
            self.countTilesY=self.countTilesY+1
        else:
            self.lastTileHeight=tileHeight



    def report( self ):
        print 'tileWidth       %d' % self.tileWidth
        print 'tileHeight      %d' % self.tileHeight
        print 'countTilesX:    %d' % self.countTilesX
        print 'countTilesY:    %d' % self.countTilesY
        print 'lastTileWidth:  %d' % self.lastTileWidth
        print 'lastTileHeight: %d' % self.lastTileHeight



class mosaic_info:
    """A class holding information about a GDAL file or a GDAL fileset"""

    def __init__(self, filename,inputDS ):
        """
        Initialize mosaic_info from filename

        filename -- Name of file to read.

        """
        self.TempDriver=gdal.GetDriverByName("MEM")
        self.filename = filename
        self.cache = DataSetCache()
        self.ogrTileIndexDS = inputDS

        self.ogrTileIndexDS.GetLayer().ResetReading()
        feature = self.ogrTileIndexDS.GetLayer().GetNextFeature()
        imgLocation = feature.GetField(0)

        fhInputTile = self.cache.get(imgLocation)

        self.bands = fhInputTile.RasterCount
        self.band_type = fhInputTile.GetRasterBand(1).DataType
        self.projection = fhInputTile.GetProjection()


        dec = AffineTransformDecorator(fhInputTile.GetGeoTransform())
        self.scaleX=dec.scaleX
        self.scaleY=dec.scaleY
        ct = fhInputTile.GetRasterBand(1).GetRasterColorTable()
        if ct is not None:
           self.ct = ct.Clone()
        else:
           self.ct = None

        extent = self.ogrTileIndexDS.GetLayer().GetExtent()
        self.ulx = extent[0];
        self.uly = extent[3]
        self.lrx = extent[1]
        self.lry = extent[2]

        self.xsize = int(round((self.lrx-self.ulx) / self.scaleX))
        self.ysize = abs(int(round((self.uly-self.lry) / self.scaleY)))


    def __del__(self):
        del self.cache
        del self.ogrTileIndexDS

    def getDataSet(self,minx,miny,maxx,maxy):

        self.ogrTileIndexDS.GetLayer().ResetReading()
        self.ogrTileIndexDS.GetLayer().SetSpatialFilterRect(minx,miny,maxx,maxy)
        features = []
        envelope = None
        while True:
            feature = self.ogrTileIndexDS.GetLayer().GetNextFeature();
            if feature is None:
                break
            features.append(feature)
            if envelope is None:
                envelope=feature.GetGeometryRef().GetEnvelope()
            else:
                featureEnv = feature.GetGeometryRef().GetEnvelope()
                envelope= ( min(featureEnv[0],envelope[0]),max(featureEnv[1],envelope[1]),
                            min(featureEnv[2],envelope[2]),max(featureEnv[3],envelope[3]))

        if envelope is None:
            return None

        #enlarge to query rect if necessairy
        envelope= ( min(minx,envelope[0]),max(maxx,envelope[1]),
                    min(miny,envelope[2]),max(maxy,envelope[3]))


        self.ogrTileIndexDS.GetLayer().SetSpatialFilter(None)

         # merge tiles


        resultSizeX =int(math.ceil(((maxx-minx) / self.scaleX )))
        resultSizeY =int(math.ceil(((miny-maxy) / self.scaleY )))

        resultDS = self.TempDriver.Create( "TEMP", resultSizeX, resultSizeY, self.bands,self.band_type,[])
        resultDS.SetGeoTransform( [minx,self.scaleX,0,maxy,0,self.scaleY] )


