from __future__ import annotations

import asyncio
import importlib.util
import math
import struct
import sys
import unittest
from pathlib import Path


SCRIPT_PATH = Path(__file__).with_name("local-whisper-stt-server.py")
SPEC = importlib.util.spec_from_file_location("local_whisper_stt_server", SCRIPT_PATH)
assert SPEC is not None and SPEC.loader is not None
MODULE = importlib.util.module_from_spec(SPEC)
sys.modules[SPEC.name] = MODULE
SPEC.loader.exec_module(MODULE)


SAMPLE_RATE = 16_000


def pcm_ms(milliseconds: float, *, amplitude: int) -> bytes:
    """Mono linear16 tone (or silence when amplitude is 0)."""

    count = int(SAMPLE_RATE * milliseconds / 1000.0)
    if amplitude <= 0:
        return b"\x00\x00" * count
    samples = [
        int(amplitude * math.sin(2 * math.pi * 220 * index / SAMPLE_RATE))
        for index in range(count)
    ]
    return struct.pack(f"<{count}h", *samples)


SPEECH = lambda ms: pcm_ms(ms, amplitude=9000)  # noqa: E731
SILENCE = lambda ms: pcm_ms(ms, amplitude=0)  # noqa: E731


class FakeTranscriber:
    def __init__(self, text: str = "안녕하세요") -> None:
        self.text = text
        self.calls: list[tuple[int, bool]] = []

    def transcribe(self, pcm: bytes, *, sample_rate: int, final: bool):
        self.calls.append((len(pcm), final))
        words = (
            (MODULE.Word(word=self.text, start=0.0, end=0.5, confidence=0.9),)
            if final
            else ()
        )
        return MODULE.Transcription(text=self.text, confidence=0.87, words=words)


def default_options(**overrides):
    options = {
        "model": "large-v3",
        "language": "ko",
        "sample_rate": SAMPLE_RATE,
        "channels": 1,
        "endpointing_ms": MODULE.DEFAULT_ENDPOINTING_MS,
        "utterance_end_ms": MODULE.DEFAULT_UTTERANCE_END_MS,
        "interim_interval_ms": MODULE.DEFAULT_INTERIM_INTERVAL_MS,
        "silence_rms": MODULE.DEFAULT_SILENCE_RMS,
    }
    options.update(overrides)
    return options


def run(coro):
    return asyncio.run(coro)


class FrameRmsTest(unittest.TestCase):
    def test_silence_and_speech_are_separated(self) -> None:
        self.assertEqual(MODULE.frame_rms(SILENCE(20)), 0)
        self.assertGreater(MODULE.frame_rms(SPEECH(20)), MODULE.DEFAULT_SILENCE_RMS)

    def test_empty_and_odd_length_input_is_silence(self) -> None:
        self.assertEqual(MODULE.frame_rms(b""), 0)
        self.assertEqual(MODULE.frame_rms(b"\x01"), 0)


class UtteranceBufferTest(unittest.TestCase):
    def test_duration_tracks_appended_bytes(self) -> None:
        buffer = MODULE.UtteranceBuffer()
        buffer.append(SPEECH(500))
        self.assertAlmostEqual(buffer.duration_ms(), 500.0, delta=1.0)

    def test_silence_alone_never_finalizes(self) -> None:
        buffer = MODULE.UtteranceBuffer()
        buffer.append(SILENCE(3_000))
        self.assertFalse(buffer.should_finalize())
        self.assertFalse(buffer.should_emit_interim())
        self.assertTrue(buffer.is_stalled())

    def test_speech_then_endpointing_silence_finalizes(self) -> None:
        buffer = MODULE.UtteranceBuffer(endpointing_ms=300)
        buffer.append(SPEECH(800))
        self.assertFalse(buffer.should_finalize())
        buffer.append(SILENCE(200))
        self.assertFalse(buffer.should_finalize())
        buffer.append(SILENCE(200))
        self.assertTrue(buffer.should_finalize())

    def test_speech_after_silence_resets_the_silence_run(self) -> None:
        buffer = MODULE.UtteranceBuffer(endpointing_ms=300)
        buffer.append(SPEECH(400))
        buffer.append(SILENCE(200))
        buffer.append(SPEECH(100))
        buffer.append(SILENCE(200))
        self.assertFalse(buffer.should_finalize())

    def test_interim_waits_for_the_configured_interval(self) -> None:
        buffer = MODULE.UtteranceBuffer(interim_interval_ms=700)
        buffer.append(SPEECH(300))
        self.assertFalse(buffer.should_emit_interim())
        buffer.append(SPEECH(500))
        self.assertTrue(buffer.should_emit_interim())
        buffer.mark_interim_emitted()
        self.assertFalse(buffer.should_emit_interim())

    def test_very_long_utterance_finalizes_even_without_silence(self) -> None:
        buffer = MODULE.UtteranceBuffer()
        for _ in range(int(MODULE.MAX_UTTERANCE_SECONDS) + 1):
            buffer.append(SPEECH(1_000))
        self.assertTrue(buffer.should_finalize())

