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

repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
tdlib_version="${TDLIB_VERSION:-1.8.29}"
tdlib_commit="${TDLIB_COMMIT:-af69dd4397b6dc1bf23ba0fd0bf429fcba6454f6}"
tdlib_repo="${TDLIB_REPO:-https://github.com/tdlib/td.git}"
source_dir="${TDLIB_SOURCE_DIR:-${repo_root}/.build/tdlib-src}"
build_root="${TDLIB_BUILD_ROOT:-${repo_root}/.build/tdlib-ios-build}"
output_root="${TDLIB_OUTPUT_ROOT:-${repo_root}/.build/tdlib-ios}"
platforms="${TDLIB_IOS_PLATFORMS:-iOS iOS-simulator}"
openssl_platforms="${TDLIB_OPENSSL_PLATFORMS:-iOS iOS-simulator}"
ios_deployment_target="${TDLIB_IOS_DEPLOYMENT_TARGET:-17.0}"
jobs="${TDLIB_BUILD_JOBS:-3}"

if [[ -z "${DEVELOPER_DIR:-}" && -d /Applications/Xcode.app/Contents/Developer ]]; then
  export DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer
fi

require_tool() {
  if ! command -v "$1" >/dev/null 2>&1; then
    printf 'Required tool not found: %s\n' "$1" >&2
    return 1
  fi
}

missing=0
for tool in git cmake c++ gperf make perl rsync xcodebuild xcrun install_name_tool; do
  require_tool "${tool}" || missing=1
done

if [[ "${missing}" -ne 0 ]]; then
  printf '\nInstall missing TDLib build dependencies on macOS with:\n' >&2
  printf '  brew install cmake gperf coreutils\n' >&2
  exit 1
fi

if ! xcrun --sdk iphoneos --show-sdk-path >/dev/null; then
  printf 'The iphoneos SDK is unavailable through xcrun.\n' >&2
  printf 'Set DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer and install the iOS platform in Xcode.\n' >&2
  exit 1
fi

mkdir -p "$(dirname "${source_dir}")" "${build_root}" "${output_root}"

if [[ ! -d "${source_dir}/.git" ]]; then
  git clone "${tdlib_repo}" "${source_dir}"
fi

git -C "${source_dir}" fetch --depth 1 origin "${tdlib_commit}"
git -C "${source_dir}" checkout --detach "${tdlib_commit}"

openssl_root="${source_dir}/example/ios/third_party/openssl"
python_apple_support_dir="${source_dir}/example/ios/Python-Apple-support"

prepare_python_apple_support() {
  if [[ ! -d "${python_apple_support_dir}/.git" ]]; then
    git clone https://github.com/beeware/Python-Apple-support "${python_apple_support_dir}"
  fi

  git -C "${python_apple_support_dir}" checkout 6f43aba0ddd5a9f52f39775d0141bd4363614020
  git -C "${python_apple_support_dir}" reset --hard
  (
    cd "${python_apple_support_dir}"
    git apply ../Python-Apple-support.patch
    # Python-Apple-support at this revision emits apple-ios-simulator-simulator
    # under newer Xcode SDK naming. Use the base OS name before appending
    # "-simulator" to the target triple.
    perl -pi -e 's/apple-\$\$\(OS_LOWER-\$\(target\)\)-simulator/apple-\$\$\(patsubst %-simulator,%,\$\$\(OS_LOWER-\$\(target\)\)\)-simulator/' Makefile
  )
}

prepare_td_auto_sources() {
  local host_build_dir="${build_root}/build-host-generate"
  local td_auto_dir="${source_dir}/td/generate/auto/td/telegram"
  local mime_auto_dir="${source_dir}/tdutils/generate/auto"

  if [[ -f "${td_auto_dir}/td_api.cpp" \
    && -f "${td_auto_dir}/td_api_json.cpp" \
    && -f "${mime_auto_dir}/mime_type_to_extension.cpp" \
    && -f "${mime_auto_dir}/extension_to_mime_type.cpp" ]]; then
    return 0
  fi