        for feature in features:
            featureName =  feature.GetField(0)
            sourceDS=self.cache.get(featureName)
            dec = AffineTransformDecorator(sourceDS.GetGeoTransform())
            #calculate read and write offsets
            readOffsetX =int(round((minx-dec.ulx) / self.scaleX))
            readOffsetY =int(round((maxy-dec.uly) / self.scaleY))
            writeOffsetX=0
            if readOffsetX<0:
                writeOffsetX=readOffsetX*-1;
                readOffsetX=0
            writeOffsetY=0
            if readOffsetY<0:
                writeOffsetY=readOffsetY*-1;
                readOffsetY=0
            #calculate read and write dimensions
            readX=min(resultSizeX,sourceDS.RasterXSize-readOffsetX,resultSizeX-writeOffsetX)
            if readX<=0:
                continue
            readY=min(resultSizeY,sourceDS.RasterYSize-readOffsetY,resultSizeY-writeOffsetY)
            if readY<=0:
                continue

#            print "READ",readOffsetX,readOffsetY,readX,readY

            for bandNr in range(1,self.bands+1):
                s_band = sourceDS.GetRasterBand( bandNr )
                t_band = resultDS.GetRasterBand( bandNr )
                if self.ct is not None:
                    t_band.SetRasterColorTable(self.ct)
                data = s_band.ReadRaster( readOffsetX,readOffsetY,readX,readY, readX,readY, self.band_type )
                t_band.WriteRaster(writeOffsetX,writeOffsetY,readX,readY,data )

        return resultDS

    def closeDataSet(self, memDS):
        del memDS
        #self.TempDriver.Delete("TEMP")


    def report( self ):
        print 'Filename: '+ self.filename
        print 'File Size: %dx%dx%d' \
              % (self.xsize, self.ysize, self.bands)
        print 'Pixel Size: %f x %f' \
              % (self.scaleX,self.scaleY)
        print 'UL:(%f,%f)   LR:(%f,%f)' \
              % (self.ulx,self.uly,self.lrx,self.lry)


def getTileIndexFromFiles( inputTiles, driverTyp):

    if Verbose:
        print "Building internal Index for %d tile(s) ..." % len(inputTiles),

    ogrTileIndexDS = createTileIndex("TileIndex",TileIndexFieldName,None,driverTyp);
    for inputTile in inputTiles:

        fhInputTile = gdal.Open(inputTile)
        if fhInputTile is None:
             return None

        dec = AffineTransformDecorator(fhInputTile.GetGeoTransform())
        points = dec.pointsFor(fhInputTile.RasterXSize, fhInputTile.RasterYSize)

        addFeature(ogrTileIndexDS,inputTile,points[0],points[1])
        del fhInputTile

    if Verbose:
        print "finished"
    #ogrTileIndexDS.GetLayer().SyncToDisk()
    return ogrTileIndexDS




def getTargetDir (level = -1):
    if level==-1:
        return TargetDir
    else:
        return TargetDir+str(level)+os.sep




def tileImage(minfo, ti ):
    """

    Tile image in mosaicinfo minfo  based on tileinfo ti

    returns list of created tiles

    """


    OGRDS=createTileIndex("TileResult_0", TileIndexFieldName, Source_SRS,TileIndexDriverTyp)


    yRange = range(1,ti.countTilesY+1)
    xRange = range(1,ti.countTilesX+1)

    for yIndex in yRange:
        for xIndex in xRange:
            offsetY=(yIndex-1)* ti.tileHeight
            offsetX=(xIndex-1)* ti.tileWidth
            if yIndex==ti.countTilesY:
                height=ti.lastTileHeight
            else:
                height=ti.tileHeight

            if xIndex==ti.countTilesX:
                width=ti.lastTileWidth
            else:
                width=ti.tileWidth
            tilename=getTileName(minfo,ti, xIndex, yIndex)
            createTile(minfo, offsetX, offsetY, width, height,tilename,OGRDS)


    if TileIndexName is not None:
        shapeName=getTargetDir()+TileIndexName
        copyTileIndexToDisk(OGRDS,shapeName)

