#!/bin/bash

set -e

install_package() {
  local cwd="$(pwd)"
  local package_name="$1"
  local package_url="$2"
  shift 2

  cd "$TEMP_PATH"
  download_package "$package_name" "$package_url"
  extract_package "$package_name"
  cd "$package_name"
  build_package "$package_name" $*
  after_install_package "$package_name"
  cd "$cwd"
}

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

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

extract_package() {
  local package_name="$1"

  { tar xzvf "${package_name}.tar.gz"
  } >$LOG_PATH 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="$PREFIX_PATH"
    make -j 2
    make install
  } >$LOG_PATH 2>&1
}

build_package_ruby() {
  local package_name="$1"

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

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

after_install_package() {
  local stub=1
}

usage() {
  echo "usage: ruby-build DEFINITION-PATH INSTALLATION-PREFIX"
  exit 1
}


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

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

SEED="$$-${RANDOM}"
LOG_PATH="/tmp/ruby-build.${SEED}.log"
TEMP_PATH="/tmp/ruby-build.${SEED}"
RUBY_BIN="${PREFIX_PATH}/bin/ruby"
CWD="$(pwd)"

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

mkdir -p "$TEMP_PATH"
source "$DEFINITION_PATH"
rm -fr "$TEMP_PATH"