import json
import os

from fastapi import APIRouter, UploadFile, File, Form, HTTPException
from fastapi.responses import StreamingResponse

import utils.util
from api.handler_registry import HANDLER_REGISTRY
from api.schema import ChatRequest
from config.settings import JSON_CACHE_DIR, REPORT_OUTPUT_DIR, SERVER_HOST, PDF_SAVE_DIR
from service.stream_service import format_sse_event, stream_calculation_sync, detect_intent, stream_review_sync
from service.history_manager import fetch_all_sessions, fetch_session_detail, remove_session_file

from service.pdf_parse_service import parse_pdf, get_latest_file

router = APIRouter()


@router.post("/api/vent/review/pdf")
async def api_review(
    file: UploadFile = File(),
    session_id: str | None = Form(default=None),
    message : str | None = Form(default=None)
):
    if not file.filename.endswith(".pdf"):
        raise HTTPException(status_code=400, detail="仅支持PDF")

    return StreamingResponse(
        stream_review_sync(file,message,session_id),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no"
        }
    )


@router.post("/api/vent/chat")
async def vent_chat(req: ChatRequest):
    return StreamingResponse(
        stream_calculation_sync(req.message, req.session_id),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive"
        }
    )

@router.get("/health")
async def health():
    return {"status": "ok", "agent": "create_agent(LangGraph)"}


@router.get("/api/history/session_list")
async def list_sessions():
    return {"code":200,"data":fetch_all_sessions()}

@router.get("/api/history/detail/{session_id}")
async def get_session_history(session_id:str):
    data = fetch_session_detail(session_id)
    return {"code":200,"data":data}


@router.delete("/api/history/delete/{session_id}")
async def remove_session(session_id: str):
    success = remove_session_file(session_id)
    if not success:
        raise HTTPException(
            status_code=404,
            detail=f"会话 {session_id} 不存在或删除失败"
        )
    return {"code": 200, "message": "会话删除成功", "data": None}



@router.get("/api/latest-json", summary="")
async def get_latest_json():
    """
    获取指定文件夹中修改时间最新的JSON文件并返回内容
    """
    hash_id = utils.util.get_user_setting("last_upload_file")

    latest_file_path = f"{JSON_CACHE_DIR}/{hash_id}.json"

    try:
        with open(latest_file_path, "r", encoding="utf-8") as f:
            data = json.load(f)
    except json.JSONDecodeError:
        raise HTTPException(status_code=500, detail="JSON文件格式错误")
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"读取文件失败: {str(e)}")

    return {"code": 200, "message": "一切ok", "data": data}



@router.get("/api/latest-pdf", summary="")
async def get_latest_pdf():

    hash_id = utils.util.get_user_setting("last_upload_file")
    pdf_filename = f"{hash_id}.pdf"
    url =  f"{SERVER_HOST}/static/save_pdf/{pdf_filename}"
    return {"code": 200, "message": "一切ok", "data": url}



@router.post("/api/vent/unified")
async def unified_vent_api(
    # 表单参数
    message: str = Form(...),
    session_id: str | None = Form(default=None),
    # 文件参数（可选）
    file: UploadFile | None = File(default=None)
):
    """
    配风管理统一入口：意图识别 + 自动分发业务
    支持：纯文本对话 / PDF文件+文本审查
    """
    # 1. 基础参数校验
    if not message.strip():
        raise HTTPException(status_code=400, detail="指令内容不能为空")

    # 2. 意图识别
    has_file = bool(file)
    intent_type = await detect_intent(session_id,message,has_file)

    # 3. 未知意图：使用stream_calculation_sync进行流式处理
    if intent_type not in HANDLER_REGISTRY:
        headers = {"Cache-Control": "no-cache", "Connection": "keep-alive"}
        return StreamingResponse(
            stream_calculation_sync(message, session_id),
            media_type="text/event-stream",
            headers=headers
        )
    # 4. 从注册表获取对应处理器
    handler = HANDLER_REGISTRY[intent_type]

    # 5. 执行当前业务的专属参数校验
    handler.validate(file)

    # 6. 生成流式响应（分两种场景调用）
    if handler.need_file:
        # 带文件：审查场景
        stream_iter = handler.stream_func(file,message, session_id)
        headers = {"Cache-Control": "no-cache", "Connection": "keep-alive", "X-Accel-Buffering": "no"}
    else:
        # 无文件：计算场景
        stream_iter = handler.stream_func(message, session_id)
        headers = {"Cache-Control": "no-cache", "Connection": "keep-alive"}

    return StreamingResponse(stream_iter, media_type="text/event-stream", headers=headers)