"""Components to handle access codes.
"""
import csv
import grok
import os
from datetime import datetime
from hurry.workflow.interfaces import IWorkflowInfo, IWorkflowState
from random import SystemRandom as random
from waeup.sirp.interfaces import IWAeUPSIRPPluggable, IObjectHistory
from waeup.sirp.accesscodes.interfaces import (
    IAccessCode, IAccessCodeBatch, IAccessCodeBatchContainer
    )
from waeup.sirp.accesscodes.workflow import DISABLED, USED

class ManageACBatches(grok.Permission):
    grok.name('waeup.manageACBatches')

class AccessCode(grok.Model):
    grok.implements(IAccessCode)

    def __init__(self, batch_serial, random_num):
        self.batch_serial = batch_serial
        self.random_num = random_num
        IWorkflowInfo(self).fireTransition('init')

    @property
    def representation(self):
        return '%s-%s-%s' % (
            self.batch_prefix, self.batch_num, self.random_num)

    @property
    def batch(self):
        return getattr(self, '__parent__', None)

    @property
    def batch_prefix(self):
        if self.batch is None:
            return ''
        return self.batch.prefix

    @property
    def batch_num(self):
        if self.batch is None:
            return ''
        return self.batch.num

    @property
    def cost(self):
        if self.batch is None:
            return None
        return self.batch.cost

    @property
    def disabled(self):
        return IWorkflowState(self).getState() == DISABLED

    @property
    def used(self):
        return IWorkflowState(self).getState() == USED

    @property
    def history(self):
        history = IObjectHistory(self)
        return '\n'.join(history.messages)

class AccessCodeBatch(grok.Container):
    """A batch of access codes.
    """
    grok.implements(IAccessCodeBatch)

    def __init__(self, creation_date, creator, batch_prefix, cost,
                 entry_num, num=None):
        super(AccessCodeBatch, self).__init__()
        self.creation_date = creation_date
        self.creator = creator
        self.prefix = batch_prefix.upper()
        self.cost = cost
        self.entry_num = entry_num
        self.num = num
        self.used_num = 0
        self.disabled_num = 0

    def _createEntries(self):
        """Create the entries for this batch.
        """
        for num, pin in enumerate(self._getNewRandomNum(num=self.entry_num)):
            self.addAccessCode(num, pin)
        return

    def _getNewRandomNum(self, num=1):
        """Create a set of ``num`` random numbers of 10 digits each.

        The number is returned as string.
        """
        curr = 1
        while curr <= num:
            pin = ''
            for x in range(10):
                pin += str(random().randint(0, 9))
            if not '%s-%s-%s' % (self.prefix, self.num, pin) in self.keys():
                curr += 1
                yield pin
            # PIN already in use

    def _getStoragePath(self):
        """Get the directory, where we store all batch-related CSV files.
        """
        site = grok.getSite()
        storagepath = site['datacenter'].storage
        ac_storage = os.path.join(storagepath, 'accesscodes')
        if not os.path.exists(ac_storage):
            os.mkdir(ac_storage)
        return ac_storage

    def getAccessCode(self, ac_id):
        """Get the AccessCode with ID ``ac_id`` or ``KeyError``.
        """
        return self[ac_id]

    def addAccessCode(self, num, pin):
        """Add an access-code.
        """
        ac = AccessCode(num, pin)
        ac.__parent__ = self
        self[ac.representation] = ac
        return

    def createCSVLogFile(self):
        """Create a CSV file with data in batch.

        Data will not contain invalidation date nor student ids.  File
        will be created in ``accesscodes`` subdir of data center
        storage path.

        Returns name of created file.
        """
        date = self.creation_date.strftime('%Y_%m_%d_%H_%M_%S')
        ac_storage = self._getStoragePath()
        csv_path = os.path.join(
            ac_storage, '%s-%s-%s-%s.csv' % (
                self.prefix, self.num, date, self.creator)
            )
        writer = csv.writer(open(csv_path, 'w'), quoting=csv.QUOTE_ALL)
        writer.writerow(['serial', 'ac', 'cost'])
        writer.writerow([self.prefix, str(self.num), "%0.2f" % self.cost])

        for value in sorted(self.values(),
                            cmp=lambda x, y: cmp(
                x.batch_serial, y.batch_serial)):
            writer.writerow(
                [str(value.batch_serial), str(value.representation)]
                )
        site = grok.getSite()
        logger = site.logger
        logger.info(
            "Created batch %s-%s" % (self.prefix, self.num))
        logger.info(
            "Written batch CSV to %s" % csv_path)
        return os.path.basename(csv_path)

