import sys
import os
import time
import timeit
import json

import settings
os.environ['PYTHONPATH'] = settings.PYTHON_PATH
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')

print(" - settings on loading databaseReset.py")


import django
print(" - django.setup - next")
try:
    django.setup()
except:
    print(" ! Cyclic reference failure. Can occur when the initial db is empty. Fixed now (in UploadFileForm) but easy to reintroduce..")
    raise
print(" - django.setup - done")

import troggle.flatpages.models
import troggle.core.models
import troggle.core.models_survex

from django.core import management
from django.db import connection, close_old_connections, connections
from django.http import HttpResponse
from django.core.urlresolvers import reverse
from django.contrib.auth.models import User

from troggle.core.models_caves import Cave, Entrance
from troggle.parsers.imports import import_caves, import_people, import_surveyscans, \
        import_logbooks, import_QMs, import_survex, import_tunnelfiles
import troggle.logbooksdump


# NOTE databaseReset.py is *imported* by views_other.py as it is used in the control panel
# presented there.

if os.geteuid() == 0:
    # This protects the server from having the wrong file permissions written on logs and caches
    print("This script should be run as expo not root - quitting")
    exit()

dbengine = ""
dbname = ""
dbdefault =""

expouser=settings.EXPOUSER
expouserpass=settings.EXPOUSERPASS
expouseremail=settings.EXPOUSER_EMAIL


def reinit_db():
    """Rebuild database from scratch. Deletes the file first if sqlite is used,
    otherwise it drops the database and creates it.
    Note - initial loading of troggle.sqlite will already have populated the models
    in memory (django python models, not the database), so there is already a full load
    of stuff known. Deleting the db file does not clear memory.
    """
    print("Reinitialising db ",end="")
    print(django.db.connections.databases['default']['NAME'])
    currentdbname = settings.DATABASES['default']['NAME']
    if currentdbname == ':memory:':
        # closing connections should wipe the in-memory database
        django.db.close_old_connections()
        for conn in django.db.connections.all():
            print(" ! Closing another connection to db...")
            conn.close()
    elif django.db.connections.databases['default']['ENGINE'] == 'django.db.backends.sqlite3':
        if os.path.isfile(currentdbname):
            try:
                print(" - deleting " + currentdbname)
                os.remove(currentdbname)
            except OSError:
                print(" ! OSError on removing: " + currentdbname + " (Is the file open in another app?\n")
                raise
        else:
            print(" - No database file found: " + currentdbname + " ..continuing, will create it.\n")
    else:
        cursor = django.db.connection.cursor()
        cursor.execute("DROP DATABASE %s" % currentdbname)
        cursor.execute("CREATE DATABASE %s" % currentdbname)
        cursor.execute("ALTER DATABASE %s CHARACTER SET=utf8" % currentdbname)
        cursor.execute("USE %s" % currentdbname)

     #Sync user - needed after reload
    print(" - Migrating: " + django.db.connections.databases['default']['NAME'])

    management.call_command('makemigrations','core', interactive=False)
    management.call_command('makemigrations','flatpages', interactive=False)
    management.call_command('migrate', interactive=False)
    management.call_command('migrate','core', interactive=False)
    management.call_command('migrate','flatpages', interactive=False)
    
    print(" - done migration on: " + settings.DATABASES['default']['NAME'])
    print("users in db already: ",len(User.objects.all()))
    try:
        print(" - Setting up admin user on: " + django.db.connections.databases['default']['NAME'])
        print(" - user: {} ({:.5}...) <{}> ".format(expouser, expouserpass, expouseremail))
        user = User.objects.create_user(expouser, expouseremail, expouserpass)
        user.is_staff = True
        user.is_superuser = True
        user.save()
    except:
        print(" ! INTEGRITY ERROR user on: " + settings.DATABASES['default']['NAME'])
        print(django.db.connections.databases['default']['NAME'])
        print(" ! You probably have not got a clean db when you thought you had.\n")
        print(" ! Also you are probably NOT running an in-memory db now.\n")
        print("users  in db: ",len(User.objects.all()))
        print("tables in db: ",len(connection.introspection.table_names()))
        memdumpsql(fn='integrityfail.sql')
        django.db.connections.databases['default']['NAME'] = ':memory:'
        #raise

