#!/usr/bin/env python3.7
# coding=utf-8

from argparse import ArgumentParser
from xml.sax.saxutils import escape
import hashlib
import json


# Two global ressources - Not very elegant but it works for now
stand_off_data = None
text = None


def meta_to_string():
    string = ''
    string += '<generator software="{} ({})" arguments="check_encoding: {}; language: {}"/>\n'.format(  # noqa
        stand_off_data['meta']['generator']['name'],
        stand_off_data['meta']['generator']['version'],
        stand_off_data['meta']['generator']['arguments']['check_encoding'],
        stand_off_data['meta']['generator']['arguments']['language']
    )
    string += '<file encoding="{}" name="{}" md5="{}"/>\n'.format(
        stand_off_data['meta']['file']['encoding'],
        stand_off_data['meta']['file']['name'],
        stand_off_data['meta']['file']['md5']
    )
    return string


def tags_to_string():
    return ''


def annotations_to_string(end=float('inf')):
    string = ''
    while stand_off_data['annotations']:
        if stand_off_data['annotations'][0]['start'] >= end:
            break
        annotation = stand_off_data['annotations'].pop(0)
        #######################################################################
        # Check for malformed annotations                                     #
        #######################################################################
        if 'tag' not in annotation:
            raise Exception('Annotation tag is missing')

        if annotation['tag'] not in stand_off_data['tags']:
            raise Exception('Unknown annotation tag: ' + annotation['tag'])

        tag_model = stand_off_data['tags'][annotation['tag']]
        if 'properties' in tag_model:
            properties_model = tag_model['properties']
            if properties_model is not None:
                required_properties = filter(lambda x: 'flags' in x and 'required' in x['flags'], properties_model)  # noqa
                if required_properties and annotation['properties'] is None:
                    raise Exception('There are required properties but the "Properties" attribute is missing')  # noqa
                for property in required_properties:
                    if property not in annotation['properties']:
                        raise Exception('Required property is missing: ' + property)  # noqa
        #######################################################################
        # Process tokens ~ cwb's positional attributes                        #
        #######################################################################
        if annotation['tag'] == 'token':
            string += '{}\t{}\t{}\t{}\t{}\n'.format(
                escape(text[annotation['start']:annotation['end']]),
                escape(annotation['properties']['pos']),
                escape(annotation['properties']['lemma']),
                escape(annotation['properties']['simple_pos']),
                escape(annotation['properties']['ner'] if 'ner' in annotation['properties'] else 'None')  # noqa
            )
        #######################################################################
        # Process other tags ~ cwb's structural attributes                    #
        #######################################################################
        else:
            properties = ''
            if 'properties' in annotation and annotation['properties'] is not None:  # noqa
                for property, value in annotation['properties'].items():
                    if not value:
                        continue
                    if properties_model and property in properties_model:
                        if 'flags' in properties_model and 'multiple' in properties_model['flags']:  # noqa
                            properties += ' {}="|{}|"'.format(property, '|'.join(value))  # noqa
                        else:
                            properties += ' {}="{}"'.format(property, value)
            string += '<' + annotation['tag'] + properties + '>\n'
            string += annotations_to_string(end=min(annotation['end'], end))
            string += '</' + annotation['tag'] + '>\n'
    return string


def main():
    global stand_off_data
    global text

    # Parse the given arguments
    parser = ArgumentParser(description='Create a vrt from JSON and txt')
    parser.add_argument('text', metavar='Path to txt file')
    parser.add_argument('stand_off_data', metavar='Path to JSON file')
    parser.add_argument('output', metavar='Path to vrt output file')
    args = parser.parse_args()

    with open(args.stand_off_data) as stand_of_data_file:
        stand_off_data = json.load(stand_of_data_file)

    with open(args.text, "rb") as text_file:
        text_md5 = hashlib.md5()
        for chunk in iter(lambda: text_file.read(128 * text_md5.block_size), b''):  # noqa
            text_md5.update(chunk)
        if text_md5.hexdigest() != stand_off_data['meta']['file']['md5']:
            raise Exception('md5 not equal')

    with open(args.text, encoding=stand_off_data['meta']['file']['encoding']) as text_file:  # noqa
        text = text_file.read()

    vrt = ''
    vrt += '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>\n'
    vrt += '<corpus>\n'
    vrt += '<text>\n'
    vrt += meta_to_string()
    vrt += tags_to_string()
    vrt += annotations_to_string()
    vrt += '</text>\n'
    vrt += '</corpus>'

    with open(args.output, 'w') as vrt_file:
        vrt_file.write(vrt)


if __name__ == '__main__':
    main()