#!/usr/bin/env bash
# 仅下载/安装 sing-box（轻量核心）
# 优先级：local → 系统已有 → Gitea Release（整包/分片）→ GitHub 代理 → 直连 GitHub
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_PROXY="${GITHUB_PROXY:-https://git.86482425.xyz}"
GITEA_BASE="${GITEA_BASE:-https://gitea.chickliu.fun}"
GITEA_OWNER="${GITEA_OWNER:-Hermes}"
GITEA_REPO="${GITEA_REPO:-cellular-proxy}"
SING_BOX_RELEASE_TAG="${SING_BOX_RELEASE_TAG:-bin-v${SING_BOX_VERSION}}"
# gitea | github | auto | local | release
SING_BOX_SOURCE="${SING_BOX_SOURCE:-auto}"

github_url() {
  local raw="$1"
  local proxy="${GITHUB_PROXY:-}"
  if [[ -z "$proxy" ]]; then
    echo "$raw"
    return
  fi
  proxy="${proxy%/}"
  case "$raw" in
    "${proxy}"/*) echo "$raw"; return ;;
  esac
  echo "${proxy}/${raw}"
}

download() {
  local url="$1" dest="$2"
  info "下载: $url"
  if command -v curl >/dev/null 2>&1; then
    curl -fL --retry 3 --connect-timeout 20 --max-time 300 -o "$dest" "$url"
  elif command -v wget >/dev/null 2>&1; then
    wget -O "$dest" "$url"
  else
    die "需要 curl 或 wget"
  fi
}

# 静默探测 URL 是否可下（不写盘）
url_ok() {
  local url="$1"
  if command -v curl >/dev/null 2>&1; then
    curl -fsSIL --connect-timeout 8 --max-time 20 -o /dev/null "$url" 2>/dev/null
  else
    return 1
  fi
}

download_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"
}

install_from_tarball() {
  local tgz="$1" ver="$2" arch="$3"
  local name="sing-box-${ver}-linux-${arch}"
  tar -xzf "$tgz" -C "$TMP"
  if [[ -x "$TMP/${name}/sing-box" ]]; then
    install -m 0755 "$TMP/${name}/sing-box" "$INSTALL_DIR/bin/sing-box"
  elif [[ -x "$TMP/sing-box" ]]; then
    install -m 0755 "$TMP/sing-box" "$INSTALL_DIR/bin/sing-box"
  else
    local found
    found="$(find "$TMP" -type f -name sing-box 2>/dev/null | head -1)"
    [[ -n "$found" && -x "$found" ]] || die "压缩包内未找到 sing-box 可执行文件"
    install -m 0755 "$found" "$INSTALL_DIR/bin/sing-box"
  fi
}

gitea_asset_url() {
  local fname="$1"
  echo "${GITEA_BASE%/}/${GITEA_OWNER}/${GITEA_REPO}/releases/download/${SING_BOX_RELEASE_TAG}/${fname}"
}

# 从 Gitea 拉整包 tar.gz
try_download_gitea_whole() {
  local ver="$1" arch="$2" dest="$3"
  local name url
  name="sing-box-${ver}-linux-${arch}.tar.gz"
  url="$(gitea_asset_url "$name")"
  info "尝试 Gitea 预置整包: $url"
  if download "$url" "$dest"; then
    return 0
  fi
  return 1
}

# 代理 504 时可能只提供分片：name.tar.gz.part-00.. + name.tar.gz.SHA256SUMS
try_download_gitea_parts() {
  local ver="$1" arch="$2" dest="$3"
  local base name sums_url part_url part_dir i max
  name="sing-box-${ver}-linux-${arch}.tar.gz"
  base="${GITEA_BASE%/}/${GITEA_OWNER}/${GITEA_REPO}/releases/download/${SING_BOX_RELEASE_TAG}"
  sums_url="${base}/${name}.SHA256SUMS"
  # 兼容旧名 SHA256SUMS（仅 armv7 曾用）
  part_dir="$TMP/parts_${arch}"
  mkdir -p "$part_dir"

  if download "$sums_url" "$part_dir/SHA256SUMS" 2>/dev/null; then
    info "发现分片清单: $sums_url"
  elif [[ "$arch" == "armv7" ]] && download "$(gitea_asset_url SHA256SUMS)" "$part_dir/SHA256SUMS" 2>/dev/null; then
    info "使用兼容清单 SHA256SUMS"
  else
    return 1
  fi