def memdumpsql(fn):
    djconn = django.db.connection
    from dump import _iterdump
    with open(fn, 'w') as f:
        for line in _iterdump(djconn):
            f.write('%s\n' % line.encode("utf8"))
    return True

def store_dbsettings():
    global dbengine
    global dbname
    global dbdefault
    dbengine = settings.DATABASES['default']['ENGINE']
    dbname = settings.DATABASES['default']['NAME']
    dbdefault = settings.DATABASES['default']

def restore_dbsettings():
    settings.DATABASES['default'] = dbdefault
    settings.DATABASES['default']['ENGINE'] = dbengine
    settings.DATABASES['default']['NAME'] = dbname
    django.db.connections.databases['default'] = dbdefault
    django.db.connections.databases['default']['ENGINE'] = dbengine
    django.db.connections.databases['default']['NAME'] = dbname

def set_in_memory_dbsettings():
    django.db.close_old_connections() # needed if MySQL running?
    for conn in django.db.connections.all():
        print(" ! Closing another connection to db in set_in_memory_dbsettings")
        conn.close()
    settings.DATABASES['default'] = {'ENGINE': 'django.db.backends.sqlite3', 
        'AUTOCOMMIT': True, 
        'ATOMIC_REQUESTS': False, 
        'NAME': ':memory:', 
        'CONN_MAX_AGE': 0, 
        'TIME_ZONE': 'UTC', 
        'OPTIONS': {}, 
        'HOST': '', 
        'USER': '', 
        'TEST': {'COLLATION': None, 'CHARSET': None, 'NAME': None, 'MIRROR': None}, 
        'PASSWORD': '', 
        'PORT': ''}
    settings.DATABASES['default']['ENGINE'] = 'django.db.backends.sqlite3'
    settings.DATABASES['default']['NAME'] = ':memory:'
    django.db.connections.databases['default']['ENGINE'] = 'django.db.backends.sqlite3'
    django.db.connections.databases['default']['NAME'] = ':memory:'

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
# These functions moved to a different file - not used currently.
#import logbooksdump
#def import_auto_logbooks():
#def dumplogbooks():

#def writeCaves():
    # Writes out all cave and entrance HTML files to 
    # folder specified in settings.CAVEDESCRIPTIONS
#    for cave in Cave.objects.all():
#        cave.writeDataFile()
#    for entrance in Entrance.objects.all():
#        entrance.writeDataFile()
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

class JobQueue():
    """A list of import operations to run. Always reports profile times
    in the same order. 
    """
    
    def __init__(self,run):
        self.runlabel = run
        self.queue = [] # tuples of (jobname, jobfunction)
        self.results = {}
        self.results_order=[
            "date","runlabel","reinit", "caves", "people",
            "logbooks", "QMs", "scans", "survex", 
            "tunnel", "test" ]
        for k in self.results_order:
            self.results[k]=[]
        self.tfile = "import_profile.json"
        self.htmlfile = "profile.html" # for HTML results table. Not yet done.

    #Adding elements to queue - enqueue
    def enq(self,label,func):
        self.queue.append((label,func))
        return True

    #Removing the last element from the queue - dequeue
    # def deq(self):
    #     if len(self.queue)>0:
    #         return self.queue.pop()
    #     return ("Queue Empty!")

    def loadprofiles(self):
        """Load timings for previous runs from file
        """
        if os.path.isfile(self.tfile):
            try:
                f = open(self.tfile, "r")
                data = json.load(f)
                for j in data:
                    self.results[j] = data[j]
            except:
                print("FAILURE parsing JSON file %s" % (self.tfile))
                # Python bug: https://github.com/ShinNoNoir/twitterwebsearch/issues/12
            f.close()
        for j in self.results_order:
            self.results[j].append(None) # append a placeholder
        return True
    
    def saveprofiles(self):
        with open(self.tfile, 'w') as f:
            json.dump(self.results, f)     
        return True

    def runqonce(self):
        """Run all the jobs in the queue provided - once
        """
        
        print("** Running job ", self.runlabel,end=" to ")
        print(django.db.connections.databases['default']['NAME'])
        jobstart = time.time()
        self.results["date"].pop()
        self.results["date"].append(jobstart)
        self.results["runlabel"].pop()
        self.results["runlabel"].append(self.runlabel)

