###
#
# This file controls the 'external' job control manager, that (periodically #
# looks / somehow is pushed an event?) picks up new jobs, and processes them.
# 
# It then stores the progress/status, etc. in job and joblog tables as needed
# via wrapper functions.
#
# The whole pa_job_manager is multi-threaded, and uses the database tables for
# state management and communication back to the pa web site
#
###

#### DDP: work out the import line for just sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, Sequence, ForeignKey, DateTime
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from shared import DB_URL
from datetime import datetime, timedelta
import pytz


# an Manager, which the Session will use for connection resources
some_manager = create_engine(DB_URL)

# create a configured "Session" class
Session = sessionmaker(bind=some_manager)

# create a Session
session = Session()

Base = declarative_base()


# global for us to keep state / let front-end know our state
pa_eng=None


#### DDP: work out the class creation line for just sqlalchemy
class PA_JobManager(Base):
    __tablename__ = "pa_job_manager"
    id = Column(Integer, Sequence('pa_job_manager_id_seq'), primary_key=True)
    state = Column(String)
    num_active_jobs = Column(Integer)
    num_completed_jobs = Column(Integer)

    def __repr__(self):
        return "<id={}, state={}, num_active_jobs={}, num_completed_jobs={}>".format( self.id, self.state, self.num_active_jobs, self.num_completed_jobs )


class Joblog(Base):
    __tablename__ = "joblog"
    id = Column(Integer, Sequence('ill_id_seq'), primary_key=True )
    job_id = Column(Integer, ForeignKey('job.id'), primary_key=True )
    log_date = Column(DateTime(timezone=True))
    log = Column(String)

    def __repr__(self):
        return "<id: {}, job_id: {}, log: {}".format(self.id, self.job_id, self.log )

################################################################################
# Class describing Action in the database, and via sqlalchemy, connected to the DB as well
################################################################################
class Job(Base):
    __tablename__ = "job"
    id = Column(Integer, Sequence('joblog_id_seq'), primary_key=True )
    start_time = Column(DateTime(timezone=True))
    last_update = Column(DateTime(timezone=True))
    name = Column(String)
    state = Column(String)
    num_passes = Column(Integer)
    current_pass = Column(Integer)
    num_files = Column(Integer)
    current_file_num = Column(Integer)
    current_file = Column(String)
    wait_for = Column(Integer)
    pa_job_state = Column(String)

    def __repr__(self):
        return "<id: {}, start_time: {}, last_update: {}, name: {}, state: {}, num_passes: {}, current_passes: {}, num_files: {}, current_file_num: {}, current_file: {}>".format(self.id, self.start_time, self.last_update, self.name, self.state, self.num_passes, self.current_pass, self.num_files, self.num_files, self.current_file_num, self.current_file)


def GetJobs():
    return session.query(Job).all()
    
def InitialiseManager():
    pa_eng=session.query(PA_JobManager).first()
    print(pa_eng)
    if( pa_eng == None ):
        pa_eng = PA_JobManager(state='Initialising', num_active_jobs=0, num_completed_jobs=0 )
        session.add(pa_eng)

    pa_eng.state = 'Scanning Jobs'
    jobs=GetJobs()
    for job in jobs:
        if job.pa_job_state != 'complete':
            print("We have a job we need to handle, its current pa_eng state is {}, internal job state is: {}".format( job.pa_job_state, job.state) )
            pa_eng.num_active_jobs = pa_eng.num_active_jobs + 1
        else:
            pa_eng.num_completed_jobs = pa_eng.num_completed_jobs +1
    print("PA job manager is up")
    pa_eng.state = 'Waiting for new Jobs'
    return

def CreateJob():
    return 

def UpdateJob():
    return

if __name__ == "__main__":
    print("PA job manager starting")
    try:
        InitialiseManager()
        session.commit()
    except Exception as e:
        print( "Failed to initialise PA Job Manager: {}".format(e) )
        session.rollback()
    print("Exiting for now")