"""
Faster-Whisper CUDA 语音识别服务
封装本地 GPU 加速的音频转写逻辑，适配 RTX 3060 Ti 8GB 显存。
"""

from __future__ import annotations

import logging
import os
import traceback
from pathlib import Path
from typing import Optional, Tuple

from config import (
    BASE_DIR,
    HF_ENDPOINT,
    HF_HOME,
    HF_HUB_DOWNLOAD_TIMEOUT,
    WHISPER_COMPUTE_TYPE,
    WHISPER_DEVICE,
    WHISPER_HF_REPO,
    WHISPER_LANGUAGE,
    WHISPER_MODEL_DIR,
    WHISPER_MODEL_SIZE,
)

logger = logging.getLogger(__name__)

_model = None
_model_error: Optional[str] = None


def _ensure_hf_env() -> None:
    os.environ.setdefault("HF_ENDPOINT", HF_ENDPOINT)
    os.environ.setdefault("HF_HUB_DOWNLOAD_TIMEOUT", str(HF_HUB_DOWNLOAD_TIMEOUT))
    os.environ.setdefault("HF_HOME", str(HF_HOME))
    WHISPER_MODEL_DIR.mkdir(parents=True, exist_ok=True)


def _whisper_local_path() -> Optional[Path]:
    """返回已预下载的本地模型目录。"""
    local = WHISPER_MODEL_DIR / WHISPER_MODEL_SIZE
    if (local / "model.bin").is_file():
        return local
    return None


def _is_cuda_error(exc: BaseException) -> bool:
    msg = str(exc).lower()
    cuda_keywords = (
        "cuda", "cudnn", "cublas", "gpu",
        "out of memory", "no kernel image", "device-side assert",
    )
    return any(k in msg for k in cuda_keywords)


def _is_network_error(exc: BaseException) -> bool:
    msg = str(exc).lower()
    return any(
        k in msg
        for k in (
            "network is unreachable",
            "connection error",
            "connecterror",
            "timed out",
            "couldn't connect",
            "name resolution",
            "hub",
        )
    )


def _build_load_error(exc: BaseException) -> str:
    lines = [
        "Whisper 模型加载失败。",
        f"详情: {exc}",
        "",
    ]
    if _is_network_error(exc):
        lines.extend([
            "原因：服务器无法访问 HuggingFace 下载模型（内网/无外网常见）。",
            "请在服务器执行（走 HF 镜像，仅需一次）：",
            f"  cd {BASE_DIR}",
            "  bash scripts/download_whisper_models.sh",
            "  pm2 restart trading_studio",
            "",
            f"模型将保存到: {WHISPER_MODEL_DIR / WHISPER_MODEL_SIZE}",
        ])
    else:
        lines.append(f"完整日志:\n{traceback.format_exc()}")
    return "\n".join(lines)


def get_whisper_model():
    """获取或初始化 Faster-Whisper 模型（优先本地预下载）。"""
    global _model, _model_error

    if _model is not None:
        return _model, None

    if _model_error is not None:
        return None, _model_error

    try:
        _ensure_hf_env()
        from faster_whisper import WhisperModel

        local = _whisper_local_path()
        if local:
            model_id = str(local)
            logger.info("Whisper 从本地加载: %s", model_id)
        else:
            model_id = WHISPER_MODEL_SIZE
            logger.warning(
                "未找到本地 Whisper 模型 (%s)，尝试在线下载（可能失败）…",
                WHISPER_MODEL_DIR / WHISPER_MODEL_SIZE,
            )

        logger.info(
            "Whisper 加载: model=%s, device=%s, compute_type=%s",
            model_id,
            WHISPER_DEVICE,
            WHISPER_COMPUTE_TYPE,
        )
        _model = WhisperModel(
            model_id,
            device=WHISPER_DEVICE,
            compute_type=WHISPER_COMPUTE_TYPE,
            download_root=str(WHISPER_MODEL_DIR),
        )
        logger.info("Whisper 模型加载成功。")
        return _model, None

    except ImportError as exc:
        _model_error = (
            "未安装 faster-whisper，请执行: pip install faster-whisper\n"
            f"原始错误: {exc}"
        )
        logger.exception("faster-whisper 导入失败")
        return None, _model_error

    except Exception as exc:
        if _is_cuda_error(exc):
            _model_error = (
                "CUDA 初始化失败，请检查 NVIDIA 驱动、CUDA 运行时及 cuDNN。\n"
                f"错误详情: {exc}"
            )
        else:
            _model_error = _build_load_error(exc)
        logger.exception("Whisper 模型加载异常")
        return None, _model_error


def transcribe_audio(audio_path: str) -> Tuple[bool, str]:
    """将音频文件转写为中文文本。"""
    if not audio_path:
        return False, "未提供音频文件路径。"

    # 识别前释放 ChatTTS，避免与 Whisper 同占 8GB 显存
    try:
        from tts_service import reset_chattts_instance

        reset_chattts_instance()
    except Exception:
        logger.debug("释放 ChatTTS 显存时跳过", exc_info=True)

    model, init_error = get_whisper_model()
    if model is None:
        return False, init_error or "Whisper 模型不可用。"

    try:
        segments, info = model.transcribe(
            audio_path,
            language=WHISPER_LANGUAGE,
            beam_size=5,
            vad_filter=True,
        )

        text_parts = [segment.text.strip() for segment in segments]
        result_text = "".join(text_parts).strip()

        if not result_text:
            return False, (
                "识别结果为空，请检查音频是否有效、音量是否足够，"
                f"或尝试更换格式。检测到语言: {getattr(info, 'language', 'unknown')}"
            )

        logger.info(
            "转写完成: 语言=%s, 概率=%.2f, 字数=%d",
            getattr(info, "language", "?"),
            getattr(info, "language_probability", 0.0),
            len(result_text),
        )
        return True, result_text

    except Exception as exc:
        if _is_cuda_error(exc):
            err = (
                "CUDA 推理异常：显存可能不足或 GPU 状态异常。\n"
                f"错误详情: {exc}"
            )
        else:
            err = f"音频转写失败: {exc}\n{traceback.format_exc()}"

        logger.exception("transcribe_audio 失败")
        return False, err


def reset_whisper_model() -> None:
    """卸载 Whisper 模型并回收 GPU 显存。"""
    global _model, _model_error
    if _model is not None:
        try:
            del _model
        except Exception:
            pass
    _model = None
    _model_error = None

    from gpu_utils import release_cuda_cache

    release_cuda_cache()
    logger.info("Whisper 模型已卸载，显存已尝试回收。")