#!/usr/bin/env bash
# 监控数据网卡 + ModemManager 重拨/重注册事件，自动等待附着并 regenerate。
# 策略：
#   1) 默认只 bind_interface（不写死源 IP）—— 多数 IP 漂移无需 pin
#   2) iface 丢失→重探；可选 BIND_SOURCE_IP 时同步源 IP
#   3) **优先以 ModemManager 日志为重拨标准**（零公网流量）：
#        home→searching / attached→detached / bearer 断连 等 → 等 IPv4 回来 → generate/restart
#   4) 不默认做公网出口探针（省流量）；仅本地 iface/MM 状态
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
# shellcheck source=lib.sh
source "$ROOT_DIR/scripts/lib.sh"

CONFIG_FILE="${CONFIG_FILE:-$ROOT_DIR/etc/settings.conf}"
if [[ ! -f "$CONFIG_FILE" && -f /opt/cellular-proxy/etc/settings.conf ]]; then
  CONFIG_FILE=/opt/cellular-proxy/etc/settings.conf
  ROOT_DIR=/opt/cellular-proxy
fi
export CONFIG_FILE

load_config

INTERVAL="${WATCH_INTERVAL_SEC:-60}"
DEBOUNCE_SEC="${WATCH_DEBOUNCE_SEC:-3}"
# ModemManager 事件驱动（默认开；只读本机 journal，不耗蜂窝公网流量）
WATCH_MM_EVENTS="${WATCH_MM_EVENTS:-true}"
WATCH_MM_UNIT="${WATCH_MM_UNIT:-ModemManager}"
WATCH_MM_SETTLE_SEC="${WATCH_MM_SETTLE_SEC:-5}"
WATCH_MM_READY_TIMEOUT_SEC="${WATCH_MM_READY_TIMEOUT_SEC:-90}"
WATCH_MM_READY_POLL_SEC="${WATCH_MM_READY_POLL_SEC:-2}"
# 同一轮 MM 抖动合并窗口（秒）：连续 searching/detached 只恢复一次
WATCH_MM_COALESCE_SEC="${WATCH_MM_COALESCE_SEC:-20}"

LOCK_DIR="${LOG_DIR:-/var/log/cellular-proxy}"
mkdir -p "$LOCK_DIR" 2>/dev/null || true
STATE_FILE="${LOCK_DIR}/watch.state"
MM_CURSOR_FILE="${LOCK_DIR}/mm.cursor"
MM_LAST_EVENT_FILE="${LOCK_DIR}/mm.last_event"
LOG_TAG="cellular-proxy-watch"

logw() { printf '[%s] %s %s\n' "$(date '+%F %T')" "$LOG_TAG" "$*" >&2; }

truthy() {
  case "${1,,}" in
    1|true|yes|on) return 0 ;;
    *) return 1 ;;
  esac
}

current_cfg_iface() {
  python3 - <<'PY' 2>/dev/null || true
import json
from pathlib import Path
for p in ("/opt/cellular-proxy/etc/config.json",):
    try:
        c=json.loads(Path(p).read_text())
        for o in c.get("outbounds") or []:
            if o.get("tag")=="cellular":
                print(o.get("bind_interface") or "")
                raise SystemExit
    except Exception:
        pass
print("")
PY
}

current_cfg_src() {
  python3 - <<'PY' 2>/dev/null || true
import json
from pathlib import Path
try:
    c=json.loads(Path("/opt/cellular-proxy/etc/config.json").read_text())
    for o in c.get("outbounds") or []:
        if o.get("tag")=="cellular":
            print(o.get("inet4_bind_address") or "")
            raise SystemExit
except Exception:
    pass
print("")
PY
}

# 将 ModemManager 日志行判定为「重拨 / 脱网 / 重注册」类事件
is_mm_redial_line() {
  local line="${1,,}"
  # 忽略纯噪声
  [[ -z "$line" ]] && return 1
  [[ "$line" == *"-- no entries --"* ]] && return 1

  # 核心：注册/分组附着状态机（本次 16:48 日志即此类）
  if [[ "$line" == *"registration state changed"* ]]; then
    return 0
  fi
  if [[ "$line" == *"packet service state changed"* ]]; then
    return 0
  fi
  if [[ "$line" == *"consolidated registration state"* && ( "$line" == *"searching"* || "$line" == *"denied"* || "$line" == *"unknown"* ) ]]; then
    return 0
  fi
  # bearer / 连接态
  if [[ "$line" == *"bearer"* && ( "$line" == *"disconnect"* || "$line" == *"connect"* || "$line" == *"failed"* ) ]]; then
    return 0
  fi
  if [[ "$line" == *"state changed"* && ( "$line" == *"connected"* || "$line" == *"disconnected"* || "$line" == *"searching"* || "$line" == *"registered"* ) ]]; then
    # 避免把完全无关的 service 状态刷进来：需 modem 语境
    if [[ "$line" == *"[modem"* || "$line" == *"modem"* || "$line" == *"3gpp"* ]]; then
      return 0
    fi
  fi
  if [[ "$line" == *"access technology changed"* ]]; then
    return 0
  fi
  if [[ "$line" == *"unexpected lte system info"* ]]; then
    return 0
  fi
  return 1
}

