"""Set up a model directory.

Requires:

    lang_data --- Rules for the tokenizer
        * prefix.txt
        * suffix.txt
        * infix.txt
        * morphs.json
        * specials.json

    corpora --- Data files
        * WordNet
        * words.sgt.prob --- Smoothed unigram probabilities
        * clusters.txt --- Output of hierarchical clustering, e.g. Brown clusters
        * vectors.tgz --- output of something like word2vec
"""
from __future__ import unicode_literals

from ast import literal_eval
import math
import gzip

import plac
from pathlib import Path

from shutil import copyfile
from shutil import copytree
import codecs
from collections import defaultdict

from spacy.en import get_lex_props
from spacy.en.lemmatizer import Lemmatizer
from spacy.vocab import Vocab
from spacy.vocab import write_binary_vectors
from spacy.strings import hash_string
from preshed.counter import PreshCounter

from spacy.parts_of_speech import NOUN, VERB, ADJ


def setup_tokenizer(lang_data_dir, tok_dir):
    if not tok_dir.exists():
        tok_dir.mkdir()

    for filename in ('infix.txt', 'morphs.json', 'prefix.txt', 'specials.json',
                     'suffix.txt'):
        src = lang_data_dir / filename
        dst = tok_dir / filename
        copyfile(str(src), str(dst))


def _read_clusters(loc):
    if not loc.exists():
        print("Warning: Clusters file not found")
        return {}
    clusters = {}
    for line in codecs.open(str(loc), 'r', 'utf8'):
        try:
            cluster, word, freq = line.split()
        except ValueError:
            continue
        # If the clusterer has only seen the word a few times, its cluster is
        # unreliable.
        if int(freq) >= 3:
            clusters[word] = cluster
        else:
            clusters[word] = '0'
    # Expand clusters with re-casing
    for word, cluster in list(clusters.items()):
        if word.lower() not in clusters:
            clusters[word.lower()] = cluster
        if word.title() not in clusters:
            clusters[word.title()] = cluster
        if word.upper() not in clusters:
            clusters[word.upper()] = cluster
    return clusters


def _read_probs(loc):
    if not loc.exists():
        print("Probabilities file not found. Trying freqs.")
        return {}, 0.0
    probs = {}
    for i, line in enumerate(codecs.open(str(loc), 'r', 'utf8')):
        prob, word = line.split()
        prob = float(prob)
        probs[word] = prob
    return probs, probs['-OOV-']


def _read_freqs(loc, max_length=100, min_doc_freq=5, min_freq=200):
    if not loc.exists():
        print("Warning: Frequencies file not found")
        return {}, 0.0
    counts = PreshCounter()
    total = 0
    if str(loc).endswith('gz'):
        file_ = gzip.open(str(loc))
    else:
        file_ = loc.open()
    for i, line in enumerate(file_):
        freq, doc_freq, key = line.split('\t', 2)
        freq = int(freq)
        counts.inc(i+1, freq)
        total += freq
    counts.smooth()
    log_total = math.log(total)
    probs = {}
    for line in loc.open():
        freq, doc_freq, key = line.split('\t', 2)
        doc_freq = int(doc_freq)
        freq = int(freq)
        if doc_freq >= min_doc_freq and freq >= min_freq and len(key) < max_length:
            word = literal_eval(key)
            smooth_count = counts.smoother(int(freq))
            log_smooth_count = math.log(smooth_count)
            probs[word] = math.log(smooth_count) - log_total
    oov_prob = math.log(counts.smoother(0)) - log_total
    return probs, oov_prob


def _read_senses(loc):
    lexicon = defaultdict(lambda: defaultdict(list))
    if not loc.exists():
        print("Warning: WordNet senses not found")
        return lexicon
    sense_names = dict((s, i) for i, s in enumerate(spacy.senses.STRINGS))
    pos_ids = {'noun': NOUN, 'verb': VERB, 'adjective': ADJ}
    for line in codecs.open(str(loc), 'r', 'utf8'):
        sense_strings = line.split()
        word = sense_strings.pop(0)
        for sense in sense_strings:
            pos, sense = sense[3:].split('.')
            sense_name = '%s_%s' % (pos[0].upper(), sense.lower())
            if sense_name != 'N_tops':
                sense_id = sense_names[sense_name]
                lexicon[word][pos_ids[pos]].append(sense_id)
    return lexicon


def setup_vocab(src_dir, dst_dir):
    if not dst_dir.exists():
        dst_dir.mkdir()

    vectors_src = src_dir / 'vectors.tgz'
    if vectors_src.exists():
        write_binary_vectors(str(vectors_src), str(dst_dir / 'vec.bin'))
    else:
        print("Warning: Word vectors file not found")
    vocab = Vocab(data_dir=None, get_lex_props=get_lex_props)
    clusters = _read_clusters(src_dir / 'clusters.txt')
    probs, oov_prob = _read_probs(src_dir / 'words.sgt.prob')
    if not probs:
        probs, oov_prob = _read_freqs(src_dir / 'freqs.txt')
    if not probs:
        oov_prob = 0.0
    else:
        oov_prob = min(probs.values())
    for word in clusters:
        if word not in probs:
            probs[word] = oov_prob

    lexicon = []
    for word, prob in reversed(sorted(list(probs.items()), key=lambda item: item[1])):
        entry = get_lex_props(word)
        entry['prob'] = float(prob)
        cluster = clusters.get(word, '0')
        # Decode as a little-endian string, so that we can do & 15 to get
        # the first 4 bits. See _parse_features.pyx
        entry['cluster'] = int(cluster[::-1], 2)
        vocab[word] = entry
    vocab.dump(str(dst_dir / 'lexemes.bin'))
    vocab.strings.dump(str(dst_dir / 'strings.txt'))
    with (dst_dir / 'oov_prob').open('w') as file_:
        file_.write('%f' % oov_prob)


def main(lang_data_dir, corpora_dir, model_dir):
    model_dir = Path(model_dir)
    lang_data_dir = Path(lang_data_dir)
    corpora_dir = Path(corpora_dir)

    assert corpora_dir.exists()
    assert lang_data_dir.exists()

    if not model_dir.exists():
        model_dir.mkdir()

    setup_tokenizer(lang_data_dir, model_dir / 'tokenizer')
    setup_vocab(corpora_dir, model_dir / 'vocab')

    if (lang_data_dir / 'gazetteer.json').exists():
        copyfile(str(lang_data_dir / 'gazetteer.json'),
                 str(model_dir / 'vocab' / 'gazetteer.json'))
    if not (model_dir / 'wordnet').exists():
        copytree(str(corpora_dir / 'wordnet' / 'dict'), str(model_dir / 'wordnet'))


if __name__ == '__main__':
    plac.call(main)