#!/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=5f9de98618eb701e053c50f08c2927e73d3dad27d35dca40303c2bcfa196d658
        path=1a1h2dykgxyzqgjryp9f70s6pkjq3dsh/nix-2.22.3-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=14546d5f0b5e85934a134faed99a83c235c8fc0832142bb7c4b7604db068c74f
        path=szkqcpc2ayhk0ldyy3ws1372bniasjzd/nix-2.22.3-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=2ed0789fc0810d9c16550f6f7322ed0366df9bbeaa62c8722a8d77f34f44d9e5
        path=fkr1ndn6arj74yfjk19gp6q4rar65qij/nix-2.22.3-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=052f79cc119178f8d1bda482511ac4b95786c351cbd5c5b6c4871baf392f46c9
        path=6nqvq4gl79f261fnxd5g3f3l621wq1mq/nix-2.22.3-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=d14fcf4bd01655d6acf6cbc85bd38522598c687a02050baa21c466895b9e1714
        path=s2x5wy95skkig86ilbi7m8rk9l96c91v/nix-2.22.3-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=d4bcaa8bfda2dd3c4779dcca73f90d48c3e66b67b3df2d153c827656327bd5f0
        path=dh7r7v3dqav7c4l39lgk7v2f09kmylwv/nix-2.22.3-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=98c0b2826f5e3082b4b6eb348246a805903ba6792f9f2f6c8e08728eb8b832cd
        path=asvnasvvd2g5n64r9k63965psh45m8rh/nix-2.22.3-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-2.22.3/nix-2.22.3-$system.tar.xz
fi

tarball=$tmpDir/nix-2.22.3-$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 2.22.3 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