# -*- coding: utf-8 -*-
# Copyright (c) 2016  Red Hat, Inc.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
# Written by Petr Šabata <contyk@redhat.com>
#            Ralph Bean <rbean@redhat.com>
#            Matt Prahl <mprahl@redhat.com>

""" SQLAlchemy Database models for the Flask app
"""

import contextlib

from datetime import datetime
from sqlalchemy import engine_from_config, event
from sqlalchemy.orm import validates, scoped_session, sessionmaker
from flask import has_app_context
import modulemd as _modulemd

from module_build_service import db, log, get_url_for, app, conf
import module_build_service.messaging

from sqlalchemy.orm import lazyload

# Just like koji.BUILD_STATES, except our own codes for modules.
BUILD_STATES = {
    # This is (obviously) the first state a module build enters.
    #
    # When a user first submits a module build, it enters this state. We parse
    # the modulemd file, learn the NVR, create a record for the module build.
    # and publish the message.
    #
    # Then, we validate that the components are available, and that we can
    # fetch them. If this is all good, then we set the build to the 'wait'
    # state. If anything goes wrong, we jump immediately to the 'failed' state.
    "init": 0,

    # Here, the scheduler picks up tasks in wait and switches to build
    # immediately. Eventually, we'll add throttling logic here so we don't
    # submit too many builds for the build system to handle
    "wait": 1,

    # The scheduler works on builds in this state. We prepare the buildroot,
    # submit builds for all the components, and wait for the results to come
    # back.
    "build": 2,

    # Once all components have succeeded, we set the top-level module build
    # to 'done'.
    "done": 3,

    # If any of the component builds fail, then we set the top-level module
    # build to 'failed' also.
    "failed": 4,

    # This is a state to be set when a module is ready to be part of a
    # larger compose. perhaps it is set by an external service that knows
    # about the Grand Plan.
    "ready": 5,

    # If the module has failed and was garbage collected by MBS
    "garbage": 6
}

INVERSE_BUILD_STATES = {v: k for k, v in BUILD_STATES.items()}


def _utc_datetime_to_iso(datetime_object):
    """
    Takes a UTC datetime object and returns an ISO formatted string
    :param datetime_object: datetime.datetime
    :return: string with datetime in ISO format
    """
    if datetime_object:
        # Converts the datetime to ISO 8601
        return datetime_object.strftime("%Y-%m-%dT%H:%M:%SZ")

    return None


@contextlib.contextmanager
def _dummy_context_mgr():
    """
    Yields None. Used in the make_session to not duplicate the code when
    app_context exists.
    """
    yield None


@contextlib.contextmanager
def make_session(conf):
    """
    Yields new SQLAlchemy database sesssion.
    """
    # Needs to be set to create app_context.
    if 'SERVER_NAME' not in app.config or not app.config['SERVER_NAME']:
        app.config['SERVER_NAME'] = 'localhost'

    # If there is no app_context, we have to create one before creating
    # the session. If we would create app_context after the session (this
    # happens in get_url_for() method), new concurrent session would be
    # created and this would lead to "database is locked" error for SQLite.
    with app.app_context() if not has_app_context() else _dummy_context_mgr():
        # TODO - we could use ZopeTransactionExtension() here some day for
        # improved safety on the backend.
        engine = engine_from_config({
            'sqlalchemy.url': conf.sqlalchemy_database_uri,
        })
        session = scoped_session(sessionmaker(bind=engine))()
        event.listen(session, "before_commit", session_before_commit_handlers)
        try:
            yield session
            session.commit()
        except Exception:
            # This is a no-op if no transaction is in progress.
            session.rollback()
            raise
        finally:
            session.close()


class MBSBase(db.Model):
    # TODO -- we can implement functionality here common to all our model classes
    __abstract__ = True


