#!/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=f9c7d619c1edfab944a4f0d2704ed576827ad2d30009ec7f069abcbbb386b4bc
        path=s77a6z49b6flxdysd20w7fk3xfnqdqyx/nix-2.17.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=5ba1b648befeb4073d558136a3a650d40764f19f6865e6cdc65de2f5baec3abb
        path=gkb19irb16rrfjzmfjf8rdnv0bawfzz8/nix-2.17.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=46db203f8024dc743419679e02cdc543cbf8454811ddfcc9310204d3bbc86acf
        path=8jc8khplng0mbvd0rap6hd5h7dvzkk08/nix-2.17.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=f278713ac76267e43942ca3815f251bbcf7393ec8c7964185d37b6f617eaab25
        path=yb5f6zpjkkkrmv7inpfxg1cbgcp9bb34/nix-2.17.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=3d82d3fe657b611cf93c140a215d41a89ec79f7d57efb6f92f885609a76335f7
        path=9xy12zj0mp2gvaxlfbb26fkv8lh2cg0l/nix-2.17.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=c9a9b83dc6fd67788f773d01f0887ae3a786d88c45699dfbfc48ce8e657d4b36
        path=l46lyx3vs5wvxb619ba0zj4jj9yabwf1/nix-2.17.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=91022bf7727aab21cf1f80a1d0d4c2e3926411a2ac63378b306d35e7aa4d6a01
        path=gd9by5z4h68yk4pb5a1kki4mifp5gwa4/nix-2.17.1-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-2.17.1/nix-2.17.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.17.1-$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 2.17.1 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