#! /usr/bin/env bash

binutils_version=$1
gcc_version=$2
tag="<sh-elf-gcc>"

has() {
  which $1 >/dev/null 2>&1
}
pacman_has() {
  pacman -Qi $1 >/dev/null 2>&1
}
apt_has() {
  apt show $1 >/dev/null 2>&1
}

download() {
  url=$1
  out=$2

  if [ -f "$out" ]; then
    echo "$tag Found $out in current directory, skipping download"
    return
  fi

  echo "$tag Downloading $url..."

  if has curl; then
    curl $url -o $out
  elif has wget; then
    wget -q --show-progress $url -O $out
  else
    echo "$tag error: no curl or wget; install one or download archives yourself" >&2
    return 1
  fi
}

# Check dependencies

if has pacman; then
  deps="mpfr mpc gmp libpng ppl flex gcc git texinfo"
  pm=pacman
  pm_has=pacman_has
  install_cmd="sudo pacman -S"
elif has apt; then
  deps="libmpfr-dev libmpc-dev libgmp-dev libpng-dev libppl-dev flex g++ git texinfo"
  pm=apt
  pm_has=apt_has
  install_cmd="sudo apt install"
else
  trust_deps=1
fi

missing=""
if [[ -z "$trust_deps" ]]; then
  for d in $deps; do
    if ! $pm_has $d; then
      missing="$missing $d"
    fi
  done
fi

# Offer to install dependencies

if [[ ! -z "$missing" ]]; then
  echo "$tag Based on $pm, some dependencies are missing: $missing"
  echo -n "$tag Do you want to run '$missing_cmd' to install them (Y/n)? "

  read do_install
  if [[ "$do_install" == "y" || "$do_install" == "Y" || "$do_install" == "" ]]; then
    $missing_cmd
  else
    echo "$tag Skipping dependencies, hoping it will build anyway."
  fi
fi

# Determine which compression to use (either gzip or xzip)

if has xz; then
  format="tar.xz"
  decompress="-J"
elif has gzip; then
  format="tar.gz"
  decompress="-z"
else
  echo "error: gcc archives need gzip or xzip to decompress!" >&2
  exit 1
fi

# Deduce source URL and file names

binutils_url="https://ftp.gnu.org/gnu/binutils/binutils-$binutils_version.$format"
binutils_archive=$(basename $binutils_url)

gcc_url="https://ftp.gnu.org/gnu/gcc/gcc-$gcc_version/gcc-$gcc_version.$format"
gcc_archive="$(basename $gcc_url)"

# Download archives

download $binutils_url $binutils_archive
download $gcc_url $gcc_archive

# Extract archive

echo "$tag Extracting $binutils_archive..."
tar -x $decompress -f $binutils_archive

echo "$tag Extracting $gcc_archive..."
tar -x $decompress -f $gcc_archive

# Create empty build folders

[[ -d "build-binutils" ]] && rm -rf build-binutils
mkdir build-binutils

[[ -d "build-gcc" ]] && rm -rf build-gcc
mkdir build-gcc