#!/usr/bin/env sh

android_sdk_root() {
    if [ -n "${ANDROID_SDK_ROOT:-}" ] && [ -d "$ANDROID_SDK_ROOT" ]; then
        printf '%s\n' "$ANDROID_SDK_ROOT"
        return 0
    fi

    if [ -n "${ANDROID_HOME:-}" ] && [ -d "$ANDROID_HOME" ]; then
        printf '%s\n' "$ANDROID_HOME"
        return 0
    fi

    if [ -n "${LOCALAPPDATA:-}" ]; then
        local_sdk="$LOCALAPPDATA/Android/Sdk"
        if command -v cygpath >/dev/null 2>&1; then
            local_sdk="$(cygpath -u "$local_sdk")"
        fi
        if [ -d "$local_sdk" ]; then
            printf '%s\n' "$local_sdk"
            return 0
        fi
    fi

    if [ -d "$HOME/Android/Sdk" ]; then
        printf '%s\n' "$HOME/Android/Sdk"
        return 0
    fi

    return 1
}

latest_android_package_dir() {
    root="$1"
    package="$2"
    package_root="$root/$package"
    [ -d "$package_root" ] || return 1
    latest="$(
        for dir in "$package_root"/*; do
            [ -d "$dir" ] || continue
            version="${dir##*/}"
            printf '%s\n' "$version"
        done | grep -E '^[0-9]+(\.[0-9]+)*$' | sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n | tail -n 1
    )"
    [ -n "$latest" ] || return 1
    printf '%s/%s\n' "$package_root" "$latest"
}

set_android_sdk_toolchain_environment() {
    sdk_root="$(android_sdk_root)" || {
        printf '%s\n' "Android SDK root was not found. Install command-line tools or set ANDROID_SDK_ROOT." >&2
        return 1
    }

    ndk_dir="$(latest_android_package_dir "$sdk_root" ndk)" || {
        printf '%s\n' "No installed Android NDK package was found under $sdk_root/ndk." >&2
        return 1
    }

    cmake_dir="$(latest_android_package_dir "$sdk_root" cmake)" || {
        printf '%s\n' "No installed Android CMake package was found under $sdk_root/cmake." >&2
        return 1
    }

    cmake_command="$cmake_dir/bin/cmake"
    [ -x "$cmake_command" ] || {
        printf '%s\n' "Android SDK CMake executable not found: $cmake_command" >&2
        return 1
    }

    export ANDROID_HOME="$sdk_root"
    export ANDROID_SDK_ROOT="$sdk_root"
    export ANDROID_NDK_HOME="$ndk_dir"
    export ANDROID_NDK_ROOT="$ndk_dir"
    export ANDROID_CMAKE_COMMAND="$cmake_command"
    export ANDROID_NDK_VERSION="${ndk_dir##*/}"
    export ANDROID_CMAKE_VERSION="${cmake_dir##*/}"
}