class ModuleBuild(MBSBase):
    __tablename__ = "module_builds"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    stream = db.Column(db.String, nullable=False)
    version = db.Column(db.String, nullable=False)
    state = db.Column(db.Integer, nullable=False)
    state_reason = db.Column(db.String)
    modulemd = db.Column(db.String, nullable=False)
    koji_tag = db.Column(db.String)  # This gets set after 'wait'
    # Koji tag to which tag the Content Generator Koji build.
    cg_build_koji_tag = db.Column(db.String)  # This gets set after wait
    copr_owner = db.Column(db.String)
    copr_project = db.Column(db.String)
    scmurl = db.Column(db.String)
    owner = db.Column(db.String, nullable=False)
    time_submitted = db.Column(db.DateTime, nullable=False)
    time_modified = db.Column(db.DateTime)
    time_completed = db.Column(db.DateTime)
    new_repo_task_id = db.Column(db.Integer)
    rebuild_strategy = db.Column(db.String, nullable=False)

    # A monotonically increasing integer that represents which batch or
    # iteration this module is currently on for successive rebuilds of its
    # components.  Think like 'mockchain --recurse'
    batch = db.Column(db.Integer, default=0)

    rebuild_strategies = {
        'all': 'All components will be rebuilt',
        'changed-and-after': ('All components that have changed and those in subsequent batches '
                              'will be rebuilt'),
        'only-changed': 'All changed components will be rebuilt'
    }

    def current_batch(self, state=None):
        """ Returns all components of this module in the current batch. """

        if not self.batch:
            raise ValueError("No batch is in progress: %r" % self.batch)

        if state is not None:
            return [
                component for component in self.component_builds
                if component.batch == self.batch and component.state == state
            ]
        else:
            return [
                component for component in self.component_builds
                if component.batch == self.batch
            ]

    def last_batch_id(self):
        """ Returns the id of the last batch """
        return max([build.batch for build in self.component_builds])

    def up_to_current_batch(self, state=None):
        """
        Returns all components of this module in the current batch and
        in the previous batches.
        """

        if not self.batch:
            raise ValueError("No batch is in progress: %r" % self.batch)

        if state is not None:
            return [
                component for component in self.component_builds
                if component.batch <= self.batch and component.state == state
            ]
        else:
            return [
                component for component in self.component_builds
                if component.batch <= self.batch
            ]

    def mmd(self):
        mmd = _modulemd.ModuleMetadata()
        try:
            mmd.loads(self.modulemd)
        except Exception:
            raise ValueError("Invalid modulemd")
        return mmd

    @property
    def previous_non_failed_state(self):
        for trace in reversed(self.module_builds_trace):
            if trace.state != BUILD_STATES['failed']:
                return trace.state

    @validates('state')
    def validate_state(self, key, field):
        if field in BUILD_STATES.values():
            return field
        if field in BUILD_STATES:
            return BUILD_STATES[field]
        raise ValueError("%s: %s, not in %r" % (key, field, BUILD_STATES))

    @validates('rebuild_strategy')
    def validate_rebuild_stategy(self, key, rebuild_strategy):
        if rebuild_strategy not in self.rebuild_strategies.keys():
            choices = ', '.join(self.rebuild_strategies.keys())
            raise ValueError('The rebuild_strategy of "{0}" is invalid. Choose from: {1}'
                             .format(rebuild_strategy, choices))
        return rebuild_strategy

    @classmethod
    def from_module_event(cls, session, event):
        if type(event) == module_build_service.messaging.MBSModule:
            return session.query(cls).filter(
                cls.id == event.module_build_id).first()
        else:
            raise ValueError("%r is not a module message."
                             % type(event).__name__)

    @classmethod
    def create(cls, session, conf, name, stream, version, modulemd, scmurl, username,
               copr_owner=None, copr_project=None, rebuild_strategy=None, publish_msg=True):
        now = datetime.utcnow()
        module = cls(
            name=name,
            stream=stream,
            version=version,
            state="init",
            modulemd=modulemd,
            scmurl=scmurl,
            owner=username,
            time_submitted=now,
            time_modified=now,
            copr_owner=copr_owner,
            copr_project=copr_project,
            # If the rebuild_strategy isn't specified, use the default
            rebuild_strategy=rebuild_strategy or conf.rebuild_strategy
        )
        # Add a state transition to "init"
        mbt = ModuleBuildTrace(state_time=now, state=module.state)
        module.module_builds_trace.append(mbt)
        session.add(module)
        session.commit()
        if publish_msg:
            module_build_service.messaging.publish(
                service='mbs',
                topic='module.state.change',
                msg=module.extended_json(),  # Note the state is "init" here...
                conf=conf,
            )
        return module

