#!/usr/bin/env bash
# 公共库
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
CONFIG_FILE="${CONFIG_FILE:-$ROOT_DIR/config/settings.conf}"

log()  { printf '[%s] %s\n' "$(date '+%F %T')" "$*" >&2; }
info() { log "INFO  $*"; }
warn() { log "WARN  $*"; }
err()  { log "ERROR $*"; }
die()  { err "$*"; exit 1; }

need_root() {
  if [[ "${EUID:-$(id -u)}" -ne 0 ]]; then
    die "请用 root 运行（sudo）"
  fi
}

load_config() {
  if [[ ! -f "$CONFIG_FILE" ]]; then
    die "缺少配置: $CONFIG_FILE
请先: cp $ROOT_DIR/config/settings.conf.example $ROOT_DIR/config/settings.conf"
  fi
  set -a
  # shellcheck disable=SC1090
  source "$CONFIG_FILE"
  set +a

  INSTALL_DIR="${INSTALL_DIR:-/opt/cellular-proxy}"
  LOG_DIR="${LOG_DIR:-/var/log/cellular-proxy}"
  CELLULAR_IFACE="${CELLULAR_IFACE:-}"
  CELLULAR_SOURCE_IP="${CELLULAR_SOURCE_IP:-}"
  REQUIRE_CELLULAR_IFACE="${REQUIRE_CELLULAR_IFACE:-true}"
  CELLULAR_IFACE_PATTERNS="${CELLULAR_IFACE_PATTERNS:-wwan,wwp,usb,enx,ppp,cdc}"
  PROXY_LISTEN_HOST="${PROXY_LISTEN_HOST:-0.0.0.0}"
  PROXY_MIXED_PORT="${PROXY_MIXED_PORT:-7890}"
  PROXY_USER="${PROXY_USER:-}"
  PROXY_PASS="${PROXY_PASS:-}"
  PANEL_LISTEN_HOST="${PANEL_LISTEN_HOST:-0.0.0.0}"
  PANEL_PORT="${PANEL_PORT:-9090}"
  PANEL_SECRET="${PANEL_SECRET:-please-change-me}"
  ENABLE_DNS="${ENABLE_DNS:-true}"
  LOG_LEVEL="${LOG_LEVEL:-warn}"
  SING_BOX_SOURCE="${SING_BOX_SOURCE:-release}"
  SING_BOX_VERSION="${SING_BOX_VERSION:-1.11.7}"
  SING_BOX_BIN="${SING_BOX_BIN:-}"
  MEMORY_MAX_MB="${MEMORY_MAX_MB:-96}"
  EGRESS_CHECK_URL="${EGRESS_CHECK_URL:-https://ifconfig.me}"
  EXPECTED_CELLULAR_PUBLIC_IP="${EXPECTED_CELLULAR_PUBLIC_IP:-}"

  for v in REQUIRE_CELLULAR_IFACE ENABLE_DNS; do
    val="${!v}"
    case "${val,,}" in
      1|true|yes|on) printf -v "$v" '%s' true ;;
      *) printf -v "$v" '%s' false ;;
    esac
  done
}

iface_exists() {
  local ifc="$1"
  [[ -n "$ifc" ]] && [[ -d "/sys/class/net/$ifc" ]]
}

is_virtual_or_skip_iface() {
  local name="$1"
  case "$name" in
    lo|docker*|br-*|veth*|virbr*|cni*|flannel*|tun*|tap*|wg*|zt*|tailscale*|easy*|et*)
      return 0
      ;;
  esac
  return 1
}

list_ifaces() {
  local name state ip
  for name in $(ls /sys/class/net 2>/dev/null | sort); do
    [[ "$name" == "lo" ]] && continue
    state="$(cat "/sys/class/net/$name/operstate" 2>/dev/null || echo unknown)"
    ip="$(ip -4 -o addr show dev "$name" 2>/dev/null | awk '{print $4}' | head -1)"
    printf '%s|%s|%s\n' "$name" "$state" "${ip:-}"
  done
}

detect_default_iface() {
  ip route show default 2>/dev/null | awk '/default/ {print $5; exit}'
}

detect_cellular_iface() {
  local configured="$1"
  if [[ -n "$configured" ]]; then
    if [[ "$configured" == "lo" ]]; then
      warn "CELLULAR_IFACE=lo 无效，将尝试自动探测"
    elif iface_exists "$configured"; then
      echo "$configured"
      return 0
    else
      warn "配置的 CELLULAR_IFACE=$configured 不存在"
      if [[ "$REQUIRE_CELLULAR_IFACE" == "true" ]]; then
        return 1
      fi
    fi
  fi

  local patterns name state ip p cand=""
  IFS=',' read -r -a patterns <<< "$CELLULAR_IFACE_PATTERNS"
  while IFS='|' read -r name state ip; do
    [[ -z "$name" ]] && continue
    is_virtual_or_skip_iface "$name" && continue
    for p in "${patterns[@]}"; do
      p="${p// /}"
      [[ -z "$p" ]] && continue
      if [[ "$name" == *"$p"* ]]; then
        if [[ "$state" == "up" || "$state" == "unknown" ]] && [[ -n "$ip" ]]; then
          echo "$name"
          return 0
        fi
        cand="${cand:-$name}"
      fi
    done
  done < <(list_ifaces)

  if [[ -n "$cand" ]]; then
    echo "$cand"
    return 0
  fi
  return 1
}

detect_source_ip() {
  local ifc="$1"
  ip -4 -o addr show dev "$ifc" 2>/dev/null | awk '{print $4}' | head -1 | cut -d/ -f1
}

arch_go() {
  case "$(uname -m)" in
    x86_64|amd64) echo amd64 ;;
    aarch64|arm64) echo arm64 ;;
    armv7l|armhf) echo armv7 ;;
    *) die "不支持的架构: $(uname -m)" ;;
  esac
}

ensure_dirs() {
  mkdir -p "$INSTALL_DIR"/{bin,etc,ui,generated} "$LOG_DIR"
}

resolve_cellular() {
  local cell
  if ! cell="$(detect_cellular_iface "$CELLULAR_IFACE")"; then
    if [[ "$REQUIRE_CELLULAR_IFACE" == "true" ]]; then
      die "无法确定数据网卡。请设置 CELLULAR_IFACE= 或运行 scripts/detect.sh"
    fi
    warn "未找到数据网卡"
    cell=""
  fi
  echo "$cell"
}