refactor models, change map package storage and map package loading

src/c3nav/mapdata/models/package.py

@@ -1,3 +1,5 @@
+from collections import OrderedDict
+
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
@@ -13,3 +15,35 @@ class Package(models.Model):
     left = models.DecimalField(_('left coordinate'), null=True, max_digits=6, decimal_places=2)
     top = models.DecimalField(_('top coordinate'), null=True, max_digits=6, decimal_places=2)
     right = models.DecimalField(_('right coordinate'), null=True, max_digits=6, decimal_places=2)
+
+    directory = models.CharField(_('folder name'), max_length=100)
+
+    @classmethod
+    def fromfile(cls, data, directory):
+        kwargs = {
+            'directory': directory
+        }
+
+        if 'name' not in data:
+            raise ValueError('pkg.json: missing package name.')
+        kwargs['name'] = data['name']
+
+        if 'bounds' in data:
+            bounds = data['bounds']
+            if len(bounds) != 2 or len(bounds[0]) != 2 or len(bounds[1]) != 2:
+                raise ValueError('pkg.json: Invalid bounds format.')
+            if not all(isinstance(i, (float, int)) for i in sum(bounds, [])):
+                raise ValueError('pkg.json: All bounds coordinates have to be int or float.')
+            if bounds[0][0] >= bounds[1][0] or bounds[0][1] >= bounds[1][1]:
+                raise ValueError('pkg.json: bounds: lower coordinate has to be first.')
+            (kwargs['bottom'], kwargs['left']), (kwargs['top'], kwargs['right']) = bounds
+
+        return kwargs
+
+    def tofile(self):
+        data = OrderedDict()
+        data['name'] = self.name
+        if self.bottom is not None:
+            data['bounds'] = ((float(self.bottom), float(self.left)), (float(self.top), float(self.right)))
+
+        return data