    def archive(self):
        """Create a CSV file for archive.
        """
        ac_storage = self._getStoragePath()
        now = datetime.now()
        timestamp = now.strftime('%Y_%m_%d_%H_%M_%S')
        csv_path = os.path.join(
            ac_storage, '%s-%s_archive-%s-%s.csv' % (
                self.prefix, self.num, timestamp, self.creator)
            )
        writer = csv.writer(open(csv_path, 'w'), quoting=csv.QUOTE_ALL)
        writer.writerow(['prefix', 'serial', 'ac', 'used',
                         'disabled', 'history'])
        writer.writerow([self.prefix, '%0.2f' % self.cost, str(self.num),
                         str(self.entry_num)])
        for value in sorted(
            self.values(),
            cmp = lambda x, y: cmp(x.batch_serial, y.batch_serial)
            ):
            writer.writerow([
                    self.prefix, value.batch_serial, value.representation,
                    value.used and '1' or '0', value.disabled and '1' or '0',
                    value.history
                    ])
        return os.path.basename(csv_path)

    def search(self, searchterm, searchtype):
        if searchtype == 'serial':
            if len(self._entries) < searchterm + 1:
                return []
            return [self._entries[searchterm]]
        if searchtype == 'pin':
            try:
                entry = self.getAccessCode(searchterm)
                return [entry]
            except KeyError:
                return []

@grok.subscribe(IAccessCodeBatch, grok.IObjectAddedEvent)
def handle_batch_added(batch, event):
    # A (maybe dirty?) workaround to make batch containers work
    # without self-maintained acids: as batches should contain their
    # set of data immediately after creation, but we cannot add
    # subobjects as long as the batch was not added already to the
    # ZODB, we trigger the item creation for the time after the batch
    # was added to the ZODB.
    batch._createEntries()
    return


class AccessCodeBatchContainer(grok.Container):
    grok.implements(IAccessCodeBatchContainer)

    def _getStoragePath(self):
        """Get the directory, where batch import files are stored.
        """
        site = grok.getSite()
        storagepath = site['datacenter'].storage
        ac_storage = os.path.join(storagepath, 'accesscodes')
        import_path = os.path.join(ac_storage, 'imports')
        if not os.path.exists(import_path):
            os.mkdir(import_path)
        return import_path

    def addBatch(self, batch):
        """Add a batch.
        """
        batch.num = self.getNum(batch.prefix)
        key = "%s-%s" % (batch.prefix, batch.num)
        self[key] = batch
        self._p_changed = True

    def createBatch(self, creation_date, creator, prefix, cost,
                    entry_num):
        """Create and add a batch.
        """
        batch_num = self.getNum(prefix)
        batch = AccessCodeBatch(creation_date, creator, prefix,
                                cost, entry_num, num=batch_num)
        self.addBatch(batch)
        return batch

    def getNum(self, prefix):
        """Get next unused num for given prefix.
        """
        num = 1
        while self.get('%s-%s' % (prefix, num), None) is not None:
            num += 1
        return num

    def getImportFiles(self):
        """Return a generator with basenames of available import files.
        """
        path = self._getStoragePath()
        for filename in sorted(os.listdir(path)):
            yield filename

    def reimport(self, filename, creator=u'UNKNOWN'):
        """Reimport a batch given in CSV file.

        CSV file must be of format as generated by createCSVLogFile
        method.
        """
        path = os.path.join(self._getStoragePath(), filename)
        reader = csv.DictReader(open(path, 'rb'), quoting=csv.QUOTE_ALL)
        entry = reader.next()
        cost = float(entry['cost'])
        num = int(entry['ac'])
        batch_name = '%s-%s' % (entry['serial'], num)
        if batch_name in self.keys():
            raise KeyError('Batch already exists: %s' % batch_name)
        #batch = AccessCodeBatch(
        #    datetime.now(), creator, entry['serial'], cost, 0, num=num)
        batch = AccessCodeBatch(
            datetime.now(), creator, entry['serial'], cost, 0, num=0)
        num_entries = 0
        self[batch_name] = batch
        for row in reader:
            pin = row['ac']
            serial = int(row['serial'])
            rand_num = pin.rsplit('-', 1)[-1]
            batch.addAccessCode(serial, rand_num)
            num_entries += 1
        batch.entry_num = num_entries

        batch.createCSVLogFile()
        return

    def search(self, searchterm, searchtype, ):
        """Look for access-codes that comply with the given params.
        """
        results = []
        if searchtype == 'serial':
            try:
                searchterm = int(searchterm)
            except:
                return []
        for batchname in self.keys():
            part_result = self[batchname].search(searchterm, searchtype)
            results.extend(part_result)
        return results

    def getAccessCode(self, ac_id):
        """Get the AccessCode with ID ``ac_id`` or ``KeyError``.
        """
        for batchname in self.keys():
            batch = self[batchname]
            try:
                return batch.getAccessCode(ac_id)
            except KeyError:
                continue
        return None

    def disable(self, ac_id, user_id):
        """Disable the AC with ID ``ac_id``.

