import torch


def amp_pha_stft(audio, n_fft, hop_size, win_size, center=True):
    hann_window = torch.hann_window(win_size).to(audio.device)
    stft_spec = torch.stft(
        audio,
        n_fft,
        hop_length=hop_size,
        win_length=win_size,
        window=hann_window,
        center=center,
        pad_mode="reflect",
        normalized=False,
        return_complex=True,
    )
    log_amp = torch.log(torch.abs(stft_spec) + 1e-4)
    pha = torch.angle(stft_spec)

    com = torch.stack((torch.exp(log_amp) * torch.cos(pha), torch.exp(log_amp) * torch.sin(pha)), dim=-1)

    return log_amp, pha, com


def amp_pha_istft(log_amp, pha, n_fft, hop_size, win_size, center=True):
    amp = torch.exp(log_amp)
    com = torch.complex(amp * torch.cos(pha), amp * torch.sin(pha))
    hann_window = torch.hann_window(win_size).to(com.device)
    audio = torch.istft(com, n_fft, hop_length=hop_size, win_length=win_size, window=hann_window, center=center)

    return audio