import os
import re
import sys
from pathlib import Path

from django.conf import settings
from django.db import transaction

from troggle.settings import SURVEX_DATA, EXPOWEB, CAVEDESCRIPTIONS, ENTRANCEDESCRIPTIONS
from troggle.core.models.troggle import DataIssue
from troggle.core.models.caves import Area, Cave, Entrance, CaveSlug, EntranceSlug, CaveAndEntrance
'''Reads all the cave description data by parsing the xml files (stored as e.g. :EXPOWEB:/cave_data/1623-161.html )
and creating the various Cave, Entrance and necessary Area objects.

This is the first import that happens after the dabase is reinitialised. 
So is the first thing that creates tables.

BUT in Django 2.0 and later we cannot do any queries on data we have just entered 
because this is all happening inside one transaction. Bummer.

django.db.transaction.TransactionManagementError: 
An error occurred in the current transaction. You can't execute queries until the end of the 'atomic' block.
'''

todo='''- db Update does not work when a cave id is in the pending list but a proper cave description file exists
   and is being imported. It should work. But currently Django aborts and he file is not read in.
   
 - Cannot use Edit This Page for pendingcaves.txt_edit as Edit This Page is expecting an html file.
   So we will need a separate file-editing capability just for this configuration file ?!
   
- crashes on MariaDB on server when deleting Caves and complains Area needs a non null parent, But this is not true.
  The only solution we have found is to let it crash, then stop and restart MariaDB (requires a logon able to sudo)
  and then restart the databasereset.py again. (status as of July 2022)
'''
entrances_xslug = {}
caves_xslug = {}
areas_xslug = {}

def dummy_entrance(k, slug, msg="DUMMY"):
    '''Returns an empty entrance object for either a PENDING cave or a DUMMY entrance if 
    user forgot to provide one when creating the cave
    '''
    ent = Entrance(
            name = k, 
            entrance_description = "Dummy entrance: auto-created when registering a new cave " +
                    "and you forgot to create an entrance for it. Click on 'Edit' to enter the correct data, then 'Submit'.",
            marking = '?')
    if ent:
        ent.save() # must save to have id before foreign keys work.
        try: # Now create a entrance slug ID
            es = EntranceSlug.objects.update_or_create(entrance = ent,
                      slug = slug, primary = False)
        except:
            message = f" ! {k:11s}  {msg} entrance create failure"
            DataIssue.objects.create(parser='caves', message=message, url=f'{slug}')
            print(message)

        ent.cached_primary_slug = slug
        ent.filename = slug + ".html"
        ent.save()
        return ent
    else:
        message = f" ! {k:11s}  {msg} cave SLUG '{slug}' create failure"
        DataIssue.objects.create(parser='caves', message=message, url=f'{slug}')
        print(message)
        raise 

def set_dummy_entrance(id, slug, cave, msg="DUMMY"):
    '''Entrance field either missing or holds a null string instead of a filename in a cave_data file.
    '''
    global entrances_xslug
    try:
        entrance = dummy_entrance(id, slug, msg="DUMMY")
        letter = ""
        entrances_xslug[slug] = entrance
        ce = CaveAndEntrance.objects.update_or_create(cave = cave, entrance_letter = "", entrance = entrance)
        message = f' ! Warning: Dummy Entrance created for {id}'
        
        DataIssue.objects.create(parser='caves', message=message, url=f'{cave.url}')
        print(message)
    except:
        message = f' ! Entrance Dummy setting failure, slug:"{slug}" cave id :"{id}" '
        DataIssue.objects.create(parser='caves', message=message, url=f'{cave.url}')
        print(message)
 
def do_pending_cave(k, url, area_1623):
    '''
    default for a PENDING cave, should be overwritten in the db later if a real cave of the same name exists 
    in expoweb/cave_data/1623-"k".html 
    '''
    slug = "1623-" + k