    if CsvFileName is not None:
        csvName=getTargetDir()+CsvFileName
        copyTileIndexToCSV(OGRDS,csvName)


    return OGRDS

def copyTileIndexToDisk(OGRDS, fileName):
    SHAPEDS = createTileIndex(fileName, TileIndexFieldName, OGRDS.GetLayer().GetSpatialRef(), "ESRI Shapefile")
    OGRDS.GetLayer().ResetReading()
    while True:
      feature = OGRDS.GetLayer().GetNextFeature()
      if feature is None:
          break
      newFeature = feature.Clone()
      basename = os.path.basename(feature.GetField(0))
      newFeature.SetField(0,basename)
      SHAPEDS.GetLayer().CreateFeature(newFeature)
    closeTileIndex(SHAPEDS)

def copyTileIndexToCSV(OGRDS, fileName):
    csvfile = open(fileName, 'w')
    OGRDS.GetLayer().ResetReading()
    while True:
      feature = OGRDS.GetLayer().GetNextFeature()
      if feature is None:
          break
      basename = os.path.basename(feature.GetField(0))
      csvfile.write(basename);
      geom = feature.GetGeometryRef()
      coords = geom.GetEnvelope();

      for i in range(len(coords)):
          csvfile.write(CsvDelimiter)
          csvfile.write("%f" % coords[i])
      csvfile.write("\n");

    csvfile.close()



def createPyramidTile(levelMosaicInfo, offsetX, offsetY, width, height,tileName,OGRDS):

    sx= levelMosaicInfo.scaleX*2
    sy= levelMosaicInfo.scaleY*2

    dec = AffineTransformDecorator([levelMosaicInfo.ulx+offsetX*sx,sx,0,
                                    levelMosaicInfo.uly+offsetY*sy,0,sy])



    s_fh = levelMosaicInfo.getDataSet(dec.ulx,dec.uly+height*dec.scaleY,
                         dec.ulx+width*dec.scaleX,dec.uly)
    if s_fh is None:
        return


    if OGRDS is not None:
        points = dec.pointsFor(width, height)
        addFeature(OGRDS, tileName, points[0], points[1])


    if BandType is None:
        bt=levelMosaicInfo.band_type
    else:
        bt=BandType

    geotransform = [dec.ulx, dec.scaleX, 0,dec.uly,0,dec.scaleY]


    bands = levelMosaicInfo.bands

    if MemDriver is None:
        t_fh = Driver.Create( tileName, width, height, bands,bt,CreateOptions)
    else:
        t_fh = MemDriver.Create( tileName, width, height, bands,bt,CreateOptions)

    if t_fh is None:
        print 'Creation failed, terminating gdal_tile.'
        sys.exit( 1 )


    t_fh.SetGeoTransform( geotransform )
    t_fh.SetProjection( levelMosaicInfo.projection)
    if levelMosaicInfo.ct is not None:
        for band in range(1,bands+1):
            t_band = t_fh.GetRasterBand( band )
            t_band.SetRasterColorTable(levelMosaicInfo.ct)

    res = gdal.ReprojectImage(s_fh,t_fh,None,None,ResamplingMethod)
    if  res!=0:
        print "Reprojection failed for %s, error %d" % (tileName,res)
        sys.exit( 1 )


    levelMosaicInfo.closeDataSet(s_fh);

    if MemDriver is not None:
        tt_fh = Driver.CreateCopy( tileName, t_fh, 0, CreateOptions )

    if Verbose:
        print tileName + " : " + str(offsetX)+"|"+str(offsetY)+"-->"+str(width)+"-"+str(height)




def createTile( minfo, offsetX,offsetY,width,height, tilename,OGRDS):
    """