    def test_reset_clears_audio_and_state(self) -> None:
        buffer = MODULE.UtteranceBuffer()
        buffer.append(SPEECH(500))
        buffer.reset()
        self.assertEqual(buffer.pcm, b"")
        self.assertFalse(buffer.saw_speech)
        self.assertEqual(buffer.duration_ms(), 0.0)


class StreamOptionsTest(unittest.TestCase):
    def test_defaults_apply_without_a_query(self) -> None:
        options = MODULE.parse_stream_options("/v1/listen")
        self.assertEqual(options["model"], MODULE.DEFAULT_MODEL)
        self.assertEqual(options["language"], MODULE.DEFAULT_LANGUAGE)
        self.assertEqual(options["sample_rate"], MODULE.DEFAULT_SAMPLE_RATE)

    def test_values_are_clamped_into_range(self) -> None:
        options = MODULE.parse_stream_options(
            "/v1/listen?sample_rate=999999&endpointing=1&utterance_end_ms=99999"
        )
        self.assertEqual(options["sample_rate"], 48_000)
        self.assertEqual(options["endpointing_ms"], 10)
        self.assertEqual(options["utterance_end_ms"], 10_000)

    def test_unparsable_numbers_fall_back_to_defaults(self) -> None:
        options = MODULE.parse_stream_options("/v1/listen?sample_rate=abc")
        self.assertEqual(options["sample_rate"], MODULE.DEFAULT_SAMPLE_RATE)

    def test_model_allowlist_and_language_shape_fail_closed(self) -> None:
        with self.assertRaises(ValueError):
            MODULE.parse_stream_options("/v1/listen?model=../etc/passwd")
        with self.assertRaises(ValueError):
            MODULE.parse_stream_options("/v1/listen?language=ko;DROP")


class TranscriptPayloadTest(unittest.TestCase):
    def test_interim_payload_omits_word_timestamps(self) -> None:
        result = MODULE.Transcription(
            text="안녕", confidence=0.5, words=(MODULE.Word("안녕", 0.0, 0.4),)
        )
        payload = MODULE.transcript_payload(
            result, is_final=False, speech_final=False, duration_seconds=1.0
        )
        self.assertEqual(payload["words"], [])
        self.assertFalse(payload["is_final"])

    def test_final_payload_carries_word_timestamps(self) -> None:
        result = MODULE.Transcription(
            text="안녕", confidence=None, words=(MODULE.Word("안녕", 0.0, 0.4, 0.8),)
        )
        payload = MODULE.transcript_payload(
            result, is_final=True, speech_final=True, duration_seconds=1.234
        )
        self.assertEqual(payload["words"][0]["word"], "안녕")
        self.assertEqual(payload["words"][0]["confidence"], 0.8)
        self.assertIsNone(payload["confidence"])
        self.assertEqual(payload["duration"], 1.234)


class StreamSessionTest(unittest.TestCase):
    def _session(self, transcriber, sent, **overrides):
        async def send(payload):
            sent.append(payload)

        return MODULE.StreamSession(
            options=default_options(**overrides),
            transcriber=transcriber,
            send=send,
        )

    def test_silence_only_stream_emits_nothing(self) -> None:
        sent: list[dict] = []
        transcriber = FakeTranscriber()
        session = self._session(transcriber, sent)
        run(session.feed(SILENCE(2_000)))
        run(session.finalize(speech_final=True))
        self.assertEqual(sent, [])
        self.assertEqual(transcriber.calls, [])

    def test_speech_emits_interim_then_final(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber(), sent)
        run(session.feed(SPEECH(800)))
        self.assertEqual(len(sent), 1)
        self.assertFalse(sent[0]["is_final"])
        run(session.feed(SILENCE(400)))
        self.assertEqual(len(sent), 2)
        self.assertTrue(sent[1]["is_final"])
        self.assertTrue(sent[1]["speech_final"])
        self.assertTrue(sent[1]["words"])

    def test_final_appends_to_the_transcript_and_resets_the_buffer(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber("첫 문장"), sent)
        run(session.feed(SPEECH(800)))
        run(session.feed(SILENCE(400)))
        self.assertEqual(session.final_segments, ["첫 문장"])
        self.assertEqual(session.buffer.pcm, b"")
        self.assertFalse(session.buffer.saw_speech)

    def test_two_utterances_produce_two_finals(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber(), sent)
        for _ in range(2):
            run(session.feed(SPEECH(800)))
            run(session.feed(SILENCE(400)))
        finals = [item for item in sent if item["is_final"]]
        self.assertEqual(len(finals), 2)
        self.assertEqual(len(session.final_segments), 2)

    def test_explicit_finalize_flushes_without_trailing_silence(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber(), sent)
        run(session.feed(SPEECH(400)))
        run(session.finalize(speech_final=True))
        self.assertTrue(sent[-1]["is_final"])

    def test_blank_model_output_is_not_emitted(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber(text="   "), sent)
        run(session.feed(SPEECH(800)))
        run(session.feed(SILENCE(400)))
        self.assertEqual(sent, [])
        self.assertEqual(session.final_segments, [])

