import os
import wave
import numpy as np

from livekit.rtc import AudioProcessingModule, AudioFrame

FIXTURES_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "fixtures")


def test_agc_modifies_audio() -> None:
    num_channels = 1

    input_wav = os.path.join(FIXTURES_DIR, "test_audio.wav")
    output_wav = os.path.join(FIXTURES_DIR, "test_processed.wav")

    apm = AudioProcessingModule(auto_gain_control=True)

    any_frame_modified = False

    with wave.open(input_wav, "rb") as wf_in:
        assert wf_in.getnchannels() == num_channels, "Input file must be mono."
        sample_rate = wf_in.getframerate()
        sampwidth = wf_in.getsampwidth()
        frames_per_chunk = sample_rate // 100

        with wave.open(output_wav, "wb") as wf_out:
            wf_out.setnchannels(num_channels)
            wf_out.setsampwidth(sampwidth)
            wf_out.setframerate(sample_rate)

            while True:
                raw_bytes = wf_in.readframes(frames_per_chunk)
                if not raw_bytes:
                    break

                data = np.frombuffer(raw_bytes, dtype=np.int16)
                if len(data) < frames_per_chunk:
                    data = np.pad(data, (0, frames_per_chunk - len(data)))

                original = data.copy()

                frame = AudioFrame(
                    data=data.tobytes(),
                    sample_rate=sample_rate,
                    num_channels=num_channels,
                    samples_per_channel=frames_per_chunk,
                )

                apm.process_stream(frame)

                processed = np.frombuffer(frame.data, dtype=np.int16)
                if not np.array_equal(original, processed):
                    any_frame_modified = True

                wf_out.writeframes(frame.data.tobytes())

    assert any_frame_modified, (
        "APM did not modify any audio frames — processing may be a no-op. "
        "With AGC enabled, output should differ from input."
    )