    default_note = f"_Survex file found in loser repo but no description in expoweb <br><br><br>\n" 
    default_note += f"INSTRUCTIONS: First open 'This survex file' (link above the CaveView panel) to find the date and info. Then " 
    default_note += f"<br><br>\n\n - (1) search in the survex file for the *ref to find a "  
    default_note += f"relevant wallet, e.g.<a href='/survey_scans/2009%252311/'>2009#11</a> and read the notes image files <br>\n - " 
    default_note += f"<br><br>\n\n - (2) search in the Expo for that year e.g. <a href='/expedition/{k[0:4]}'>{k[0:4]}</a> to find a "  
    default_note += f"relevant logbook entry, remember that the date may have been recorded incorrectly, " 
    default_note += f"so check for trips i.e. logbook entries involving the same people as were listed in the survex file, " 
    default_note += f"and you should also check the scanned copy of the logbook (linked from each logbook entry page) " 
    default_note += f"just in case a vital trip was not transcribed, then <br>\n - " 
    default_note += f"click on 'Edit this cave' and copy the information you find in the survex file and the logbook" 
    default_note += f"and delete all the text in the 'Notes' section - which is the text you are reading now." 
    default_note += f"<br><br>\n\n - Only two fields on this  form are essential. " 
    default_note += f"Documentation of all the fields on 'Edit this cave' form is in <a href='/handbook/survey/caveentryfields.html'>handbook/survey/caveentryfields</a>"
    default_note += f"<br><br>\n\n - " 
    default_note += f"When you Submit it will create a new file in expoweb/cave_data/ " 
    default_note += f"<br><br>\n\n - Now you can edit the entrance info: click on Edit below for the dummy entrance. " 
    default_note += f"and then Submit to save it (if you forget to do this, a dummy entrance will be created for your new cave description)."
    default_note += f"<br><br>\n\n - Finally, you need to find a nerd to edit the file '<var>expoweb/cave_data/pending.txt</var>' " 
    default_note += f"to remove the line <br><var>{slug}</var><br> as it is no longer 'pending' but 'done. Well Done."

    
    cave = Cave(
            unofficial_number = k, 
            underground_description = "Pending cave write-up - creating as empty object. No XML file available yet.",
            survex_file = "caves-1623/" + k + "/" + k +".svx",
            url = url,
            notes = default_note)
    if cave:
        cave.save() # must save to have id before foreign keys work. This is also a ManyToMany key.
        cave.area.add(area_1623)
        cave.save()
        message = f" ! {k:12} {cave.underground_description}"
        DataIssue.objects.create(parser='caves', message=message, url=url)
        print(message)
        
        try: # Now create a cave slug ID
            cs = CaveSlug.objects.update_or_create(cave = cave,
                      slug = slug, primary = False)
        except:
            message = f" ! {k:11s}  PENDING cave SLUG create failure"
            DataIssue.objects.create(parser='caves', message=message)
            print(message)
    else:
        message = f' ! {k:11s}  PENDING cave create failure'
        DataIssue.objects.create(parser='caves', message=message)
        print(message)

    try:
        ent = dummy_entrance(k, slug, msg="PENDING")
        ceinsts = CaveAndEntrance.objects.update_or_create(cave = cave, entrance_letter = "", entrance = ent)
        for ceinst in ceinsts:
            if str(ceinst) == str(cave):  # magic runes... why is the next value a Bool?
                ceinst.cave = cave
                ceinst.save()
                break
    except:
        message = f" ! {k:11s}  PENDING entrance + cave UNION create failure  '{cave}' [{ent}]"
        DataIssue.objects.create(parser='caves', message=message)
        print(message)


def readcaves():
    '''Reads the xml-format HTML files in the EXPOWEB repo, not from the loser repo.
    '''
    # For those caves which do not have cave_data/1623-xxx.html XML files even though they exist and have surveys
    # should put this in a simple list which can be edited using 'Edit this file'
    pending = set()
    fpending = Path(CAVEDESCRIPTIONS, "pendingcaves.txt")
    if fpending.is_file():
        with open(fpending, "r") as fo:
            cids = fo.readlines()
        for cid in cids:
            pending.add(cid.rstrip('\n'))

