#!/usr/bin/env python3

import sys
from cmusphinx import s3mixw
import struct
import numpy


class Sendump:
    def __init__(self, filename):
        self.integer_format = None
        self.load(filename)

    def unpack_endian(self, s):
        if self.integer_format is None:
            self.integer_format = 'I'
        nbytes = struct.unpack(self.integer_format, s)[0]
        if nbytes > 65536:
            self.integer_format = '!I'
            nbytes = struct.unpack(self.integer_format, s)[0]
        return nbytes

    def readstr(self, fh):
        nbytes = self.unpack_endian(fh.read(4))
        if nbytes == 0:
            return None
        else:
            return fh.read(nbytes)[0:-1]

    def mixw(self):
        return self.opdf

    def load(self, filename):
        mixture_count = 0
        model_count = 0
        mixw_shift = 10
        cluster_bits = 8
        feature_count = 0
        cluster_count = 0

        sendump = open(filename, "rb")
        _ = self.readstr(sendump)  # title
        while True:
            header = self.readstr(sendump)
            if header is None:
                break
            if header.startswith(b"mixture_count"):
                mixture_count = (int)(header.split()[1])
            if header.startswith(b"model_count"):
                model_count = (int)(header.split()[1])
            if header.startswith(b"mixw_shift"):
                mixw_shift = (int)(header.split()[1])
            if header.startswith(b"cluster_bits"):
                cluster_bits = (int)(header.split()[1])
            if header.startswith(b"feature_count"):
                feature_count = (int)(header.split()[1])
            if header.startswith(b"cluster_count"):
                cluster_count = (int)(header.split()[1])

        if cluster_count == 0:
            # Number of codewords and pdfs
            model_count = self.unpack_endian(sendump.read(4))
            mixture_count = self.unpack_endian(sendump.read(4))
        print("rows (model_count): %d, columns (mixture_count): %d, "
              "features (feature_count): %d"
              % (model_count, mixture_count, feature_count))

        # Now read the stuff
        self.opdf = numpy.empty((mixture_count, feature_count, model_count))
        for i in range(0, feature_count):
            for j in range(0, model_count):
                # Read bytes, expand to ints, shift them up
                mixw = numpy.fromfile(sendump, 'B',
                                      mixture_count).astype('i') << mixw_shift
                # Negate, exponentiate, and untranspose
                self.opdf[:, i, j] = numpy.power(1.0001, -mixw)


def usage():
    print("Usage: %s IN_SENDUMP OUT_MIXW" % sys.argv[0])


if __name__ == '__main__':
    if len(sys.argv) < 3:
        usage()
        sys.exit(2)
    sendump = Sendump(sys.argv[1])
    with s3mixw.open(sys.argv[2], 'wb') as s3m:
        s3m.writeall(sendump.mixw())