    Create tile
    return name of created tile

    """

    if BandType is None:
        bt=minfo.band_type
    else:
        bt=BandType


    dec = AffineTransformDecorator([minfo.ulx,minfo.scaleX,0,minfo.uly,0,minfo.scaleY])


    s_fh = minfo.getDataSet(dec.ulx+offsetX*dec.scaleX,dec.uly+offsetY*dec.scaleY+height*dec.scaleY,
                         dec.ulx+offsetX*dec.scaleX+width*dec.scaleX,
                         dec.uly+offsetY*dec.scaleY)
    if s_fh is None:
        return;


    geotransform = [dec.ulx+offsetX*dec.scaleX, dec.scaleX, 0,
                    dec.uly+offsetY*dec.scaleY,  0,dec.scaleY]

    if OGRDS is not None:
        dec2 = AffineTransformDecorator(geotransform)
        points = dec2.pointsFor(width, height)
        addFeature(OGRDS, tilename, points[0], points[1])



    bands = minfo.bands

    if MemDriver is None:
        t_fh = Driver.Create( tilename, width, height, bands,bt,CreateOptions)
    else:
        t_fh = MemDriver.Create( tilename, width, height, bands,bt,CreateOptions)

    if t_fh is None:
        print 'Creation failed, terminating gdal_tile.'
        sys.exit( 1 )

    t_fh.SetGeoTransform( geotransform )
    if Source_SRS is not None:
        t_fh.SetProjection( Source_SRS.ExportToWkt())

    readX=min(s_fh.RasterXSize,width)
    readY=min(s_fh.RasterYSize,height)
    for band in range(1,bands+1):
        s_band = s_fh.GetRasterBand( band )
        t_band = t_fh.GetRasterBand( band )
        if minfo.ct is not None:
            t_band.SetRasterColorTable(minfo.ct)

#        data = s_band.ReadRaster( offsetX,offsetY,width,height,width,height, t_band.DataType )
        data = s_band.ReadRaster( 0,0,readX,readY,readX,readY,  t_band.DataType )
        t_band.WriteRaster( 0,0,readX,readY, data,readX,readY, t_band.DataType )

    minfo.closeDataSet(s_fh);

    if MemDriver is not None:
        tt_fh = Driver.CreateCopy( tilename, t_fh, 0, CreateOptions )

    if Verbose:
        print tilename + " : " + str(offsetX)+"|"+str(offsetY)+"-->"+str(width)+"-"+str(height)



def createTileIndex(dsName,fieldName,srs,driverName):

    OGRDriver = ogr.GetDriverByName(driverName);
    if OGRDriver is None:
        print 'ESRI Shapefile driver not found'
        sys.exit( 1 )

    OGRDataSource=OGRDriver.Open(dsName)
    if OGRDataSource is not None:
        OGRDataSource.Destroy()
        OGRDriver.DeleteDataSource(dsName)
        if Verbose:
            print 'truncating index '+ dsName

    OGRDataSource=OGRDriver.CreateDataSource(dsName)
    if OGRDataSource is None:
        print 'Could not open datasource '+dsName
        sys.exit( 1 )

    OGRLayer = OGRDataSource.CreateLayer("index", srs, ogr.wkbPolygon)
    if OGRLayer is None:
        print 'Could not create Layer'
        sys.exit( 1 )

    OGRFieldDefn = ogr.FieldDefn(fieldName,ogr.OFTString)
    if OGRFieldDefn is None:
        print 'Could not create FieldDefn for '+fieldName
        sys.exit( 1 )

    OGRFieldDefn.SetWidth(256)
    if OGRLayer.CreateField(OGRFieldDefn) != 0:
        print 'Could not create Field for '+fieldName
        sys.exit( 1 )

    return OGRDataSource

def addFeature(OGRDataSource,location,xlist,ylist):

    OGRLayer=OGRDataSource.GetLayer();
    OGRFeature = ogr.Feature(OGRLayer.GetLayerDefn())
    if OGRFeature is None:
        print 'Could not create Feature'
        sys.exit( 1 )