    with transaction.atomic():
        print(" - Deleting Caves and Entrances")
        # attempting to avoid MariaDB crash when doing this
        try:
            Area.objects.all().delete()
        except:
            pass
        try:
            Cave.objects.all().delete()
        except:
            pass
        try:
            Entrance.objects.all().delete()
        except:
            pass
        # Clear the cave data issues and the caves as we are reloading
        DataIssue.objects.filter(parser='areas').delete()
        DataIssue.objects.filter(parser='caves').delete()
        DataIssue.objects.filter(parser='caves ok').delete()
        DataIssue.objects.filter(parser='entrances').delete()
        
        print(" - Creating Areas 1623 and 1626")
        # This crashes on the server with MariaDB even though a null parent is explicitly allowed.
        area_1623= Area.objects.create(short_name = "1623", parent=None)
        print(" - Saving Area 1623")
        area_1623.save()
        area_1626= Area.objects.create(short_name = "1626", parent=None)
        print(" - Saving Area 1626")
        area_1626.save()

        print (" - Setting pending caves")
        # Do this first, so that these empty entries are overwritten as they get properly created.
        

        for k in pending:
            url = "1623/" + k # Note we are not appending the .htm as we are modern folks now.
            try:    
                do_pending_cave(k, url, area_1623)
            except:
                message = " ! Error. Cannot create pending cave and entrance, pending-id:{}".format(k)
                DataIssue.objects.create(parser='caves', message=message)
                print(message)
                raise

    with transaction.atomic():
        print(" - settings.CAVEDESCRIPTIONS: ", CAVEDESCRIPTIONS)
        print(" - Reading Entrances from entrance descriptions xml files")
        for filename in next(os.walk(ENTRANCEDESCRIPTIONS))[2]: #Should be a better way of getting a list of files
            # if filename.endswith('.html'):
                # if Path(filename).stem[5:] in pending:
                        # print(f'Skipping pending entrance dummy file <{filename}>')
                # else:
                    # readentrance(filename)
            readentrance(filename)

        print(" - Reading Caves from cave descriptions xml files")
        for filename in next(os.walk(CAVEDESCRIPTIONS))[2]: #Should be a better way of getting a list of files
            if filename.endswith('.html'):
                readcave(filename)

def readentrance(filename):
    global entrances_xslug
    global caves_xslug
    global areas_xslug

