"""设置路由：查询/修改运行时可调参数。

config.yaml 是只读挂载，改它需重启容器。本路由把部分参数（batch_size 等）
存到 DB 的 setting 表，通过 config.save_setting() + reload_settings() 实现
运行时热更新：保存后清 lru_cache，后续任务读到新值。

当前可调项与 config._OVERIDEABLE_FIELDS 对齐。
"""

from __future__ import annotations

import logging

from fastapi import APIRouter
from pydantic import BaseModel, Field

from ..config import _OVERIDEABLE_FIELDS, get_settings, save_setting

logger = logging.getLogger("audio2text.settings")
router = APIRouter(prefix="/api/settings", tags=["settings"])


# ---------------- 响应 / 请求 DTO ----------------

class SettingsResponse(BaseModel):
    """当前生效的设置值（YAML 基础 + DB 覆盖后的合并值）。"""
    asr_batch_size: int
    asr_beam_size: int
    translation_batch_size: int
    translation_sort_by_length: bool
    # 不可改但展示的只读信息
    asr_model: str
    asr_device: str
    asr_compute_type: str
    translation_model: str
    translation_device: str


class SettingsUpdate(BaseModel):
    """设置更新请求：只传要改的字段，未传的保持不变。"""
    asr_batch_size: int | None = Field(default=None, ge=1, le=128)
    asr_beam_size: int | None = Field(default=None, ge=1, le=10)
    translation_batch_size: int | None = Field(default=None, ge=1, le=256)
    translation_sort_by_length: bool | None = None


# ---------------- 字段映射：DTO 字段名 -> config 点分路径 ----------------

_FIELD_MAP: dict[str, str] = {
    "asr_batch_size": "asr.batch_size",
    "asr_beam_size": "asr.beam_size",
    "translation_batch_size": "translation.batch_size",
    "translation_sort_by_length": "translation.sort_by_length",
}


# ---------------- 接口 ----------------

@router.get("", summary="查询当前生效的设置")
def get_current_settings() -> SettingsResponse:
    """返回当前生效的设置（YAML 基础 + DB 覆盖合并后的值）。"""
    s = get_settings()
    return SettingsResponse(
        asr_batch_size=s.asr.batch_size,
        asr_beam_size=s.asr.beam_size,
        translation_batch_size=s.translation.batch_size,
        translation_sort_by_length=s.translation.sort_by_length,
        asr_model=s.asr.model,
        asr_device=s.asr.device,
        asr_compute_type=s.asr.compute_type,
        translation_model=s.translation.model,
        translation_device=s.translation.device,
    )


@router.put("", summary="更新设置（保存后对后续任务生效）")
def update_settings(req: SettingsUpdate) -> dict:
    """保存修改的设置项到 DB，清配置缓存。

    只处理请求中非 None 的字段。保存后立即生效（后续任务读到新值），
    已在跑的任务不受影响（任务在各阶段开始时读配置）。
    """
    changed: dict = {}
    for field, path in _FIELD_MAP.items():
        val = getattr(req, field)
        if val is not None:
            save_setting(path, val)
            changed[field] = val
            logger.info("设置已更新：%s = %s（对后续任务生效）", path, val)
    if not changed:
        return {"status": "no_change", "changed": {}}
    return {"status": "saved", "changed": changed}