# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4
from __future__ import division

import logging

import json
from datetime import datetime

from utils import valid, datetime2ts, ts2datetime

import settings
import db
import sqlalchemy as sa
import state
from websocket import trigger_event

logger = logging.getLogger('oml.changelog')

class Changelog(db.Model):
    '''
        additem               itemid    metadata from file (info) + OLID
        edititem              itemid    name->id (i.e. olid-> OL...M)
        removeitem            itemid
        addlist               name
        editlist              name {name: newname}
        orderlists            [name, name, name]
        removelist            name
        addlistitems          listname [ids]
        removelistitems       listname [ids]
        editusername          username
        editcontact           string
        addpeer               peerid peername
        removepeer            peerid peername

        editmeta              key, value data (i.e. 'isbn', '0000000000', {title: 'Example'})
        resetmeta             key, value
    '''
    __tablename__ = 'changelog'
    id = sa.Column(sa.Integer(), primary_key=True)

    created = sa.Column(sa.DateTime())
    timestamp = sa.Column(sa.BigInteger())

    user_id = sa.Column(sa.String(43))
    revision = sa.Column(sa.BigInteger())
    data = sa.Column(sa.Text())
    sig = sa.Column(sa.String(96))

    @classmethod
    def record(cls, user, action, *args):
        c = cls()
        c.created = datetime.utcnow()
        c.timestamp = datetime2ts(c.created)
        c.user_id = user.id
        c.revision = cls.query.filter_by(user_id=user.id).count()
        c.data = json.dumps([action] + list(args))
        _data = str(c.revision) + str(c.timestamp) + c.data
        c.sig = settings.sk.sign(_data, encoding='base64')
        db.session.add(c)
        db.session.commit()
        if state.nodes:
            state.nodes.queue('peered', 'pushChanges', [c.json()])

    @classmethod
    def apply_changes(cls, user, changes):
        for change in changes:
            if not Changelog.apply_change(user, change, trigger=False):
                logger.debug('FAIL %s', change)
                break
                return False
        if changes:
            trigger_event('change', {});
        return True

    @classmethod
    def apply_change(cls, user, change, rebuild=False, trigger=True):
        revision, timestamp, sig, data = change
        last = Changelog.query.filter_by(user_id=user.id).order_by('-revision').first()
        next_revision = last.revision + 1 if last else 0
        if revision == next_revision:
            _data = str(revision) + str(timestamp) + data
            if rebuild:
                sig = settings.sk.sign(_data, encoding='base64')
            if valid(user.id, _data, sig):
                c = cls()
                c.created = datetime.utcnow()
                c.timestamp = timestamp
                c.user_id = user.id
                c.revision = revision
                c.data = data
                c.sig = sig
                args = json.loads(data)
                logger.debug('apply change from %s: %s', user.name, args)
                if getattr(c, 'action_' + args[0])(user, timestamp, *args[1:]):
                    logger.debug('change applied')
                    db.session.add(c)
                    db.session.commit()
                    if trigger:
                        trigger_event('change', {});
                    return True
            else:
                logger.debug('INVLAID SIGNATURE ON CHANGE %s', change)
                raise Exception, 'invalid signature'
        else:
            logger.debug('revsion does not match! got %s expecting %s', revision, next_revision)
            return False

    def __repr__(self):
        return self.data

    def verify(self):
        _data = str(self.revision) + str(self.timestamp) + self.data
        return valid(self.user_id, _data, self.sig)

    @classmethod
    def _rebuild(cls):
        for c in cls.query.filter_by(user_id=settings.USER_ID):
            _data = str(c.revision) + str(c.timestamp) + c.data
            c.sig = settings.sk.sign(_data, encoding='base64')
            db.session.add(c)
        db.session.commit()

    def json(self):
        timestamp = self.timestamp or datetime2ts(self.created)
        return [self.revision, timestamp, self.sig, self.data]

    @classmethod
    def restore(cls, user_id, path=None):
        from user.models import User
        user = User.get_or_create(user_id)
        if not path:
            path = '/tmp/oml_changelog_%s.json' % user_id
        with open(path, 'r') as fd:
            for change in fd:
                change = json.loads(change)
                cls.apply_change(user, change, user_id == settings.USER_ID)

