import os, arcpy, common, loaders

DUPL_FILE = 'tmp_dupl'

MERGE_FILE = 'tmp_merged'

INTER_FILE = 'tmp_intersect'

SHPLEN_FLD = 'TMP_SHLEN'

class Halver(loaders.FunctionUpdater):

return {'halved' : inprow['doubled'] / 2.0}

with common.runtool(4) as parameters:

conns, trafFld, tolerance, outPath = parameters

location = os.path.dirname(outPath)

duplPath = common.addExt(os.path.join(location, DUPL_FILE))

mergePath = common.addExt(os.path.join(location, MERGE_FILE))

interPath = common.addExt(os.path.join(location, INTER_FILE))

common.progress('preparing connections')

arcpy.CopyFeatures_management(conns, duplPath)

arcpy.Merge_management([conns, duplPath], mergePath)

common.progress('intersecting connections')

arcpy.Intersect_analysis([mergePath], interPath, 'ALL', tolerance, 'INPUT')

# create a shape length field

common.progress('marking traffic')

arcpy.AddField_management(interPath, SHPLEN_FLD, 'Double')

arcpy.CalculateField_management(interPath, SHPLEN_FLD, '!shape.length!', 'PYTHON_9.3')

common.progress('summarizing traffic')

arcpy.Dissolve_management(interPath, outPath, [SHPLEN_FLD], [[trafFld, 'SUM']], 'SINGLE_PART')

common.progress('initializing traffic fields')

arcpy.AddField_management(outPath, trafFld, common.typeOfField(conns, trafFld))

sumFld = 'SUM_' + trafFld # TODO: shapefile field name length adjustments...

Halver(outPath, {'doubled' : sumFld}, {'halved' : trafFld}).decompose('computing traffic fields')

# prog = common.progressor('adjusting total flow counts', common.count(outPath))

# outRows = arcpy.UpdateCursor(outPath)

# for row in outRows:

# unduplVal = row.getValue(sumFld) / 2

# row.setValue(trafFld, unduplVal)

# outRows.updateRow(row)

# prog.move()

# del row, outRows

# prog.end()

common.progress('deleting temporary fields')

arcpy.DeleteField_management(outPath, [sumFld, SHPLEN_FLD])

common.progress('deleting temporary files')

common.delete(duplPath, mergePath, interPath)