    # Note: these are HTML files in the EXPOWEB repo, not from the loser repo.
    with open(os.path.join(ENTRANCEDESCRIPTIONS, filename)) as f:
        contents = f.read()
    context = filename
    #print("Reading file ENTRANCE {} / {}".format(ENTRANCEDESCRIPTIONS, filename))
    entrancecontentslist = getXML(contents, "entrance", maxItems = 1, context = context)
    if len(entrancecontentslist) != 1:
        message = f'! BAD ENTRANCE at "{filename}"'
        DataIssue.objects.create(parser='caves', message=message)
        print(message)
    else:
        entrancecontents = entrancecontentslist[0]
        non_public = getXML(entrancecontents, "non_public", maxItems = 1, context = context)
        name = getXML(entrancecontents, "name", maxItems = 1, context = context)
        slugs = getXML(entrancecontents, "slug", context = context)
        entrance_description = getXML(entrancecontents, "entrance_description", maxItems = 1, context = context)
        explorers = getXML(entrancecontents, "explorers", maxItems = 1, context = context)
        map_description = getXML(entrancecontents, "map_description", maxItems = 1, context = context)
        location_description = getXML(entrancecontents, "location_description", maxItems = 1, context = context)
        approach = getXML(entrancecontents, "approach", maxItems = 1, context = context)
        underground_description = getXML(entrancecontents, "underground_description", maxItems = 1, context = context)
        photo = getXML(entrancecontents, "photo", maxItems = 1, context = context)
        marking = getXML(entrancecontents, "marking", maxItems = 1, context = context)
        marking_comment = getXML(entrancecontents, "marking_comment", maxItems = 1, context = context)
        findability = getXML(entrancecontents, "findability", maxItems = 1, context = context)
        findability_description = getXML(entrancecontents, "findability_description", maxItems = 1, context = context)
        alt = getXML(entrancecontents, "alt", maxItems = 1, context = context)
        northing = getXML(entrancecontents, "northing", maxItems = 1, context = context)
        easting = getXML(entrancecontents, "easting", maxItems = 1, context = context)
        tag_station = getXML(entrancecontents, "tag_station", maxItems = 1, context = context)
        exact_station = getXML(entrancecontents, "exact_station", maxItems = 1, context = context)
        other_station = getXML(entrancecontents, "other_station", maxItems = 1, context = context)
        other_description = getXML(entrancecontents, "other_description", maxItems = 1, context = context)
        bearings = getXML(entrancecontents, "bearings", maxItems = 1, context = context)
        url = getXML(entrancecontents, "url", maxItems = 1, context = context)
        if len(non_public) == 1 and len(slugs) >= 1 and len(name) >= 1 and  len(entrance_description) == 1 and  len(explorers) == 1 and  len(map_description) == 1 and  len(location_description) == 1 and  len(approach) == 1 and  len(underground_description) == 1 and  len(marking) == 1 and  len(marking_comment) == 1 and  len(findability) == 1 and  len(findability_description) == 1 and  len(alt) == 1 and  len(northing) == 1 and  len(easting) == 1 and  len(tag_station) == 1 and  len(exact_station) == 1 and  len(other_station) == 1 and  len(other_description) == 1 and  len(bearings) == 1 and  len(url) == 1:
            e, state = Entrance.objects.update_or_create(name = name[0],
                         non_public = {"True": True, "False": False, "true": True, "false": False,}[non_public[0]],
                         entrance_description = entrance_description[0],
                         explorers = explorers[0],
                         map_description = map_description[0],
                         location_description = location_description[0],
                         approach = approach[0],
                         underground_description = underground_description[0],
                         photo = photo[0],
                         marking = marking[0],
                         marking_comment = marking_comment[0],
                         findability = findability[0],
                         findability_description = findability_description[0],
                         alt = alt[0],
                         northing = northing[0],
                         easting = easting[0],
                         tag_station = tag_station[0],
                         exact_station = exact_station[0],
                         other_station = other_station[0],
                         other_description = other_description[0],
                         bearings = bearings[0],
                         url = url[0],
                         filename = filename,
                         cached_primary_slug = slugs[0])
            primary = True
            for slug in slugs:
                #print("entrance slug:{} filename:{}".format(slug, filename))
                try:
                    cs = EntranceSlug.objects.update_or_create(entrance = e,
                                             slug = slug,
                                             primary = primary)
                except:
                    # need to cope with duplicates
                    message = f" ! FAILED to get precisely one ENTRANCE when updating using: cave_entrance/{filename}"
                    DataIssue.objects.create(parser='caves', message=message, url=f'/cave/{slug}/edit/')
                    kents = EntranceSlug.objects.all().filter(entrance = e,
                                                 slug = slug,
                                                 primary = primary)
                    for k in kents:
                        message = " ! - DUPLICATE in db. entrance:"+ str(k.entrance) + ", slug:" + str(k.slug()) 
                        DataIssue.objects.create(parser='caves', message=message, url=f'/cave/{slug}/edit/')
                        print(message)
                    for k in kents:
                        if k.slug() != None:
                            print(" ! - OVERWRITING this one: slug:"+ str(k.slug()))
                            k.notes = "DUPLICATE entrance found on import. Please fix\n" + k.notes
                            c = k
                primary = False
        else: # more than one item in long list
            message = f' ! {slug:12} ABORT loading this entrance. in "{filename}"'
            DataIssue.objects.create(parser='caves', message=message, url=f'/cave/{slug}/edit/')
            print(message)

def readcave(filename):
    '''Assumes any area it hasn't seen before is a subarea of 1623
    '''
    global entrances_xslug
    global caves_xslug
    global areas_xslug
    
