#!/bin/sh
# Clojure Installer for Unix
# Copyright (c) 2020 Michael Chen
# Licensed under MIT


download () {
    local target="$1";
    local uri="$2";

    if [ -z "$target" ];
    then
        echo "No valid download target" >&2;
        exit 1;
    fi

    if [ -z "$uri" ];
    then
        echo "No valid URI" >&2;
        exit 1;
    fi

    if command -v wget --version 2>/dev/null 1>&2;
    then
        wget -O "$target" "$uri";
    elif command -v curl --version 2>/dev/null 1>&2;
    then
        curl "$uri" --output "$target";
    else
        echo "Neither wget nor curl on the system" >&2;
        exit 1;
    fi
}

# Check whether Git is available.
if ! command -v git --version 2>/dev/null 1>&2;
then
    echo "No Git on the system" >&2;
    exit 1;
fi

# Get prefix from user input.
prefix="$1";

# Fallback to default prefix.
if [ -z "$prefix" ];
then
    prefix="$HOME";
fi

clojure_root="$prefix/clojure";

cwd="$(pwd)";

if [ -d "$clojure_root" ];
then
    cd "$clojure_root" || (
        echo "Failed to go to $clojure_root" >&2;
        exit 1;
    );

    # Update a local Clojure repo if it exists.
    git pull;
else
    # Clone a Clojure repo if it doesn't exist.
    git clone https://github.com/clojure/clojure.git "$clojure_root";

    cd "$clojure_root" || (
        echo "Failed to go to $clojure_root" >&2;
        exit 1;
    );
fi

mkdir "$clojure_root/scripts" || (
    echo "Failed to create $clojure_root/scripts" >&2;
    exit 1;
);

# Download clojure script.
download "$clojure_root/cljrun" \
    "https://raw.githubusercontent.com/cwchentw/clojure-install/master/clojure/cljrun";

# Check whether clojure script exists.
if ! [ -f "$clojure_root/cljrun" ];
then
    echo "Failed to download clojure script" >&2;
    exit 1;
fi

chmod +x "$clojure_root/cljrun";

# Download build script.
download "$clojure_root/scripts/build" \
    "https://raw.githubusercontent.com/cwchentw/clojure-install/master/clojure/build";

# Check whether build script exists.
if ! [ -f "$clojure_root/scripts/build" ];
then
    echo "Failed to download build script" >&2;
    exit 1;
fi

chmod +x "$clojure_root/scripts/build";

# Download clean script.
download "$clojure_root/scripts/clean" \
    "https://raw.githubusercontent.com/cwchentw/clojure-install/master/clojure/clean";

# Check whether clean script exists.
if ! [ -f "$clojure_root/scripts/clean" ];
then
    echo "Failed to download clean script" >&2;
    exit 1;
fi

chmod +x "$clojure_root/scripts/clean";

"$clojure_root/scripts/clean";
"$clojure_root/scripts/build";

echo "Remember to add $clojure_root to PATH variable";

cd "$cwd";