#!/usr/bin/env bash
# Static deps for Android into third_party/prefix-android-ABI: mbedTLS and
# libcurl (HTTP(S) only, mbedTLS), the same pair the Linux release uses --
# a phone has no system libcurl and bionic's CA store is /system/etc/security,
# so libcurl is built here rather than taken from the platform.
#
#   scripts/build_third_party_android.sh arm64-v8a|x86_64 [all|mbedtls|curl]
#
# Needs the NDK in ANDROID_NDK_HOME (a directory with
# build/cmake/android.toolchain.cmake). On NixOS the packaged one is:
#   export ANDROID_NDK_HOME=$(
#     NIXPKGS_ALLOW_UNFREE=1 nix build --impure --no-link --print-out-paths \
#       'nixpkgs#androidenv.androidPkgs.ndk-bundle')/libexec/android-sdk/ndk-bundle
# Host tools: cmake ninja make.
set -euo pipefail
ROOT="$(cd "$(dirname "$0")/.." && pwd)"
ABI="${1:?usage: $0 arm64-v8a|x86_64 [all|mbedtls|curl]}"
TP="$ROOT/third_party"
PREFIX="$TP/prefix-android-$ABI"
SRC="$TP/src"
WORK="$TP/build-android-$ABI"
JOBS="${JOBS:-$(nproc 2>/dev/null || echo 4)}"

MBEDTLS_VER=3.6.7
MBEDTLS_SHA=a7e8bcbec0e6f761b4af24f25677626b35f762f68eef79c08677a363212d11f6
CURL_VER=8.22.0
CURL_SHA=f7ef3ae8a22e521f289803fe93543eb64c329b58aa73a9e224dfd915a2a5f4f7

# Android 7.0: what bionic gives the engine (threads, exec, /system CA store).
API_LEVEL="${API_LEVEL:-24}"
# Per-app CAs land in the user store; the system bundle is the readable one.
CA_PATH=/system/etc/security/cacerts

NDK="${ANDROID_NDK_HOME:-${ANDROID_NDK_ROOT:-}}"
if [[ -z "$NDK" || ! -f "$NDK/build/cmake/android.toolchain.cmake" ]]; then
  echo "set ANDROID_NDK_HOME to an NDK (see the header of this script)" >&2
  exit 1
fi
TOOLCHAIN="$NDK/build/cmake/android.toolchain.cmake"

need() { command -v "$1" >/dev/null || { echo "missing: $1" >&2; exit 1; }; }
need cmake
need ninja
mkdir -p "$PREFIX" "$SRC" "$WORK"

fetch() { # file sha url...
  local file="$1" sha="$2" u
  shift 2
  if [[ -f "$SRC/$file" ]] && echo "$sha  $SRC/$file" | sha256sum -c --quiet - 2>/dev/null; then
    return 0
  fi
  for u in "$@"; do
    echo "  try $u"
    if curl -fsSL --retry 2 --connect-timeout 15 --max-time 600 -o "$SRC/$file.part" "$u" &&
        echo "$sha  $SRC/$file.part" | sha256sum -c --quiet -; then
      mv "$SRC/$file.part" "$SRC/$file"
      return 0
    fi
  done
  rm -f "$SRC/$file.part"
  echo "download failed: $file" >&2
  exit 1
}

unpack() { # file dir
  rm -rf "${WORK:?}/$2"
  tar -C "$WORK" -xf "$SRC/$1"
}

gh() { # path -> GitHub URL candidates (CN proxies first)
  printf '%s\n' "https://ghfast.top/https://github.com/$1" \
    "https://ghproxy.net/https://github.com/$1" "https://github.com/$1"
}

cmake_android() { # src build args...
  local s="$1" b="$2"
  shift 2
  cmake -S "$s" -B "$b" -G Ninja \
    -DCMAKE_TOOLCHAIN_FILE="$TOOLCHAIN" \
    -DANDROID_ABI="$ABI" -DANDROID_PLATFORM="android-$API_LEVEL" \
    -DANDROID_NDK="$NDK" \
    -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="$PREFIX" \
    -DCMAKE_PREFIX_PATH="$PREFIX" -DCMAKE_INSTALL_LIBDIR=lib \
    -DCMAKE_POSITION_INDEPENDENT_CODE=OFF \
    "$@"
  cmake --build "$b" -j"$JOBS"
  cmake --install "$b"
}

build_mbedtls() {
  local f="mbedtls-$MBEDTLS_VER.tar.bz2"
  mapfile -t urls < <(gh "Mbed-TLS/mbedtls/releases/download/mbedtls-$MBEDTLS_VER/$f")
  fetch "$f" "$MBEDTLS_SHA" "${urls[@]}"
  unpack "$f" "mbedtls-$MBEDTLS_VER"
  # 3.6.x keeps its own entropy source on Android, no /dev/urandom probing.
  cmake_android "$WORK/mbedtls-$MBEDTLS_VER" "$WORK/mbedtls-$MBEDTLS_VER/build" \
    -DENABLE_TESTING=OFF -DENABLE_PROGRAMS=OFF -DGEN_FILES=OFF \
    -DUSE_STATIC_MBEDTLS_LIBRARY=ON -DUSE_SHARED_MBEDTLS_LIBRARY=OFF \
    -DMBEDTLS_FATAL_WARNINGS=OFF
  echo "mbedTLS $MBEDTLS_VER -> $PREFIX"
}

build_curl() {
  local f="curl-$CURL_VER.tar.xz"
  mapfile -t urls < <(gh "curl/curl/releases/download/curl-${CURL_VER//./_}/$f")
  fetch "$f" "$CURL_SHA" "https://curl.se/download/$f" "${urls[@]}"
  unpack "$f" "curl-$CURL_VER"
  cmake_android "$WORK/curl-$CURL_VER" "$WORK/curl-$CURL_VER/build" \
    -DBUILD_SHARED_LIBS=OFF -DBUILD_STATIC_LIBS=ON \
    -DCURL_USE_MBEDTLS=ON -DCURL_USE_OPENSSL=OFF \
    -DMBEDTLS_INCLUDE_DIR="$PREFIX/include" \
    -DMBEDTLS_LIBRARY="$PREFIX/lib/libmbedtls.a" \
    -DMBEDX509_LIBRARY="$PREFIX/lib/libmbedx509.a" \
    -DMBEDCRYPTO_LIBRARY="$PREFIX/lib/libmbedcrypto.a" \
    -DCURL_CA_BUNDLE=none -DCURL_CA_PATH="$CA_PATH" \
    -DHTTP_ONLY=ON -DCURL_DISABLE_LDAP=ON -DCURL_USE_LIBPSL=OFF \
    -DCURL_USE_LIBSSH2=OFF -DCURL_USE_LIBSSH=OFF -DUSE_LIBIDN2=OFF \
    -DUSE_NGHTTP2=OFF -DCURL_ZLIB=OFF -DCURL_BROTLI=OFF -DCURL_ZSTD=OFF \
    -DCURL_USE_GSSAPI=OFF -DENABLE_THREADED_RESOLVER=ON \
    -DBUILD_CURL_EXE=OFF -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=OFF \
    -DBUILD_LIBCURL_DOCS=OFF -DBUILD_MISC_DOCS=OFF -DENABLE_CURL_MANUAL=OFF
  echo "curl $CURL_VER -> $PREFIX"
}

case "${2:-all}" in
mbedtls) build_mbedtls ;;
curl) build_curl ;;
all)
  build_mbedtls
  build_curl
  ;;
*)
  echo "usage: $0 ABI [all|mbedtls|curl]" >&2
  exit 1
  ;;
esac
echo "DONE android-$ABI"