#!/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=d500531e9dc21c69d03923f20a88b46f9a02d31112de2204b6021fab8c55982e
        path=cxh2lx91mkrvps58bwg0w9kwjxgij4hp/nix-2.16.2-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=0db4b29b624711af784fa3e1ca16f1f1b85b5d1576e051cff56477a7012b5db7
        path=jak54wwgf3r0v3kny7a9c78kqmwdq5id/nix-2.16.2-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=49c793dfa8b9e5513b59499efd83ebb76ed9e9b19218986caedf2e0a95460f66
        path=v23zabmxj3xmnx05ixdbxr6ma33q47dn/nix-2.16.2-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=c5cf0d020f9ba2a0d8acd3c156549854fbeb2f615bdcd1c2817ae6f4907ac609
        path=1x5fk32i9aj8gdzh2x634g4fdf4i4rdk/nix-2.16.2-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=8992da6f88089e1f0c09c40f3b322723cb28451cba57e367c20a88e8e66d6f8d
        path=bm66y9z7vpzwlq79slswy1ydlrccadhf/nix-2.16.2-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=040f48191d2b15d734dbaa9c84befd71dda33d06c03bbfceb5331a99e3842c3d
        path=spz0iis4a6gn7vn8imrammf455wd5nad/nix-2.16.2-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=260b584e00aed6ba82eca247c4e425bc4b12bafbbc33151b45644cb2e00f0934
        path=qk3hr34h64p5nacc893qbc7nkn561mri/nix-2.16.2-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-2.16.2/nix-2.16.2-$system.tar.xz
fi

tarball=$tmpDir/nix-2.16.2-$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 2.16.2 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