# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4


from datetime import datetime
import json

import sqlalchemy as sa
from sqlalchemy.sql.expression import text

from utils import datetime2ts, ts2datetime
from websocket import trigger_event
import db
import settings
import state

import logging
logger = logging.getLogger(__name__)

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
        editpeer              peerid {username: string, contact: string}
    '''
    __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, **kwargs):
        commit = True
        if '_commit' in kwargs:
            commit = kwargs['_commit']
            del kwargs['_commit']
        if '_ts' in kwargs:
            timestamp = kwargs['_ts']
            del kwargs['_ts']
        else:
            timestamp = None
        c = cls()
        c.created = datetime.utcnow()
        if not timestamp:
            timestamp = c.created
        c.timestamp = datetime2ts(timestamp)
        c.user_id = user.id
        c.revision = cls.query.filter_by(user_id=user.id).count()
        c.data = json.dumps([action] + list(args), ensure_ascii=False)
        _data = str(c.revision) + str(c.timestamp) + c.data
        _data = _data.encode()
        state.db.session.add(c)
        if commit:
            state.db.session.commit()
        logger.debug('record change: %s', c.json())

    @classmethod
    def apply_changes(cls, user_, changes, first=False):
        from user.models import User
        user = user_
        trigger = changes
        if trigger:
            trigger_event('change', {})
        if first:
            items = set()
            lists = {}
            peers = set()
            for change in changes:
                if change[2][0] == 'additem':
                    items.add(change[2][1])
                if change[2][0] == 'addlist':
                    lists[change[2][1]] = set()
                if change[2][0] == 'addlistitems':
                    if not change[2][1] in lists:
                        lists[change[2][1]] = set()
                    for i in change[2][2]:
                        lists[change[2][1]].add(i)
                if change[2][0] == 'addpeer':
                    peers.add(change[2][1])
            for i in user.library.items:
                if i.id not in items and user in i.users:
                    i.users.remove(user)
                    if i.users:
                        i.update()
                    else:
                        i.delete()
            for name in lists:
                qs = user.lists.filter_by(name=name)
                if qs.count():
                    l = qs[0]
                    for i in l.get_items():
                        if i.id not in lists[name]:
                            if i.id in l.items:
                                l.items.remove(i.id)
            for peer in User.query:
                if user.id in peer.info.get('users', {}) and peer.id not in peers:
                    del peer.info['users'][user.id]
                    peer.save()

        for change in changes:
            if state.shutdown:
                return False
            if user.id in state.removepeer:
                del state.removepeer[user.id]
                return False
            if not cls.apply_change(user, change, trigger=False):
                logger.debug('FAIL %s', change)
                trigger = False
                break
                return False
        if trigger:
            trigger_event('change', {})
        return True

    @classmethod
    def apply_change(cls, user, change, trigger=True):
        revision, timestamp, data = change
        last = cls.query.filter_by(user_id=user.id).order_by(text('-revision')).first()
        next_revision = last.revision + 1 if last else 0
        if revision >= next_revision:
            c = cls()
            c.created = datetime.utcnow()
            c.timestamp = timestamp
            c.user_id = user.id
            c.revision = revision
            c.data = json.dumps(data)
            logger.debug('apply change from %s: %s(%s)', user.name, data[0], data[1:])
            if getattr(c, 'action_' + data[0])(user, timestamp, *data[1:]):
                logger.debug('change applied')
                state.db.session.add(c)
                state.db.session.commit()
                if trigger:
                    trigger_event('change', {})
                return True
            else:
                logger.debug('could not apply change')
        else:
            logger.debug('revsion does not match! got %s expecting %s', revision, next_revision)
            return False

    def __repr__(self):
        return self.data

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


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

    def action_edititem(self, user, timestamp, itemid, meta):
        from user.models import Metadata
        m = Metadata.get_or_create(user.id, itemid)
        m.edit(meta, modified=ts2datetime(timestamp))
        from item.models import Item
        i = Item.get(itemid)
        if i:
            i.sync_metadata()
            if state.tasks:
                #state.tasks.queue('syncmetadata', [i.id])
                state.tasks.queue('getpreview', i.id)
        return True

    def action_removeitem(self, user, timestamp, itemid):
        from item.models import Item
        from user.models import Metadata
        i = Item.get(itemid)
        if i:
            if user in i.users:
                i.users.remove(user)
            if i.users:
                i.update()
            else:
                i.delete()
        Metadata.query.filter_by(user_id=user.id, item_id=itemid).delete()
        return True

    def action_addlist(self, user, timestamp, name, query=None):
        from user.models import List
        if name == '':
            return True
        l = List.get_or_create(user.id, name)
        trigger_event('addlist', {'id': l.public_id, 'user': user.id})
        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()
        trigger_event('editlist', {'id': l.public_id, 'user': user.id})
        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
        trigger_event('orderlists', {'user': user.id})
        return True

    def action_removelist(self, user, timestamp, name):
        from user.models import List
        l = List.get(user.id, name)
        if l:
            l.remove()
        trigger_event('removelist', {'id': l.public_id})
        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)
            Changelog.record(state.user(), 'editpeer', self.id, self.json(['username']))
        user.save()
        return True

    def action_editcontact(self, user, timestamp, contact):
        if user.info.get('contact') != contact:
            user.info['contact'] = contact
            user.save()
            Changelog.record(state.user(), 'editpeer', user.id, user.json(['contact']))
        return True

    def action_addpeer(self, user, timestamp, peerid, username):
        if len(peerid) == 16:
            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_editpeer(self, user, timestamp, peerid, data):
        if len(peerid) == 16:
            from user.models import User
            peer = User.get_or_create(peerid)
            update = False
            if not peer.peered:
                for key in ('username', 'contact'):
                    if key in data and peer.info.get(key) != data[key]:
                        peer.info[key] = data[key]
                        update = True
            if update:
                peer.save()
        return True

