-module(humanise@bytes1024).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([to_string/1, as_bytes/1, as_kibibytes/1, as_mebibytes/1, as_gibibytes/1, as_tebibytes/1, humanise/1]).
-export_type([bytes/0]).

-type bytes() :: {bytes, float()} |
    {kibibytes, float()} |
    {mebibytes, float()} |
    {gibibytes, float()} |
    {tebibytes, float()}.

-spec to_string(bytes()) -> binary().
to_string(Bytes) ->
    {N@5, Suffix} = case Bytes of
        {bytes, N} ->
            {N, <<"B"/utf8>>};

        {kibibytes, N@1} ->
            {N@1, <<"KiB"/utf8>>};

        {mebibytes, N@2} ->
            {N@2, <<"MiB"/utf8>>};

        {gibibytes, N@3} ->
            {N@3, <<"GiB"/utf8>>};

        {tebibytes, N@4} ->
            {N@4, <<"TiB"/utf8>>}
    end,
    util:format(N@5, Suffix).

-spec as_bytes(bytes()) -> float().
as_bytes(Bytes) ->
    case Bytes of
        {bytes, N} ->
            N;

        {kibibytes, N@1} ->
            N@1 * 1024.0;

        {mebibytes, N@2} ->
            N@2 * 1048576.0;

        {gibibytes, N@3} ->
            N@3 * 1073741824.0;

        {tebibytes, N@4} ->
            N@4 * 1099511627776.0
    end.

-spec as_kibibytes(bytes()) -> float().
as_kibibytes(Bytes) ->
    case 1024.0 of
        +0.0 -> +0.0;
        -0.0 -> -0.0;
        Gleam@denominator -> as_bytes(Bytes) / Gleam@denominator
    end.

-spec as_mebibytes(bytes()) -> float().
as_mebibytes(Bytes) ->
    case 1048576.0 of
        +0.0 -> +0.0;
        -0.0 -> -0.0;
        Gleam@denominator -> as_bytes(Bytes) / Gleam@denominator
    end.

-spec as_gibibytes(bytes()) -> float().
as_gibibytes(Bytes) ->
    case 1073741824.0 of
        +0.0 -> +0.0;
        -0.0 -> -0.0;
        Gleam@denominator -> as_bytes(Bytes) / Gleam@denominator
    end.

-spec as_tebibytes(bytes()) -> float().
as_tebibytes(Bytes) ->
    case 1099511627776.0 of
        +0.0 -> +0.0;
        -0.0 -> -0.0;
        Gleam@denominator -> as_bytes(Bytes) / Gleam@denominator
    end.

-spec humanise(bytes()) -> bytes().
humanise(Bytes) ->
    B = as_bytes(Bytes),
    gleam@bool:guard(
        B < 1024.0,
        {bytes, B},
        fun() -> gleam@bool:guard(B < 1048576.0, {kibibytes, case 1024.0 of
                        +0.0 -> +0.0;
                        -0.0 -> -0.0;
                        Gleam@denominator -> B / Gleam@denominator
                    end}, fun() ->
                    gleam@bool:guard(
                        B < 1073741824.0,
                        {mebibytes, case 1048576.0 of
                                +0.0 -> +0.0;
                                -0.0 -> -0.0;
                                Gleam@denominator@1 -> B / Gleam@denominator@1
                            end},
                        fun() ->
                            gleam@bool:guard(
                                B < 1099511627776.0,
                                {gibibytes, case 1073741824.0 of
                                        +0.0 -> +0.0;
                                        -0.0 -> -0.0;
                                        Gleam@denominator@2 -> B / Gleam@denominator@2
                                    end},
                                fun() -> {tebibytes, case 1099511627776.0 of
                                            +0.0 -> +0.0;
                                            -0.0 -> -0.0;
                                            Gleam@denominator@3 -> B / Gleam@denominator@3
                                        end} end
                            )
                        end
                    )
                end) end
    ).