#!/usr/bin/env bash

set -euo pipefail

repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"

is_java_home_usable() {
  local candidate="${1:-}"
  if [[ -z "$candidate" || ! -x "$candidate/bin/java" || ! -x "$candidate/bin/javac" ]]; then
    return 1
  fi
  local version
  version="$("$candidate/bin/javac" -version 2>&1 | awk '{print $2}' | cut -d. -f1)"
  [[ "$version" =~ ^[0-9]+$ ]] || return 1
  [[ "$version" -ge 17 ]]
}

resolve_java_home_from_path() {
  if ! command -v javac >/dev/null 2>&1; then
    return 1
  fi
  local javac_path candidate
  javac_path="$(readlink -f "$(command -v javac)")"
  candidate="$(cd "$(dirname "$javac_path")/.." && pwd)"
  if is_java_home_usable "$candidate"; then
    printf '%s\n' "$candidate"
    return 0
  fi
  return 1
}

resolve_java_home() {
  if is_java_home_usable "${JAVA_HOME:-}"; then
    printf '%s\n' "$JAVA_HOME"
    return 0
  fi
  if resolve_java_home_from_path >/dev/null 2>&1; then
    resolve_java_home_from_path
    return 0
  fi
  return 1
}

is_sdk_dir_usable() {
  local candidate="${1:-}"
  [[ -n "$candidate" && -x "$candidate/cmdline-tools/latest/bin/sdkmanager" ]]
}

resolve_sdk_dir() {
  local candidates=(
    "${ANDROID_SDK_ROOT:-}"
    "${ANDROID_HOME:-}"
    "$HOME/Android/Sdk"
    "$HOME/android-sdk"
    "/opt/android-sdk"
    "/usr/lib/android-sdk"
  )
  local candidate
  for candidate in "${candidates[@]}"; do
    if is_sdk_dir_usable "$candidate"; then
      printf '%s\n' "$candidate"
      return 0
    fi
  done
  return 1
}

write_local_properties() {
  local sdk_dir="$1"
  printf 'sdk.dir=%s\n' "$sdk_dir" > "$repo_root/local.properties"
}

JAVA_HOME="$(resolve_java_home)" || {
  echo "Missing usable JDK 17+." >&2
  echo "Install openjdk-17-jdk globally and make it available via JAVA_HOME or PATH." >&2
  return 1 2>/dev/null || exit 1
}

ANDROID_SDK_ROOT="$(resolve_sdk_dir)" || {
  echo "Missing usable Android SDK." >&2
  echo "Expected cmdline-tools/latest/bin/sdkmanager in one of:" >&2
  echo "  \$ANDROID_SDK_ROOT, \$ANDROID_HOME, \$HOME/Android/Sdk, \$HOME/android-sdk, /opt/android-sdk, or /usr/lib/android-sdk" >&2
  return 1 2>/dev/null || exit 1
}

export JAVA_HOME
export ANDROID_SDK_ROOT
export ANDROID_HOME="$ANDROID_SDK_ROOT"
export PATH="$JAVA_HOME/bin:$ANDROID_SDK_ROOT/platform-tools:$PATH"

write_local_properties "$ANDROID_SDK_ROOT"

echo "JAVA_HOME=$JAVA_HOME"
echo "ANDROID_SDK_ROOT=$ANDROID_SDK_ROOT"
echo "ANDROID_TOOLCHAIN_ORIGIN=global"