# cython: profile=True
from __future__ import unicode_literals

from libc.stdlib cimport calloc, free

from ext.murmurhash cimport MurmurHash64A
from ext.murmurhash cimport MurmurHash64B

from spacy.lexeme cimport init_lexeme
from spacy.lexeme cimport BLANK_WORD

from spacy.string_tools cimport is_whitespace

from . import util
from os import path
cimport cython


cdef load_tokenization(Vocab* vocab, dict bacov, token_rules):
    cdef Lexeme* word
    cdef StringHash hashed
    for chunk, lex, tokens in token_rules:
        hashed = hash_string(chunk, len(chunk))
        assert vocab[0][hashed] == 0, chunk
        word = _add(vocab, bacov, <Splitter>NULL, hashed, lex, len(lex), len(lex))
        for i, lex in enumerate(tokens):
            token_string = '%s:@:%d:@:%s' % (chunk, i, lex)
            length = len(token_string)
            hashed = hash_string(token_string, length)
            word.tail = _add(vocab, bacov, <Splitter>NULL, hashed, lex, 0, len(lex))
            word = word.tail


cdef load_browns(Vocab* vocab, dict bacov, Splitter find_split):
    cdef Lexeme* w
    data_dir = path.join(path.dirname(__file__), '..', 'data', 'en')
    case_stats = util.load_case_stats(data_dir)
    brown_loc = path.join(data_dir, 'clusters')
    cdef size_t start 
    cdef int end 
    with util.utf8open(brown_loc) as browns_file:
        for i, line in enumerate(browns_file):
            cluster_str, token_string, freq_str = line.split()
            # Decode as a little-endian string, so that we can do & 15 to get
            # the first 4 bits. See redshift._parse_features.pyx
            cluster = int(cluster_str[::-1], 2)
            upper_pc, title_pc = case_stats.get(token_string.lower(), (0.0, 0.0))
            start = 0
            end = -1
            hashed = hash_string(token_string, len(token_string))

            word = _add(vocab, bacov, find_split, hashed, token_string,
                        len(token_string), len(token_string))


cdef vector[Lexeme_addr] tokenize(Vocab* vocab, dict bacov, Splitter splitter,
                                  unicode string) except *:
    cdef size_t length = len(string)
    cdef Py_UNICODE* characters = <Py_UNICODE*>string

    cdef size_t i
    cdef Py_UNICODE c

    cdef vector[Lexeme_addr] tokens = vector[Lexeme_addr]()
    cdef Py_UNICODE* current = <Py_UNICODE*>calloc(len(string), sizeof(Py_UNICODE))
    cdef size_t word_len = 0
    cdef Lexeme* token
    for i in range(length):
        c = characters[i]
        if _is_whitespace(c):
            if word_len != 0:
                token = <Lexeme*>lookup(vocab, bacov, splitter, -1, current, word_len)
                while token != NULL:
                    tokens.push_back(<Lexeme_addr>token)
                    token = token.tail
                for j in range(word_len+1):
                    current[j] = 0
                word_len = 0
        else:
            current[word_len] = c
            word_len += 1
    if word_len != 0:
        token = <Lexeme*>lookup(vocab, bacov, splitter, -1, current, word_len)
        while token != NULL:
            tokens.push_back(<Lexeme_addr>token)
            token = token.tail
    free(current)
    return tokens

cdef inline bint _is_whitespace(Py_UNICODE c) nogil:
    if c == ' ':
        return True
    elif c == '\n':
        return True
    elif c == '\t':
        return True
    else:
        return False

cdef Lexeme_addr lookup(Vocab* vocab, dict bacov, Splitter find_split, int start,
                        Py_UNICODE* string, size_t length) except 0:
    '''Fetch a Lexeme representing a word string. If the word has not been seen,
    construct one, splitting off any attached punctuation or clitics.  A
    reference to BLANK_WORD is returned for the empty string.
    
    To specify the boundaries of the word if it has not been seen, use lookup_chunk.
    '''
    if length == 0:
        return <Lexeme_addr>&BLANK_WORD
    cdef StringHash hashed = hash_string(string, length)
    cdef Lexeme* word_ptr = <Lexeme*>vocab[0][hashed]
    if word_ptr == NULL:
        start = find_split(string, length) if start == -1 else start
        word_ptr = _add(vocab, bacov, find_split, hashed, string, start, length)
    return <Lexeme_addr>word_ptr


cpdef vector[size_t] expand_chunk(size_t addr) except *:
    cdef vector[size_t] tokens = vector[size_t]()
    word = <Lexeme*>addr
    while word is not NULL:
        tokens.push_back(<size_t>word)
        word = word.tail
    return tokens


cdef StringHash hash_string(Py_UNICODE* s, size_t length) nogil:
    '''Hash unicode with MurmurHash64A'''
    return MurmurHash64A(<Py_UNICODE*>s, length * sizeof(Py_UNICODE), 0)


cdef unicode unhash(dict bacov, StringHash hash_value):
    '''Fetch a string from the reverse index, given its hash value.'''
    return bacov[hash_value]


@cython.nonecheck(False)
cdef Lexeme* _add(Vocab* vocab, dict bacov, Splitter find_split, StringHash hashed,
                  unicode string, int split, size_t length):
    word = init_lexeme(vocab, bacov, find_split, string, hashed, split, length)
    vocab[0][hashed] = <Lexeme_addr>word
    bacov[hashed] = string
    return word