# --- routers/diagnostics.py ---
import re
import asyncssh
from logger import get_logger
from fastapi import APIRouter, HTTPException, Query
from typing import Dict, Any

logger = get_logger("app.diagnostics")
router = APIRouter(prefix="/cm-diagnostics", tags=["Diagnostics"])

@router.get("/")
async def get_cm_diagnostics(
    host: str = Query(...),
    username: str = Query(...),
    password: str = Query(...),
    mac: str = Query(..., description="Cable Modem MAC Address")
) -> Dict[str, Any]:
    
    mac = mac.strip().lower()
    if not mac:
        raise HTTPException(status_code=400, detail="MAC Address is required")

    result_data = {
        "mac": mac,
        "ip": "N/A",
        "state": "N/A",
        "cpe_count": 0,
        "phy": {
            "tx_power": None,
            "rx_power": None
        },
        "upstreams": [],    
        "mer_channels": {}  
    }

    try:
        async with asyncssh.connect(host, username=username, password=password, known_hosts=None) as conn:
            logger.debug(f"🚀 [Diagnostics] 開始診斷 MAC: {mac}")

            # ==========================================
            # 1. 查詢基本狀態
            # ==========================================
            cmd_base = "show cable modem " + mac + " | nomore"
            res_base = await conn.run(cmd_base, check=False)
            if res_base.exit_status == 0 and res_base.stdout:
                for line in res_base.stdout.splitlines():
                    if mac in line.lower():
                        tokens = line.split()
                        for t in tokens:
                            if re.match(r"^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$", t): 
                                result_data["ip"] = t
                            elif re.match(r"^[a-z]-online|online|offline|init.*|reject", t, re.IGNORECASE): 
                                result_data["state"] = t
                        nums = [t for t in tokens if t.isdigit()]
                        if nums:
                            result_data["cpe_count"] = int(nums[-1])
                        break

            # ==========================================
            # 2. 查詢 PHY 狀態 (💡 修復：移除寫死的 us/oad 判斷，改用通用特徵)
            # ==========================================
            cmd_phy = "show cable modem " + mac + " phy | nomore"
            res_phy = await conn.run(cmd_phy, check=False)
            if res_phy.exit_status == 0 and res_phy.stdout:
                tx_list = []
                rx_list = []
                for line in res_phy.stdout.splitlines():
                    line_lower = line.lower()
                    if mac in line_lower:
                        tokens = line.split()
                        if len(tokens) >= 6:
                            ch_name = tokens[1]
                            # 💡 只要名稱包含 ":" 和 "/"，就認定是合法的通道 (例如 Oa32, Oad32, Us32)
                            if ":" in ch_name and "/" in ch_name:
                                try:
                                    snr_val = float(tokens[4])
                                    result_data["upstreams"].append({"channel": ch_name, "snr": snr_val})
                                except:
                                    pass
                            try:
                                tx_val = float(tokens[3].split('/')[0])
                                rx_list_val = float(tokens[5].split('/')[0])
                                tx_list.append(tx_val)
                                rx_list.append(rx_list_val)
                            except:
                                pass
                                
                if tx_list: result_data["phy"]["tx_power"] = round(sum(tx_list)/len(tx_list), 2)
                if rx_list: result_data["phy"]["rx_power"] = round(sum(rx_list)/len(rx_list), 2)

            # ==========================================
            # 3. 尋找所有 OFDM 通道
            # ==========================================
            cmd_help = "show cable modem " + mac + " ofdm-channel ?"
            res_help = await conn.run(cmd_help, check=False)
            text_to_search = (res_help.stdout or "") + "\n" + (res_help.stderr or "")
            
            cmd_verb = "show cable modem " + mac + " verbose | nomore"
            res_verb = await conn.run(cmd_verb, check=False)
            text_to_search += "\n" + (res_verb.stdout or "")

            matches = re.findall(r"\b(Of(?:dm)?\d*[\d/:]+)\b", text_to_search, re.IGNORECASE)
            ofdm_channels = []
            for m in matches:
                clean_m = m.lower()
                if clean_m.startswith("of"):
                    clean_m = "Of" + clean_m[2:]
                if clean_m not in ofdm_channels:
                    ofdm_channels.append(clean_m)
            ofdm_channels.sort()

            # ==========================================
            # 4. 對每一個 OFDM 通道查詢 MER
            # ==========================================
            for ch in ofdm_channels:
                cmd_mer = "show cable modem " + mac + " ofdm-channel " + ch + " mer | nomore"
                res_mer = await conn.run(cmd_mer, check=False)
                
                histogram = {}
                min_mer = 999
                
                if res_mer.exit_status == 0 and res_mer.stdout:
                    mer_lines = re.finditer(r"(\d+)\s*(?:db|dB)?\s*\|[^|]*\|?\s*(\**)", res_mer.stdout, re.IGNORECASE)
                    for match in mer_lines:
                        db_val = match.group(1)
                        stars = match.group(2)
                        if stars:
                            histogram[db_val] = len(stars) * 100
                            db_int = int(db_val)
                            if db_int < min_mer:
                                min_mer = db_int
                
                health = "unknown"
                if histogram and min_mer != 999:
                    if min_mer >= 41: health = "good"
                    elif min_mer >= 38: health = "warning"
                    else: health = "critical"
                    
                result_data["mer_channels"][ch] = {
                    "histogram": histogram,
                    "health": health,
                    "min_mer": min_mer if min_mer != 999 else "N/A"
                }

        logger.debug(f"✅ [Diagnostics] 解析結果: {result_data}")
        return {"status": "success", "data": result_data}

    except Exception as e:
        logger.error("CM Diagnostics Error: " + str(e))
        raise HTTPException(status_code=500, detail="設備連線或查詢失敗: " + str(e))