#!/usr/bin/env bash
#
# Builds rocksdb once, with the shared and the static library, and installs it
# into a prefix of its own (default: $HOME/rocksdb). Works on Fedora, Rocky
# Linux, RHEL, Debian, Ubuntu and MacOS.
#
# The version to build is, in this order:
#   1. the one given with -v
#   2. the one of the rocksdb package of the distribution, so that the static
#      library matches the headers and the shared library collocatordb was
#      built against
#   3. a pinned one that is known to compile with the compilers of Rocky Linux
#      9 (gcc 11) up to Fedora (gcc 16) and MacOS (clang)
#
# Examples:
#   scripts/build-rocksdb.sh                  # build the version of the distribution
#   scripts/build-rocksdb.sh -v 10.2.1        # build a specific version
#   scripts/build-rocksdb.sh -p /opt/rocksdb  # install somewhere else
#
set -euo pipefail

PINNED_VERSION=10.2.1
PREFIX=$HOME/rocksdb
VERSION=
SOURCE_DIR=
STATIC_ONLY=0

usage() {
    sed -n '2,17p' "$0"
    exit "${1:-0}"
}

while [ $# -gt 0 ]; do
    case $1 in
        -p|--prefix)  PREFIX=$2; shift 2 ;;
        -v|--version) VERSION=$2; shift 2 ;;
        -s|--source)  SOURCE_DIR=$2; shift 2 ;;
        --static-only) STATIC_ONLY=1; shift ;;
        -h|--help)    usage 0 ;;
        *) echo "Unknown option: $1" >&2; usage 1 ;;
    esac
done

SOURCE_DIR=${SOURCE_DIR:-$PREFIX-src}

# --- the version -------------------------------------------------------------
if [ -z "$VERSION" ]; then
    if command -v rpm > /dev/null && rpm -q rocksdb > /dev/null 2>&1; then
        VERSION=$(rpm -q --qf '%{VERSION}' rocksdb)
    elif command -v dpkg-query > /dev/null && dpkg-query -W librocksdb-dev > /dev/null 2>&1; then
        VERSION=$(dpkg-query -W -f '${Version}' librocksdb-dev | cut -d- -f1)
    elif command -v brew > /dev/null && brew list --versions rocksdb > /dev/null 2>&1; then
        VERSION=$(brew list --versions rocksdb | awk '{print $2}' | cut -d' ' -f1)
    else
        VERSION=$PINNED_VERSION
        echo "No rocksdb package found, building the pinned version $VERSION."
        echo "Give another one with -v, see https://github.com/facebook/rocksdb/tags"
    fi
fi
echo "Building rocksdb $VERSION"

# --- the prerequisites -------------------------------------------------------
missing=
for tool in git cmake make; do
    command -v $tool > /dev/null || missing="$missing $tool"
done
if ! command -v c++ > /dev/null && ! command -v g++ > /dev/null && ! command -v clang++ > /dev/null; then
    missing="$missing c++"
fi
# The compression libraries rocksdb is built with below. Where they are
# missing the build still succeeds, just without them, so this is a hint.
compression_hint=
if command -v pkg-config > /dev/null; then
    for lib in snappy zlib bzip2 liblz4 libzstd; do
        pkg-config --exists $lib 2> /dev/null || compression_hint="$compression_hint $lib"
    done
fi
if [ -n "$missing" ]; then
    echo "Missing build tools:$missing" >&2
    echo >&2
    echo "Install them and the compression libraries:" >&2
    echo "  Fedora, Rocky, RHEL: sudo dnf install cmake gcc-c++ git snappy-devel zlib-devel bzip2-devel lz4-devel libzstd-devel" >&2
    echo "  Debian, Ubuntu:      sudo apt-get install cmake g++ git libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev libzstd-dev" >&2
    echo "  MacOS:               brew install cmake snappy zlib bzip2 lz4 zstd" >&2
    exit 1
fi
if [ -n "$compression_hint" ]; then
    echo "Warning: pkg-config does not find:$compression_hint" >&2
    echo "rocksdb will be built without them. The devel packages named above provide them." >&2
fi

