# -*- coding: utf-8 -*-
"""
hpack/huffman_decoder
~~~~~~~~~~~~~~~~~~~~~

An implementation of a bitwise prefix tree specially built for decoding
Huffman-coded content where we already know the Huffman table.
"""
huffman_code_list = [
    0x1ff8,
    0x7fffd8,
    0xfffffe2,
    0xfffffe3,
    0xfffffe4,
    0xfffffe5,
    0xfffffe6,
    0xfffffe7,
    0xfffffe8,
    0xffffea,
    0x3ffffffc,
    0xfffffe9,
    0xfffffea,
    0x3ffffffd,
    0xfffffeb,
    0xfffffec,
    0xfffffed,
    0xfffffee,
    0xfffffef,
    0xffffff0,
    0xffffff1,
    0xffffff2,
    0x3ffffffe,
    0xffffff3,
    0xffffff4,
    0xffffff5,
    0xffffff6,
    0xffffff7,
    0xffffff8,
    0xffffff9,
    0xffffffa,
    0xffffffb,
    0x14,
    0x3f8,
    0x3f9,
    0xffa,
    0x1ff9,
    0x15,
    0xf8,
    0x7fa,
    0x3fa,
    0x3fb,
    0xf9,
    0x7fb,
    0xfa,
    0x16,
    0x17,
    0x18,
    0x0,
    0x1,
    0x2,
    0x19,
    0x1a,
    0x1b,
    0x1c,
    0x1d,
    0x1e,
    0x1f,
    0x5c,
    0xfb,
    0x7ffc,
    0x20,
    0xffb,
    0x3fc,
    0x1ffa,
    0x21,
    0x5d,
    0x5e,
    0x5f,
    0x60,
    0x61,
    0x62,
    0x63,
    0x64,
    0x65,
    0x66,
    0x67,
    0x68,
    0x69,
    0x6a,
    0x6b,
    0x6c,
    0x6d,
    0x6e,
    0x6f,
    0x70,
    0x71,
    0x72,
    0xfc,
    0x73,
    0xfd,
    0x1ffb,
    0x7fff0,
    0x1ffc,
    0x3ffc,
    0x22,
    0x7ffd,
    0x3,
    0x23,
    0x4,
    0x24,
    0x5,
    0x25,
    0x26,
    0x27,
    0x6,
    0x74,
    0x75,
    0x28,
    0x29,
    0x2a,
    0x7,
    0x2b,
    0x76,
    0x2c,
    0x8,
    0x9,
    0x2d,
    0x77,
    0x78,
    0x79,
    0x7a,
    0x7b,
    0x7ffe,
    0x7fc,
    0x3ffd,
    0x1ffd,
    0xffffffc,
    0xfffe6,
    0x3fffd2,
    0xfffe7,
    0xfffe8,
    0x3fffd3,
    0x3fffd4,
    0x3fffd5,
    0x7fffd9,
    0x3fffd6,
    0x7fffda,
    0x7fffdb,
    0x7fffdc,
    0x7fffdd,
    0x7fffde,
    0xffffeb,
    0x7fffdf,
    0xffffec,
    0xffffed,
    0x3fffd7,
    0x7fffe0,
    0xffffee,
    0x7fffe1,
    0x7fffe2,
    0x7fffe3,
    0x7fffe4,
    0x1fffdc,
    0x3fffd8,
    0x7fffe5,
    0x3fffd9,
    0x7fffe6,
    0x7fffe7,
    0xffffef,
    0x3fffda,
    0x1fffdd,
    0xfffe9,
    0x3fffdb,
    0x3fffdc,
    0x7fffe8,
    0x7fffe9,
    0x1fffde,
    0x7fffea,
    0x3fffdd,
    0x3fffde,
    0xfffff0,
    0x1fffdf,
    0x3fffdf,
    0x7fffeb,
    0x7fffec,
    0x1fffe0,
    0x1fffe1,
    0x3fffe0,
    0x1fffe2,
    0x7fffed,
    0x3fffe1,
    0x7fffee,
    0x7fffef,
    0xfffea,
    0x3fffe2,
    0x3fffe3,
    0x3fffe4,
    0x7ffff0,
    0x3fffe5,
    0x3fffe6,
    0x7ffff1,
    0x3ffffe0,
    0x3ffffe1,
    0xfffeb,
    0x7fff1,
    0x3fffe7,
    0x7ffff2,
    0x3fffe8,
    0x1ffffec,
    0x3ffffe2,
    0x3ffffe3,
    0x3ffffe4,
    0x7ffffde,
    0x7ffffdf,
    0x3ffffe5,
    0xfffff1,
    0x1ffffed,
    0x7fff2,
    0x1fffe3,
    0x3ffffe6,
    0x7ffffe0,
    0x7ffffe1,
    0x3ffffe7,
    0x7ffffe2,
    0xfffff2,
    0x1fffe4,
    0x1fffe5,
    0x3ffffe8,
    0x3ffffe9,
    0xffffffd,
    0x7ffffe3,
    0x7ffffe4,
    0x7ffffe5,
