#!/usr/bin/env bash

RUBY_BUILD_VERSION="20110912.1"

set -E
exec 3<&2 # preserve original stderr at fd 3

resolve_link() {
  $(type -p greadlink readlink | head -1) $1
}

abs_dirname() {
  local cwd="$(pwd)"
  local path="$1"

  while [ -n "$path" ]; do
    cd "${path%/*}"
    local name="${path##*/}"
    path="$(resolve_link "$name" || true)"
  done

  pwd
  cd "$cwd"
}

build_failed() {
  { echo
    echo "BUILD FAILED"
    echo
    echo "Inspect or clean up the working tree at ${TEMP_PATH}"
    echo "Results logged to ${LOG_PATH}"
    echo
  } >&3
  exit 1
}

install_package() {
  install_package_using "tarball" 1 $*
}

install_git() {
  install_package_using "git" 2 $*
}

install_package_using() {
  local package_type="$1"
  local package_type_nargs="$2"
  local package_name="$3"
  shift 3

  pushd "$TEMP_PATH" >&4
  "fetch_${package_type}" "$package_name" $*
  shift $(($package_type_nargs))
  make_package "$package_name" $*
  popd >&4

  echo "Installed ${package_name} to ${PREFIX_PATH}" >&2
}

make_package() {
  local package_name="$1"
  shift

  pushd "$package_name" >&4
  build_package "$package_name" $*
  after_install_package "$package_name"
  fix_directory_permissions
  popd >&4

  echo "Installed ${package_name} to ${PREFIX_PATH}" >&2
}

fetch_tarball() {
  local package_name="$1"
  local package_url="$2"

  echo "Downloading ${package_url}..." >&2
  { curl "$package_url" > "${package_name}.tar.gz"
    tar xzvf "${package_name}.tar.gz"
  } >&4 2>&1
}

fetch_git() {
  local package_name="$1"
  local git_url="$2"
  local git_ref="$3"

  echo "Cloning ${git_url}..." >&2
  { git clone --depth 1 --branch "$git_ref" "$git_url" "${package_name}"
  } >&4 2>&1
}

build_package() {
  local package_name="$1"
  shift

  if [ "$#" -eq 0 ]; then
    local commands="standard"
  else
    local commands="$*"
  fi

  echo "Installing ${package_name}..." >&2

  for command in $commands; do
    "build_package_${command}"
  done
}

build_package_standard() {
  local package_name="$1"

  { ./configure --prefix="$PREFIX_PATH"
    make -j 2
    make install
  } >&4 2>&1
}

build_package_autoconf() {
  { autoconf
  } >&4 2>&1
}

build_package_ruby() {
  local package_name="$1"

  { "$RUBY_BIN" setup.rb
  } >&4 2>&1
}

build_package_rbx() {
  local package_name="$1"

  { ./configure --prefix="$PREFIX_PATH" --gemsdir="$PREFIX_PATH"
    rake install
  } >&4 2>&1
}

build_package_copy() {
  cp -R . "$PREFIX_PATH"
}

after_install_package() {
  local stub=1
}

fix_directory_permissions() {
  # Ensure installed directories are not world-writable to avoid Bundler warnings
  find "$PREFIX_PATH" -type d -exec chmod go-w {} \;
}

use_gcc42_on_lion() {
  if [ "$(uname -s)" = "Darwin" ]; then
    if [ "$(expr "$(sw_vers -productVersion | cut -f 2 -d .)" \>= 7 || true)" -eq 1 ]; then
      export CC=/usr/bin/gcc-4.2
    fi
  fi
}

version() {
  echo "ruby-build ${RUBY_BUILD_VERSION}"
}

usage() {
  { version
    echo "usage: ruby-build [-v|--verbose] definition prefix"
    echo "       ruby-build --definitions"
  } >&2

  if [ -z "$1" ]; then
    exit 1
  fi
}

list_definitions() {
  { for definition in "${RUBY_BUILD_ROOT}/share/ruby-build/"*; do
      echo "${definition##*/}"
    done
  } | sort
}



unset VERBOSE
RUBY_BUILD_ROOT="$(abs_dirname "$0")/.."

case "$1" in
"-h" | "--help" )
  usage without_exiting
  { echo
    echo "  -v/--verbose     Verbose mode: print compilation status to stdout"
    echo "  --definitions    List all built-in definitions"
    echo
  } >&2
  exit 0
  ;;
"--definitions" )
  list_definitions
  exit 0
  ;;
"--version" )
  version
  exit 0
  ;;
"-v" | "--verbose" )
  VERBOSE=true
  shift
  ;;
esac


DEFINITION_PATH="$1"
if [ -z "$DEFINITION_PATH" ]; then
  usage
elif [ ! -e "$DEFINITION_PATH" ]; then
  BUILTIN_DEFINITION_PATH="${RUBY_BUILD_ROOT}/share/ruby-build/${DEFINITION_PATH}"
  if [ -e "$BUILTIN_DEFINITION_PATH" ]; then
    DEFINITION_PATH="$BUILTIN_DEFINITION_PATH"
  else
    echo "ruby-build: definition not found: ${DEFINITION_PATH}" >&2
    exit 1
  fi
fi

PREFIX_PATH="$2"
if [ -z "$PREFIX_PATH" ]; then
  usage
fi

if [ -z "$TMPDIR" ]; then
  TMP="/tmp"
else
  TMP="${TMPDIR%/}"
fi

SEED="$(date "+%Y%m%d%H%M%S").$$"
LOG_PATH="${TMP}/ruby-build.${SEED}.log"
TEMP_PATH="${TMP}/ruby-build.${SEED}"
RUBY_BIN="${PREFIX_PATH}/bin/ruby"
CWD="$(pwd)"

exec 4<> "$LOG_PATH" # open the log file at fd 4
if [ -n "$VERBOSE" ]; then
  tail -f "$LOG_PATH" &
  trap "kill 0" SIGINT SIGTERM EXIT
fi

export LDFLAGS="-L'${PREFIX_PATH}/lib' ${LDFLAGS}"
export CPPFLAGS="-I'${PREFIX_PATH}/include' ${CPPFLAGS}"

unset RUBYOPT
unset RUBYLIB

trap build_failed ERR
mkdir -p "$TEMP_PATH"
source "$DEFINITION_PATH"
rm -fr "$TEMP_PATH"
trap - ERR