-module(mlx_fft_nif).

%% FFT and signal processing NIF functions
-export([
    %% 1D FFT operations
    fft/2, ifft/2, rfft/2, irfft/2,
    
    %% 2D FFT operations
    fft2/2, ifft2/2, rfft2/2, irfft2/2,
    
    %% N-D FFT operations
    fftn/3, ifftn/3, rfftn/3, irfftn/3,
    
    %% FFT shift operations
    fftshift/2, ifftshift/2,
    
    %% Frequency utilities
    fftfreq/3, rfftfreq/3,
    
    %% Signal processing
    convolve/3, correlate/3,
    
    %% Window functions
    hann/1, hamming/1, blackman/1, bartlett/1,
    
    %% Spectral functions
    stft/4, istft/3
]).

%% Load the NIF library
-on_load(init/0).

-spec init() -> ok | {error, term()}.
init() ->
    PrivDir = case code:priv_dir(mlx) of
        {error, _} ->
            EbinDir = filename:dirname(code:which(?MODULE)),
            AppPath = filename:dirname(EbinDir),
            filename:join(AppPath, "priv");
        Path ->
            Path
    end,
    erlang:load_nif(filename:join(PrivDir, "mlx_fft_nif"), 0).

%% NIF stubs - these will be replaced by the actual NIF implementations
%% 1D FFT operations
-spec fft(reference(), integer() | undefined) -> {ok, reference()} | {error, term()}.
fft(_Input, _N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec ifft(reference(), integer() | undefined) -> {ok, reference()} | {error, term()}.
ifft(_Input, _N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec rfft(reference(), integer() | undefined) -> {ok, reference()} | {error, term()}.
rfft(_Input, _N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec irfft(reference(), integer() | undefined) -> {ok, reference()} | {error, term()}.
irfft(_Input, _N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% 2D FFT operations
-spec fft2(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
fft2(_Input, _S) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec ifft2(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
ifft2(_Input, _S) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec rfft2(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
rfft2(_Input, _S) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec irfft2(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
irfft2(_Input, _S) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% N-D FFT operations
-spec fftn(reference(), [integer()] | undefined, [integer()] | undefined) -> {ok, reference()} | {error, term()}.
fftn(_Input, _S, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec ifftn(reference(), [integer()] | undefined, [integer()] | undefined) -> {ok, reference()} | {error, term()}.
ifftn(_Input, _S, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec rfftn(reference(), [integer()] | undefined, [integer()] | undefined) -> {ok, reference()} | {error, term()}.
rfftn(_Input, _S, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec irfftn(reference(), [integer()] | undefined, [integer()] | undefined) -> {ok, reference()} | {error, term()}.
irfftn(_Input, _S, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% FFT shift operations
-spec fftshift(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
fftshift(_Input, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec ifftshift(reference(), [integer()] | undefined) -> {ok, reference()} | {error, term()}.
ifftshift(_Input, _Axes) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% Frequency utilities
-spec fftfreq(integer(), number(), atom()) -> {ok, reference()} | {error, term()}.
fftfreq(_N, _D, _Dtype) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec rfftfreq(integer(), number(), atom()) -> {ok, reference()} | {error, term()}.
rfftfreq(_N, _D, _Dtype) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% Signal processing
-spec convolve(reference(), reference(), atom()) -> {ok, reference()} | {error, term()}.
convolve(_Input, _Kernel, _Mode) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec correlate(reference(), reference(), atom()) -> {ok, reference()} | {error, term()}.
correlate(_Input, _Kernel, _Mode) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% Window functions
-spec hann(integer()) -> {ok, reference()} | {error, term()}.
hann(_N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec hamming(integer()) -> {ok, reference()} | {error, term()}.
hamming(_N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec blackman(integer()) -> {ok, reference()} | {error, term()}.
blackman(_N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec bartlett(integer()) -> {ok, reference()} | {error, term()}.
bartlett(_N) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

%% Spectral functions
-spec stft(reference(), reference(), integer(), integer()) -> {ok, reference()} | {error, term()}.
stft(_Input, _Window, _NpFft, _HopLength) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).

-spec istft(reference(), reference(), integer()) -> {ok, reference()} | {error, term()}.
istft(_Stft, _Window, _HopLength) ->
    erlang:nif_error({nif_not_loaded, ?MODULE}).