%%%-------------------------------------------------------------------
%%% @author cheese
%%% @copyright (C) 2014, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 11. Jan 2014 11:16 AM
%%%-------------------------------------------------------------------
-module(bytes_extension).
-author("cheese").
-include_lib("kernel/include/logger.hrl").

%% API
-export([bin_to_hexstr/1, list_to_hexstr/1, hex_to_bytes/1, bcd_int/1, bcd_int_list/1, bcd_string/1, int_as_hex/1,
  bcd_to_int/1, binary_length/1, binary_pad_left/3, int_to_bcd/1, int_to_bcd/2, last_byte/1, are_equal/2, generate_uuid/0,
  are_starts_from/2]).

-export([hex/1, int_to_hex/1, hex_to_bytes_internal/2, hex_char_num/1, bcdlist_to_integer_list/2, integerlist_to_integer/3, get_int_bcd/1,
  integerlist_to_string/2, one_string_hex_to_int/1, internal_int_to_bcd/3, internal_last_byte/2,
  internal_string_to_bcd/2]).


hex_char_num($0) -> 0;
hex_char_num($1) -> 1;
hex_char_num($2) -> 2;
hex_char_num($3) -> 3;
hex_char_num($4) -> 4;
hex_char_num($5) -> 5;
hex_char_num($6) -> 6;
hex_char_num($7) -> 7;
hex_char_num($8) -> 8;
hex_char_num($9) -> 9;
hex_char_num($A) -> 10;
hex_char_num($a) -> 10;
hex_char_num($B) -> 11;
hex_char_num($b) -> 11;
hex_char_num($C) -> 12;
hex_char_num($c) -> 12;
hex_char_num($D) -> 13;
hex_char_num($d) -> 13;
hex_char_num($E) -> 14;
hex_char_num($e) -> 14;
hex_char_num($F) -> 15;
hex_char_num($f) -> 15.


hex(N) when N == 0 ->
  $0;
hex(N) when N == 1 ->
  $1;
hex(N) when N == 2 ->
  $2;
hex(N) when N == 3 ->
  $3;
hex(N) when N == 4 ->
  $4;
hex(N) when N == 5 ->
  $5;
hex(N) when N == 6 ->
  $6;
hex(N) when N == 7 ->
  $7;
hex(N) when N == 8 ->
  $8;
hex(N) when N == 9 ->
  $9;
hex(N) when N == 10 ->
  $A;
hex(N) when N == 11 ->
  $B;
hex(N) when N == 12 ->
  $C;
hex(N) when N == 13 ->
  $D;
hex(N) when N == 14 ->
  $E;
hex(N) when N == 15 ->
  $F;
hex(_N) ->
  $?.

int_to_hex(N) when N < 256 ->
  [hex(N div 16), hex(N rem 16)].

list_to_hexstr([]) ->
  [];
list_to_hexstr([H | T]) ->
  int_to_hex(H) ++ list_to_hexstr(T).

bin_to_hexstr(Bytes) ->
  list_to_bitstring(list_to_hexstr(binary_to_list(Bytes))).

hex_to_bytes(Hex) ->
  Len = length(Hex),
  case Len rem 2 of
    0 ->
      hex_to_bytes_internal(Hex, []);
    _ ->
      {error, {invalid_length, Len}}
  end.

hex_to_bytes_internal([], Acc) ->
  binary:list_to_bin(lists:reverse(Acc));
hex_to_bytes_internal([L1 | [L2 | Tail]], Acc) ->
  hex_to_bytes_internal(Tail, [(16 * hex_char_num(L1) + hex_char_num(L2)) | Acc]);
hex_to_bytes_internal(In, Acc) ->
  {error, {invalid_data, In, Acc}}.


bcd_int_list(Data) ->
  HexStr = list_to_hexstr(binary_to_list(Data)),
  bcdlist_to_integer_list(HexStr, []).

bcd_int(Data) ->
  integerlist_to_integer(lists:reverse(bcd_int_list(Data)), 1, 0).

bcd_string(Data) ->
  integerlist_to_string(bcd_int_list(Data), []).

integerlist_to_string([], Res) ->
  list_to_binary(lists:reverse(Res));
integerlist_to_string([Head | Tail], Res) ->
  Val = hex(Head),
  integerlist_to_string(Tail, [Val | Res]).


integerlist_to_integer([], _Coef, Res) ->
  Res;
integerlist_to_integer([Head | Tail], Coef, Res) ->
  integerlist_to_integer(Tail, Coef * 10, Res + Head * Coef).

bcdlist_to_integer_list([], Res) ->
  lists:reverse(Res);
bcdlist_to_integer_list([H | Tail], Res) ->
  bcdlist_to_integer_list(Tail, [get_int_bcd(H) | Res]).

get_int_bcd(Val) when Val >= $0, Val < $9; Val == $9 ->
  Val - $0;
get_int_bcd(Val) when Val >= $a, Val < $z; Val == $z ->
  (Val - $a) + 10;
get_int_bcd(Val) when Val >= $A, Val < $Z; Val == $Z ->
  (Val - $A) + 10.

int_as_hex(Int) ->
  Hi = Int div 10,
  Low = Int rem 10,
  Hi * 16 + Low.