    OGRFeature.SetField(TileIndexFieldName,location);
    wkt = 'POLYGON ((%f %f,%f %f,%f %f,%f %f,%f %f ))' % (xlist[0],ylist[0],
            xlist[1],ylist[1],xlist[2],ylist[2],xlist[3],ylist[3],xlist[0],ylist[0])
    OGRGeometry=ogr.CreateGeometryFromWkt(wkt,OGRLayer.GetSpatialRef())
    if (OGRGeometry is None):
        print 'Could not create Geometry'
        sys.exit( 1 )

    OGRFeature.SetGeometryDirectly(OGRGeometry)

    OGRLayer.CreateFeature(OGRFeature)
    OGRFeature.Destroy()

def closeTileIndex(OGRDataSource):
    OGRDataSource.Destroy()


def buildPyramid(minfo,createdTileIndexDS,tileWidth, tileHeight):

    inputDS=createdTileIndexDS
    for level in range(1,Levels+1):
        levelMosaicInfo = mosaic_info(minfo.filename,inputDS)
        levelOutputTileInfo = tile_info(levelMosaicInfo.xsize/2,levelMosaicInfo.ysize/2,tileWidth,tileHeight)
        inputDS=buildPyramidLevel(levelMosaicInfo,levelOutputTileInfo,level)


def buildPyramidLevel(levelMosaicInfo,levelOutputTileInfo, level):
    yRange = range(1,levelOutputTileInfo.countTilesY+1)
    xRange = range(1,levelOutputTileInfo.countTilesX+1)

    OGRDS=createTileIndex("TileResult_"+str(level), TileIndexFieldName, Source_SRS,TileIndexDriverTyp)

    for yIndex in yRange:
        for xIndex in xRange:
            offsetY=(yIndex-1)* levelOutputTileInfo.tileHeight
            offsetX=(xIndex-1)* levelOutputTileInfo.tileWidth
            if yIndex==levelOutputTileInfo.countTilesY:
                height=levelOutputTileInfo.lastTileHeight
            else:
                height=levelOutputTileInfo.tileHeight

            if xIndex==levelOutputTileInfo.countTilesX:
                width=levelOutputTileInfo.lastTileWidth
            else:
                width=levelOutputTileInfo.tileWidth
            tilename=getTileName(levelMosaicInfo,levelOutputTileInfo, xIndex, yIndex,level)
            createPyramidTile(levelMosaicInfo, offsetX, offsetY, width, height,tilename,OGRDS)


    if TileIndexName is not None:
        shapeName=getTargetDir(level)+TileIndexName
        copyTileIndexToDisk(OGRDS,shapeName)

    if CsvFileName is not None:
        csvName=getTargetDir(level)+CsvFileName
        copyTileIndexToCSV(OGRDS,csvName)


    return OGRDS

def getTileName(minfo,ti,xIndex,yIndex,level = -1):
    """
    creates the tile file name
    """
    max = ti.countTilesX
    if (ti.countTilesY > max):
        max=ti.countTilesY
    countDigits= len(str(max))
    parts=os.path.splitext(os.path.basename(minfo.filename))
    if parts[0][0]=="@" : #remove possible leading "@"
       parts = ( parts[0][1:len(parts[0])], parts[1])

    if Extension is None:
        format=getTargetDir(level)+parts[0]+"_%0"+str(countDigits)+"i"+"_%0"+str(countDigits)+"i"+parts[1]
    else:
        format=getTargetDir(level)+parts[0]+"_%0"+str(countDigits)+"i"+"_%0"+str(countDigits)+"i"+"."+Extension
    return format % (yIndex,xIndex)

def UsageFormat():
    print 'Valid formats:'
    count = gdal.GetDriverCount()
    for index in range(count):
       driver= gdal.GetDriver(index)
       print driver.ShortName

