#!/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=9345c1485dadb1cb66ed54aa97c692ab38f7ead2d609230564e6673490f30365
        path=dhpm22y6m1y9h8hikkincl69f4gvibjw/nix-2.15.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=b33735c53387778f8ba7ec0402d1966f7bf5b5d0a7b664c9fb57223a6114b3f1
        path=ilxv9d2an2l80z10c2lk5adfhqz2k2wk/nix-2.15.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=ced2420cb5f4a02a247d748343f67d81b5b9d8fa47a105ea8fc4730f66948115
        path=d601ziicjfs4icdjl0z51zqxfpfldlbr/nix-2.15.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=933459bb594a000a031eaf932bec2ae4e137ea4707e8c9ccedbcade060562b40
        path=44cja5fmn7q4ipaj6c0vd9jlds3xjv69/nix-2.15.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=945a9cea4834c41730681991f328c583b4dd08deefc3abf19f4e9c6ea97df3e4
        path=nsgqg552a4c2bgcig99zjwiy7pi1x370/nix-2.15.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=dea313995f9d0676ad3eea4ae864bfcedff5cb390467f208435b73971d5cc5eb
        path=w4qh7bbyf208wpvkhqf3np2zzlv0ifsf/nix-2.15.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=2301d03db8528aeca80192e918243f297ab3413f9181bfd5e5ef1f567a87290d
        path=1pg4a766s6aff93rnywbksjdg1mcs5cm/nix-2.15.1-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-2.15.1/nix-2.15.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.15.1-$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 2.15.1 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