install.sh

#!/usr/bin/env bash

echo "Let's get you set up with Rustlings!"

echo "Checking requirements..."
if [ -x "$(command -v git)" ]
then
    echo "SUCCESS: Git is installed"
else
    echo "ERROR: Git does not seem to be installed."
    echo "Please download Git using your package manager or over https://git-scm.com/!"
    exit 1
fi

if [ -x "$(command -v rustc)" ]
then
    echo "SUCCESS: Rust is installed"
else
    echo "ERROR: Rust does not seem to be installed."
    echo "Please download Rust using https://rustup.rs!"
    exit 1
fi

if [ -x "$(command -v cargo)" ]
then
    echo "SUCCESS: Cargo is installed"
else
    echo "ERROR: Cargo does not seem to be installed."
    echo "Please download Rust and Cargo using https://rustup.rs!"
    exit 1
fi

# Look up python installations, starting with 3 with a fallback of 2
if [ -x "$(command -v python3)" ]
then
    PY="$(command -v python3)"
elif [ -x "$(command -v python)" ]
then
    PY="$(command -v python)"
elif [ -x "$(command -v python2)" ]
then
    PY="$(command -v python2)"
elif [ -x "$(command -v jq)" ]
then
    PY="" # we will ignore python and try to use jq
    JQ="$(command -v jq)" #jq is much faster than python for json parsing
else
    echo "WARNING: No working python installation was found; trying jq"
    #echo "Please install python and add it to the PATH variable"
    #exit 1
fi

# install jq for faster and more efficient json parsing
if [ -x "$(command -v brew)" ] && uname -a|grep -q Darwin;
then # probably OSX
    command -v jq 1>/dev/null|| $(command -v brew ) install jq
    JQ="$(command -v jq)" #jq is much faster than python for json parsing
fi

# Function that compares two versions strings v1 and v2 given in arguments (e.g 1.31 and 1.33.0).
# Returns 1 if v1 > v2, 0 if v1 == v2, 2 if v1 < v2.
vercomp() {
    if [[ $1 == $2 ]]
    then
        return 0
    fi
    v1=( ${1//./ } )
    v2=( ${2//./ } )
    len1=${#v1[@]}
    len2=${#v2[@]}
    max_len=$len1
    if [[ $max_len -lt $len2 ]]
    then
        max_len=$len2
    fi
    for i in `seq 0 $max_len`
    do
        # Fill empty fields with zeros in v1
        if [ -z "${v1[$i]}" ]
        then
            v1[$i]=0
        fi
        # And in v2
        if [ -z "${v2[$i]}" ]
        then
            v2[$i]=0
        fi
        if [ ${v1[$i]} -gt ${v2[$i]} ]
        then
            return 1
        fi
        if [ ${v1[$i]} -lt ${v2[$i]} ]
        then
            return 2
        fi
    done
    return 0
}

RustVersion=$(rustc --version | cut -d " " -f 2)
MinRustVersion=1.31
vercomp $RustVersion $MinRustVersion
if [ $? -eq 2 ]
then
    echo "ERROR: Rust version is too old: $RustVersion - needs at least $MinRustVersion"
    echo "Please update Rust with 'rustup update'"
    exit 1
else
    echo "SUCCESS: Rust is up to date"
fi

Path=${1:-rustlings/}
echo "Cloning Rustlings at $Path..."
git clone -q https://github.com/rust-lang/rustlings $Path

# function to locate the version number from the latest releases JSON
locate_version(){
  if [ -x "$JQ" ]; then
    curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest | $JQ -r .tag_name
  elif [ -x "$PY" ]; then
    curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest | ${PY} -c "import json,sys;obj=json.load(sys.stdin);print(obj['tag_name']);"
  else # try to use BASH to locate the version number in the json
    #if [ ! -f "/tmp/rustlings_latest.json" ]; then
    #  curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest > /tmp/rustlings_latest.json
    #  #curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest|grep tag_name|awk '{print $NF}'|tr -d '"'|tr -d ','
    #fi
    #if [ -f "/tmp/rustlings_latest.json" ]; then #  the advantage of writing to a temp file is that we can error if the network, (or curl) fail.
    #  ## Writing to a temp file so that my tests don't hammer the github api
    #  #grep tag_name /tmp/rustlings_latest.json|awk '{print $NF}'|tr -d '"'|tr -d ','
    #  # the above line is faster but requires awk and tr 
    #  VER=$(grep tag_name /tmp/rustlings_latest.json)
      VER=$(curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest|grep tag_name)
      VER=${VER%\"*} # shadowing
      VER=${VER##*\"}
    if [ "$VER" ];then # we can do this in memory, rather than writing to /tmp/
      echo $VER
    else
      # echo 3.0.0 # we could fall back to a default version and change this to a WARNING?
      echo "ERROR: unable to parse json using either jq or python" >&2
      exit 1
    fi
  fi
}

Version="$(locate_version)"
CargoBin="${CARGO_HOME:-$HOME/.cargo}/bin"

echo "Checking out version $Version..."
cd $Path
git checkout -q tags/$Version

echo "Installing the 'rustlings' executable..."
cargo install --force --path .

if ! [ -x "$(command -v rustlings)" ]
then
    echo "WARNING: Please check that you have '$CargoBin' in your PATH environment variable!"
fi

# Checking whether Clippy is installed.
# Due to a bug in Cargo, this must be done with Rustup: https://github.com/rust-lang/rustup/issues/1514
Clippy=$(rustup component list | grep "clippy" | grep "installed")
if [ -z "$Clippy" ]
then
    echo "Installing the 'cargo-clippy' executable..."
    rustup component add clippy
fi

echo "All done! Run 'rustlings' to get started."