        for i in self.queue:
            start = time.time()
            i[1]()    #  looks ugly but invokes function passed in the second item in the tuple
            duration = time.time()-start
            print("\n*- Ended \"",  i[0], "\"  %.1f seconds" % duration)
            self.results[i[0]].pop()  # the null item
            self.results[i[0]].append(duration)
               

        jobend = time.time()
        jobduration = jobend-jobstart
        print("** Ended job   %s  -  %.1f seconds total." % (self.runlabel,jobduration))
        return True


    def append_placeholders(self):
        for j in self.results_order:
            self.results[j].append(None) # append a placeholder

    def run_now_django_tests(self,n):
        store_dbsettings()
        # this leaves the db set to :memory: whatever it was initially
        management.call_command('test', verbosity=n)
        django.db.close_old_connections() 
        restore_dbsettings()
        # and whatever I do, it stays that way !

    def skip_memory_phase(self):
        if not self.runlabel:
            return True
        else:
            if self.runlabel == "" or self.runlabel[0:2] == "F-":
                return True
        return False

    def run(self):
        """First runs all the jobs in the queue against a scratch in-memory db
        then re-runs the import against the db specified in settings.py
        Default behaviour is to skip the in-memory phase.
        When MySQL is the db the in-memory phase crashes as MySQL does not properly
        relinquish some kind of db connection (not fixed yet)
        """
        self.loadprofiles()
        store_dbsettings()

        print("-- start   ",  django.db.connections.databases['default']['ENGINE'], django.db.connections.databases['default']['NAME'])

        if dbname ==":memory:":
            # just run, and save the sql file
            self.runqonce()
            memdumpsql('memdump.sql') # saved contents of scratch db, could be imported later..
            self.saveprofiles()
        elif self.skip_memory_phase():
            self.runqonce() 
            self.saveprofiles()
        else:
            # run all the imports through :memory: first
            set_in_memory_dbsettings()

            print("-- phase 1 ",  settings.DATABASES['default']['ENGINE'], settings.DATABASES['default']['NAME'])

            # the jobqueue may not start from scratch so we need to initialise the db properly first
            # because we are using an empty :memory: database
            # But initiating twice crashes it; so be sure to do it once only.

            # Damn. migrate() is still calling MySQL somehow **conn_params not sqlite3. So crashes on expo server.
            if ("reinit",reinit_db) not in self.queue:
                reinit_db()
            if ("caves",import_caves) not in self.queue:
                import_caves() # sometime extract the initialising code from this and put in reinit...
            if ("people",import_people) not in self.queue:
                import_people() # sometime extract the initialising code from this and put in reinit...
                
            django.db.close_old_connections() # maybe not needed here
            
            self.runqonce() 
            memdumpsql('memdump2.sql')
            self.showprofile() 
            
            # restore the original db and import again
            # if we wanted to, we could re-import the SQL generated in the first pass to be
            # blazing fast. But for the present just re-import the lot.
            restore_dbsettings()
            print("-- phase 2 ",  settings.DATABASES['default']['ENGINE'], settings.DATABASES['default']['NAME'])
            print(django.db.connections.databases['default']['NAME'])

            django.db.close_old_connections() # maybe not needed here
            for j in self.results_order:
                self.results[j].pop() # throw away results from :memory: run
            self.append_placeholders()

            django.db.close_old_connections() 
            #django.setup()  # should this be needed?
            
            self.runqonce() 
            self.saveprofiles()
    
        return True

    def showprofile(self):
        """Prints out the time it took to run the jobqueue
        """
        for k in self.results_order:
            if k =="test":
                break
            elif k =="date":
                print("     days ago ", end=' ')
            else:
                print('%10s (s)' % k, end=' ')
            percen=0
            r = self.results[k]  
            
