# --- routers/leaf_options.py ---
from fastapi import APIRouter, BackgroundTasks, HTTPException, Request, Body
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from typing import List
import json, os, asyncio, re
import database
from cmts_scraper import sync_cmts_leaves_async
from shared import CMTS_DEVICE, USE_DB

router = APIRouter(tags=["Options"])

# 🌟 1. 動態獲取快取檔名 (加入 host 隔離)
def get_cache_file(host: str, config_type: str):
    safe_host = host.replace(".", "_")
    return f"{safe_host}_{config_type}_cache.json"

# ==========================================
# 🌟 2. 全域廣播機制 (SSE) - 升級為「IP + 模式」頻道分流
# ==========================================
# 將狀態改為空字典，動態根據 host_configType 建立
SCAN_STATUS = {}
active_clients = {}

async def broadcast_message(message_dict: dict, host: str, config_type: str = "running"):
    """將訊息推播給特定頻道的連線前端"""
    channel_key = f"{host}_{config_type}"
    dead_clients = set()
    
    # SSE 協定嚴格要求必須以 "data: " 開頭，並以 "\n\n" 結尾
    message_str = f"data: {json.dumps(message_dict)}\n\n"
    
    for client_queue in active_clients.get(channel_key, set()):
        try:
            await client_queue.put(message_str)
        except Exception:
            dead_clients.add(client_queue)
    for dead in dead_clients:
        active_clients[channel_key].discard(dead)

@router.get("/cmts-leaf-options/stream")
async def sse_stream(request: Request, host: str, config_type: str = "running"):
    """前端一載入就會連上這個路由，持續監聽特定頻道的廣播"""
    channel_key = f"{host}_{config_type}"
    client_queue = asyncio.Queue()
    
    if channel_key not in active_clients:
        active_clients[channel_key] = set()
    active_clients[channel_key].add(client_queue)
    
    async def event_generator():
        try:
            while True:
                # 主動檢查斷線，避免死鎖
                if await request.is_disconnected():
                    break
                try:
                    # [修復 Leak] 延長 timeout 降低輪詢負擔
                    message = await asyncio.wait_for(client_queue.get(), timeout=5.0)
                    yield message
                except asyncio.TimeoutError:
                    yield ": keepalive\n\n"
                    
        except asyncio.CancelledError:
            pass
        finally:
            # [修復 Leak] 確保斷線時 Queue 絕對會被移出 active_clients 釋放記憶體
            if channel_key in active_clients:
                active_clients[channel_key].discard(client_queue)
            
    return StreamingResponse(event_generator(), media_type="text/event-stream")

@router.get("/scan-status")
async def get_scan_status(host: str, config_type: str = "running"):
    channel_key = f"{host}_{config_type}"
    return {"is_scanning": SCAN_STATUS.get(channel_key, False)}

# ==========================================
# 🌟 3. 快取讀取與背景掃描任務
# ==========================================
class SyncOptionsRequest(BaseModel):
    host: str # 🌟 新增 host 參數
    username: str = "" # 🌟 新增 username 參數
    password: str = "" # 🌟 新增 password 參數
    leaf_paths: List[str]
    config_type: str = "running" 

@router.get("/cmts-leaf-options")
async def get_leaf_options(host: str, config_type: str = "running"): 
    if USE_DB:
        try:
            db_options = await database.get_all_leaf_options(host, config_type)
            if db_options is not None:
                # 取得 metadata
                metadata = await database.get_device_status(host, config_type)
                if metadata:
                    db_options["__metadata__"] = metadata
                return db_options
            else:
                # 若回傳 None 表示 DB 連線異常，執行 Fallback
                print("⚠️ [Fallback] 資料庫無法取得資料，自動切換至 JSON 快取讀取...")
        except Exception as e:
            print(f"⚠️ [Fallback] 資料庫讀取發生例外: {e}，自動切換至 JSON 快取讀取...")

    cache_file = get_cache_file(host, config_type)
    if not os.path.exists(cache_file): return {}
    
    # 🌟 優化 3：將讀取動作丟到背景執行緒
    def read_json_from_file(filepath):
        with open(filepath, "r", encoding="utf-8") as f:
            return json.load(f)
            
    return await asyncio.to_thread(read_json_from_file, cache_file)

async def run_scan_task(host: str, username: str, password: str, paths: List[str], config_type: str):
    """在背景執行的爬蟲任務，並將進度廣播出去"""
    global SCAN_STATUS
    channel_key = f"{host}_{config_type}"
    try:
        await broadcast_message({"event": "scan_start"}, host, config_type)
        