    # Note: these are HTML files in the EXPOWEB repo, not from the loser repo.
    with open(os.path.join(CAVEDESCRIPTIONS, filename)) as f:
        contents = f.read()
    context = filename
    cavecontentslist = getXML(contents, "cave", maxItems = 1, context = context)
    if len(cavecontentslist) != 1:
        message = f'! BAD CAVE at "{filename}"'
        DataIssue.objects.create(parser='caves', message=message)
        print(message)
    else:
        cavecontents = cavecontentslist[0]
        non_public = getXML(cavecontents, "non_public", maxItems = 1, context = context)
        slugs = getXML(cavecontents, "caveslug", maxItems = 1, context = context)
        official_name = getXML(cavecontents, "official_name", maxItems = 1, context = context)
        areas = getXML(cavecontents, "area", context = context)
        kataster_code = getXML(cavecontents, "kataster_code", maxItems = 1, context = context)
        kataster_number = getXML(cavecontents, "kataster_number", maxItems = 1, context = context)
        unofficial_number = getXML(cavecontents, "unofficial_number", maxItems = 1, context = context)
        explorers = getXML(cavecontents, "explorers", maxItems = 1, context = context)
        underground_description = getXML(cavecontents, "underground_description", maxItems = 1, context = context)
        equipment = getXML(cavecontents, "equipment", maxItems = 1, context = context)
        references = getXML(cavecontents, "references", maxItems = 1, context = context)
        survey = getXML(cavecontents, "survey", maxItems = 1, context = context)
        kataster_status = getXML(cavecontents, "kataster_status", maxItems = 1, context = context)
        underground_centre_line = getXML(cavecontents, "underground_centre_line", maxItems = 1, context = context)
        notes = getXML(cavecontents, "notes", maxItems = 1, context = context)
        length = getXML(cavecontents, "length", maxItems = 1, context = context)
        depth = getXML(cavecontents, "depth", maxItems = 1, context = context)
        extent = getXML(cavecontents, "extent", maxItems = 1, context = context)
        survex_file = getXML(cavecontents, "survex_file", maxItems = 1, context = context)
        description_file = getXML(cavecontents, "description_file", maxItems = 1, context = context)
        url = getXML(cavecontents, "url", maxItems = 1, context = context)
        entrances = getXML(cavecontents, "entrance", context = context)
                
        if len(non_public) == 1 and len(slugs) >= 1 and len(official_name) == 1 and len(areas) >= 1 and len(kataster_code) == 1 and len(kataster_number) == 1 and len(unofficial_number) == 1 and len(explorers) == 1 and len(underground_description) == 1 and len(equipment) == 1 and len(references) == 1 and len(survey) == 1 and len(kataster_status) == 1 and len(underground_centre_line) == 1 and len(notes) == 1 and len(length) == 1 and len(depth) == 1 and len(extent) == 1 and len(survex_file) == 1 and len(description_file ) == 1 and len(url) == 1:
            try:
                c, state = Cave.objects.update_or_create(non_public = {"True": True, "False": False, "true": True, "false": False,}[non_public[0]],
                         official_name = official_name[0],
                         kataster_code = kataster_code[0],
                         kataster_number = kataster_number[0],
                         unofficial_number = unofficial_number[0],
                         explorers = explorers[0],
                         underground_description = underground_description[0],
                         equipment = equipment[0],
                         references = references[0],
                         survey = survey[0],
                         kataster_status = kataster_status[0],
                         underground_centre_line = underground_centre_line[0],
                         notes = notes[0],
                         length = length[0],
                         depth = depth[0],
                         extent = extent[0],
                         survex_file = survex_file[0],
                         description_file = description_file[0],
                         url = url[0],
                         filename = filename)
            except:
                print(" ! FAILED to get only one CAVE when updating using: "+filename)
                kaves = Cave.objects.all().filter(kataster_number=kataster_number[0])
                for k in kaves:
                    message = " ! - DUPLICATES in db. kataster:"+ str(k.kataster_number) + ", slug:" + str(k.slug()) 
                    DataIssue.objects.create(parser='caves', message=message)
                    print(message)
                for k in kaves:
                    if k.slug() != None:
                        print(" ! - OVERWRITING this one: slug:"+ str(k.slug()))
                        k.notes = "DUPLICATE kataster number found on import. Please fix\n" + k.notes
                        c = k
                
