#!/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=df1b8e5635c15ebf674165ac5e13a11bce059f593ad49b0665a4ed1df98a9089
        path=yx6jn663cjmw3nhgj8vpf7jg9v369b9w/nix-2.16.3-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=2b99633d5d9af01880b6a2fbd55144612072c36ab988cc3f800e686c75ef0b65
        path=dl1wrv322vx6rmpby8fg16cgqhhr5n7g/nix-2.16.3-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=0ba17090778140f497c3ae9d2f6188aea03410d067dde55dc3f91b8a5afa7386
        path=y1cc2jb24xiz0h7yi4pmksv7ixjghp6p/nix-2.16.3-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=bcb07e045b2d74301840898c62d2ef557ce23c4965284d8991bc8d26083abef2
        path=xqw6yj2p1ag16n79qrnlzy8hlsnryd3c/nix-2.16.3-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=a220a5595bd03aac3f75af8c4bdc5d54a19819753358124c80a740fefe5f7d03
        path=p3p2c9wcipzfh1gjbxq1rl8q6qqmmj87/nix-2.16.3-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=1709413475f2ef91876eadd8100eda845f8f0f61d10d5b086c48175bc8a77262
        path=fsxvi6hg9zvpq87ch11j1kl5bdr8ll5i/nix-2.16.3-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=ced98161c013ca579039cf89c3a7933f05d5011aa108d3f485ebaed7d012e937
        path=1mjx1abnqhbjyxslyzic9fmz0iv24ld9/nix-2.16.3-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://mirrors.tuna.tsinghua.edu.cn/nix//nix-2.16.3/nix-2.16.3-$system.tar.xz
fi

tarball=$tmpDir/nix-2.16.3-$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 2.16.3 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