from datetime import datetime
from flask import request, render_template, session
from sqlalchemy import desc, asc

from common.models.document import DocumentVersion, Document
from common.utils.filtered_list_view import FilteredListView
from common.utils.view_assistants import prepare_table_for_macro


class DocumentVersionListView(FilteredListView):
    allowed_filters = ['file_type', 'processing', 'processing_error']
    allowed_sorts = ['id', 'processing_started_at', 'processing_finished_at', 'processing_error']

    def get_query(self):
        return DocumentVersion.query.join(Document).filter(Document.tenant_id == session.get('tenant', {}).get('id'))

    def apply_filters(self, query):
        filters = request.args.to_dict()

        if filters.get('file_type'):
            query = query.filter(DocumentVersion.file_type == filters['file_type'])

        if filters.get('processing'):
            query = query.filter(DocumentVersion.processing == (filters['processing'] == 'true'))

        if filters.get('processing_error'):
            if filters['processing_error'] == 'true':
                query = query.filter(DocumentVersion.processing_error.isnot(None))
            elif filters['processing_error'] == 'false':
                query = query.filter(DocumentVersion.processing_error.is_(None))

        if filters.get('start_date'):
            query = query.filter(
                DocumentVersion.processing_started_at >= datetime.strptime(filters['start_date'], '%Y-%m-%d'))

        if filters.get('end_date'):
            query = query.filter(
                DocumentVersion.processing_finished_at <= datetime.strptime(filters['end_date'], '%Y-%m-%d'))

        return query

    def apply_sorting(self, query):
        sort_by = request.args.get('sort_by', 'id')
        sort_order = request.args.get('sort_order', 'asc')

        if sort_by in self.allowed_sorts:
            column = getattr(DocumentVersion, sort_by)
            if sort_order == 'asc':
                query = query.order_by(asc(column))
            elif sort_order == 'desc':
                query = query.order_by(desc(column))

        return query

    def get(self):
        query = self.get_query()
        query = self.apply_filters(query)
        query = self.apply_sorting(query)
        pagination = self.paginate(query)

        rows = prepare_table_for_macro(
            pagination.items,
            [('id', ''), ('file_type', ''), ('processing', ''),
             ('processing_started_at', ''), ('processing_finished_at', ''),
             ('processing_error', '')]
        )

        context = {
            'rows': rows,
            'pagination': pagination,
            'filters': request.args.to_dict(),
            'sort_by': request.args.get('sort_by', 'id'),
            'sort_order': request.args.get('sort_order', 'asc'),
            'filter_options': self.get_filter_options()
        }
        return render_template(self.template, **context)

    def get_filter_options(self):
        return {
            'file_type': [('pdf', 'PDF'), ('docx', 'DOCX')],
            'processing': [('true', 'Processing'), ('false', 'Not Processing')],
            'processing_error': [('true', 'With Errors'), ('false', 'Without Errors')]
        }