#!/bin/bash
# 取出 relay.xxmxxs.top 证书链上的根/中间证书，准备打进 APK。
#
# 背景：手表报 SSLHandshakeException: Chain validation failed
#       链路是 xxmxxs.top <- GTS WE1 <- GTS Root R4 <- GlobalSign Root CA
#       廉价手表的根证书库常常缺 GTS Root R4，
#       于是找不到信任锚 -> 握手失败。
#       把这两个根打进 APK，校验时"系统库 + 内置"任一通过即可。
set -u

OUT=/root/ca-bundle
mkdir -p "$OUT"
cd "$OUT"

echo "===== 抓完整证书链 ====="
echo | openssl s_client -showcerts -connect relay.xxmxxs.top:443 \
    -servername relay.xxmxxs.top 2>/dev/null > /root/chain.txt
grep -c 'BEGIN CERTIFICATE' /root/chain.txt | sed 's/^/  链上证书数: /'

# 把每张证书拆出来
awk '/BEGIN CERTIFICATE/,/END CERTIFICATE/' /root/chain.txt > /root/chain.pem
csplit -z -f "$OUT/cert" -b "%02d.pem" /root/chain.pem \
    '/-----BEGIN CERTIFICATE-----/' '{*}' >/dev/null 2>&1 || true

echo
echo "===== 每张证书的信息 ====="
for f in "$OUT"/cert*.pem; do
    [ -f "$f" ] || continue
    echo "  --- $(basename "$f") ---"
    openssl x509 -in "$f" -noout -subject -issuer 2>/dev/null \
        | sed 's/^/    /'
done

echo
echo "===== 找 GTS Root R4 的自签名证书 ====="
# GTS Root R4 是通过 GlobalSign 交叉签名的；
# 真正需要内置的是**自签名的根**（GTS Root R4 self-signed 与 GlobalSign Root CA）。
for candidate in \
    "https://i.pki.goog/r4.crt" \
    "https://pki.goog/repo/certs/gtsr4.pem" \
    "https://pki.goog/repo/certs/gsr2.pem"; do
    name=$(basename "$candidate")
    if curl -s --max-time 20 -o "$OUT/$name" "$candidate" 2>/dev/null \
       && [ -s "$OUT/$name" ]; then
        # 有的下载下来是 DER，转成 PEM
        if ! grep -q 'BEGIN CERTIFICATE' "$OUT/$name" 2>/dev/null; then
            openssl x509 -inform DER -in "$OUT/$name" \
                -out "$OUT/${name}.pem" 2>/dev/null \
                && rm -f "$OUT/$name"
        fi
        echo "  ✓ $candidate"
        openssl x509 -in "$OUT/${name}.pem" -noout -subject -issuer 2>/dev/null \
            | sed 's/^/      /'
    else
        echo "  ✗ $candidate"
    fi
done

echo
echo "===== 系统里现成的根证书（Debian 上有）====="
for name in "GlobalSign_Root_CA.pem" "gtsrootr4.pem" "GTS_Root_R4.pem"; do
    found=$(find /etc/ssl/certs /usr/share/ca-certificates -name "$name" 2>/dev/null | head -1)
    [ -n "$found" ] && echo "  ✓ $found"
done

echo
echo "===== 汇总可用的 PEM ====="
ls -la "$OUT"/*.pem 2>/dev/null | sed 's/^/  /'