"""A function to append Spatial Data Modeller parameters to Geoprocessor History
    for those SDM tools that have the following values:
    gp: geoprocessor object
    unitCell: unit cell area in sq km
    TrainPts: training sites Points feature class
"""
import traceback, sys

ToMetric = {
    'square meters to square kilometers' : 0.000001,
    'square feet to square kilometers' : 0.09290304 * 1e-6,
    'square inches to square kilometers' : 0.00064516 * 1e-6,
    'square miles to square kilometers' : 2.589988110647
    }
def appendSDMValues(gp, unitCell, TrainPts):
    try:
        if not gp.workspace:
            gp.adderror('Workspace not set')
        gp.addmessage("Workspace: %s"%gp.workspace)
        if not gp.scratchworkspace:
            gp.adderror('Scratch workspace mask not set')
        gp.addmessage("Scratch workspace: %s"%gp.scratchworkspace)
        if not gp.mask:
            gp.adderror('Study Area mask not set')
        maskrows = gp.SearchCursor(gp.describe(gp.mask).catalogpath)
        maskrow = maskrows.next()
        count =  0
        while maskrow:
            count += maskrow.count
            maskrow = maskrows.next()
        mapUnits = getMapUnits(gp).lower().strip()
        if not mapUnits.startswith('meter'):
            gp.addError('Incorrect output map units: Check units of study area.')
        conversion = getMapConversion(gp, mapUnits)
        if not gp.cellsize:
            gp.adderror('Study Area cellsize not set')
        cellsize = float(gp.cellsize)
        total_area = count * cellsize **2 * conversion
        num_unit_cells = total_area / unitCell
        num_tps = gp.GetCount_management(TrainPts)
        priorprob = num_tps / num_unit_cells
        if not (0 < priorprob <= 1.0):
            gp.adderror('Incorrect no. of training sites or unit cell area')
        gp.addmessage('Prior Probability: %0.6f' %priorprob)
        gp.addmessage('Training Set: %s'%gp.describe(TrainPts).catalogpath)
        gp.addmessage('Number of Training Sites: %s' %num_tps)
        gp.addmessage('Study Area Raster: %s'%gp.describe(gp.mask).catalogpath)
        gp.addmessage('Study Area Area (sq km): %s'%total_area)
        gp.addmessage('Unit Cell Area (sq km): %s'%unitCell)
        gp.addmessage('Map Units: %s'%mapUnits)
        #gp.addmessage('Map Units to Square Kilometers Conversion: %f'%conversion)
        
    except:
        # get the traceback object
        tb = sys.exc_info()[2]
        # tbinfo contains the line number that the code failed on and the code from that line
        tbinfo = traceback.format_tb(tb)[0]
        # concatenate information together concerning the error into a message string
        pymsg = "PYTHON ERRORS:\nTraceback Info:\n" + tbinfo + "\nError Info:\n    " + \
            str(sys.exc_type)+ ": " + str(sys.exc_value) + "\n"
        # generate a message string for any geoprocessing tool errors
        if len(gp.GetMessages(2)) > 0:
            msgs = "GP ERRORS:\n" + gp.GetMessages(2) + "\n"
            gp.AddError(msgs)

        # return gp messages for use with a script tool
        gp.AddError(pymsg)

        raise

def getMapConversion(gp, mapUnits):
    pluralMapUnits = {'meter':'meters', 'foot':'feet', 'inch':'inches', 'mile':'miles'}
    conversion = ToMetric["square %s to square kilometers"%pluralMapUnits[mapUnits]]
    return conversion    

def getMapUnits(gp):
    """ Get document map units from g.outputcoordinatesystem """
    try:
        #Get spatial reference of geoprocessor
        ocs = gp.outputcoordinatesystem
        if not ocs:
            gp.adderror('Output Coordinate System not set')
            raise Exception
        #Replace apostrophes with quotations
        ocs = ocs.replace("'",'"')
        #Open scratch file for output
        prjfile = gp.createuniquename('coordsys', gp.scratchworkspace) + '.prj'
        #Write spatial reference string to scratch file
        fdout = open(prjfile,'w')
        fdout.write(ocs)
        fdout.write('\n')
        fdout.close()
        #Create spatial reference object
        spatref = gp.createobject('spatialreference')
        #Populate it by parsing of scratch file
        spatref.createfromfile(prjfile)
        #Return map units value
        if spatref.type == 'Projected':
            return spatref.linearunitname
        elif spatref.type == 'Geographic':
            return spatref.angularunitname
        else:
            return None        
    except:
        import traceback, sys
        # get the traceback object
        tb = sys.exc_info()[2]
        # tbinfo contains the line number that the code failed on and the code from that line
        tbinfo = traceback.format_tb(tb)[0]
        # concatenate information together concerning the error into a message string
        pymsg = "PYTHON ERRORS:\nTraceback Info:\n" + tbinfo + "\nError Info:\n    " + \
            str(sys.exc_type)+ ": " + str(sys.exc_value) + "\n"
        # generate a message string for any geoprocessing tool errors
        msgs = "GP ERRORS:\n" + gp.GetMessages(2) + "\n"
        gp.AddError(msgs)

        # return gp messages for use with a script tool
        gp.AddError(pymsg)

        # print messages for use in Python/PythonWin
        print pymsg
        print msgs

if __name__ == '__main__':
    import arcgisscripting
    gp = arcgisscripting.create()
    training_sites = gp.getParameterAsText(0)
    unit_area = gp.getparameter(1)
    appendSDMValues(gp, unit_area, training_sites)