"""
文件/长任务处理进度：阶段常量与上报助手。

进度约定：
  - 0–30：HTTP 上传（主要由前端 onUploadProgress 展示；入库后后端从 30 起）
  - 30–90：解析 / OCR / 分块 / 向量化
  - 90–100：摘要与收尾
"""
from __future__ import annotations

from typing import Awaitable, Callable, Optional, Type

import asyncpg

# ---------- 阶段 ----------
STAGE_UPLOADING = "uploading"
STAGE_PROCESSING = "processing"
STAGE_DOWNLOADING = "downloading"
STAGE_PARSING = "parsing"
STAGE_OCR = "ocr"
STAGE_SPLITTING = "splitting"
STAGE_EMBEDDING = "embedding"
STAGE_SUMMARIZING = "summarizing"
STAGE_EXTRACTING = "extracting"
STAGE_INDEXING = "indexing"
STAGE_COMPLETED = "completed"
STAGE_FAILED = "failed"

ProgressCallback = Callable[[int, str], Awaitable[None]]

STAGE_LABELS: dict[str, str] = {
    STAGE_UPLOADING: "上传中",
    STAGE_PROCESSING: "处理中",
    STAGE_DOWNLOADING: "下载文件",
    STAGE_PARSING: "解析文档",
    STAGE_OCR: "文字识别",
    STAGE_SPLITTING: "文本分块",
    STAGE_EMBEDDING: "向量化",
    STAGE_SUMMARIZING: "生成摘要",
    STAGE_EXTRACTING: "抽取实体关系",
    STAGE_INDEXING: "建立索引",
    STAGE_COMPLETED: "已完成",
    STAGE_FAILED: "失败",
}


async def _noop_progress(_percent: int, _stage: str) -> None:
    pass


class FileProgressReporter:
    """节流上报，避免同一进度重复写库。"""

    def __init__(self, callback: Optional[ProgressCallback] = None):
        self._callback = callback or _noop_progress
        self._last_percent = -1

    async def report(self, percent: int, stage: str) -> None:
        percent = max(0, min(100, int(percent)))
        if percent <= self._last_percent:
            return
        self._last_percent = percent
        await self._callback(percent, stage)


def make_db_progress_callback(
    pool,
    file_id: int,
    service_cls: Type,
) -> ProgressCallback:
    """为知识库/聊天文件创建写库进度回调。"""

    async def _callback(percent: int, stage: str) -> None:
        async with pool.acquire() as conn:
            await service_cls.update_file_progress(conn, file_id, percent, stage)

    return _callback


def stage_label(stage: Optional[str]) -> str:
    if not stage:
        return "处理中"
    return STAGE_LABELS.get(stage, stage)