from binascii import hexlify, unhexlify
from os import listdir, makedirs, path, remove, rmdir
import string
from threading import RLock
import time
import traceback

from paths import lookupAppdataFolder
from storage import InventoryStorage, InventoryItem

class FilesystemInventory(InventoryStorage):
    topDir = "inventory"
    objectDir = "objects"
    metadataFilename = "metadata"
    dataFilename = "data"

    def __init__(self):
        super(self.__class__, self).__init__()
        self.baseDir = path.join(lookupAppdataFolder(), FilesystemInventory.topDir)
        for createDir in [self.baseDir, path.join(self.baseDir, "objects")]:
            if path.exists(createDir):
                if not path.isdir(createDir):
                    raise IOError("%s exists but it's not a directory" % (createDir))
            else:
                makedirs(createDir)
        self.lock = RLock() # Guarantees that two receiveDataThreads don't receive and process the same message concurrently (probably sent by a malicious individual)
        self._inventory = {}
        self._load()

    def __contains__(self, hash):
        retval = False
        for streamDict in self._inventory.values():
            if hash in streamDict:
                return True
        return False

    def __getitem__(self, hash):
        for streamDict in self._inventory.values():
            try:
                retval = streamDict[hash]
            except KeyError:
                continue
            if retval.payload is None:
                retval = InventoryItem(retval.type, retval.stream, self.getData(hash), retval.expires, retval.tag)
            return retval
        raise KeyError(hash)

    def __setitem__(self, hash, value):
        with self.lock:
            value = InventoryItem(*value)
            try:
                makedirs(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash)))
            except OSError:
                pass
            try:
                with open(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash), FilesystemInventory.metadataFilename), 'w') as f:
                    f.write("%s,%s,%s,%s," % (value.type, value.stream, value.expires, hexlify(value.tag)))
                with open(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash), FilesystemInventory.dataFilename), 'w') as f:
                    f.write(value.payload)
            except IOError:
                raise KeyError
            try:
                self._inventory[value.stream][hash] = value
            except KeyError:
                self._inventory[value.stream] = {}
                self._inventory[value.stream][hash] = value

    def __delitem__(self, hash):
        for stream in self._inventory.keys():
            try:
                del self._inventory[stream][hash]
            except KeyError:
                pass
        with self.lock:
            try:
                remove(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash), FilesystemInventory.metadataFilename))
            except IOError:
                pass
            try:
                remove(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash), FilesystemInventory.dataFilename))
            except IOError:
                pass
            try:
                rmdir(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hash)))
            except IOError:
                pass

    def __iter__(self):
        elems = []
        for streamDict in self._inventory.values():
            elems.extend (streamDict.keys())
        return elems.__iter__()

    def __len__(self):
        retval = 0
        for streamDict in self._inventory.values():
            retval += len(streamDict)
        return retval

    def _load(self):
        newInventory = {}
        for hashId in self.object_list():
            try:
                objectType, streamNumber, expiresTime, tag = self.getMetadata(hashId)
                try:
                    newInventory[streamNumber][hashId] = InventoryItem(objectType, streamNumber, None, expiresTime, tag)
                except KeyError:
                    newInventory[streamNumber] = {}
                    newInventory[streamNumber][hashId] = InventoryItem(objectType, streamNumber, None, expiresTime, tag)
            except KeyError:
                print "error loading %s" % (hexlify(hashId))
                pass
        self._inventory = newInventory
        for i, v in self._inventory.items():
            print "loaded stream: %s, %i items" % (i, len(v))

    def stream_list(self):
        return self._inventory.keys()

    def object_list(self):
        return [unhexlify(x) for x in listdir(path.join(self.baseDir, FilesystemInventory.objectDir))]

    def getData(self, hashId):
        try:
            with open(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hashId), FilesystemInventory.dataFilename), 'r') as f:
                return f.read()
        except IOError:
            raise AttributeError

    def getMetadata(self, hashId):
        try:
            with open(path.join(self.baseDir, FilesystemInventory.objectDir, hexlify(hashId), FilesystemInventory.metadataFilename), 'r') as f:
                objectType, streamNumber, expiresTime, tag, undef = string.split(f.read(), ",", 4)
                return [int(objectType), int(streamNumber), int(expiresTime), unhexlify(tag)]
        except IOError:
            raise KeyError

    def by_type_and_tag(self, objectType, tag):
        retval = []
        for stream, streamDict in self._inventory:
            for hashId, item in streamDict:
                if item.type == objectType and item.tag == tag:
                    try: 
                        if item.payload is None:
                            item.payload = self.getData(hashId)
                    except IOError:
                        continue
                    retval.append(InventoryItem(item.type, item.stream, item.payload, item.expires, item.tag))
        return retval

    def hashes_by_stream(self, stream):
        try:
            return self._inventory[stream].keys()
        except KeyError:
            return []

    def unexpired_hashes_by_stream(self, stream):
        t = int(time.time())
        try:
            return [x for x, value in self._inventory[stream].items() if value.expires > t]
        except KeyError:
            return []

    def flush(self):
        self._load()

    def clean(self):
        minTime = int(time.time()) - (60 * 60 * 30)
        deletes = []
        for stream, streamDict in self._inventory.items():
            for hashId, item in streamDict.items():
                if item.expires < minTime:
                    deletes.append(hashId)
        for hashId in deletes:
            del self[hashId]