    @classmethod
    def aggregated_changes(cls, since=None, user_id=None):
        from item.models import Item
        from user.models import List
        from user.models import User
        if not user_id:
            user_id = settings.USER_ID
        qs = cls.query.filter_by(user_id=user_id)
        qs = Changelog.query.filter_by(user_id=user_id)
        if since:
            qs = qs.filter(Changelog.revision>=since)
        changes = {}
        orderlists = False
        editcontact = False
        editusername = False
        for c in qs.order_by('timestamp'):
            revision = c.revision
            timestamp = c.timestamp
            data = json.loads(c.data)
            op = data[0]
            if op in ('editmeta', 'resetmeta'):
                continue
            action = changes.setdefault(op, {})
            if op == 'additem':
                item_id = data[1]
                info = data[2]
                action[item_id] = [revision, timestamp, info]
                if item_id in changes.get('removeitem', []):
                    del changes['removeitem'][item_id]
                i = Item.get(item_id)
                if i:
                    changes.setdefault('edititem', {})[item_id] = [revision+1, timestamp, i.meta]
            elif op == 'edititem':
                item_id = data[1]
                meta = data[2]
                if not item_id in action:
                    action[item_id] = [revision, timestamp, meta]
                else:
                    action[item_id][0] = revision
                    action[item_id][1] = timestamp
                    action[item_id][2].update(meta)
            elif op == 'removeitem':
                item_id = data[1]
                if item_id in changes.get('additem', []):
                    del changes['additem'][item_id]
                else:
                    action[item_id] = [revision, timestamp]
                if item_id in changes.get('edititem', []):
                    del changes['edititem'][item_id]
            elif op == 'addlist':
                list_id = data[1]
                if list_id:
                    ids = data[2] if len(data) > 2 else []
                    action[list_id] = [revision, timestamp, ids]
            elif op == 'editlist':
                old_id = data[1]
                new_id = data[2]['name']
                r = revision
                if old_id not in changes.get('addlist', []):
                    action[old_id] = [revision, timestamp, {'name': new_id}]
                    r += 1
                for a in ('addlist', 'addlistitems', 'removelistitems'):
                    if a in changes and old_id in changes[a]:
                        changes[a][new_id] = changes[a].pop(old_id)
                        changes[a][new_id][0] = r
            elif op == 'orderlists':
                orderlists = True
            elif op == 'removelist':
                list_id = data[1]
                if list_id not in changes.get('addlist', []):
                    action[list_id] = [revision, timestamp]
                for a in ('addlist', 'addlistitems', 'removelistitems'):
                    if a in changes and list_id in changes[a]:
                        del changes[a][list_id]
            elif op == 'addlistitems':
                list_id = data[1]
                if not list_id:
                    continue
                listitems = data[2]
                if list_id not in action:
                    action[list_id] = [revision, timestamp, []]
                action[list_id][0] = revision
                action[list_id][1] = timestamp
                action[list_id][2] += listitems
                #remove from removelistitems!
                if list_id in changes.get('remvelistitems', {}):
                    changes['remvelistitems'][list_id] = [
                        i for i in changes['remvelistitems'][list_id] if i not in listitems
                    ]
            elif op == 'removelistitems':
                list_id = data[1]
                listitems = data[2]
                #remove from additemlists
                removed = []
                if list_id in changes.get('addlistitems',{}):
                    removed = [
                        i for i in changes['addlistitems'][list_id] if i in listitems
                    ]
                    changes['addlistitems'][list_id] = [
                        i for i in changes['addlistitems'][list_id] if i not in listitems
                    ]
                #remove remaining items
                listitems = [
                    i for i in listitems if i not in removed
                ]
                if listitems:
                    action[list_id] = [revision, timestamp, listitems]
            elif op == 'editusername':
                editusername = True
            elif op == 'editcontact':
                editcontact = True
            elif op == 'addpeer':
                peer_id = data[1]
                username = data[2]
                if len(peer_id) == 16:
                    peer = User.get(peer_id)
                    if peer:
                        username = peer.json().get('username', 'anonymous')
                    action[peer_id] = [revision, timestamp, username]
                    if peer_id in changes.get('removepeer', []):
                        del changes['removepeer'][peer_id]
            elif op == 'removepeer':
                peer_id = data[1]
                if peer_id in changes.get('addpeer', []):
                    del changes['addpeer'][peer_id]
                else:
                    action[peer_id] = [revision, timestamp]
            elif op == 'editpeer':
                peer_id = data[1]
                if not peer_id in action:
                    peer = User.get(peer_id)
                    if peer:
                        data = peer.json(['username', 'contact'])
                        action[peer_id] = [revision, timestamp, data]
            else:
                logger.debug('unknonw action %s', data)
        _changes = []
        for op in list(changes):
            if not changes[op]:
                del changes[op]
            else:
                for id in changes[op]:
                    data = changes[op][id]
                    rv = data[0]
                    ts = data[1]
                    data = [op, id] + data[2:]
                    _changes.append([rv, ts, data])
        _changes.sort(key=lambda change: (change[0], change[1]))
        if orderlists:
            ids = [l.name for l in List.query.filter_by(user_id=user_id,type='static').order_by('index_') if l.name]
            if len(ids) > 1:
                _changes.append([-1, timestamp, ['orderlists', ids]])
        userinfo = state.user().json()
        if editusername:
            _changes.append([-1, timestamp, ['editusername', userinfo['username']]])
        if editcontact:
            _changes.append([-1, timestamp, ['editcontact', userinfo['contact']]])
        if _changes:
            r = revision
            for c in reversed(_changes):
                c[0] = r
                r -= 1
        return _changes