  # 从清单提取 part 文件名（去掉路径前缀）
  mapfile -t parts < <(awk '{print $2}' "$part_dir/SHA256SUMS" | sed 's|^\./||' | grep -E '\.part-[0-9]+$' || true)
  if [[ ${#parts[@]} -eq 0 ]]; then
    # 无清单文件名时按 part-00..99 探测
    parts=()
    for i in $(seq -w 0 99); do
      part_url="${base}/${name}.part-${i}"
      if url_ok "$part_url"; then
        parts+=("${name}.part-${i}")
      else
        [[ ${#parts[@]} -gt 0 ]] && break
      fi
    done
  fi
  [[ ${#parts[@]} -gt 0 ]] || return 1

  info "Gitea 分片下载 ${#parts[@]} 片 → 合并 $name"
  : >"$dest"
  for p in "${parts[@]}"; do
    p="${p#./}"
    # 若清单里只有 basename part-xx，补全前缀
    case "$p" in
      *.part-*) ;;
      *) p="${name}.part-${p##*-}" ;;
    esac
    # 清单可能是 relative part name only like sing-box-...part-00
    if [[ "$p" != *"/"* && "$p" != ${name}.part-* && "$p" == *.part-* ]]; then
      :
    fi
    part_url="${base}/${p}"
    if ! download "$part_url" "$part_dir/$p"; then
      # 尝试无前缀名
      local bn
      bn="$(basename "$p")"
      part_url="${base}/${bn}"
      download "$part_url" "$part_dir/$bn" || return 1
      p="$bn"
    fi
    cat "$part_dir/$p" >>"$dest"
  done

  # 可选校验
  if command -v sha256sum >/dev/null 2>&1; then
    (
      cd "$part_dir"
      # 规范化清单路径
      sed 's| \./| |; s|^\([a-f0-9]*\)  \./|\1  |' SHA256SUMS > SHA256SUMS.norm || cp SHA256SUMS SHA256SUMS.norm
      if sha256sum -c SHA256SUMS.norm --status 2>/dev/null; then
        info "分片 SHA256 校验通过"
      else
        warn "分片 SHA256 校验跳过/未严格通过（已合并，继续）"
      fi
    ) || true
  fi

  # 快速完整性：tar 列表
  tar -tzf "$dest" >/dev/null
  return 0
}

try_download_gitea() {
  local ver="$1" arch="$2" dest="$3"
  if try_download_gitea_whole "$ver" "$arch" "$dest"; then
    return 0
  fi
  warn "Gitea 整包不可用，尝试分片合并（大文件/代理 504 兜底）"
  if try_download_gitea_parts "$ver" "$arch" "$dest"; then
    return 0
  fi
  return 1
}

try_download_github_release() {
  local ver="$1" arch="$2" dest="$3"
  local name raw_url
  name="sing-box-${ver}-linux-${arch}"
  raw_url="https://github.com/SagerNet/sing-box/releases/download/v${ver}/${name}.tar.gz"
  download_github "$raw_url" "$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:-}" && "$SING_BOX_SOURCE" != "gitea" && "$SING_BOX_SOURCE" != "github" ]]; 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"
  tgz="$TMP/sb.tgz"
  ok=0
  case "$SING_BOX_SOURCE" in
    gitea)
      try_download_gitea "$ver" "$ARCH" "$tgz" || die "Gitea 预置包下载失败（tag=$SING_BOX_RELEASE_TAG arch=$ARCH）"
      ok=1
      ;;
    github|release)
      try_download_github_release "$ver" "$ARCH" "$tgz"
      ok=1
      ;;
    auto|*)
      if try_download_gitea "$ver" "$ARCH" "$tgz"; then
        ok=1
        info "已从 Gitea Release 获取 sing-box"
      else
        warn "Gitea 预置包不可用，回退 GitHub（经 ${GITHUB_PROXY:-直连}）"
        try_download_github_release "$ver" "$ARCH" "$tgz"
        ok=1
      fi
      ;;
  esac
  [[ "$ok" -eq 1 ]] || die "无法下载 sing-box"
  install_from_tarball "$tgz" "$ver" "$ARCH"
  info "已安装 sing-box v${ver} (${ARCH})"
  "$INSTALL_DIR/bin/sing-box" version 2>/dev/null | head -3 || true
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