import os
from datetime import datetime as dt, timezone as tz
from flask import request, redirect, url_for, flash, render_template, Blueprint, session, current_app
from flask_security import hash_password, roles_required, roles_accepted, current_user
from sqlalchemy import desc
from sqlalchemy.orm import joinedload
from werkzeug.utils import secure_filename

from ..models.document import Document, DocumentLanguage, DocumentVersion
from ..extensions import db
from .document_forms import AddDocumentForm
from ..utils.middleware import mw_before_request

document_bp = Blueprint('document_bp', __name__, url_prefix='/document')


@document_bp.before_request
def before_request():
    mw_before_request()


@document_bp.route('/add_document', methods=['GET', 'POST'])
@roles_accepted('Super User', 'Tenant Admin')
def add_document():
    form = AddDocumentForm()
    error = None

    # If the form is submitted
    if request.method == 'POST' and form.validate_on_submit():
        file = form.file.data
        filename = secure_filename(file.filename)
        extension = filename.rsplit('.', 1)[1].lower()

        # Create the Document
        new_doc = Document()
        if form.name.data == '':
            new_doc.name = filename.rsplit('.', 1)[0]
        else:
            new_doc.name = form.name.data

        if form.valid_from.data or form.valid_from.data != '':
            new_doc.valid_from = form.valid_from.data
        else:
            new_doc.valid_from = dt.now(tz.utc)
        new_doc.tenant_id = session['tenant']['id']
        set_logging_information(new_doc, dt.now(tz.utc))

        # Create the DocumentLanguage
        new_doc_lang = create_language_for_document(new_doc, form.language.data)

        # Create the DocumentVersion
        new_doc_vers = DocumentVersion()
        new_doc_vers.document_language = new_doc_lang
        set_logging_information(new_doc_vers, dt.now(tz.utc))

        try:
            db.session.add(new_doc)
            db.session.add(new_doc_lang)
            db.session.add(new_doc_vers)
            db.session.commit()
            new_doc_lang.latest_version = new_doc_vers
            db.session.commit()
        except Exception as e:
            db.session.rollback()
            error = e.args

        # Save the file and process the document
        if error is None:
            flash('Document added successfully.', 'success')
            upload_file_for_version(new_doc_vers, file, extension)
        else:
            flash('Error adding document.', 'error')
            current_app.logger.error(f'Error adding document for tenant {session["tenant"]["id"]}: {error}')

    # return render_template('document/add_document.html', form=form)


@document_bp.route('/documents', methods=['GET', 'POST'])
@roles_accepted('Super User', 'Tenant Admin')
def documents():
    page = request.args.get('page', 1, type=int)
    per_page = request.args.get('per_page', 10, type=int)

    query = Document.query.order_by(desc(Document.created_at)).options(
        joinedload(Document.languages).joinedload(DocumentLanguage.versions))

    pagination = query.paginate(page=page, per_page=per_page, error_out=False)
    docs = pagination.items

    rows = prepare_document_data(docs)

    return render_template('document/documents.html', rows=rows, pagination=pagination)


@document_bp.route('/process_version/<int:version_id>', methods=['POST'])
@roles_accepted('Super User', 'Tenant Admin')
def process_version(version_id):
    version = DocumentVersion.query.get_or_404(version_id)
    if not version.processing:
        print(f'Placeholder for processing version: {version_id}')

    return redirect(url_for('documents'))


def set_logging_information(obj, timestamp):
    obj.created_at = timestamp
    obj.updated_at = timestamp
    obj.created_by = current_user.id
    obj.updated_by = current_user.id


def create_language_for_document(document, language):
    new_doc_lang = DocumentLanguage()
    if language == '':
        new_doc_lang.language = session['default_language']
    else:
        new_doc_lang.language = language

    new_doc_lang.document = document

    set_logging_information(new_doc_lang, dt.now(tz.utc))

    return new_doc_lang


def upload_file_for_version(doc_vers, file, extension):
    error = None
    doc_vers.file_type = extension
    doc_vers.file_name = doc_vers.calc_file_name()
    doc_vers.file_location = doc_vers.calc_file_location()

    upload_path = os.path.join(current_app.config['UPLOAD_FOLDER'], doc_vers.file_location)
    if not os.path.exists(upload_path):
        os.makedirs(upload_path, exist_ok=True)
    file.save(os.path.join(upload_path, doc_vers.file_name))
    try:
        db.session.commit()
    except Exception as e:
        db.session.rollback()
        error = e.args
    if error is None:
        flash('Document saved successfully.', 'success')
        current_app.logger.info(f'Starting Doucment processing for tenant {session['tenant']['id']} for document '
                                f'version {doc_vers.id}')
        # TODO: processing of document to embeddings (async)
        flash('Document processing started.', 'info')
    else:
        flash('Error saving document.', 'error')
        current_app.logger.error(f'Error saving document for tenant {session["tenant"]["id"]}: {error}')


# Sample code for adding or updating versions and ensuring latest_version is set in DocumentLanguage
# def add_or_update_version(language_id, version_data):
#     new_version = Version(language_id=language_id, **version_data)
#     db.session.add(new_version)
#     db.session.flush()  # Ensures new_version gets an ID assigned if it's new
#
#     # Assuming we always call this when we know it's the latest
#     language = Language.query.get(language_id)
#     language.latest_version_id = new_version.id
#     db.session.commit()

# sample code for using latest_version in the application
# @app.route('/language/<int:language_id>')
# def show_language(language_id):
#     language = Language.query.get_or_404(language_id)
#     latest_version = language.latest_version  # This is now a direct, efficient database access
#     return render_template('language_details.html', language=language, latest_version=latest_version)


def prepare_document_data(docs):
    rows = []
    for doc in docs:
        doc_row = [{'value': doc.name, 'class': '', 'type': 'text'},
                   {'value': doc.created_at.strftime("%Y-%m-%d %H:%M:%S"), 'class': '', 'type': 'text'}]
        # Document basic details
        if doc.valid_from:
            doc_row.append({'value': doc.valid_from.strftime("%Y-%m-%d"), 'class': '', 'type': 'text'})
        else:
            doc_row.append({'value': '', 'class': '', 'type': 'text'})

        # Nested languages and versions
        languages_rows = []
        for lang in doc.languages:
            lang_row = [{'value': lang.language, 'class': '', 'type': 'text'}]

            # Latest version details if available (should be available ;-) )
            if lang.latest_version:
                lang_row.append({'value': lang.latest_version.created_at.strftime("%Y-%m-%d %H:%M:%S"),
                                    'class': '', 'type': 'text'})
                if lang.latest_version.url:
                    lang_row.append({'value': lang.latest_version.url,
                                            'class': '', 'type': 'link', 'href': lang.latest_version.url})
                else:
                    lang_row.append({'value': '', 'class': '', 'type': 'text'})

                if lang.latest_version.file_name:
                    lang_row.append({'value': lang.latest_version.file_name, 'class': '', 'type': 'text'})
                else:
                    lang_row.append({'value': '', 'class': '', 'type': 'text'})

                if lang.latest_version.file_type:
                    lang_row.append({'value': lang.latest_version.file_type, 'class': '', 'type': 'text'})
                else:
                    lang_row.append({'value': '', 'class': '', 'type': 'text'})
                    # Include other details as necessary

            languages_rows.append(lang_row)

        doc_row.append({'is_group': True, 'colspan': '4',
                        'headers': ['Language', 'Latest Version', 'URL', 'File Name', 'Type'],
                        'sub_rows': languages_rows})
        rows.append(doc_row)
    return rows