"""
In this file you'll find functions used to load initial data in a safe and django way,
plus some tools to check and repair your DB.

See doc/DESIGN.txt for caveats about database
"""
import traceback
import os
import shutil
import random
import string

from django.core.exceptions import ObjectDoesNotExist, ValidationError
from django.contrib.auth.models import User
from django.db.utils import DatabaseError
from django.core.files import File
from django.core.files.base import ContentFile
from django.utils.importlib import import_module

import twistranet
from twistranet.twistapp.models import *
from twistranet.twistapp.lib import permissions
from twistranet.twistapp.lib.slugify import slugify
from twistranet.twistapp.lib.log import *

from django.conf import settings

def repair():
    """
    Repair a possibly damaged database.
    For example, incomplete fixtures can be a problem; use this to repair.
    We use that before launching tests. We should one day export a well-formed test fixture...
    
    Warning: can be very slow on a normal system!
    
    Will not erase data it doesn't know how to handle.
    """
    # Login
    __account__ = SystemAccount.objects.get()
    
    # Put all Django admin users inside the first admin community
    django_admins = UserAccount.objects.filter(user__is_superuser = True)
    admin_community = AdminCommunity.objects.get()
    for user in django_admins:
        if not admin_community in user.communities:
            admin_community.join(user, is_manager = True)


def bootstrap():
    """
    Load initial data if it's not present.
    This method is SAFE, ie. it won't destroy any existing data, only add missing stuff`.
    
    This should be called every time twistranet is started!
    """
    try:
        # Let's log in.
        __account__ = SystemAccount.objects.__booster__.get()
    except SystemAccount.DoesNotExist:
        log.info("No SystemAccount available. That means this instance has never been bootstraped, so let's do it now.")
        raise RuntimeError("Please sync your databases with 'manage.py syncdb' before bootstraping.")
    except:
        # Default fixture probably not installed yet. Don't do anything yet.
        log.info("DatabaseError while bootstraping. Your tables are probably not created yet.")
        traceback.print_exc()
        return

    # Now create the bootstrap / default / help fixture objects.
    # Import your fixture there, if you don't do so they may not be importable.
    from twistranet.fixtures.bootstrap import FIXTURES as BOOTSTRAP_FIXTURES
    from twistranet.fixtures.help_en import FIXTURES as HELP_EN_FIXTURES
    # XXX TODO: Make a fixture registry? Or fix fixture import someway?
    try:
        from twistrans.fixtures.help_fr import FIXTURES as HELP_FR_FIXTURES
        from twistrans.fixtures.bootstrap_fr import FIXTURES as BOOTSTRAP_FR_FIXTURES
    except ImportError:
        HELP_FR_FIXTURES = []
        BOOTSTRAP_FR_FIXTURES = []
        log.info("twistrans not installed, translations are not installed.")
    
    # Load fixtures
    for obj in BOOTSTRAP_FIXTURES:          obj.apply()

    # Special treatment for bootstrap: Set the GlobalCommunity owner = AdminCommunity
    glob = GlobalCommunity.objects.get()
    admin_cty = AdminCommunity.objects.get()
    glob.owner = admin_cty
    glob.publisher = glob
    glob.save()
    admin_cty.publisher = glob
    admin_cty.save()

    # Create default resources by associating them to the SystemAccount and publishing them on GlobalCommunity.
    default_resources_dir = os.path.abspath(
        os.path.join(
            os.path.split(twistranet.__file__)[0],
            'fixtures',
            'resources',
        )
    )
    log.debug("Default res. dir: %s" % default_resources_dir)
    for root, dirs, files in os.walk(default_resources_dir):
        for fname in files:
            slug = os.path.splitext(os.path.split(fname)[1])[0]
            objects = Resource.objects.filter(slug = slug)
            if objects:
                if len(objects) > 1:
                    raise IntegrityError("More than one resource with '%s' slug" % slug)
                r = objects[0]
            else:
                r = Resource()
    
            # Copy file to its actual location with the storage API
            source_fn = os.path.join(root, fname)
            r.publisher = glob
            r.resource_file = File(open(source_fn, "rb"), fname)
            r.slug = slugify(slug)
            r.save()
        break   # XXX We don't handle subdirs yet.
    
    # Set SystemAccount picture (which is a way to check if things are working properly).
    __account__.picture = Resource.objects.get(slug = "default_tn_picture")
    __account__.save()

    # Install HELP fixture.
    for obj in HELP_EN_FIXTURES:            obj.apply()
        
    # Have we got an admin account? If not, we generate one now.
    django_admins = UserAccount.objects.filter(user__is_superuser = True)
    admin_password = None
    if not django_admins.exists():
        admin_password = ""
        for i in range(6):
            admin_password = "%s%s" % (admin_password, random.choice(string.lowercase + string.digits))
        admin = User.objects.create(
            username = settings.TWISTRANET_DEFAULT_ADMIN_USERNAME,
            first_name = settings.TWISTRANET_DEFAULT_ADMIN_FIRSTNAME,
            last_name = settings.TWISTRANET_DEFAULT_ADMIN_LASTNAME,
            email = settings.TWISTRANET_ADMIN_EMAIL,
            is_superuser = True,
        )
        admin.set_password(admin_password)
        admin.save()
        
    # Sample data only imported if asked to in settings.py
    if settings.TWISTRANET_IMPORT_SAMPLE_DATA:
        from twistranet.fixtures import sample
        sample.create_users()
        for obj in sample.get_fixtures():
            obj.apply()
        
        # Add relations bwn sample users
        # A <=> admin
        # B  => admin
        # A = UserAccount.objects.get(slug = "a")
        # B = UserAccount.objects.get(slug = "b")
        # admin = UserAccount.objects.get(slug = "admin")
        # A.follow(admin)
        # admin.follow(A)
        # B.follow(admin)
        
    # Import COGIP sample (if requested)
    if settings.TWISTRANET_IMPORT_COGIP:
        from twistranet.fixtures.cogip import load_cogip
        # We disable email sending
        backup_EMAIL_BACKEND = settings.EMAIL_BACKEND
        settings.EMAIL_BACKEND = 'django.core.mail.backends.dummy.EmailBackend'
        load_cogip()
        settings.EMAIL_BACKEND = backup_EMAIL_BACKEND

    # Repair permissions
    repair()
    
    # Display admin password
    if admin_password is not None:
        print "\n\n" \
            "  You can now run your server with 'manage.py runserver'.\n" \
            "  Your initial administrator login/password are '%s / %s'" % (settings.TWISTRANET_DEFAULT_ADMIN_USERNAME, admin_password)
    

def check_consistancy():
    """
    Check DB consistancy.
    This method is SAFE (doesn't write anything) but is blocking if a problem is detected.
    """
    # XXX Check that there's 1! global community
    # XXX Check that there's 1! admin community
    
