#!/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=56e47db8c477f848e0bca5258bba086fc7223538793c37cd258bc977708da6a9
        path=bwaa49vq6d52gx7lbahlfs45a20n7gr9/nix-2.22.4-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=7233c31a09d3547fdcc3af13f8287b3cec78d06923e5c4818879361c1c9aa709
        path=56n4mas6g6v695d6vacqnpzsc4vkr884/nix-2.22.4-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=c68f2cebe136189469cbfb7f685066b15b625135e2bde8bb2ebae50a3e37f6b3
        path=8bmkpf89l455j4978208pq3ri2vlwncw/nix-2.22.4-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=1ca91c8cac8f1b40036b729bd7febf39f421da7638ab2d3c1a39df8887ce6896
        path=4067m6yiqim4cag854zqv6jbcnq3g0d1/nix-2.22.4-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=1597a277f1c1aec59fd861b7d026625c34dfb365653e97fe88e2410c68c74d28
        path=99cbc847bz0l9gykrrcnf0fk9gjjsw2l/nix-2.22.4-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=d0e225c6d858c1d2133dda88a9e81e9e373712702688e1a936414151f8ae2577
        path=28lsw9kp8id4fx5f7b071xg9pnzkz1d1/nix-2.22.4-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=e3944ec177d318fc4e881183e51f2403579748460d9ddd3327807648da1e1fa3
        path=03kqgmk377hyzp8vhw3dzk6jl4bcljhq/nix-2.22.4-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-2.22.4/nix-2.22.4-$system.tar.xz
fi

tarball=$tmpDir/nix-2.22.4-$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 2.22.4 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