#!/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=8b0de20005d80dc98afc8494a5231b192c9fb6c76c6e164664200e8b8f304ead
        path=fxzan65fci5zfxb6j0c2rf8432ykbjxz/nix-2.12.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=6b85b7f8e3fac7112c6761a53b599a7ae19b18061e71c900cabb541f6cdbe85e
        path=0d5xjsy4c5nqc36ahyz3j4ai8w87yk9y/nix-2.12.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=4eba1eb9c7923278d991a484647b23d0c838b1fd4a53419e9a306d067b3bbfaf
        path=dw78xss3rhaxnx0jdwlkpkj92cri8845/nix-2.12.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=f90f27c0ed4a267de767f97ccc427397ebed10a5c619ddd9bdb0c8808bab2a00
        path=dr4yqfdkyp5265sizj2mhyfml40qwlvl/nix-2.12.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=bca98a3b223d953fb79310b9763bd631b399e681a7a6a038a9ab5c3c3f8d68c7
        path=y0bbh7bmi8qiza05y9gr5kbj6mcp1icx/nix-2.12.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=abaf00b870f2e52401979420fc1cebe3df86fb25030d22a7e4b1ae3ca79915b2
        path=g53ihvqnw9m8xcw7n5499np4lvzdi971/nix-2.12.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=78630f5a595b381d3233fa9645b464a29e3cf240f896a5a36651b49c572d0ac8
        path=wvqy5zk92p5dkr27mcvnqch5prla0kfr/nix-2.12.1-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-2.12.1/nix-2.12.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.12.1-$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 2.12.1 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