one_string_hex_to_int(<<"0">>) ->
  0;
one_string_hex_to_int(<<"1">>) ->
  1;
one_string_hex_to_int(<<"2">>) ->
  2;
one_string_hex_to_int(<<"3">>) ->
  3;
one_string_hex_to_int(<<"4">>) ->
  4;
one_string_hex_to_int(<<"5">>) ->
  5;
one_string_hex_to_int(<<"6">>) ->
  6;
one_string_hex_to_int(<<"7">>) ->
  7;
one_string_hex_to_int(<<"8">>) ->
  8;
one_string_hex_to_int(<<"9">>) ->
  9;
one_string_hex_to_int(<<"A">>) ->
  10;
one_string_hex_to_int(<<"B">>) ->
  11;
one_string_hex_to_int(<<"C">>) ->
  12;
one_string_hex_to_int(<<"D">>) ->
  13;
one_string_hex_to_int(<<"E">>) ->
  14;
one_string_hex_to_int(<<"F">>) ->
  15.


internal_bcd_to_int(<<>>, Res) ->
  trunc(Res);
internal_bcd_to_int(<<Num:8, Tail/binary>>, Res) ->
  N1 = Num div 16,
  N2 = Num rem 16,
  Len = binary_length(Tail),
  internal_bcd_to_int(Tail, (N1 * 10 + N2) * math:pow(10, 2 * Len) + Res).

%% 17 -> 16*1+1 -> 11
bcd_to_int(Data) ->
  internal_bcd_to_int(Data, 0).

binary_length(Bytes) ->
  byte_size(Bytes).

%% 12345 => <<x01 x23 x45>> => <<1, 35, 69>>
int_to_bcd(0) ->
  <<0>>;
int_to_bcd(Num) ->
  Pow = trunc(math:log10(Num)) div 2 + 1,
  internal_int_to_bcd(Num, Pow, <<>>).

%% 12345 => <<x01 x23 x45>> => <<1, 35, 69>>
int_to_bcd(Num, CountBytes) ->
  bytes_extension:binary_pad_left(int_to_bcd(Num), CountBytes, 0).

internal_int_to_bcd(Num, 1, Res) ->
  N_Hi = (Num rem 100) div 10,
  N_Low = Num rem 10,
  <<Res/binary, (N_Hi * 16 + N_Low):8>>;
internal_int_to_bcd(Num, Pow, Res) ->
  Pow100 = trunc(math:pow(10, Pow * 2)),
  Pow10 = trunc(math:pow(10, Pow * 2 - 1)),
  Pow1 = trunc(math:pow(10, Pow * 2 - 2)),
  N_Hi = (Num rem Pow100 - Num rem Pow10) div Pow10,
  N_Low = (Num rem Pow10 - Num rem Pow1) div Pow1,
  internal_int_to_bcd(Num, Pow - 1, <<Res/binary, (N_Hi * 16 + N_Low):8>>).

binary_pad_left(Bytes, Count, OneByte) ->
  case binary_length(Bytes) >= Count of
    true ->
      Bytes;
    false ->
      binary_pad_left(<<OneByte:8, Bytes/binary>>, Count, OneByte)
  end.

internal_string_to_bcd(<<>>, Res) ->
  Res;
internal_string_to_bcd(<<Str1:1/binary, Str2:1/binary, Tail/binary>>, Res) ->
 ?LOG_INFO("===========================================", []),
  ?LOG_INFO("Str1: ~w: Str2: ~w", [Str1, Str2]),
  Num1 = one_string_hex_to_int(<<Str1/binary>>),
  Num2 = one_string_hex_to_int(<<Str2/binary>>),
  Sum = Num1 * 16 + Num2,
  ?LOG_INFO("Num1: ~w: Num2: ~w, Val: ~w", [Num1, Num2, Sum]),
  internal_string_to_bcd(<<Tail/binary>>, <<Res/binary, Sum/integer>>);
internal_string_to_bcd(InBytes, Res) ->
  error({error, {internal_string_to_bcd, invalid_param, InBytes, Res}}).

last_byte(Data) ->
  Byte = internal_last_byte(Data, 0),
  ?LOG_INFO("LastByte: ~w: Data: ~w", [Byte, Data]),
  Byte.

internal_last_byte(<<>>, Prev) ->
  Prev;
internal_last_byte(<<Head/integer, Tail/binary>>, _Prev) ->
  internal_last_byte(<<Tail/binary>>, Head).


are_equal(<<>>, <<>>) ->
  true;
are_equal(<<Head1:8, Tail1/binary>>, <<Head2:8, Tail2/binary>>) when Head1 == Head2 ->
  are_equal(<<Tail1/binary>>, <<Tail2/binary>>);
are_equal(_, _) ->
  false.


generate_uuid() ->
  <<A:32, B:16, C:16, D:16, E:48>> =crypto:strong_rand_bytes(16),
  Str = io_lib:format("~8.16.0b-~4.16.0b-4~3.16.0b-~4.16.0b-~12.16.0b",
    [A, B, C band 16#0fff, D band 16#3fff bor 16#8000, E]),
  list_to_binary(Str).


are_starts_from(_, <<>>) ->
  true;
are_starts_from(<<HeadMessage:8, TailMessage/binary>>, <<HeadPrefix:8, TailPrefix/binary>>) when HeadMessage == HeadPrefix ->
  are_starts_from(<<TailMessage/binary>>, <<TailPrefix/binary>>);
are_starts_from(_, _) ->
  false.