init_mm_cursor_now() {
  # 升级/首次启动：锚到「现在」，不回放历史，避免一启动就误 rebind
  [[ -f "$MM_CURSOR_FILE" ]] && return 0
  if ! command -v journalctl >/dev/null 2>&1; then
    return 1
  fi
  local cur
  cur="$(journalctl -u "$WATCH_MM_UNIT" -n 0 --show-cursor --no-pager 2>/dev/null | sed -n 's/^-- cursor: //p' | tail -1 || true)"
  if [[ -n "$cur" ]]; then
    printf '%s\n' "$cur" >"$MM_CURSOR_FILE"
    logw "mm cursor initialized (no backlog replay)"
    return 0
  fi
  # 无 journal 时写空标记
  : >"$MM_CURSOR_FILE"
  return 0
}

# 扫描 cursor 之后的 MM 日志；命中则打印摘要并 return 0
scan_mm_events_since_cursor() {
  truthy "$WATCH_MM_EVENTS" || return 1
  command -v journalctl >/dev/null 2>&1 || return 1
  init_mm_cursor_now || true

  local out hits=0 sample=""
  # --after-cursor 需要已有 cursor；首次空文件则用 -n 0 建锚后返回无事件
  if [[ ! -s "$MM_CURSOR_FILE" ]]; then
    init_mm_cursor_now || true
    return 1
  fi

  # 用临时 cursor 复制，避免 journalctl 在无新条目时搞乱；成功读后再写回
  local cur
  cur="$(tr -d '\r\n' <"$MM_CURSOR_FILE" 2>/dev/null || true)"
  if [[ -z "$cur" ]]; then
    init_mm_cursor_now || true
    return 1
  fi

  out="$(journalctl -u "$WATCH_MM_UNIT" --after-cursor="$cur" --no-pager -o short-iso 2>/dev/null || true)"
  # 推进 cursor 到最新（即使本轮无匹配事件也推进，避免重复扫）
  local newcur
  newcur="$(journalctl -u "$WATCH_MM_UNIT" -n 0 --show-cursor --no-pager 2>/dev/null | sed -n 's/^-- cursor: //p' | tail -1 || true)"
  if [[ -n "$newcur" ]]; then
    printf '%s\n' "$newcur" >"$MM_CURSOR_FILE"
  fi

  [[ -z "$out" ]] && return 1
  while IFS= read -r line; do
    [[ -z "$line" || "$line" == --* ]] && continue
    if is_mm_redial_line "$line"; then
      hits=$((hits + 1))
      sample="$line"
    fi
  done <<<"$out"

  if (( hits > 0 )); then
    printf '%s\n' "$sample" >"$MM_LAST_EVENT_FILE" 2>/dev/null || true
    logw "mm redial/re-register events=${hits} last=${sample}"
    return 0
  fi
  return 1
}

mm_line_looks_recovered() {
  local line="${1,,}"
  [[ "$line" == *"registration state changed"*"home"* ]] && return 0
  [[ "$line" == *"packet service state changed"*"attached"* ]] && return 0
  [[ "$line" == *"consolidated registration state"* && "$line" == *"'home'"* ]] && return 0
  return 1
}

# 等待蜂窝数据面可用：iface 存在 + IPv4；可选 mmcli connected
wait_cellular_ready() {
  local cell="${1:-}"
  local deadline now src
  deadline=$(( $(date +%s) + WATCH_MM_READY_TIMEOUT_SEC ))
  logw "wait cellular ready iface=${cell:-?} timeout=${WATCH_MM_READY_TIMEOUT_SEC}s"

  while true; do
    now="$(date +%s)"
    if (( now >= deadline )); then
      logw "wait cellular ready: timeout"
      return 1
    fi

