# Copyright 2014 OpenStack Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import sqlalchemy
from sqlalchemy import create_engine, MetaData, Table, Column, Integer, String, Boolean, DateTime, Text, select, func
from sqlalchemy.schema import ForeignKey
from sqlalchemy.orm import mapper, sessionmaker, relationship, column_property, scoped_session
from sqlalchemy.orm.session import Session
from sqlalchemy.sql.expression import and_

metadata = MetaData()
project_table = Table(
    'project', metadata,
    Column('key', Integer, primary_key=True),
    Column('name', String(255), index=True, unique=True, nullable=False),
    Column('subscribed', Boolean, index=True, default=False),
    Column('description', Text, nullable=False, default=''),
    )
change_table = Table(
    'change', metadata,
    Column('key', Integer, primary_key=True),
    Column('project_key', Integer, ForeignKey("project.key"), index=True),
    Column('id', String(255), index=True, unique=True, nullable=False),
    Column('number', Integer, index=True, unique=True, nullable=False),
    Column('branch', String(255), index=True, nullable=False),
    Column('change_id', String(255), index=True, nullable=False),
    Column('topic', String(255), index=True),
    Column('owner', String(255), index=True),
    Column('subject', Text, nullable=False),
    Column('created', DateTime, index=True, nullable=False),
    Column('updated', DateTime, index=True, nullable=False),
    Column('status', String(8), index=True, nullable=False),
    Column('hidden', Boolean, index=True, nullable=False),
    Column('reviewed', Boolean, index=True, nullable=False),
    )
revision_table = Table(
    'revision', metadata,
    Column('key', Integer, primary_key=True),
    Column('change_key', Integer, ForeignKey("change.key"), index=True),
    Column('number', Integer, index=True, nullable=False),
    Column('message', Text, nullable=False),
    Column('commit', String(255), nullable=False),
    Column('parent', String(255), nullable=False),
    )
message_table = Table(
    'message', metadata,
    Column('key', Integer, primary_key=True),
    Column('revision_key', Integer, ForeignKey("revision.key"), index=True),
    Column('id', String(255), index=True), #, unique=True, nullable=False),
    Column('created', DateTime, index=True, nullable=False),
    Column('name', String(255)),
    Column('message', Text, nullable=False),
    Column('pending', Boolean, index=True, nullable=False),
    )
comment_table = Table(
    'comment', metadata,
    Column('key', Integer, primary_key=True),
    Column('revision_key', Integer, ForeignKey("revision.key"), index=True),
    Column('id', String(255), index=True), #, unique=True, nullable=False),
    Column('in_reply_to', String(255)),
    Column('created', DateTime, index=True, nullable=False),
    Column('name', String(255)),
    Column('file', Text, nullable=False),
    Column('parent', Boolean, nullable=False),
    Column('line', Integer),
    Column('message', Text, nullable=False),
    Column('pending', Boolean, index=True, nullable=False),
    )
label_table = Table(
    'label', metadata,
    Column('key', Integer, primary_key=True),
    Column('change_key', Integer, ForeignKey("change.key"), index=True),
    Column('category', String(255), nullable=False),
    Column('value', Integer, nullable=False),
    Column('description', String(255), nullable=False),
    )
permitted_label_table = Table(
    'permitted_label', metadata,
    Column('key', Integer, primary_key=True),
    Column('change_key', Integer, ForeignKey("change.key"), index=True),
    Column('category', String(255), nullable=False),
    Column('value', Integer, nullable=False),
    )
approval_table = Table(
    'approval', metadata,
    Column('key', Integer, primary_key=True),
    Column('change_key', Integer, ForeignKey("change.key"), index=True),
    Column('name', String(255)),
    Column('category', String(255), nullable=False),
    Column('value', Integer, nullable=False),
    Column('pending', Boolean, index=True, nullable=False),
    )


class Project(object):
    def __init__(self, name, subscribed=False, description=''):
        self.name = name
        self.subscribed = subscribed
        self.description = description

    def createChange(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        c = Change(*args, **kw)
        self.changes.append(c)
        session.add(c)
        session.flush()
        return c