        # 呼叫爬蟲 (帶入設備連線資訊與 config_type)
        async for chunk in sync_cmts_leaves_async(
            host=host,
            username=username,
            password=password,
            leaf_paths=paths,
            config_type=config_type 
        ):
            if isinstance(chunk, str):
                await broadcast_message(json.loads(chunk), host, config_type)
            else:
                await broadcast_message(chunk, host, config_type)
                
        await broadcast_message({"event": "done"}, host, config_type)
    except Exception as e:
        await broadcast_message({"event": "error", "message": str(e)}, host, config_type)
    finally:
        # 解除特定頻道的鎖定
        SCAN_STATUS[channel_key] = False

@router.post("/cmts-leaf-options/sync")
async def sync_leaf_options(request: SyncOptionsRequest, background_tasks: BackgroundTasks):
    global SCAN_STATUS
    if not request.leaf_paths: 
        raise HTTPException(status_code=400)
    
    channel_key = f"{request.host}_{request.config_type}"
    
    if SCAN_STATUS.get(channel_key, False):
        return {"status": "busy", "message": f"⚠️ {request.config_type} 模式的掃描任務正在執行中，請勿重複點擊！"}
    
    SCAN_STATUS[channel_key] = True
    
    # 保留您原本完美的路徑清理邏輯
    cmts_query_paths = []
    for p in request.leaf_paths:
        clean_p = p.replace("::", " ")
        clean_p = re.sub(r"\s*\[\d+\]", "", clean_p)
        cmts_query_paths.append(clean_p)
    
    cmts_query_paths = list(dict.fromkeys(cmts_query_paths))
    
    # 決定帳密 (優先使用 request 傳來的，否則 fallback 到 shared.CMTS_DEVICE)
    # 🌟 加上 or "" 確保最終結果絕對是字串，消除 Pylance 警告
    user = request.username or CMTS_DEVICE.get("username") or ""
    pwd = request.password or CMTS_DEVICE.get("password") or ""
    
    background_tasks.add_task(run_scan_task, request.host, user, pwd, cmts_query_paths, request.config_type)
    return {"status": "started"}

# ==========================================
# 🌟 4. 清除快取 API
# ==========================================
@router.post("/clear_cache")
async def clear_specific_cache(host: str, config_type: str = "running", paths_to_clear: list = Body(...)): 
    cleared_count = 0
    
    # 1. 嘗試清除 DB
    if USE_DB:
        try:
            db_cleared = await database.delete_leaf_options(host, config_type, paths_to_clear)
            if db_cleared >= 0:
                cleared_count = db_cleared
            else:
                print("⚠️ [Fallback] 資料庫清除失敗，自動切換至 JSON 快取清除...")
        except Exception as e:
            print(f"⚠️ [Fallback] 資料庫清除發生例外: {e}，自動切換至 JSON 快取清除...")

    # 2. 清除 JSON (如果 DB 沒清掉，或 USE_DB=False，或者是連同舊檔一起清確保乾淨)
    cache_file = get_cache_file(host, config_type) 
    
    if not os.path.exists(cache_file):
        # 如果是走 DB，且有清掉，回傳 DB 的結果
        if USE_DB and cleared_count > 0:
            return {"status": "success", "cleared_count": cleared_count}
        return {"status": "success", "cleared_count": 0, "message": "快取檔案不存在"}

    try:
        with open(cache_file, "r", encoding="utf-8") as f:
            cache_data = json.load(f)
            
        json_cleared_count = 0
        for path in paths_to_clear:
            if path in cache_data:
                del cache_data[path]
                json_cleared_count += 1
                
        if json_cleared_count > 0:
            with open(cache_file, "w", encoding="utf-8") as f:
                json.dump(cache_data, f, ensure_ascii=False, indent=4)
                
        # 回傳較大的那個數值
        final_count = max(cleared_count, json_cleared_count)
        return {"status": "success", "cleared_count": final_count}
        
    except Exception as e:
        # 確保回傳標準 JSON 格式
        return {"status": "error", "message": f"資料庫連線與快取存取皆失敗: {str(e)}"}