# =============================================================================
def Usage():
     print 'Usage: gdal_retile.py '
     print '        [-v] [-co NAME=VALUE]* [-of out_format]'
     print '        [-ps pixelWidth pixelHeight]'
     print '        [-ot  {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/'
     print '               CInt16/CInt32/CFloat32/CFloat64}]'
     print '        [ -tileIndex tileIndexName [-tileIndexField fieldName]]'
     print '        [ -csv fileName [-csvDelim delimiter]]'
     print '        [-s_srs srs_def]  [-pyramidOnly] -levels numberoflevels'
     print '        [-r {near/bilinear/cubic/cubicspline}]'
     print '        -targetDir TileDirectory input_files'

# =============================================================================


# =============================================================================
#
# Program mainline.
#

def main(args):

    global Verbose
    global CreateOptions
    global Names
    global TileWidth
    global TileHeight
    global Format
    global BandType
    global Driver
    global Extension
    global MemDriver
    global TileIndexFieldName
    global TileIndexName
    global CsvDelimiter
    global CsvFileName

    global TileIndexDriverTyp
    global Source_SRS
    global TargetDir
    global ResamplingMethod
    global Levels
    global PyramidOnly

    gdal.AllRegister()

    argv = gdal.GeneralCmdLineProcessor( args )
    if argv is None:
        return 1

    # Parse command line arguments.
    i = 1
    while i < len(argv):
        arg = argv[i]

        if arg == '-of':
            i+=1
            Format = argv[i]
        elif arg == '-ot':
            i+=1
            BandType = gdal.GetDataTypeByName( argv[i] )
            if BandType == gdal.GDT_Unknown:
                print 'Unknown GDAL data type: ', argv[i]
                return 1
        elif arg == '-co':
            i+=1
            CreateOptions.append( argv[i] )


        elif arg == '-v':
            Verbose = True

        elif arg == '-targetDir':
            i+=1
            TargetDir=argv[i]

            if os.path.exists(TargetDir)==False:
                print "TargetDir " + TargetDir + " does not exist"
                return 1
            if TargetDir[len(TargetDir)-1:] != os.sep:
                TargetDir =  TargetDir+os.sep

        elif arg == '-ps':
            i+=1
            TileWidth=int(argv[i])
            i+=1
            TileHeight=int(argv[i])

        elif arg == '-r':
            i+=1
            ResamplingMethodString=argv[i]
            if ResamplingMethodString=="near":
                ResamplingMethod=GRA_NearestNeighbour
            elif ResamplingMethodString=="bilinear":
                 ResamplingMethod=GRA_Bilinear
            elif ResamplingMethodString=="cubic":
                 ResamplingMethod=GRA_Cubic
            elif ResamplingMethodString=="cubicspline":
                 ResamplingMethod=GRA_CubicSpline
            else:
                print "Unknown resampling method:" ,ResamplingMethodString
                return 1
        elif arg == '-levels':
            i+=1
            Levels=int(argv[i])
            if Levels<1:
                print "Invalid number of levels", Levels
                return 1
        elif arg == '-s_srs':
            i+=1
            Source_SRS = osr.SpatialReference()
            if Source_SRS.SetFromUserInput( argv[i] ) != 0:
                print 'invalid -s_srs: ' + argv[i];
                return 1;

        elif arg ==  "-pyramidOnly":
            PyramidOnly=True
        elif arg == '-tileIndex':
            i+=1
            TileIndexName=argv[i]
            parts=os.path.splitext(TileIndexName)
            if len(parts[1])==0:
                TileIndexName+=".shp"

        elif arg == '-tileIndexField':
            i+=1
            TileIndexFieldName=argv[i]
        elif arg == '-csv':
            i+=1
            CsvFileName=argv[i]
            parts=os.path.splitext(CsvFileName)
            if len(parts[1])==0:
                CsvFileName+=".csv"
        elif arg == '-csvDelim':
            i+=1
            CsvDelimiter=argv[i]
        elif arg[:1] == '-':
            print 'Unrecognised command option: ', arg
            Usage()
            return 1

