"""WAeUP data center.

The waeup data center cares for management of upload data and provides
tools for importing/exporting CSV data.
"""
import logging
import os
import shutil
import struct
import grok
from datetime import datetime
from zope.component import getMultiAdapter
from zope.component.interfaces import ObjectEvent
from waeup.csvfile import getCSVFile
from waeup.interfaces import (IDataCenter, IWAeUPCSVImporter,
                              ICSVDataReceivers, IDataCenterFile,
                              IDataCenterStorageMovedEvent)
from waeup.utils.helpers import copyFileSystemTree

class DataCenter(grok.Container):
    """A data center contains CSV files.
    """
    grok.implements(IDataCenter)
    storage = os.path.join(os.path.dirname(__file__), 'files')

    @property
    def logger(self):
        """Get a logger for datacenter actions.
        """
        # We need a different logger for every site...
        site = grok.getSite()
        sitename = getattr(site, '__name__', 'app')
        loggername = 'waeup.sirp.%s.datacenter' % sitename
        logger = logging.getLogger(loggername)
        if not logger.handlers:
            logger = self._setupLogger(logger)
        return logger

    def __init__(self, *args, **kw):
        super(DataCenter, self).__init__(*args, **kw)
        self._createSubDirs()
        
    def _setupLogger(self, logger):
        """Setup datacenter logger.
        """
        logdir = os.path.join(self.storage, 'logs')
        if not os.path.exists(logdir):
            os.mkdir(logdir)
        filename = os.path.join(logdir, 'datacenter.log')

        # Create a rotating file handler logger for datacenter.
        handler = logging.handlers.RotatingFileHandler(
            filename, maxBytes=5*1024**1, backupCount=5)
        formatter = logging.Formatter(
            '%(asctime)s - %(levelname)s - %(message)s')
        handler.setFormatter(formatter)
        
        # Here we decide, whether our messages will _also_ go to
        # application log.
        logger.propagate = False
        logger.setLevel(logging.DEBUG)
        logger.addHandler(handler)
        return logger

    def _createSubDirs(self):
        """Create standard subdirs.
        """
        for name in ['finished', 'unfinished']:
            path = os.path.join(self.storage, name)
            if os.path.exists(path):
                continue
            os.mkdir(path)
        return
    
    def getReceivers(self):
        receivers = []
        curr_obj = getattr(self, '__parent__', None)
        while curr_obj is not None:
            if ICSVDataReceivers.providedBy(curr_obj):
                receivers = self.getCSVDataReceivers(curr_obj)
                break
            curr_obj = getattr(curr_obj, '__parent__', None)
        return receivers

    def getReceiverIds(self):
        """Get a dict of available receivers.

        The keys of the result are the receiver ids.
        """
        receivers = self.getReceivers()
        return dict([(self.getReceiverId(x), x) for x in receivers])
    
    def getImporters(self):
        """Get a list of all importers available.

        The search for available importers is done in two steps:

        1) Look for a utility providing ICSVDataReceiver,

        2) For every item of that utility: try to get an adapter
           providing IWAeUPCSVImporter.
        """
        result = []
        receivers = self.getReceivers()
        files = self.getFiles()
        for receiver in receivers:
            for file in files:
                wrapped_file = getCSVFile(file.context)
                try:
                    importer = getMultiAdapter((wrapped_file, receiver),
                                           IWAeUPCSVImporter)
                    result.append(importer)
                except:
                    # No multi-adapter for this combination available...
                    pass
        return result
    
    def getFiles(self, sort='name'):
        """Get a list of files stored in `storage`.

        Files are sorted by basename.
        """
        result = []
        if not os.path.exists(self.storage):
            return result
        for filename in sorted(os.listdir(self.storage)):
            fullpath = os.path.join(self.storage, filename)
            if not os.path.isfile(fullpath):
                continue
            result.append(DataCenterFile(fullpath))
        if sort == 'date':
            # sort results in newest-first order...
            result = sorted(result, key=lambda x: x.getTimeStamp(),
                            reverse=True)
        return result

    def getLogFiles(self):
        """Get the files from logs/ subdir. Files are sorted by name.
        """
        result = []
        logdir = os.path.join(self.storage, 'logs')
        if not os.path.exists(logdir):
            os.mkdir(logdir)
        for name in sorted(os.listdir(logdir)):
            if not os.path.isfile(os.path.join(logdir, name)):
                continue
            result.append(
                LogFile(os.path.join(self.storage, 'logs', name)))
        return result
            