# --- the sources -------------------------------------------------------------
if [ -d "$SOURCE_DIR/.git" ]; then
    echo "Reusing the checkout in $SOURCE_DIR"
    git -C "$SOURCE_DIR" fetch --depth 1 origin "refs/tags/v$VERSION"
    git -C "$SOURCE_DIR" checkout -q FETCH_HEAD
else
    git clone https://github.com/facebook/rocksdb.git --branch "v$VERSION" --depth 1 "$SOURCE_DIR"
fi

# --- the build ---------------------------------------------------------------
# lib64 where the distribution has one (Fedora, Rocky, RHEL, openSUSE), lib
# elsewhere. Both are searched for a prefix by cmake, this is for the user.
if [ -d /usr/lib64 ] && [ ! -e /etc/debian_version ]; then
    LIBDIR=lib64
else
    LIBDIR=lib
fi

# So that the compression libraries of homebrew are found on MacOS
BREW_PREFIX=
if command -v brew > /dev/null; then
    BREW_PREFIX="-DCMAKE_PREFIX_PATH=$(brew --prefix)"
fi

# WITH_GFLAGS and WITH_LIBURING are off so that the static library does not
# drag them into everything that links it. FAIL_ON_WARNINGS off so that a
# newer compiler does not turn rocksdb's own warnings into errors. And
# -include cstdint because older rocksdb versions declare uint64_t and friends
# without including it, which newer compilers no longer tolerate - Fedora 44
# packages 10.2.1 and builds it with gcc 16, for instance. Where it is already
# included, the flag changes nothing.
cmake -S "$SOURCE_DIR" -B "$SOURCE_DIR/build" \
      -DCMAKE_BUILD_TYPE=Release \
      -DCMAKE_CXX_FLAGS="-include cstdint" \
      -DFAIL_ON_WARNINGS=OFF \
      -DWITH_TESTS=OFF -DWITH_ALL_TESTS=OFF \
      -DWITH_BENCHMARK_TOOLS=OFF -DWITH_TOOLS=OFF -DWITH_CORE_TOOLS=OFF \
      -DWITH_GFLAGS=OFF -DWITH_LIBURING=OFF \
      -DWITH_SNAPPY=ON -DWITH_LZ4=ON -DWITH_ZLIB=ON -DWITH_ZSTD=ON -DWITH_BZ2=ON \
      -DROCKSDB_BUILD_SHARED=$([ $STATIC_ONLY = 1 ] && echo OFF || echo ON) \
      -DCMAKE_INSTALL_PREFIX="$PREFIX" \
      -DCMAKE_INSTALL_LIBDIR="$LIBDIR" \
      $BREW_PREFIX
cmake --build "$SOURCE_DIR/build" -j "${CMAKE_BUILD_PARALLEL_LEVEL:-$(getconf _NPROCESSORS_ONLN 2> /dev/null || sysctl -n hw.ncpu)}"
cmake --install "$SOURCE_DIR/build"

# --- what to do with it ------------------------------------------------------
echo
echo "Installed rocksdb $VERSION:"
echo "  headers:  $PREFIX/include"
echo "  static:   $PREFIX/$LIBDIR/librocksdb.a"
[ $STATIC_ONLY = 1 ] || echo "  shared:   $PREFIX/$LIBDIR/$( [ "$(uname)" = Darwin ] && echo librocksdb.dylib || echo librocksdb.so )"
echo
echo "Build collocatordb against it with:"
echo "  cmake -S . -B build -DCMAKE_PREFIX_PATH=$PREFIX -DCMAKE_INSTALL_PREFIX=/usr/local"
echo
echo "Build dereko2vec against it with:"
echo "  cmake -S . -B build -DSTATIC_ROCKSDB=ON -DCMAKE_PREFIX_PATH=$PREFIX"
if [ $STATIC_ONLY = 0 ] && [ "$(uname)" = Linux ]; then
    echo
    echo "Programs that use the shared library find it after:"
    echo "  echo $PREFIX/$LIBDIR | sudo tee /etc/ld.so.conf.d/rocksdb.conf && sudo ldconfig"
fi