"""Components to handle access codes.
"""
import csv
import grok
import os
from random import SystemRandom as random
from waeup.sirp.interfaces import IWAeUPSIRPPluggable
from waeup.sirp.accesscodes.interfaces import (
    IAccessCode, IAccessCodeBatch, IAccessCodeBatchContainer
    )

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

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

    def __init__(self, batch_serial, random_num, cost,
                 invalidation_date=None, student_id=None):
        self.batch_serial = batch_serial
        self.random_num = random_num
        self.cost = cost
        self.invalidation_date = invalidation_date
        self.student_id = student_id

    @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

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
        self.cost = cost
        self.entry_num = entry_num
        self.num = num

    def createEntries(self):
        """Create the entries for this batch.
        """
        rands = self.getNewRandomNum(num=self.entry_num)
        for num in range(self.entry_num):
            ac = AccessCode(num, rands[num], self.cost)
            self[str(num)] = ac
        return
        
    def getNewRandomNum(self, num=1):
        """Create a set of ``num`` random numbers of 10 digits each.

        The number is returned as string.
        """
        results = {}
        while len(results) < num:
            pin = ''
            for x in range(10):
                pin += str(random().randint(0, 9))
            results[pin] = True
        return results.keys()

    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.
        """
        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)
        date = self.creation_date.strftime('%Y_%m_%d_%H_%M_%S')
        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 key, value in self.items():
            writer.writerow(
                [str(value.batch_serial), str(value.representation)]
                )
        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)

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

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

    def getNum(self, prefix):
        """Get next unused num for given prefix.
        """
        num = 1
        prefix = prefix.upper()
        while self.get('%s-%s' % (prefix, num), None):
            num += 1
        return num

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