    def test_oversized_frame_fails_closed(self) -> None:
        sent: list[dict] = []
        session = self._session(FakeTranscriber(), sent)
        with self.assertRaises(MODULE.TranscriptionError):
            run(session.feed(b"\x00" * (MODULE.MAX_FRAME_BYTES + 1)))

    def test_final_transcription_requests_word_timestamps(self) -> None:
        sent: list[dict] = []
        transcriber = FakeTranscriber()
        session = self._session(transcriber, sent)
        run(session.feed(SPEECH(800)))
        run(session.feed(SILENCE(400)))
        self.assertIn(False, [final for _, final in transcriber.calls])
        self.assertIn(True, [final for _, final in transcriber.calls])


class DeviceResolutionTest(unittest.TestCase):
    def test_cpu_request_uses_int8(self) -> None:
        self.assertEqual(MODULE.resolve_device("cpu"), ("cpu", "int8"))

    def test_invalid_device_fails_closed(self) -> None:
        with self.assertRaises(ValueError):
            MODULE.resolve_device("tpu")

    def test_auto_returns_a_supported_pair(self) -> None:
        device, compute = MODULE.resolve_device("auto")
        self.assertIn(device, {"cuda", "cpu"})
        self.assertIn(compute, {"float16", "int8"})

    def test_auto_prefers_cuda_when_present(self) -> None:
        self.assertEqual(
            MODULE.resolve_device("auto", cuda_available=True), ("cuda", "float16")
        )

    def test_explicit_cuda_without_a_device_fails(self) -> None:
        with self.assertRaises(ValueError):
            MODULE.resolve_device("cuda", cuda_available=False)


class WarmupPcmTest(unittest.TestCase):
    def test_warmup_buffer_is_bytes_of_the_expected_length(self) -> None:
        pcm = MODULE.warmup_pcm(16_000, milliseconds=500)
        self.assertIsInstance(pcm, bytes)
        self.assertEqual(len(pcm), 16_000 // 2 * 2)
        self.assertEqual(MODULE.frame_rms(pcm), 0)

    def test_warmup_buffer_is_never_empty(self) -> None:
        self.assertGreaterEqual(len(MODULE.warmup_pcm(8_000, milliseconds=0)), 2)


class _FakeTranscriberFactory:
    """Records constructions and can fail warmup on a chosen device."""

    def __init__(self, *, failing_device: str | None = None) -> None:
        self.failing_device = failing_device
        self.built: list[tuple[str, str, str]] = []

    def __call__(self, model: str, device: str, compute_type: str):
        self.built.append((model, device, compute_type))
        failing = self.failing_device

        class _Transcriber:
            def __init__(self) -> None:
                self.device = device
                self.compute_type = compute_type
                self.model_name = model

            def warmup(self) -> None:
                if failing is not None and device == failing:
                    raise RuntimeError("Could not locate cudnn_ops64_9.dll")

        return _Transcriber()


class TranscriberBuildTest(unittest.TestCase):
    def test_auto_falls_back_to_cpu_when_cuda_warmup_fails(self) -> None:
        """cuDNN 부재처럼 '장치는 보이지만 추론이 죽는' 경우를 잡는다."""

        factory = _FakeTranscriberFactory(failing_device="cuda")
        transcriber = MODULE.build_transcriber(
            "small", "auto", factory=factory, cuda_available=True
        )
        self.assertEqual(transcriber.device, "cpu")
        self.assertEqual(transcriber.compute_type, "int8")
        self.assertEqual(
            factory.built, [("small", "cuda", "float16"), ("small", "cpu", "int8")]
        )

    def test_auto_keeps_cuda_when_warmup_succeeds(self) -> None:
        factory = _FakeTranscriberFactory()
        transcriber = MODULE.build_transcriber(
            "small", "auto", factory=factory, cuda_available=True
        )
        self.assertEqual(transcriber.device, "cuda")
        self.assertEqual(len(factory.built), 1)

    def test_explicit_cuda_never_downgrades_silently(self) -> None:
        factory = _FakeTranscriberFactory(failing_device="cuda")
        with self.assertRaises(MODULE.TranscriptionError):
            MODULE.build_transcriber(
                "small", "cuda", factory=factory, cuda_available=True
            )
        self.assertEqual(factory.built, [("small", "cuda", "float16")])

    def test_cpu_warmup_failure_is_not_retried(self) -> None:
        factory = _FakeTranscriberFactory(failing_device="cpu")
        with self.assertRaises(MODULE.TranscriptionError):
            MODULE.build_transcriber(
                "small", "auto", factory=factory, cuda_available=False
            )
        self.assertEqual(factory.built, [("small", "cpu", "int8")])


class CliTest(unittest.TestCase):
    def test_server_refuses_to_start_without_enable(self) -> None:
        self.assertEqual(MODULE.main([]), 2)

    def test_host_is_loopback_only(self) -> None:
        parser = MODULE.build_parser()
        with self.assertRaises(SystemExit):
            parser.parse_args(["--host", "0.0.0.0"])


if __name__ == "__main__":
    unittest.main()