    def transition(self, conf, state, state_reason=None):
        """ Record that a build has transitioned state. """
        now = datetime.utcnow()
        old_state = self.state
        self.state = state
        self.time_modified = now

        if INVERSE_BUILD_STATES[self.state] in ['done', 'failed']:
            self.time_completed = now

        if state_reason:
            self.state_reason = state_reason

        # record module's state change
        mbt = ModuleBuildTrace(state_time=now,
                               state=self.state,
                               state_reason=state_reason)
        self.module_builds_trace.append(mbt)

        log.info("%r, state %r->%r" % (self, old_state, self.state))
        if old_state != self.state:
            module_build_service.messaging.publish(
                service='mbs',
                topic='module.state.change',
                msg=self.extended_json(),
                conf=conf,
            )

    @classmethod
    def local_modules(cls, session, name=None, stream=None):
        """
        Returns list of local module builds added by
        utils.load_local_builds(...). When `name` or `stream` is set,
        it is used to further limit the result set.

        If conf.system is not set to "mock" or "test", returns empty
        list everytime, because local modules make sense only when
        building using Mock backend or during tests.
        """
        if conf.system in ["koji", "copr"]:
            return []

        filters = {}
        if name:
            filters["name"] = name
        if stream:
            filters["stream"] = stream
        local_modules = session.query(ModuleBuild).filter_by(
            **filters).all()
        if not local_modules:
            return []

        local_modules = [m for m in local_modules
                         if m.koji_tag and
                         m.koji_tag.startswith(conf.mock_resultsdir)]
        return local_modules

    @classmethod
    def by_state(cls, session, state):
        return session.query(ModuleBuild).filter_by(state=BUILD_STATES[state]).all()

    @classmethod
    def from_repo_done_event(cls, session, event):
        """ Find the ModuleBuilds in our database that should be in-flight...
        ... for a given koji tag.

        There should be at most one.
        """
        if event.repo_tag.endswith('-build'):
            tag = event.repo_tag[:-6]
        else:
            tag = event.repo_tag
        query = session.query(cls)\
            .filter(cls.koji_tag == tag)\
            .filter(cls.state == BUILD_STATES["build"])

        count = query.count()
        if count > 1:
            raise RuntimeError("%r module builds in flight for %r" % (count, tag))

        return query.first()

    @classmethod
    def from_tag_change_event(cls, session, event):
        tag = event.tag[:-6] if event.tag.endswith('-build') else event.tag
        query = session.query(cls)\
            .filter(cls.koji_tag == tag)\
            .filter(cls.state == BUILD_STATES["build"])

        count = query.count()
        if count > 1:
            raise RuntimeError("%r module builds in flight for %r" % (count, tag))

        return query.first()

    def short_json(self):
        return {
            'id': self.id,
            'state': self.state,
            'state_name': INVERSE_BUILD_STATES[self.state],
            'stream': self.stream,
            'version': self.version,
            'name': self.name,
        }

    def json(self):
        json = self.short_json()
        json.update({
            'state_reason': self.state_reason,
            'owner': self.owner,
            'rebuild_strategy': self.rebuild_strategy,
            'scmurl': self.scmurl,
            'time_submitted': _utc_datetime_to_iso(self.time_submitted),
            'time_modified': _utc_datetime_to_iso(self.time_modified),
            'time_completed': _utc_datetime_to_iso(self.time_completed),
            'koji_tag': self.koji_tag,
            'tasks': self.tasks(),
        })
        return json

