#!/bin/sh

# This script installs the Nix package manager on your system by
# downloading a binary distribution and running its installer script
# (which in turn creates and populates /nix).

{ # Prevent execution if this script was only partially downloaded
oops() {
    echo "$0:" "$@" >&2
    exit 1
}

umask 0022

tmpDir="$(mktemp -d -t nix-binary-tarball-unpack.XXXXXXXXXX || \
          oops "Can't create temporary directory for downloading the Nix binary tarball")"
cleanup() {
    rm -rf "$tmpDir"
}
trap cleanup EXIT INT QUIT TERM

require_util() {
    command -v "$1" > /dev/null 2>&1 ||
        oops "you do not have '$1' installed, which I need to $2"
}

case "$(uname -s).$(uname -m)" in
    Linux.x86_64)
        hash=b3108f6a648db40c2b52f5f0310c70dbb754ae84b7e068aa22e916a4776aaf73
        path=rrva36wan2hjmgdz580gkbx6j6nfmldi/nix-2.13.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=eb7e29ef780b1b179e55c863d2f27df9623028bd826f4b5ce96a53394c98ad9f
        path=7r5il4mcwyjd9c13r22rc62yxi9rfxav/nix-2.13.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=8f22ef2d2f26dc2c168664b1582402780fb8f708658fa1723f84cd5c6d6fd2c9
        path=3sif6bp6c3x6rghlcv859hxq13a8v56q/nix-2.13.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=3421d92eb495228cb868065f568ffb94ccef58e48d4cc92925a172338dca17cf
        path=w6p73qrdcpczfvr2g5js2pjhx06kbg3i/nix-2.13.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=00cf9552b12ed1a8f2e74e5891fbcedf8d1c3f5413868b5b26f291b088314f1d
        path=3j44y7n2710bvm5arcrs8ajld6c2rhk8/nix-2.13.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=8dd80d7df5bb824e19f137ae43570dc5878ae01dfe8a5e2e5b59d67c318b06e2
        path=26xra5m71jbmmk6rmpjs50bgrljf8l6j/nix-2.13.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=c555cc91121770b81fab445bd3245d25ea72c5728a457238c721ac473c635c00
        path=z59zc6v9pfj8vgbyc5sy1aw1pyqp7d3q/nix-2.13.1-aarch64-darwin.tar.xz
        system=aarch64-darwin
        ;;
    *) oops "sorry, there is no binary distribution of Nix for your platform";;
esac

# Use this command-line option to fetch the tarballs using nar-serve or Cachix
if [ "${1:-}" = "--tarball-url-prefix" ]; then
    if [ -z "${2:-}" ]; then
        oops "missing argument for --tarball-url-prefix"
    fi
    url=${2}/${path}
    shift 2
else
    url=https://releases.nixos.org/nix/nix-2.13.1/nix-2.13.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.13.1-$system.tar.xz

require_util tar "unpack the binary tarball"
if [ "$(uname -s)" != "Darwin" ]; then
    require_util xz "unpack the binary tarball"
fi

if command -v curl > /dev/null 2>&1; then
    fetch() { curl --fail -L "$1" -o "$2"; }
elif command -v wget > /dev/null 2>&1; then
    fetch() { wget "$1" -O "$2"; }
else
    oops "you don't have wget or curl installed, which I need to download the binary tarball"
fi

echo "downloading Nix 2.13.1 binary tarball for $system from '$url' to '$tmpDir'..."
fetch "$url" "$tarball" || oops "failed to download '$url'"

if command -v sha256sum > /dev/null 2>&1; then
    hash2="$(sha256sum -b "$tarball" | cut -c1-64)"
elif command -v shasum > /dev/null 2>&1; then
    hash2="$(shasum -a 256 -b "$tarball" | cut -c1-64)"
elif command -v openssl > /dev/null 2>&1; then
    hash2="$(openssl dgst -r -sha256 "$tarball" | cut -c1-64)"
else
    oops "cannot verify the SHA-256 hash of '$url'; you need one of 'shasum', 'sha256sum', or 'openssl'"
fi

if [ "$hash" != "$hash2" ]; then
    oops "SHA-256 hash mismatch in '$url'; expected $hash, got $hash2"
fi

unpack=$tmpDir/unpack
mkdir -p "$unpack"
tar -xJf "$tarball" -C "$unpack" || oops "failed to unpack '$url'"

script=$(echo "$unpack"/*/install)

[ -e "$script" ] || oops "installation script is missing from the binary tarball!"
export INVOKED_FROM_INSTALL_IN=1
"$script" "$@"

} # End of wrapping