#!/usr/bin/env bash
# 仅下载 sing-box（轻量核心）
set -euo pipefail
ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
# shellcheck source=lib.sh
source "$ROOT_DIR/scripts/lib.sh"
load_config
need_root
ensure_dirs
mkdir -p /var/lib/cellular-proxy

ARCH="$(arch_go)"
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT

# GitHub 下载代理：默认 https://git.86482425.xyz
# 空字符串 = 直连 GitHub；也可设为其它镜像前缀（末尾可带或不带 /）
GITHUB_PROXY="${GITHUB_PROXY:-https://git.86482425.xyz}"

github_url() {
  # 把 https://github.com/... 加上代理前缀
  local raw="$1"
  local proxy="${GITHUB_PROXY:-}"
  if [[ -z "$proxy" ]]; then
    echo "$raw"
    return
  fi
  proxy="${proxy%/}"
  # 已是代理地址则不重复加
  case "$raw" in
    "${proxy}"/*) echo "$raw"; return ;;
  esac
  # 常见 ghproxy 风格：https://proxy/https://github.com/...
  echo "${proxy}/${raw}"
}

download() {
  local url="$1" dest="$2"
  info "下载: $url"
  if command -v curl >/dev/null 2>&1; then
    curl -fL --retry 3 --connect-timeout 20 -o "$dest" "$url"
  elif command -v wget >/dev/null 2>&1; then
    wget -O "$dest" "$url"
  else
    die "需要 curl 或 wget"
  fi
}

download_github() {
  # 先走代理，失败再直连 GitHub
  local raw="$1" dest="$2"
  local proxied
  proxied="$(github_url "$raw")"
  if [[ "$proxied" != "$raw" ]]; then
    info "经 GitHub 代理下载: $proxied"
    if download "$proxied" "$dest"; then
      return 0
    fi
    warn "代理下载失败，尝试直连 GitHub: $raw"
  fi
  download "$raw" "$dest"
}

if [[ "$SING_BOX_SOURCE" == "local" ]]; then
  [[ -n "$SING_BOX_BIN" && -x "$SING_BOX_BIN" ]] || die "SING_BOX_SOURCE=local 但 SING_BOX_BIN 无效"
  install -m 0755 "$SING_BOX_BIN" "$INSTALL_DIR/bin/sing-box"
  info "已安装本地 sing-box"
elif command -v sing-box >/dev/null 2>&1 && [[ -z "${FORCE_DOWNLOAD:-}" ]]; then
  install -m 0755 "$(command -v sing-box)" "$INSTALL_DIR/bin/sing-box"
  info "复用系统 sing-box: $(command -v sing-box)"
else
  ver="$SING_BOX_VERSION"
  name="sing-box-${ver}-linux-${ARCH}"
  raw_url="https://github.com/SagerNet/sing-box/releases/download/v${ver}/${name}.tar.gz"
  download_github "$raw_url" "$TMP/sb.tgz"
  tar -xzf "$TMP/sb.tgz" -C "$TMP"
  install -m 0755 "$TMP/${name}/sing-box" "$INSTALL_DIR/bin/sing-box"
  info "已安装 sing-box v${ver}"
fi

# 安装中文静态 UI
mkdir -p "$INSTALL_DIR/ui"
if [[ -f "$ROOT_DIR/ui/index.html" ]]; then
  cp -a "$ROOT_DIR/ui/." "$INSTALL_DIR/ui/"
  info "已安装内置中文面板 -> $INSTALL_DIR/ui"
else
  warn "未找到 ui/index.html"
fi

info "二进制就绪:"
ls -la "$INSTALL_DIR/bin"
du -sh "$INSTALL_DIR/bin" "$INSTALL_DIR/ui" 2>/dev/null || true