#
# Objects that are used by all the storage engines.
#
import time
import json
import logging

class WeaveStorageException(Exception):
	def __init__(self, value, nestedException=None):
		self.value = value
		self.nested = nestedException
	
	def __repr__(self):
		return "<WeaveStorageException: %s>" % self.value

	def __str__(self):
		return self.value

class WeaveStorageBase(object):
	"""The required interface that storage implementations must provide."""

	def get_context(self, name):
		raise NotImplementedException()

	def get(self, context, collection, id, query=None):
		raise NotImplementedException()

	def collection_modification_date(self, context, collection):
		raise NotImplementedException()

	def collection_timestamps(self, context):
		raise NotImplementedException()

	def collection_counts(self, context):
		raise NotImplementedException()

	def add_or_modify(self, context, collection, item, id=None, query=None):
		raise NotImplementedException()

	def delete(self, context, collection, id=None, query=None):
		raise NotImplementedException()


class WBO(object):
	"""Represents a single object that is stored in a storage engine.
	
	The name is inappropriately connected to the idea of a web browser object,
	since there's nothing web-browser-ish about this implementation."""

	# modified is in centiseconds

	def __init__(self, data=None, id=None, parentid=None, predecessorid=None, sortindex=None, payload=None, modified=None):
		"""Can take either a 'data', which is a JSON-formatted blob (or the dict resulting from same),
		or a bunch of named parameters.
		
		Messy to take both signatures through the constructor.  Refactor."""
		
		if data:
			if type(data) == str or type(data) == unicode:
				data = json.loads(data)
				
			self.id = None
			if 'id' in data:
				id = data['id']
				if not (type(id) == str or type(id) == unicode):
					id = unicode(id)
				if len(id) > 64:
					raise WeaveStorageException("Illegal id value")
				self.id = id

			self.parentid = None
			self.predecessorid = None
			self.sortindex = None
			self.payload = None
			self.modified = None
			
			if 'payload' in data:
				payloadObj = data['payload']
				if type(payloadObj) != str and type(payloadObj) != unicode:
					self.payload = json.dumps(payloadObj)
				else:
					self.payload = payloadObj

			self.update(data, updateModifiedDate='payload' in data)

		else:
			self.id = id
			self.parentid = parentid
			self.predecessorid = predecessorid
			self.sortindex = sortindex
			self.payload = payload
			self.modified = modified
				
	def asjson(self):
		m = {}
		m['id'] = self.id
		if self.parentid: m['parentid'] = self.parentid
		if self.predecessorid: m['predecessorid'] = self.predecessorid
		if self.sortindex: m['sortindex'] = self.sortindex
		if self.payload: m['payload'] = self.payload
		if self.modified: m['modified'] = float(self.modified) / 100
		
		return json.dumps(m)
		
	def __repr__(self):
		return self.asjson()

	def __str__(self):
		return self.asjson()
				
	def update(self, fromMap, updateModifiedDate = False):
	
		# The modification date is only changed if the payload
		# or parentID is changed.  Changes to sortindex and predecessorID do
		# not update the modification date.
	
		if 'parentid' in fromMap:
			if len(fromMap['parentid']) > 64:# this is really a storage-engine specific limit; refactor
				raise WeaveStorageException("Illegal parentid value")
			self.parentid = fromMap['parentid']
			updateModifiedDate = True

		if 'predecessorid' in fromMap:
			if len(fromMap['predecessorid']) > 64:# this is really a storage-engine specific limit; refactor
				raise WeaveStorageException("Illegal predecessorid value")
			self.predecessorid = fromMap['predecessorid']

		if 'sortindex' in fromMap:
			val = fromMap['sortindex']
			if type(val) == int:
				if val > 99999999999: # this is really a storage-engine specific limit; refactor
					raise WeaveStorageException("Illegal sortindex value")
				self.sortindex = val
			elif type(val) == str or type(val) == unicode:
				if len(val) > 11:
					raise WeaveStorageException("Illegal sortindex value")
				try:
					self.sortindex = int(val)
				except:
					# Python raises an exception for "5.5", even though it will take "5".
					# See if we can convert through floating point.
					try:
						self.sortindex = int(float(val))
					except:
						raise WeaveStorageException('Illegal sortindex value')

		if updateModifiedDate:
			self.modified = int(time.time() * 100)