import re
from django.db import DatabaseError, transaction
from django.utils.html import linebreaks

from quotes.models import QuoteTag, Quote, Work, Author

def get_or_create_author(authorname, resultcontext):
    authorname = authorname.strip()
    try:
        return Author.objects.get(name=authorname)
    except Author.DoesNotExist:
        a = Author.objects.create(name=authorname,
                                  pvt_notes="<p>Created during mass import</p>")
        resultcontext["created_authors"] += [a]
        return a

def get_or_create_work(workname, author, resultcontext):
    workname = workname.strip()
    try:
        return Work.objects.get(name=workname, author=author)
    except Work.DoesNotExist:
        w = Work.objects.create(name=workname,
                                author=author,
                                pvt_notes="<p>Created during mass import</p>")
        resultcontext["created_works"] += [w]
        return w

def get_or_create_tag(tagname, resultcontext):
    try:
        return QuoteTag.objects.get(tag=tagname)
    except QuoteTag.DoesNotExist:
        t = QuoteTag.objects.create(tag=tagname)
        resultcontext["created_tags"] += [t]
        return t
    
def add_tags_on_quote(quote, tagline, resultcontext):
    for tagname in tagline.split(","):
        tagname = tagname.strip()
        if not tagname:
            continue
        tag = get_or_create_tag(tagname, resultcontext)
        quote.tags.add(tag)

def paragraphize(text):
    text = text.strip()
    return linebreaks(text)
        
def create_quote(quotetext, authorname, workname, tagline, resultcontext):
    author = get_or_create_author(authorname, resultcontext)
    work = get_or_create_work(workname, author, resultcontext)
    quotetext = paragraphize(quotetext)
    quote = Quote.objects.create(text=quotetext, work=work)
    add_tags_on_quote(quote, tagline, resultcontext)
    resultcontext["created_quotes"] += [quote]

def create_all_quotes(allquotes, resultcontext):
    quotesep = re.compile(r'^\s*===+.*$', re.MULTILINE)
    elemsep = re.compile(r'^\s*---+.*$', re.MULTILINE)
    
    for fullquote in quotesep.split(allquotes):
        if not fullquote: continue

        elements = elemsep.split(fullquote)
        if len(elements) not in [3, 4]:
            resultcontext["rejected"] += [fullquote]
            continue
        quotetext, authorname, workname = elements[0:3]
        if len(elements) == 4:
            tagline = elements[3]
        else:
            tagline = ''
        create_quote(quotetext, authorname, workname, tagline,
                     resultcontext)

def domassimport(allquotes):
    resultcontext = {}
    resultcontext["created_quotes"] = []
    resultcontext["created_tags"] = []
    resultcontext["created_works"] = []
    resultcontext["created_authors"] = []
    resultcontext["rejected"] = []
    resultcontext["fatal_error"] = False

    try:
        with transaction.atomic():
            create_all_quotes(allquotes, resultcontext)
    except DatabaseError as e:
        resultcontext["fatal_error"] = True
        resultcontext["fatal_error_message"] = e.__cause__

    return resultcontext