from flask import current_app
from app import db
from app.models import User, Corpus, CorpusFile
from datetime import datetime
import json
import os
import shutil


class SandpaperConverter:
    def __init__(self, json_db_file, data_dir):
        self.json_db_file = json_db_file
        self.data_dir = data_dir

    def run(self):
        with open(self.json_db_file, 'r') as f:
            json_db = json.loads(f.read())

        for json_user in json_db:
            if not json_user['confirmed']:
                current_app.logger.info(f'Skip unconfirmed user {json_user["username"]}')
                continue
            user_dir = os.path.join(self.data_dir, str(json_user['id']))
            self.convert_user(json_user, user_dir)
            db.session.commit()


    def convert_user(self, json_user, user_dir):
        current_app.logger.info(f'Create User {json_user["username"]}...')
        user = User(
            confirmed=json_user['confirmed'],
            email=json_user['email'],
            last_seen=datetime.fromtimestamp(json_user['last_seen']),
            member_since=datetime.fromtimestamp(json_user['member_since']),
            password_hash=json_user['password_hash'],  # TODO: Needs to be added manually
            username=json_user['username']
        )
        db.session.add(user)
        db.session.flush(objects=[user])
        db.session.refresh(user)
        try:
            user.makedirs()
        except OSError as e:
            current_app.logger.error(e)
            db.session.rollback()
            raise Exception('Internal Server Error')
        for json_corpus in json_user['corpora'].values():
            if not json_corpus['files'].values():
                current_app.logger.info(f'Skip empty corpus {json_corpus["title"]}')
                continue
            corpus_dir = os.path.join(user_dir, 'corpora', str(json_corpus['id']))
            self.convert_corpus(json_corpus, user, corpus_dir)
        current_app.logger.info('Done')


    def convert_corpus(self, json_corpus, user, corpus_dir):
        current_app.logger.info(f'Create Corpus {json_corpus["title"]}...')
        corpus = Corpus(
            user=user,
            creation_date=datetime.fromtimestamp(json_corpus['creation_date']),
            description=json_corpus['description'],
            title=json_corpus['title']
        )
        db.session.add(corpus)
        db.session.flush(objects=[corpus])
        db.session.refresh(corpus)
        try:
            corpus.makedirs()
        except OSError as e:
            current_app.logger.error(e)
            db.session.rollback()
            raise Exception('Internal Server Error')
        for json_corpus_file in json_corpus['files'].values():
            self.convert_corpus_file(json_corpus_file, corpus, corpus_dir)
        current_app.logger.info('Done')


    def convert_corpus_file(self, json_corpus_file, corpus, corpus_dir):
        current_app.logger.info(f'Create CorpusFile {json_corpus_file["title"]}...')
        corpus_file = CorpusFile(
            corpus=corpus,
            address=json_corpus_file['address'],
            author=json_corpus_file['author'],
            booktitle=json_corpus_file['booktitle'],
            chapter=json_corpus_file['chapter'],
            editor=json_corpus_file['editor'],
            filename=json_corpus_file['filename'],
            institution=json_corpus_file['institution'],
            journal=json_corpus_file['journal'],
            mimetype='application/vrt+xml',
            pages=json_corpus_file['pages'],
            publisher=json_corpus_file['publisher'],
            publishing_year=json_corpus_file['publishing_year'],
            school=json_corpus_file['school'],
            title=json_corpus_file['title']
        )
        db.session.add(corpus_file)
        db.session.flush(objects=[corpus_file])
        db.session.refresh(corpus_file)
        try:
            shutil.copy2(
                os.path.join(corpus_dir, json_corpus_file['filename']),
                corpus_file.path
            )
        except:
            current_app.logger.warning(
                'Can not convert corpus file: '
                f'{os.path.join(corpus_dir, json_corpus_file["filename"])}'
                ' -> '
                f'{corpus_file.path}'
            )
        current_app.logger.info('Done')