    0xfffec,
    0xfffff3,
    0xfffed,
    0x1fffe6,
    0x3fffe9,
    0x1fffe7,
    0x1fffe8,
    0x7ffff3,
    0x3fffea,
    0x3fffeb,
    0x1ffffee,
    0x1ffffef,
    0xfffff4,
    0xfffff5,
    0x3ffffea,
    0x7ffff4,
    0x3ffffeb,
    0x7ffffe6,
    0x3ffffec,
    0x3ffffed,
    0x7ffffe7,
    0x7ffffe8,
    0x7ffffe9,
    0x7ffffea,
    0x7ffffeb,
    0xffffffe,
    0x7ffffec,
    0x7ffffed,
    0x7ffffee,
    0x7ffffef,
    0x7fffff0,
    0x3ffffee,
    0x3fffffff,
]
huffman_code_lengths = [
    13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28,
    28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28,
    6, 10, 10, 12, 13,  6,  8, 11, 10, 10,  8, 11,  8,  6,  6,  6,
    5,  5,  5,  6,  6,  6,  6,  6,  6,  6,  7,  8, 15,  6, 12, 10,
    13,  6,  7,  7,  7,  7,  7,  7,  7,  7,  7,  7,  7,  7,  7,  7,
    7,  7,  7,  7,  7,  7,  7,  7,  8,  7,  8, 13, 19, 13, 14,  6,
    15,  5,  6,  5,  6,  5,  6,  6,  6,  5,  7,  7,  6,  6,  6,  5,
    6,  7,  6,  5,  5,  6,  7,  7,  7,  7,  7, 15, 11, 14, 13, 28,
    20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23,
    24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24,
    22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23,
    21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23,
    26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25,
    19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27,
    20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23,
    26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26,
    30,
]


class HuffmanEncoder:
    huffman_codes = list(zip(
        huffman_code_list,
        huffman_code_lengths
    ))
    
    """
    Encodes a string according to the Huffman encoding table defined in the
    HPACK specification.
    """
    
    def encode(self, bytes_to_encode: bytes):
        """
        Given a string of bytes, encodes them according to the HPACK Huffman
        specification.
        """
        # If handed the empty string, just immediately return.
        if not bytes_to_encode:
            return b''

        final_num = 0
        final_int_len = 0

        # Turn each byte into its huffman code. These codes aren't necessarily
        # octet aligned, so keep track of how far through an octet we are. To
        # handle this cleanly, just use a single giant integer.
        for byte in bytes_to_encode:
            huffman_bit, bin_int_len = self.huffman_codes[byte]
            bin_int = huffman_bit & ((1 << bin_int_len) - 1)
            final_num = (final_num << bin_int_len) | bin_int
            final_int_len += bin_int_len

        # Pad out to an octet with ones.
        bits_to_be_padded = (8 - (final_int_len % 8)) % 8
        final_num = (final_num << bits_to_be_padded) | ((1 << bits_to_be_padded) - 1)

        # Calculate the number of bytes required and directly convert the integer to bytes
        total_bytes = (final_int_len + bits_to_be_padded) // 8
        encoded_bytes = final_num.to_bytes(total_bytes, byteorder='big')

        return encoded_bytes