        ``user_id`` is the user ID of the user triggering the
        process. Already disabled ACs are left untouched.
        """
        ac = self.getAccessCode(ac_id)
        if ac is None:
            return
        ac.__parent__.disable(ac_id, user_id)
        return

    def enable(self, ac_id):
        """(Re-)enable the AC with ID ``ac_id``.

        This leaves the given AC in state ``unused``. Already enabled
        ACs are left untouched.
        """
        ac = self.getAccessCode(ac_id)
        if ac is None:
            return
        ac.__parent__.enable(ac_id)
        return

    def invalidate(self, ac_id):
        """Invalidate the AC with ID ``ac_id``.
        """
        ac = self.getAccessCode(ac_id)
        if ac is None:
            return
        ac.__parent__.invalidate(ac_id)
        return


class AccessCodePlugin(grok.GlobalUtility):
    grok.name('accesscodes')
    grok.implements(IWAeUPSIRPPluggable)

    def setup(self, site, name, logger):
        site['accesscodes'] = AccessCodeBatchContainer()
        logger.info('Installed container for access code batches.')
        return

    def update(self, site, name, logger):
        if not 'accesscodes' in site.keys():
            logger.info('Updating site at %s. Installing access codes.' % (
                    site,))
            self.setup(site, name, logger)
        else:
            logger.info(
                'AccessCodePlugin: Updating site at %s: Nothing to do.' % (
                    site, ))
        return

def get_access_code(access_code):
    """Get an access code instance.

    An access code here is a string like ``PUDE-1-1234567890``.

    Returns ``None`` if the given code cannot be found.

    This is a convenicence function that is faster than looking up a
    batch container for the approriate access code.
    """
    site = grok.getSite()
    if not isinstance(access_code, basestring):
        return None
    try:
        batch_id, ac_id = access_code.rsplit('-', 1)
    except:
        return None
    batch = site['accesscodes'].get(batch_id, None)
    if batch is None:
        return None
    try:
        code = batch.getAccessCode(access_code)
    except KeyError:
        return None
    return code

def fire_transition(access_code, arg, toward=False, comment=None):
    """Fire workflow transition for access code.

    The access code instance is looked up via `access_code` (a string
    like ``APP-1-12345678``).

    `arg` tells what kind of transition to trigger. This will be a
    transition id like ``'use'`` or ``'init'``, or some transition
    target like :var:`waeup.sirp.accesscodes.workflow.INITIALIZED`.

    If `toward` is ``False`` (the default) you have to pass a
    transition id as `arg`, otherwise you must give a transition
    target.

    If `comment` is specified (default is ``None``) the given string
    will be passed along as transition comment. It will appear in the
    history of the changed access code. You can use this to place
    remarks like for which object the access code was used or similar.

    :func:`fire_transition` might raise exceptions depending on the
    reason why the requested transition cannot be performed.

    The following exceptions can occur during processing:

    :exc:`KeyError`:
      signals not existent access code, batch or site.

    :exc:`ValueError`:
      signals illegal format of `access_code` string. The regular format is
      ``APP-N-XXXXXXXX``.

    :exc:`hurry.workflow.interfaces.InvalidTransitionError`:
      the transition requested cannot be performed because the workflow
      rules forbid it.

    :exc:`Unauthorized`:
      the current user is not allowed to perform the requested transition.

    """
    try:
        batch_id, ac_id = access_code.rsplit('-', 1)
    except ValueError:
        raise ValueError(
            'Invalid access code format: %s (use: APP-N-XXXXXXXX)' % (
                access_code,))
    try:
        ac = grok.getSite()['accesscodes'][batch_id].getAccessCode(access_code)
    except TypeError:
        raise KeyError(
            'No site available for looking up accesscodes')
    info = IWorkflowInfo(ac)
    if toward:
        info.fireTransitionToward(arg, comment=comment)
    else:
        info.fireTransition(arg, comment=comment)
    return True

def invalidate_accesscode(access_code, comment=None):
    """Invalidate AccessCode denoted by string ``access_code``.

    Fires an appropriate transition to perform the task.

    `comment` is a string that will appear in the access code
    history.

    See :func:`fire_transition` for possible exceptions and their
    meanings.
    """
    return fire_transition(access_code, 'use', comment=comment)

def disable_accesscode(access_code, comment=None):
    """Disable AccessCode denoted by string ``access_code``.

    Fires an appropriate transition to perform the task.

    `comment` is a string that will appear in the access code
    history.

    See :func:`fire_transition` for possible exceptions and their
    meanings.
    """
    return fire_transition(
        access_code, DISABLED, toward=True, comment=comment)

def reenable_accesscode(access_code, comment=None):
    """Reenable AccessCode denoted by string ``access_code``.

    Fires an appropriate transition to perform the task.

    `comment` is a string that will appear in the access code
    history.

    See :func:`fire_transition` for possible exceptions and their
    meanings.
    """
    return fire_transition(access_code, 'reenable', comment=comment)