    @classmethod
    def export(cls, user_id, path=None):
        if not path:
            path = '/tmp/oml_changelog_%s.json' % user_id
        with open(path, 'w') as fd:
            for c in cls.query.filter_by(user_id=user_id).order_by('revision'):
                fd.write(json.dumps(c.json()) + '\n')

    def action_additem(self, user, timestamp, itemid, info):
        from item.models import Item
        i = Item.get(itemid)
        if i and i.timestamp > timestamp:
            if user not in i.users:
                i.users.append(user)
                i.update()
            return True
        if not i:
            i = Item.get_or_create(itemid, info)
            i.modified = ts2datetime(timestamp)
        if user not in i.users:
            i.users.append(user)
        i.update()
        return True

    def action_edititem(self, user, timestamp, itemid, meta):
        from item.models import Item
        i = Item.get(itemid)
        if not i:
            logger.debug('ignore edititem for unknown item %s %s', timestamp, itemid)
            return True
        if i.timestamp > timestamp:
            logger.debug('ignore edititem change %s %s %s', timestamp, itemid, meta)
            return True
        keys = filter(lambda k: k in Item.id_keys, meta.keys())
        if keys:
            key = keys[0]
            primary = [key, meta[key]]
            if not meta[key] and i.meta.get('primaryid', [''])[0] == key:
                logger.debug('remove id mapping %s %s', i.id, primary)
                i.update_primaryid(*primary)
                i.modified = ts2datetime(timestamp)
            elif meta[key] and i.meta.get('primaryid') != primary:
                logger.debug('edit mapping %s %s', i.id, primary)
                i.update_primaryid(*primary)
                i.modified = ts2datetime(timestamp)
        else:
            if 'primaryid' in i.meta:
                return True
            i.update_meta(meta)
            i.modified = ts2datetime(timestamp)
        i.save()
        return True

    def action_removeitem(self, user, timestamp, itemid):
        from item.models import Item
        i = Item.get(itemid)
        if not i or i.timestamp > timestamp:
            return True
        if user in i.users:
            i.users.remove(user)
        if i.users:
            i.update()
        else:
            i.delete()
        return True

    def action_addlist(self, user, timestamp, name, query=None):
        from user.models import List
        l = List.create(user.id, name)
        return True

    def action_editlist(self, user, timestamp, name, new):
        from user.models import List
        l = List.get_or_create(user.id, name)
        if 'name' in new:
            l.name = new['name']
        l.save()
        return True

    def action_orderlists(self, user, timestamp, lists):
        from user.models import List
        idx = 0
        for name in lists:
            l = List.get_or_create(user.id, name)
            l.index_ = idx
            l.save()
            idx += 1
        return True

    def action_removelist(self, user, timestamp, name):
        from user.models import List
        l = List.get(user.id, name)
        if l:
            l.remove()
        return True

    def action_addlistitems(self, user, timestamp, name, ids):
        from user.models import List
        l = List.get_or_create(user.id, name)
        l.add_items(ids)
        return True

    def action_removelistitems(self, user, timestamp, name, ids):
        from user.models import List
        l = List.get(user.id, name)
        if l:
            l.remove_items(ids)
        return True

    def action_editusername(self, user, timestamp, username):
        from user.models import List
        old = user.nickname
        user.info['username'] = username
        user.update_name()
        if old != user.nickname:
            List.rename_user(old, user.nickname)
        user.save()
        return True

    def action_editcontact(self, user, timestamp, contact):
        user.info['contact'] = contact
        user.save()
        return True

    def action_addpeer(self, user, timestamp, peerid, username):
        from user.models import User
        if not 'users' in user.info:
            user.info['users'] = {}
        user.info['users'][peerid] = username
        user.save()
        peer = User.get_or_create(peerid)
        if not 'username' in peer.info:
            peer.info['username'] = username
            peer.update_name()
            peer.save()
        return True

    def action_removepeer(self, user, timestamp, peerid):
        if 'users' in user.info and peerid in user.info['users']:
            del user.info['users'][peerid]
            user.save()
            #fixme, remove from User table if no other connection exists
        return True

    def action_editmeta(self, user, timestamp, key, value, data):
        from item.models import Metadata
        m = Metadata.get(key, value)
        if not m or m.timestamp < timestamp:
            if not m:
                m = Metadata.get_or_create(key, value)
            if m.edit(data):
                m.update_items()
        return True

    def action_resetmeta(self, user, timestamp, key, value):
        from item.models import Metadata
        m = Metadata.get(key, value)
        if m and m.timestamp < timestamp:
            m.reset()
        return True