class Change(object):
    def __init__(self, project, id, number, branch, change_id,
                 owner, subject, created, updated, status,
                 topic=False, hidden=False, reviewed=False):
        self.project_key = project.key
        self.id = id
        self.number = number
        self.branch = branch
        self.change_id = change_id
        self.topic = topic
        self.owner = owner
        self.subject = subject
        self.created = created
        self.updated = updated
        self.status = status
        self.hidden = hidden
        self.reviewed = reviewed

    def getCategories(self):
        categories = []
        for label in self.labels:
            if label.category in categories:
                continue
            categories.append(label.category)
        return categories

    def getMaxForCategory(self, category):
        if not hasattr(self, '_approval_cache'):
            self._updateApprovalCache()
        return self._approval_cache.get(category, 0)

    def _updateApprovalCache(self):
        cat_min = {}
        cat_max = {}
        cat_value = {}
        for approval in self.approvals:
            cur_min = cat_min.get(approval.category, 0)
            cur_max = cat_max.get(approval.category, 0)
            cur_min = min(approval.value, cur_min)
            cur_max = max(approval.value, cur_max)
            cat_min[approval.category] = cur_min
            cat_max[approval.category] = cur_max
            cur_value = cat_value.get(approval.category, 0)
            if abs(cur_min) > abs(cur_value):
                cur_value = cur_min
            if abs(cur_max) > abs(cur_value):
                cur_value = cur_max
            cat_value[approval.category] = cur_value
        self._approval_cache = cat_value

    def createRevision(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        r = Revision(*args, **kw)
        self.revisions.append(r)
        session.add(r)
        session.flush()
        return r

    def createLabel(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        l = Label(*args, **kw)
        self.labels.append(l)
        session.add(l)
        session.flush()
        return l

    def createApproval(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        l = Approval(*args, **kw)
        self.approvals.append(l)
        session.add(l)
        session.flush()
        return l

    def createPermittedLabel(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        l = PermittedLabel(*args, **kw)
        self.permitted_labels.append(l)
        session.add(l)
        session.flush()
        return l

class Revision(object):
    def __init__(self, change, number, message, commit, parent):
        self.change_key = change.key
        self.number = number
        self.message = message
        self.commit = commit
        self.parent = parent

    def createMessage(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        m = Message(*args, **kw)
        self.messages.append(m)
        session.add(m)
        session.flush()
        return m

    def createComment(self, *args, **kw):
        session = Session.object_session(self)
        args = [self] + list(args)
        c = Comment(*args, **kw)
        self.comments.append(c)
        session.add(c)
        session.flush()
        return c

class Message(object):
    def __init__(self, revision, id, created, name, message, pending=False):
        self.revision_key = revision.key
        self.id = id
        self.created = created
        self.name = name
        self.message = message
        self.pending = pending

class Comment(object):
    def __init__(self, revision, id, in_reply_to, created, name, file, parent, line, message, pending=False):
        self.revision_key = revision.key
        self.id = id
        self.in_reply_to = in_reply_to
        self.created = created
        self.name = name
        self.file = file
        self.parent = parent
        self.line = line
        self.message = message
        self.pending = pending

class Label(object):
    def __init__(self, change, category, value, description):
        self.change_key = change.key
        self.category = category
        self.value = value
        self.description = description

class PermittedLabel(object):
    def __init__(self, change, category, value):
        self.change_key = change.key
        self.category = category
        self.value = value

class Approval(object):
    def __init__(self, change, name, category, value, pending=False):
        self.change_key = change.key
        self.name = name
        self.category = category
        self.value = value
        self.pending = pending