        else:
            Names.append( arg )
        i+=1

    if len(Names) == 0:
        print 'No input files selected.'
        Usage()
        return 1

    if (TileWidth==0 or TileHeight==0):
        print "Invalid tile dimension %d,%d" % (TileWidth,TileHeight)
        return 1

    if (TargetDir is None):
        print "Missing Directory for Tiles -targetDir"
        Usage()
        return 1

    if Levels > 0:    #prepare Dirs for pyramid
        for levelIndx in range (1,Levels+1):
            leveldir=TargetDir+str(levelIndx)+os.sep
            if (os.path.exists(leveldir)):
                continue
            os.mkdir(leveldir)
            if (os.path.exists(leveldir)==False):
                print "Cannot create level dir:", leveldir
                return 1
            if Verbose :
                print "Created level dir: ",leveldir


    Driver = gdal.GetDriverByName(Format)
    if Driver is None:
        print 'Format driver %s not found, pick a supported driver.' % Format
        UsageFormat()
        return 1




    DriverMD = Driver.GetMetadata()
    Extension=DriverMD.get(DMD_EXTENSION);
    if not DriverMD.has_key('DCAP_CREATE'):
        MemDriver=gdal.GetDriverByName("MEM")


    tileIndexDS=getTileIndexFromFiles(Names,TileIndexDriverTyp)
    if tileIndexDS is None:
        print "Error building tile index"
        return 1;
    minfo = mosaic_info(Names[0],tileIndexDS)
    ti=tile_info(minfo.xsize,minfo.ysize, TileWidth, TileHeight)

    if Source_SRS is None and len(minfo.projection) > 0 :
       Source_SRS = osr.SpatialReference()
       if Source_SRS.SetFromUserInput( minfo.projection ) != 0:
           print 'invalid projection  ' + minfo.projection;
           return 1

    if Verbose:
        minfo.report()
        ti.report()


    if PyramidOnly==False:
       dsCreatedTileIndex = tileImage(minfo,ti)
       tileIndexDS.Destroy()
    else:
       dsCreatedTileIndex=tileIndexDS

    if Levels>0:
       buildPyramid(minfo,dsCreatedTileIndex,TileWidth, TileHeight)

    if Verbose:
        print "FINISHED"
    return 0

def initGlobals():
    """ Only used for unit tests """
    global Verbose
    global CreateOptions
    global Names
    global TileWidth
    global TileHeight
    global Format
    global BandType
    global Driver
    global Extension
    global MemDriver
    global TileIndexFieldName
    global TileIndexName
    global TileIndexDriverTyp
    global CsvDelimiter
    global CsvFileName
    global Source_SRS
    global TargetDir
    global ResamplingMethod
    global Levels
    global PyramidOnly

    Verbose=False
    CreateOptions = []
    Names=[]
    TileWidth=256
    TileHeight=256
    Format='GTiff'
    BandType = None
    Driver=None
    Extension=None
    MemDriver=None
    TileIndexFieldName='location'
    TileIndexName=None
    TileIndexDriverTyp="Memory"
    CsvDelimiter=";"
    CsvFileName=None

    Source_SRS=None
    TargetDir=None
    ResamplingMethod=GRA_NearestNeighbour
    Levels=0
    PyramidOnly=False


#global vars
Verbose=False
CreateOptions = []
Names=[]
TileWidth=256
TileHeight=256
Format='GTiff'
BandType = None
Driver=None
Extension=None
MemDriver=None
TileIndexFieldName='location'
TileIndexName=None
TileIndexDriverTyp="Memory"
CsvDelimiter=";"
CsvFileName=None
Source_SRS=None
TargetDir=None
ResamplingMethod=GRA_NearestNeighbour
Levels=0
PyramidOnly=False



if __name__ == '__main__':
    sys.exit(main(sys.argv))