    def setStoragePath(self, path, move=False, overwrite=False):
        """Set the path where to store files.
        """
        path = os.path.abspath(path)
        not_copied = []
        if not os.path.exists(path):
            raise ValueError('The path given does not exist: %s' % path)
        if move is True:

            not_copied = copyFileSystemTree(self.storage, path,
                                            overwrite=overwrite)
        self.storage = path
        self._createSubDirs()
        # Adjust logger...
        logger = self.logger
        handlers = logger.handlers
        for handler in handlers:
            logger.removeHandler(handler)
        self._setupLogger(logger)
        grok.notify(DataCenterStorageMovedEvent(self))
        return not_copied

    def getCSVDataReceivers(self, obj):
        """Get a list of attributes, that can receive CSV data.

        We also get a list of values, if obj is a container that
        contains value items.
        """
        result = []
        for attr_name in dir(obj):
            if attr_name.startswith('_'):
                continue
            try:
                attr = getattr(obj, attr_name)
                # This might fail...
                #IWAeUPCSVImporter(attr)
                result.append(attr)
            except:
                pass
        if hasattr(obj, 'values'):
            try:
                result.extend(obj.values())
            except:
                pass
        return result

    def getPossibleImports(self):
        """Get list of possible imports.

        A single import is defined as a tuple
        
          ( <file-descr>, <importers> )
        
        where ``<file-descr>`` is an `IDataCenterFile` object and
        ``<importers>`` is a list of `IWAeUPCSVImporter` objects.
        """
        result = []
        importers = self.getImporters()
        for filedescr in self.getFiles():
            possible_importers = []
            for importer in importers:
                if importer.csvfile.path != filedescr.context:
                    continue
                importer_context = (
                    importer, self.getReceiverId(importer.receiver))
                possible_importers.append(importer_context)
            if len(possible_importers) == 0:
                continue
            result.append((filedescr, possible_importers))
        return result

    def getReceiverId(self, obj):
        """Get a unique id for an object.

        If the object is stored in ZODB it should contain a `_p_oid`
        attribute, which is guaranteed to be unique over the ZODB.

        If the object has no such attribute, then it will be held in
        memory only and will vanish as soon as the request is over. In
        this case we can use the memory address of it.

        Both, the id() result and the ZODB oid, are actually integers
        which we return as strings. To make the difference chrystal
        clear, we prepend ``z`` to ids taken from ZODB oids.
        """
        if not hasattr(obj, '_p_oid'):
            return str(id(obj))
        oid = getattr(obj, '_p_oid')
        if oid is None:
            # The persistent object is not stored in the ZODB
            return str(id(obj))
        return 'z%s' % struct.unpack('>Q', oid)[0]

    def doImport(self, path, receiverid, clear=None):
        receivers = self.getReceiverIds()
        if receiverid not in receivers.keys():
            raise ValueError('The requested data receiver cannot be found.')
        receiver = receivers[receiverid]
        filewrapper = getCSVFile(path)
        if filewrapper is None:
            raise ValueError('Format of CSV file not supported.')
        importer = getMultiAdapter((filewrapper, receiver), IWAeUPCSVImporter)
        if clear is not None:
            importer.doImport(clear_old_data=clear)
        else:
            importer.doImport()
        return

    def _moveFile(self, source, dest):
        """Move file source to dest preserving ctime, mtime, etc.
        """
        if not os.path.exists(source):
            self.logger.warn('No such source path: %s' % source)
            return
        if source == dest:
            return
        shutil.copyfile(source, dest)
        shutil.copystat(source, dest)
        os.unlink(source)
    
    def distProcessedFiles(self, successful, source_path, finished_file,
                           pending_file, move_orig=True):
        """Put processed files into final locations.

        ``successful`` is a boolean that tells, whether processing was
        successful.

        ``source_path``: path to file that was processed.

        ``finished_file``, ``pending_file``: paths to the respective
        generated .pending and .finished file. The .pending file path
        may be ``None``.

        If finished file is placed in a location outside the local
        storage dir, the complete directory is removed
        afterwards. Regular importers should put their stuff in
        dedicated temporary dirs.
        