mapper(Project, project_table, properties=dict(
        changes=relationship(Change, backref='project',
                             order_by=change_table.c.number),
        unreviewed_changes=relationship(Change,
                                        primaryjoin=and_(project_table.c.key==change_table.c.project_key,
                                                         change_table.c.hidden==False,
                                                         change_table.c.reviewed==False),
                                        order_by=change_table.c.number,
                                        ),
        reviewed_changes=relationship(Change,
                                      primaryjoin=and_(project_table.c.key==change_table.c.project_key,
                                                       change_table.c.hidden==False,
                                                       change_table.c.reviewed==True),
                                        order_by=change_table.c.number,
                                      ),
        updated = column_property(
            select([func.max(change_table.c.updated)]).where(
                change_table.c.project_key==project_table.c.key)
            ),
        ))
mapper(Change, change_table, properties=dict(
        revisions=relationship(Revision, backref='change',
                               order_by=revision_table.c.number),
        messages=relationship(Message,
                              secondary=revision_table,
                              order_by=message_table.c.created),
        labels=relationship(Label, backref='change', order_by=(label_table.c.category,
                                                               label_table.c.value)),
        permitted_labels=relationship(PermittedLabel, backref='change',
                                      order_by=(permitted_label_table.c.category,
                                                permitted_label_table.c.value)),
        approvals=relationship(Approval, backref='change', order_by=(approval_table.c.category,
                                                                     approval_table.c.value)),
        pending_approvals=relationship(Approval,
                                       primaryjoin=and_(change_table.c.key==approval_table.c.change_key,
                                                        approval_table.c.pending==True),
                                       order_by=(approval_table.c.category,
                                                 approval_table.c.value))
        ))
mapper(Revision, revision_table, properties=dict(
        messages=relationship(Message, backref='revision'),
        comments=relationship(Comment, backref='revision',
                              order_by=(comment_table.c.line,
                                        comment_table.c.created)),
        pending_comments=relationship(Comment,
                                      primaryjoin=and_(revision_table.c.key==comment_table.c.revision_key,
                                                       comment_table.c.pending==True),
                                      order_by=(comment_table.c.line,
                                                comment_table.c.created)),
        ))
mapper(Message, message_table)
mapper(Comment, comment_table)
mapper(Label, label_table)
mapper(PermittedLabel, permitted_label_table)
mapper(Approval, approval_table)

class Database(object):
    def __init__(self, app):
        self.app = app
        self.engine = create_engine(self.app.config.dburi)
        metadata.create_all(self.engine)
        self.session_factory = sessionmaker(bind=self.engine)
        self.session = scoped_session(self.session_factory)

    def getSession(self):
        return DatabaseSession(self.session)

class DatabaseSession(object):
    def __init__(self, session):
        self.session = session

    def __enter__(self):
        return self

    def __exit__(self, etype, value, tb):
        if etype:
            self.session().rollback()
        else:
            self.session().commit()
        self.session().close()
        self.session = None

    def abort(self):
        self.session().rollback()

    def commit(self):
        self.session().commit()

    def delete(self, obj):
        self.session().delete(obj)

    def getProjects(self, subscribed=False):
        if subscribed:
            return self.session().query(Project).filter_by(subscribed=subscribed).order_by(Project.name).all()
        else:
            return self.session().query(Project).order_by(Project.name).all()

    def getProject(self, key):
        try:
            return self.session().query(Project).filter_by(key=key).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getProjectByName(self, name):
        try:
            return self.session().query(Project).filter_by(name=name).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getChange(self, key):
        try:
            return self.session().query(Change).filter_by(key=key).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getChangeByID(self, id):
        try:
            return self.session().query(Change).filter_by(id=id).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getRevision(self, key):
        try:
            return self.session().query(Revision).filter_by(key=key).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getRevisionByCommit(self, commit):
        try:
            return self.session().query(Revision).filter_by(commit=commit).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getRevisionByNumber(self, change, number):
        try:
            return self.session().query(Revision).filter_by(change_key=change.key, number=number).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getComment(self, key):
        try:
            return self.session().query(Comment).filter_by(key=key).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getCommentByID(self, id):
        try:
            return self.session().query(Comment).filter_by(id=id).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getMessage(self, key):
        try:
            return self.session().query(Message).filter_by(key=key).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getMessageByID(self, id):
        try:
            return self.session().query(Message).filter_by(id=id).one()
        except sqlalchemy.orm.exc.NoResultFound:
            return None

    def getPendingMessages(self):
        return self.session().query(Message).filter_by(pending=True).all()

    def createProject(self, *args, **kw):
        o = Project(*args, **kw)
        self.session().add(o)
        self.session().flush()
        return o