    def extended_json(self, show_state_url=False):
        """
        :kwarg show_state_url: this will determine if `get_url_for` should be run to determine
        what the `state_url` is. This should be set to `False` when extended_json is called from
        the backend because it forces an app context to be created, which causes issues with
        SQLAlchemy sessions.
        """
        json = self.json()
        state_url = None
        if show_state_url:
            state_url = get_url_for('module_build', id=self.id)
        json.update({
            'component_builds': [build.id for build in self.component_builds],
            'modulemd': self.modulemd,
            'state_trace': [{'time': _utc_datetime_to_iso(record.state_time),
                             'state': record.state,
                             'state_name': INVERSE_BUILD_STATES[record.state],
                             'reason': record.state_reason}
                            for record
                            in self.state_trace(self.id)],
            'state_url': state_url
        })

        return json

    def tasks(self):
        """
        :return: dictionary containing the tasks associated with the build
        """
        tasks = dict()
        if self.id and self.state != 'init':
            for build in ComponentBuild.query\
                    .filter_by(module_id=self.id)\
                    .options(lazyload('module_build'))\
                    .all():
                tasks[build.format] = tasks.get(build.format, {})
                tasks[build.format][build.package] = dict(
                    task_id=build.task_id,
                    state=build.state,
                    state_reason=build.state_reason,
                    nvr=build.nvr,
                    # TODO -- it would be really nice from a UX PoV to get a
                    # link to the remote task here.
                )

        return tasks

    def state_trace(self, module_id):
        return ModuleBuildTrace.query.filter_by(
            module_id=module_id).order_by(ModuleBuildTrace.state_time).all()

    def __repr__(self):
        return (("<ModuleBuild %s, id=%d, stream=%s, version=%s, state %r,"
                 " batch %r, state_reason %r>")
                % (self.name, self.id, self.stream, self.version, INVERSE_BUILD_STATES[self.state],
                   self.batch, self.state_reason))


class ModuleBuildTrace(MBSBase):
    __tablename__ = "module_builds_trace"
    id = db.Column(db.Integer, primary_key=True)
    module_id = db.Column(db.Integer, db.ForeignKey('module_builds.id'), nullable=False)
    state_time = db.Column(db.DateTime, nullable=False)
    state = db.Column(db.Integer, nullable=True)
    state_reason = db.Column(db.String, nullable=True)

    module_build = db.relationship('ModuleBuild', backref='module_builds_trace', lazy=False)

    def json(self):
        retval = {
            'id': self.id,
            'module_id': self.module_id,
            'state_time': _utc_datetime_to_iso(self.state_time),
            'state': self.state,
            'state_reason': self.state_reason,
        }

        return retval

    def __repr__(self):
        return ("<ModuleBuildTrace %s, module_id: %s, state_time: %r, state: %s, state_reason: %s>"
                % (self.id, self.module_id, self.state_time, self.state, self.state_reason))


class ComponentBuild(MBSBase):
    __tablename__ = "component_builds"
    id = db.Column(db.Integer, primary_key=True)
    package = db.Column(db.String, nullable=False)
    scmurl = db.Column(db.String, nullable=False)
    # XXX: Consider making this a proper ENUM
    format = db.Column(db.String, nullable=False)
    task_id = db.Column(db.Integer)  # This is the id of the build in koji
    # This is the commit hash that component was built with
    ref = db.Column(db.String, nullable=True)
    # XXX: Consider making this a proper ENUM (or an int)
    state = db.Column(db.Integer)
    # Reason why the build failed
    state_reason = db.Column(db.String)
    # This stays as None until the build completes.
    nvr = db.Column(db.String)
    # True when this component build is tagged into buildroot (-build tag).
    tagged = db.Column(db.Boolean, default=False)
    # True when this component build is tagged into final tag.
    tagged_in_final = db.Column(db.Boolean, default=False)
    # True when this component build is build-time only (should be tagged only
    # to -build tag)
    build_time_only = db.Column(db.Boolean, default=False)

