from datetime import datetime
from .. import db
from ..decorators import background
from ..models import Corpus, CorpusFile
import xml.etree.ElementTree as ET
import os
import shutil


@background
def build_corpus(corpus_id, *args, **kwargs):
    app = kwargs['app']
    with app.app_context():
        corpus = Corpus.query.get(corpus_id)
        if corpus is None:
            return
        corpus.status = 'File processing'
        db.session.commit()
        corpus_dir = os.path.join(app.config['NOPAQUE_STORAGE'],
                                  str(corpus.user_id), 'corpora',
                                  str(corpus.id))
        output_dir = os.path.join(corpus_dir, 'merged')
        shutil.rmtree(output_dir, ignore_errors=True)
        os.mkdir(output_dir)
        master_element_tree = ET.ElementTree(
            ET.fromstring('<corpus>\n</corpus>'))
        for corpus_file in corpus.files:
            file = os.path.join(corpus_dir, corpus_file.filename)
            element_tree = ET.parse(file)
            text_node = element_tree.find('text')
            text_node.set('address', corpus_file.address or "NULL")
            text_node.set('author', corpus_file.author)
            text_node.set('booktitle', corpus_file.booktitle or "NULL")
            text_node.set('chapter', corpus_file.chapter or "NULL")
            text_node.set('editor', corpus_file.editor or "NULL")
            text_node.set('institution', corpus_file.institution or "NULL")
            text_node.set('journal', corpus_file.journal or "NULL")
            text_node.set('pages', corpus_file.pages or "NULL")
            text_node.set('publisher', corpus_file.publisher or "NULL")
            text_node.set('publishing_year', str(corpus_file.publishing_year))
            text_node.set('school', corpus_file.school or "NULL")
            text_node.set('title', corpus_file.title)
            element_tree.write(file)
            master_element_tree.getroot().insert(1, text_node)
        output_file = os.path.join(output_dir, 'corpus.vrt')
        master_element_tree.write(output_file, xml_declaration=True,
                                  encoding='utf-8')
        corpus.status = 'submitted'
        corpus.last_edited_date = datetime.utcnow()
        db.session.commit()


@background
def delete_corpus(corpus_id, *args, **kwargs):
    app = kwargs['app']
    with app.app_context():
        corpus = Corpus.query.get(corpus_id)
        if corpus is None:
            return
        path = os.path.join(app.config['NOPAQUE_STORAGE'], str(corpus.user_id),
                            'corpora', str(corpus.id))
        shutil.rmtree(path, ignore_errors=True)
        corpus.delete()


@background
def delete_corpus_file(corpus_file_id, *args, **kwargs):
    app = kwargs['app']
    with app.app_context():
        corpus_file = CorpusFile.query.get(corpus_file_id)
        if corpus_file is None:
            return
        path = os.path.join(app.config['NOPAQUE_STORAGE'], corpus_file.dir,
                            corpus_file.filename)
        try:
            os.remove(path)
        except Exception:
            pass
        else:
            corpus_file.delete()