            for area_slug in areas:
                if area_slug in areas_xslug:
                    newArea = areas_xslug[area_slug]
                else:
                    area = Area.objects.filter(short_name = area_slug)
                    if area:
                        newArea = area[0]
                    else:
                        newArea = Area(short_name = area_slug, parent = Area.objects.get(short_name = "1623"))
                        newArea.save()
                    areas_xslug[area_slug] = newArea
                c.area.add(newArea)
            primary = True
            for slug in slugs:
                if slug in caves_xslug:
                    cs = caves_xslug[slug]
                else:
                    try: # we want to overwrite a PENDING cave if we are now importing the 1623-xxx.html file for it
                        cs = CaveSlug.objects.update_or_create(cave = c,
                                  slug = slug,
                                  primary = primary)
                        caves_xslug[slug] = cs
                    except Exception as ex:
                        # This fails to do an update! It just crashes.. to be fixed
                        message = " ! Cave update/create failure : %s, skipping file cave_data/%s with exception\nException: %s" % (slug, context, ex.__class__)
                        DataIssue.objects.create(parser='caves', message=message)
                        print(message)
                    
                primary = False

            if not entrances or len(entrances) < 1:
                # missing entrance link in cave_data/1623-* .html file
                set_dummy_entrance(slug[5:], slug, c, msg="DUMMY")
            else:
                for entrance in entrances:
                    eslug = getXML(entrance, "entranceslug", maxItems = 1, context = context)[0]
                    letter = getXML(entrance, "letter", maxItems = 1, context = context)[0]
                    if len(entrances) == 1 and not eslug: # may be empty: <entranceslug></entranceslug>
                        set_dummy_entrance(slug[5:], slug, c, msg="DUMMY")
                    else:
                        try:
                            if eslug in entrances_xslug:
                                entrance = entrances_xslug[eslug]
                            else:
                                entrance = Entrance.objects.get(entranceslug__slug = eslug)
                                entrances_xslug[eslug] = entrance
                            ce = CaveAndEntrance.objects.update_or_create(cave = c, entrance_letter = letter, entrance = entrance)
                        except:
                            message = f' ! Entrance setting failure, slug:"{slug}" #entrances:{len(entrances)} {entrance} letter:"{letter}" cave:"{c}" filename:"cave_data/{filename}"'
                            DataIssue.objects.create(parser='caves', message=message, url=f'{c.url}_edit/')
                            print(message)
                        
            if survex_file[0]:
                if not (Path(SURVEX_DATA) / survex_file[0]).is_file():
                    message = f' ! {slug:12} survex filename does not exist :LOSER:"{survex_file[0]}" in "{filename}"'
                    DataIssue.objects.create(parser='caves', message=message, url=f'/{slug}_cave_edit/')
                    print(message)
                    

            if description_file[0]: # if not an empty string
                message = f' - {slug:12} complex description filename "{description_file[0]}" inside "{CAVEDESCRIPTIONS}/{filename}"'
                DataIssue.objects.create(parser='caves ok', message=message, url=f'/{slug}_cave_edit/')
                print(message)

                if not (Path(EXPOWEB) / description_file[0]).is_file():
                    message = f' ! {slug:12} description filename  "{EXPOWEB}/{description_file[0]}" does not refer to a real file'
                    DataIssue.objects.create(parser='caves', message=message, url=f'/{slug}_cave_edit/')
                    print(message)
                    #c.description_file="" # done only once, to clear out cruft.
                    #c.save()
        else: # more than one item in long list
            message = f' ! ABORT loading this cave. in "{filename}"'
            DataIssue.objects.create(parser='caves', message=message, url=f'/{slug}_cave_edit/')
            print(message)

def getXML(text, itemname, minItems = 1, maxItems = None, printwarnings = True, context = ""):
    items = re.findall("<%(itemname)s>(.*?)</%(itemname)s>" % {"itemname": itemname}, text, re.S)
    if len(items) < minItems and printwarnings:
        message = " ! %(count)i x %(itemname)s found, at least %(min)i expected. Load ABORT. " % {"count": len(items),
                                                                           "itemname": itemname,
                                                                           "min": minItems} + " in file " + context
        DataIssue.objects.create(parser='caves', message=message, url=""+context)
        print(message)
        
    if maxItems is not None and len(items) > maxItems and printwarnings:
        message = " ! %(count)i x %(itemname)s found, no more than %(max)i expected in this XML unit. Load ABORT. " % {"count": len(items),
                                                                               "itemname": itemname,
                                                                               "max": maxItems} + " in file " + context
        DataIssue.objects.create(parser='caves', message=message)
        print(message)
    return items