    # A monotonically increasing integer that represents which batch or
    # iteration this *component* is currently in.  This relates to the owning
    # module's batch.  This one defaults to None, which means that this
    # component is not currently part of a batch.
    batch = db.Column(db.Integer, default=0)

    module_id = db.Column(db.Integer, db.ForeignKey('module_builds.id'), nullable=False)
    module_build = db.relationship('ModuleBuild', backref='component_builds', lazy=False)
    reused_component_id = db.Column(
        db.Integer, db.ForeignKey('component_builds.id'))

    @classmethod
    def from_component_event(cls, session, event):
        if isinstance(event, module_build_service.messaging.KojiBuildChange):
            if event.module_build_id:
                return session.query(cls).filter_by(
                    task_id=event.task_id, module_id=event.module_build_id)\
                    .one()
            else:
                return session.query(cls).filter(
                    cls.task_id == event.task_id).first()
        else:
            raise ValueError("%r is not a koji message." % event['topic'])

    @classmethod
    def from_component_name(cls, session, component_name, module_id):
        return session.query(cls).filter_by(
            package=component_name, module_id=module_id).first()

    def state_trace(self, component_id):
        return ComponentBuildTrace.query.filter_by(
            component_id=component_id).order_by(ComponentBuildTrace.state_time).all()

    def json(self):
        retval = {
            'id': self.id,
            'package': self.package,
            'format': self.format,
            'task_id': self.task_id,
            'state': self.state,
            'state_reason': self.state_reason,
            'module_build': self.module_id,
        }

        try:
            # Koji is py2 only, so this fails if the main web process is
            # running on py3.
            import koji
            retval['state_name'] = koji.BUILD_STATES.get(self.state)
        except ImportError:
            pass

        return retval

    def extended_json(self, show_state_url=False):
        """
        :kwarg show_state_url: this will determine if `get_url_for` should be run to determine
        what the `state_url` is. This should be set to `False` when extended_json is called from
        the backend because it forces an app context to be created, which causes issues with
        SQLAlchemy sessions.
        """
        json = self.json()
        state_url = None
        if show_state_url:
            state_url = get_url_for('component_build', id=self.id)
        json.update({
            'state_trace': [{'time': _utc_datetime_to_iso(record.state_time),
                             'state': record.state,
                             'state_name': INVERSE_BUILD_STATES[record.state],
                             'reason': record.state_reason}
                            for record
                            in self.state_trace(self.id)],
            'state_url': state_url
        })

        return json

    def __repr__(self):
        return "<ComponentBuild %s, %r, state: %r, task_id: %r, batch: %r, state_reason: %s>" % (
            self.package, self.module_id, self.state, self.task_id, self.batch, self.state_reason)


class ComponentBuildTrace(MBSBase):
    __tablename__ = "component_builds_trace"
    id = db.Column(db.Integer, primary_key=True)
    component_id = db.Column(db.Integer, db.ForeignKey('component_builds.id'), nullable=False)
    state_time = db.Column(db.DateTime, nullable=False)
    state = db.Column(db.Integer, nullable=True)
    state_reason = db.Column(db.String, nullable=True)
    task_id = db.Column(db.Integer, nullable=True)

    component_build = db.relationship('ComponentBuild', backref='component_builds_trace',
                                      lazy=False)

    def json(self):
        retval = {
            'id': self.id,
            'component_id': self.component_id,
            'state_time': _utc_datetime_to_iso(self.state_time),
            'state': self.state,
            'state_reason': self.state_reason,
            'task_id': self.task_id,
        }

        return retval

    def __repr__(self):
        return ("<ComponentBuildTrace %s, component_id: %s, state_time: %r, state: %s,"
                " state_reason: %s, task_id: %s>") % (self.id, self.component_id, self.state_time,
                                                      self.state, self.state_reason, self.task_id)


def session_before_commit_handlers(session):
    # new and updated items
    for item in (set(session.new) | set(session.dirty)):
        # handlers for component builds
        if isinstance(item, ComponentBuild):
            cbt = ComponentBuildTrace(
                state_time=datetime.utcnow(),
                state=item.state,
                state_reason=item.state_reason,
                task_id=item.task_id)
            item.component_builds_trace.append(cbt)