#!/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=43bdcee039ed3ddce45016c333f048f1847567e577331769b570aa53644bc911
        path=6421vbz77y3kw3v0yw166yv4xwk8j5jh/nix-2.31.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=fc6070b67412aabd9c7069ad2366bc15cbcc226029e646fb66d8ad7b521e93bf
        path=prgx6r83iwbww21mi3vq8yw459rydh7n/nix-2.31.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=05900dbd782effd90d779969f7121ae01c8e4d04ed1ed40ddc0cf35cb34c6528
        path=qikr9x12i615ppsdf5ic1cz6pj2drgbr/nix-2.31.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=16127bac322b4eb9020b0931e20e34c9d6dff2435647785cbed078ac90bd4c5f
        path=h3yricfk6rbfd8y3pi9bk4yfdwf594yn/nix-2.31.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=407f742de77ee8a9b21c2feedfef15368e50695987a1d3a8cdf8c89366e862e9
        path=d218i8g47zc7ib99fzz4vsjvcr3nd8dh/nix-2.31.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=f55dccf8748adced46f0860aca6edd625cc35174c1a2759568b22fda81b231ac
        path=szvrwn95qr9wmsvj4qc4bb1jjy3sj2db/nix-2.31.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=22ff628f4fc45a9d46c0d6add0b4b9f3dce4ada848ca5274524ba8561edcfa11
        path=gj2ak072v32ffxlg95lw5dbcx5nyl6wg/nix-2.31.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=914c81dd92b26a5d73dfb9e9e3629bfea108668efefd80d3d42553e4a76b4424
        path=f9gnidqcqcwwdwyq41jvrp3b4v3knnr9/nix-2.31.0-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-2.31.0/nix-2.31.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.31.0-$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 2.31.0 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