    load_config
    cell="${CELLULAR_IFACE:-$cell}"
    if [[ -z "$cell" ]] || ! iface_exists "$cell"; then
      cell="$(detect_cellular_iface "" || true)"
    fi
    if [[ -n "$cell" ]] && iface_exists "$cell"; then
      src="$(detect_source_ip "$cell" || true)"
      if [[ -n "$src" ]]; then
        # 若 mmcli 可用，尽量确认 modem 已 connected/attached（失败不阻断，有 IPv4 即可）
        if command -v mmcli >/dev/null 2>&1; then
          if mmcli -L 2>/dev/null | grep -qi modem; then
            if mmcli -m any 2>/dev/null | grep -qiE 'state:[[:space:]]*connected|packet service state:[[:space:]]*attached|registration:[[:space:]]*home'; then
              logw "cellular ready: iface=$cell src=$src (mmcli ok)"
              printf '%s\n' "$cell"
              return 0
            fi
            # 有 IPv4 但 mmcli 尚未 home：再等一小会儿
            sleep "$WATCH_MM_READY_POLL_SEC"
            src2="$(detect_source_ip "$cell" || true)"
            if [[ -n "$src2" ]]; then
              logw "cellular ready: iface=$cell src=$src2 (ipv4 present; mmcli not yet home)"
              printf '%s\n' "$cell"
              return 0
            fi
          else
            logw "cellular ready: iface=$cell src=$src"
            printf '%s\n' "$cell"
            return 0
          fi
        else
          logw "cellular ready: iface=$cell src=$src"
          printf '%s\n' "$cell"
          return 0
        fi
      fi
    fi
    sleep "$WATCH_MM_READY_POLL_SEC"
  done
}

need_refresh() {
  load_config
  local cell="${CELLULAR_IFACE:-}"
  local live_src="" cfg_iface cfg_src
  cfg_iface="$(current_cfg_iface)"
  cfg_src="$(current_cfg_src)"

  if [[ -z "$cell" ]] || ! iface_exists "$cell"; then
    logw "iface missing or empty (CELLULAR_IFACE=${cell:-<空>}) → rebind"
    return 0
  fi

  live_src="$(detect_source_ip "$cell" || true)"
  if [[ -z "$live_src" ]]; then
    # 网卡在但无 IPv4：可能刚重拨；不立刻 die，等下一轮或 MM 恢复路径
    logw "wwan up but no IPv4 yet on $cell"
    if [[ -n "$cfg_src" ]]; then
      return 0
    fi
    return 1
  fi

  if [[ -n "$cfg_iface" && "$cfg_iface" != "$cell" ]]; then
    logw "cfg iface $cfg_iface != settings $cell"
    return 0
  fi

  # 仅当配置写了 inet4_bind_address 且与 live 不一致时才需要
  if [[ -n "$cfg_src" && "$cfg_src" != "$live_src" ]]; then
    logw "stale source IP cfg=$cfg_src live=$live_src"
    return 0
  fi

  # settings 里的 SOURCE_IP 过期也同步（即使 config 未 pin）
  if [[ -n "${CELLULAR_SOURCE_IP:-}" && "${CELLULAR_SOURCE_IP}" != "$live_src" ]]; then
    persist_cellular_to_settings "$CONFIG_FILE" "$cell" "$live_src" || true
  fi

  return 1
}

do_refresh() {
  load_config
  local cell="${CELLULAR_IFACE:-}"
  local src=""
  local reason="${1:-manual}"

  if [[ -z "$cell" ]] || ! iface_exists "$cell"; then
    cell="$(detect_cellular_iface "" || true)"
    if [[ -z "$cell" ]]; then
      logw "detect failed; skip reason=$reason"
      return 1
    fi
  fi
  src="$(detect_source_ip "$cell" || true)"
  if [[ -z "$src" ]]; then
    logw "no IPv4 on $cell yet; skip generate reason=$reason"
    return 1
  fi
  persist_cellular_to_settings "$CONFIG_FILE" "$cell" "$src" || true
  logw "refresh: reason=$reason iface=$cell src=$src"
  # 走 cpxy generate（含 check + restart）；失败则直接 scripts
  if command -v cpxy >/dev/null 2>&1; then
    cpxy generate >/dev/null 2>&1 || {
      # shellcheck source=/dev/null
      source "$ROOT_DIR/scripts/lib.sh"
      load_config
      "$ROOT_DIR/scripts/generate.sh" "$ROOT_DIR/generated"
      install -m 0644 "$ROOT_DIR/generated/config.json" "$ROOT_DIR/etc/config.json"
      install -m 0644 "$ROOT_DIR/generated/runtime.env" "$ROOT_DIR/etc/runtime.env" 2>/dev/null || true
      systemctl restart cellular-proxy 2>/dev/null || true
    }
  else
    "$ROOT_DIR/scripts/generate.sh" "$ROOT_DIR/generated"
    install -m 0644 "$ROOT_DIR/generated/config.json" "$ROOT_DIR/etc/config.json"
    systemctl restart cellular-proxy 2>/dev/null || true
  fi
  printf '%s reason=%s iface=%s src=%s\n' "$(date -Iseconds)" "$reason" "$cell" "$src" >"$STATE_FILE" 2>/dev/null || true
  logw "refresh done reason=$reason"
}