        See datacenter.txt for more info about how this works.
        """
        basename = os.path.basename(source_path)
        pending_name = basename
        pending = False
        finished_dir = os.path.join(self.storage, 'finished')
        unfinished_dir = os.path.join(self.storage, 'unfinished')

        if basename.endswith('.pending.csv'):
            maybe_basename = "%s.csv" % basename.split('.', 2)[0]
            maybe_src = os.path.join(unfinished_dir, maybe_basename)
            if os.path.isfile(maybe_src):
                basename = maybe_basename
                pending = True
                
        base, ext = os.path.splitext(basename)
        finished_name = "%s.finished%s" % (base, ext)
        if not pending:
            pending_name = "%s.pending%s" % (base, ext)

        # Put .pending and .finished file into respective places...
        pending_dest = os.path.join(self.storage, pending_name)
        finished_dest = os.path.join(finished_dir, finished_name)
        self._moveFile(finished_file, finished_dest)
        if pending_file is not None:
            self._moveFile(pending_file, pending_dest)

        # Put source file into final location...
        finished_dest = os.path.join(finished_dir, basename)
        unfinished_dest = os.path.join(unfinished_dir, basename)
        if successful and not pending:
            self._moveFile(source_path, finished_dest)
        elif successful and pending:
            self._moveFile(unfinished_dest, finished_dest)
            os.unlink(source_path)
        elif not successful and not pending:
            self._moveFile(source_path, unfinished_dest)

        # If finished and pending-file were created in a location
        # outside datacenter storage, we remove it.
        maybe_temp_dir = os.path.dirname(finished_file)
        if os.path.commonprefix(
            [self.storage, maybe_temp_dir]) != self.storage:
            shutil.rmtree(maybe_temp_dir)
        return

    
class DataCenterFile(object):
    """A description of a file stored in data center.
    """
    grok.implements(IDataCenterFile)
    
    def __init__(self, context):
        self.context = context
        self.name = os.path.basename(self.context)
        self.size = self.getSize()
        self.uploaddate = self.getDate()
        self.lines = self.getLinesNumber()

    def getDate(self):
        """Get a human readable datetime representation.
        """
        date = datetime.fromtimestamp(os.path.getctime(self.context))
        return date.strftime('%c')

    def getTimeStamp(self):
        """Get a (machine readable) timestamp.
        """
        return os.path.getctime(self.context)
    
    def getSize(self):
        """Get a human readable file size.
        """
        bytesize = os.path.getsize(self.context)
        size = "%s bytes" % bytesize
        units = ['kb', 'MB', 'GB']
        for power, unit in reversed(list(enumerate(units))):
            power += 1
            if bytesize >= 1024 ** power:
                size = "%.2f %s" % (bytesize/(1024.0**power), unit)
                break
        return size

    def getLinesNumber(self):
        """Get number of lines.
        """
        num = 0
        for line in open(self.context, 'rb'):
            num += 1
        return num
    
class LogFile(DataCenterFile):
    """A description of a log file.
    """
    def __init__(self, context):
        super(LogFile, self).__init__(context)
        self._markers = dict()
        self._parsed = False
        self.userid = self.getUserId()
        self.mode = self.getMode()
        self.stats = self.getStats()
        self.source = self.getSourcePath()

    def _parseFile(self, maxline=10):
        """Find markers in a file.
        """
        if self._parsed:
            return
        for line in open(self.context, 'rb'):
            line = line.strip()
            if not ':' in line:
                continue
            name, text = line.split(':', 1)
            self._markers[name.lower()] = text
        self._parsed = True
        return

    def _getMarker(self, marker):
        marker = marker.lower()
        if not self._parsed:
            self._parseFile()
        if marker in self._markers.keys():
            return self._markers[marker]
    
    def getUserId(self):
        return self._getMarker('user') or '<UNKNOWN>'

    def getMode(self):
        return self._getMarker('mode') or '<NOT SET>'

    def getStats(self):
        return self._getMarker('processed') or '<Info not avail.>'

    def getSourcePath(self):
        return self._getMarker('source') or None
    
class Import(object):
    """Helper class to aggregate imports and their data.
    """
    def __init__(self, filedescr, importers):
        self.file = filedescr
        self.importers = []
        for importer, receiverid in importers:
            importer.receiverid = receiverid
            self.importers.append(importer)

class DataCenterStorageMovedEvent(ObjectEvent):
    """An event fired, when datacenter storage moves.
    """
    grok.implements(IDataCenterStorageMovedEvent)