'''

@author: olivier.massot, sept. 2018
'''
import shapefile

SHAPES = {1:"Point", 3:"Polyligne", 5:"Polygone"}

class ShapeError(IOError): pass

class ShapeFile():
    shapes = {1: "POINT", 3:"POLYLIGNE", 5:"POLYGONE"}
    
    def __enter__(self, path_):
        if not path_.isfile():
            raise FileNotFoundError("Fichier introuvable")
     
        try:
            self.sf = shapefile.Reader(path_)
        except shapefile.ShapefileException:
            raise ShapeError("Fichier Shape illisible")
        
        try:
            _ = self.shapes[self.sf.shapeType]
        except KeyError:
            raise ShapeError("Type de géométrie non reconnue")

        return self
    
    def fields(self):
        return [f[0] for f in self.sf.fields if f[0] != 'DeletionFlag']
        
    def records(self):
        return self.sf.shapeRecords()
        
    def __exit__(self):
        del self.sf