# MM 事件后：settle → 等数据面 → refresh（即使未 pin 源 IP，也重启清半开连接）
handle_mm_recover() {
  local now last=0
  now="$(date +%s)"
  if [[ -f "$STATE_FILE" ]]; then
    # 合并窗口：避免 searching→registering→home 连打三次
    last="$(stat -c %Y "$STATE_FILE" 2>/dev/null || echo 0)"
    if (( now - last < WATCH_MM_COALESCE_SEC )); then
      # 若 state 很新且是 mm 恢复，跳过
      if grep -q 'reason=mm' "$STATE_FILE" 2>/dev/null; then
        logw "mm recover coalesced (<${WATCH_MM_COALESCE_SEC}s)"
        return 0
      fi
    fi
  fi

  sleep "${WATCH_MM_SETTLE_SEC}"
  local cell=""
  cell="$(wait_cellular_ready "${CELLULAR_IFACE:-}" || true)"
  if [[ -z "$cell" ]]; then
    # 超时仍尝试一轮 need_refresh / refresh（可能仅有短暂 IPv4）
    logw "mm recover: ready wait failed; try best-effort refresh"
  fi
  do_refresh "mm" || true
}

last_run=0
trigger() {
  local now reason="${1:-poll}"
  now="$(date +%s)"
  if (( now - last_run < DEBOUNCE_SEC )); then
    return 0
  fi
  last_run=$now

  # 1) ModemManager 重拨标准（零公网流量）
  if scan_mm_events_since_cursor; then
    handle_mm_recover
    return 0
  fi

  # 2) 原有 iface / stale pin 逻辑
  if need_refresh; then
    do_refresh "$reason" || true
  fi
}

# oneshot mode (systemd timer)
if [[ "${1:-}" == "--once" ]]; then
  trigger "once"
  exit 0
fi

# long-running: periodic + ip monitor + MM journal follow
logw "start interval=${INTERVAL}s debounce=${DEBOUNCE_SEC}s mm_events=${WATCH_MM_EVENTS} mm_unit=${WATCH_MM_UNIT}"
init_mm_cursor_now || true

# initial
trigger "start"

child_pids=()
cleanup() {
  local p
  for p in "${child_pids[@]:-}"; do
    kill "$p" 2>/dev/null || true
  done
  exit 0
}
trap cleanup TERM INT

# Prefer event-driven if available; always keep poll as safety net
if command -v ip >/dev/null 2>&1; then
  (
    ip -o monitor address link 2>/dev/null | while read -r line; do
      cell="${CELLULAR_IFACE:-}"
      if [[ -f "$CONFIG_FILE" ]]; then
        cell="$(awk -F= '/^CELLULAR_IFACE=/{print $2; exit}' "$CONFIG_FILE" 2>/dev/null || true)"
      fi
      if [[ -n "$cell" ]] && [[ "$line" == *"$cell"* || "$line" == *Deleted* || "$line" == *wwan* || "$line" == *usb* || "$line" == *enx* ]]; then
        sleep "$DEBOUNCE_SEC"
        trigger "ip-monitor"
      fi
    done
  ) &
  child_pids+=($!)
fi

# ModemManager 实时日志（标准：重拨/重注册）
if truthy "$WATCH_MM_EVENTS" && command -v journalctl >/dev/null 2>&1; then
  (
    # -n 0：不回放历史；-f：跟随
    journalctl -u "$WATCH_MM_UNIT" -f -n 0 --no-pager 2>/dev/null | while IFS= read -r line; do
      if is_mm_redial_line "$line"; then
        logw "mm live: $line"
        printf '%s\n' "$line" >"$MM_LAST_EVENT_FILE" 2>/dev/null || true
        # 推进 cursor，避免 poll 再扫到同一批
        newcur="$(journalctl -u "$WATCH_MM_UNIT" -n 0 --show-cursor --no-pager 2>/dev/null | sed -n 's/^-- cursor: //p' | tail -1 || true)"
        [[ -n "$newcur" ]] && printf '%s\n' "$newcur" >"$MM_CURSOR_FILE"
        sleep "$DEBOUNCE_SEC"
        handle_mm_recover
      fi
    done
  ) &
  child_pids+=($!)
  logw "mm journal follow enabled unit=$WATCH_MM_UNIT"
else
  logw "mm journal follow disabled or journalctl missing"
fi

while true; do
  sleep "$INTERVAL"
  trigger "poll"
done