            for i in range(len(r)):
                if k == "runlabel": 
                    if r[i]:
                        rp =   r[i]
                    else:
                        rp = "      - "
                    print('%8s' % rp, end=' ')
                elif k =="date":
                    # Calculate dates as days before present
                    if r[i]:
                        if i == len(r)-1:
                            print("    this", end=' ')
                        else:
                            # prints one place to the left of where you expect
                            if r[len(r)-1]:
                                s = r[i]-r[len(r)-1]
                            elif r[len(r)-2]:
                                s = r[i]-r[len(r)-2]
                            else:
                                s = 0
                            days = (s)/(24*60*60)
                            print('%8.2f' % days, end=' ')
                elif r[i]: 
                    print('%8.1f' % r[i], end=' ')
                    if i == len(r)-1 and r[i-1]:
                        percen = 100* (r[i] - r[i-1])/r[i-1]
                        if abs(percen) >0.1:
                            print('%8.1f%%' % percen, end=' ')
                else:
                    print("      - ", end=' ')
            print("")
        print("\n")
        return True


def usage():
    print("""Usage is 'python databaseReset.py <command> [runlabel]'
             where command is:
             test      - testing... imports people and prints profile. Deletes nothing.
             profile   - print the profile from previous runs. Import nothing.

             reset     - normal usage: clear database and reread everything from files - time-consuming
             caves     - read in the caves (must run first after initialisation)
             people    - read in the people from folk.csv (must run after 'caves')
             logbooks  - read in the logbooks
             QMs       - read in the QM csv files (older caves only)
             scans     - the survey scans in all the wallets (must run before survex)
             survex    - read in the survex files - all the survex blocks and entrances x/y/z 
             tunnel    - read in the Tunnel files - which scans the survey scans too

             autologbooks - Not used. read in autologbooks (what are these?)
             dumplogbooks - Not used. write out autologbooks (not working?)

             and [runlabel] is an optional string identifying this run of the script
             in the stored profiling data 'import-profile.json'
             
             if [runlabel] is absent or begins with "F-" then it will skip the :memory: pass
             
             caves and logbooks must be run on an empty db before the others as they
             set up db tables used by the others.
             
             the commands are first run on an in-memory empty database before being run on
             the actual persistent database. This is very fast and checks for import errors.
             
             the initial in-memory phase is on an empty db, so always runs caves & people for this phase
             """)

if __name__ == "__main__":

    if os.geteuid() == 0:
        print("Do not run as root or using sudo - file permissions for cache files and logs will break")
        print("Aborting run.")
        exit()
    if len(sys.argv)>2:
        runlabel = sys.argv[len(sys.argv)-1]
    else: 
        runlabel=None

    jq = JobQueue(runlabel)
    
    if len(sys.argv)==1:
        usage()
        exit()
    elif "test" in sys.argv:
        jq.enq("caves",import_caves)
        jq.enq("people",import_people)
        #jq.run_now_django_tests(2)
    elif "caves" in sys.argv:
        jq.enq("caves",import_caves)
    elif "logbooks" in sys.argv:
        jq.enq("logbooks",import_logbooks)
    elif "people" in sys.argv:
        jq.enq("people",import_people)
    elif "QMs" in sys.argv:
        jq.enq("QMs",import_QMs)
    elif "reset" in sys.argv:
        jq.enq("reinit",reinit_db)
        jq.enq("caves",import_caves)
        jq.enq("people",import_people)
        jq.enq("scans",import_surveyscans)
        jq.enq("logbooks",import_logbooks)
        jq.enq("QMs",import_QMs)
        jq.enq("tunnel",import_tunnelfiles)
        jq.enq("survex",import_survex)
    elif "scans" in sys.argv:
        jq.enq("scans",import_surveyscans)
    elif "survex" in sys.argv:
        jq.enq("survex",import_survex)
    elif "tunnel" in sys.argv:
        jq.enq("tunnel",import_tunnelfiles)
    elif "autologbooks" in sys.argv: # untested in 2020
        import_auto_logbooks()
    elif "dumplogbooks" in sys.argv: # untested in 2020
        dumplogbooks()
#   elif "writecaves" in sys.argv: # untested in 2020 - will overwrite input files!!
#       writeCaves()
    elif "profile" in sys.argv: 
        jq.loadprofiles()
        jq.showprofile()
        exit()
    elif "help" in sys.argv:
        usage()
        exit()
    else:
        usage()
        print("%s not recognised as a command." % sys.argv[1])
        exit()

    store_dbsettings()
    #set_in_memory_dbsettings()
    
    #set_in_memory_dbsettings() # seems to be ignored. Appears to be set but in reality.
    #jq.run_now_django_tests(1) # actually does set db to :memory: - but invisibly !

    jq.run()
    jq.showprofile()