  ZERO_AR_DATE=1 cmake -S "${source_dir}" -B "${host_build_dir}" \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
    -DCMAKE_MAKE_PROGRAM=make

  cmake --build "${host_build_dir}" --target prepare_cross_compiling -- -j"${jobs}"
}

prepare_openssl_platform() {
  local platform="$1"
  local output_dir="${openssl_root}/${platform}"

  if [[ -f "${output_dir}/lib/libcrypto.a" && -f "${output_dir}/lib/libssl.a" ]]; then
    return 0
  fi

  prepare_python_apple_support

  (
    cd "${python_apple_support_dir}"
    rm -rf "build/${platform}" "install/${platform}" "merge/${platform}"
    make "OpenSSL-${platform}"
  )

  rm -rf "${output_dir}"
  mkdir -p "${output_dir}/lib"
  cp "${python_apple_support_dir}/merge/${platform}/openssl/lib/libcrypto.a" "${output_dir}/lib/"
  cp "${python_apple_support_dir}/merge/${platform}/openssl/lib/libssl.a" "${output_dir}/lib/"
  cp -R "${python_apple_support_dir}/merge/${platform}/openssl/include" "${output_dir}/include"
}

if [[ ! -f "${openssl_root}/iOS/lib/libcrypto.a" || ! -f "${openssl_root}/iOS-simulator/lib/libcrypto.a" ]]; then
  printf 'OpenSSL for iOS was not found under %s.\n' "${openssl_root}" >&2
  printf 'Building only required OpenSSL platforms: %s\n' "${openssl_platforms}"
  for platform in ${openssl_platforms}; do
    prepare_openssl_platform "${platform}"
  done
fi

prepare_td_auto_sources

build_platform() {
  local td_platform="$1"
  local ios_platform
  local out_platform

  case "${td_platform}" in
    iOS)
      ios_platform="OS"
      out_platform="iphoneos"
      ;;
    iOS-simulator)
      ios_platform="SIMULATOR"
      out_platform="iphonesimulator"
      ;;
    *)
      printf 'Unsupported TDLib iOS platform: %s\n' "${td_platform}" >&2
      return 1
      ;;
  esac

  local openssl_path="${openssl_root}/${td_platform}"
  local openssl_crypto_library="${openssl_path}/lib/libcrypto.a"
  local openssl_ssl_library="${openssl_path}/lib/libssl.a"
  local build_dir="${build_root}/build-${td_platform}"
  local install_dir="${build_root}/install-${td_platform}"
  local output_dir="${output_root}/${out_platform}"

  if [[ ! -f "${openssl_crypto_library}" || ! -f "${openssl_ssl_library}" ]]; then
    printf 'OpenSSL libraries are missing for %s under %s\n' "${td_platform}" "${openssl_path}" >&2
    return 1
  fi

  rm -rf "${build_dir}" "${install_dir}" "${output_dir}"
  mkdir -p "${build_dir}" "${install_dir}" "${output_dir}/include" "${output_dir}/lib"

  ZERO_AR_DATE=1 cmake -S "${source_dir}" -B "${build_dir}" \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
    -DCMAKE_INSTALL_PREFIX="${install_dir}" \
    -DCMAKE_TOOLCHAIN_FILE="${source_dir}/CMake/iOS.cmake" \
    -DIOS_PLATFORM="${ios_platform}" \
    -DIOS_DEPLOYMENT_TARGET="${ios_deployment_target}" \
    -DCMAKE_MAKE_PROGRAM=make \
    -DOPENSSL_FOUND=1 \
    -DOPENSSL_CRYPTO_LIBRARY="${openssl_crypto_library}" \
    -DOPENSSL_SSL_LIBRARY="${openssl_ssl_library}" \
    -DOPENSSL_INCLUDE_DIR="${openssl_path}/include" \
    -DOPENSSL_LIBRARIES="${openssl_crypto_library};${openssl_ssl_library}"

  cmake --build "${build_dir}" --target install -- -j"${jobs}"

  install_name_tool -id @rpath/libtdjson.dylib "${install_dir}/lib/libtdjson.dylib"
  rsync -a "${install_dir}/include/" "${output_dir}/include/"
  cp "${install_dir}/lib/libtdjson.dylib" "${output_dir}/lib/libtdjson.dylib"
  cp "${install_dir}/lib/libtdjson.dylib" "${output_dir}/lib/libtdjson.${tdlib_version}.dylib"

  printf 'Installed TDLib %s for %s at %s\n' "${tdlib_version}" "${td_platform}" "${output_dir}"
}

for platform in ${platforms}; do
  build_platform "${platform}"
done