#!/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=e83cdb492564a416ee2d0ef1f5571693196c7d7b851abf2f3d67c0282aeda440
        path=yscm7dlzcvyjm0g5sjlp2mj6vcqwlvyv/nix-2.21.4-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=aa4a6784e3b487d158ee85072871e9fed8d049dfe4b77d92dcf6cb06898c9c9f
        path=bjmxkjn0sk9kb90x69i5zlrfig3gql9x/nix-2.21.4-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=7c6f237384414523d92d6369b1a12cc9a7aa49eafd6d43f8688597124c576836
        path=ydhjzx5y00plbnbx6pc4m02xxsf3yg87/nix-2.21.4-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=2243e2319dd0e36e414ffde5d7de9d2f9bdef51c6033e50de5216b3985250654
        path=ys52523wiy4vw6fvxbfqa7f1a2nw1njk/nix-2.21.4-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=0cf6227093d0be403f60a21e14b08fd1cee93834e908ff11ff62ef3cac63a6d9
        path=pyq4i9qysynz9saswsw74xsfn1wz4yfd/nix-2.21.4-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=0637c6bccb73063112eeb1b2f371aedabd4295d307176c2b8ab8e33f0e7fa941
        path=7r5chw5bw799v3amagdhr68nhfkhignf/nix-2.21.4-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=051f1361a4e7f7c223d75f39f9858a5cd4e6aaa4ed7d2678699fe28b24e5cef5
        path=67njv0xd0nn4s0jgd5mawl00im96idh4/nix-2.21.4-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-2.21.4/nix-2.21.4-$system.tar.xz
fi

tarball=$tmpDir/nix-2.21.4-$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 2.21.4 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