# coding=utf-8
# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import argparse
import itertools
import json
from lsh import cache, minhash
import numpy as np
import time
import pickle
import sys

# This function is adapted from:
#   https://github.com/mattilyra/LSH/blob/master/examples/Introduction.ipynb
def shingles(text, char_ngram=5):
    return set(text[head:head + char_ngram]
               for head in range(0, len(text) - char_ngram))


# This function is adapted from:
#  https://github.com/mattilyra/LSH/blob/master/examples/Introduction.ipynb
def jaccard(set_a, set_b):
    intersection = set_a & set_b
    union = set_a | set_b
    return len(intersection) / len(union)


if __name__ == '__main__':

    print('parsing the arguments ...')

    parser = argparse.ArgumentParser()
    parser.add_argument('--seed', type=int, default=1234,
                       help='Random seed used for python, numpy')
    parser.add_argument('--inputs', nargs = '*', default=None, help = \
                        'Pairwise list of the input files and keys, '
                        'e.g. --inputs cc.json cc_id news.json news_id')
    parser.add_argument('--load-fingerprints', nargs = '*', default=None,
                       help='Load fingerprints from a list of pickle files,'
                        ' e.g. cc.pkl news.pkl')
    parser.add_argument('--save-fingerprints', type=str, default=None,
                       help='Save the fingerprints of the inputs.')
    parser.add_argument('--output', type=str, default=None,
                       help='Output file name that consists of all ids'
                        ' with matching similarities')
    args = parser.parse_args()

    print('finding possible duplicate content ...')

    # set seed and get an array of seeds of 100 integers
    np.random.seed(args.seed)
    seeds = np.random.randint(0, 1e6, size=100)

    # initialize minhash and lsh cache
    hasher = minhash.MinHasher(seeds=seeds, char_ngram=5, hashbytes=4)
    lshcache = cache.Cache(bands=10, hasher=hasher)

    url_doc = {}

    # load fingerprints from pickle file if needed
    if args.load_fingerprints is not None:
        for count_fp, fp_file_name in enumerate(args.load_fingerprints):
            print("Loading fingerprints from pickle file {}".format(
                fp_file_name), flush=True)
            fp = open(fp_file_name, "rb")
            if count_fp == 0:
                # assign directory for the first pkl
                lshcache = pickle.load(fp)
                url_doc = pickle.load(fp)
            else:
                # append these to lshcache and url_doc
                local_lshcache = pickle.load(fp)
                local_url_doc = pickle.load(fp)
                for url in local_lshcache.fingerprints.keys():
                    url_doc[url] = local_url_doc[url]
                    lshcache.add_fingerprint(local_lshcache.fingerprints[url], url)
            fp.close()

    counter = 0
    start_time = time.time()

    print("Computing fingerprints", flush=True)

    # compute finger prints of the inputs if any
    # input file and the key to use as id
    if args.inputs is not None:
        assert len(args.inputs) % 2 == 0
        for input_file, key in zip(args.inputs[::2], args.inputs[1::2]):
            print(' document processing {} with key {}'.format(input_file, key),
                flush=True)
            # traverse all the texts and add fingerprints
            with open(input_file, 'r') as f_input:
                for line in f_input:
                    try:
                        myjson = json.loads(line)
                        url = myjson[key]
                        text = myjson['text']
                        counter += 1
                        url_doc[url] = text
                        lshcache.add_fingerprint(hasher.fingerprint(text), url)
                    except Exception as e:
                        print('Error:', e)
                    if counter % 10000 == 0:
                        print(' [read]> processed {} documents in {:.2f} '
                            'seconds ...'.format(counter, time.time() - \
                            start_time), flush=True)

    # Save the fingerprints if needed
    if args.save_fingerprints is not None:
        print("Saving fingerprints to pickle file {}".format(
            args.save_fingerprints), flush=True)
        with open(args.save_fingerprints, 'wb') as f_save:
            pickle.dump(lshcache, f_save)
            pickle.dump(url_doc, f_save)

    counter = 0
    start_time = time.time()
    deduped = 0
    # compute jaccard index of the input texts and write to file if needed
    if args.output is not None:
        f_out = open(args.output, 'wb')
        for b in lshcache.bins:
            for bucket_id in b:
                if len(b[bucket_id]) > 1:
                    items = list(b[bucket_id])
                    main_url = items[0]
                    main_dhingles = shingles(url_doc[main_url])
                    remove_urls = []
                    for i in range(1, len(items)):
                        counter += 1
                        other_url= items[i]
                        other_shingles = shingles(url_doc[other_url])
                        try:
                            jaccard_sim = jaccard(main_dhingles, other_shingles)
                        except Exception as e:
                            print('Error:', e)
                        if jaccard_sim > 0.5:
                            remove_urls.append({other_url: jaccard_sim})
                            deduped += 1
                        if counter % 10000 == 0:
                            print(' [write]> processed {} documents in {:.2f} '
                                  'seoncds and deduped {} documents ...'.
                                  format(counter, time.time() - start_time,
                                         deduped), flush=True)
                    if len(remove_urls) > 0:
                        myjson = json.dumps({main_url: remove_urls},
                                            ensure_ascii=False)
                        f_out.write(myjson.encode('utf-8'))
                        f_out.write('\n'.encode('utf-8'))
        f_out.close()

    print('done :-)')