#!/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=97fdbae23ac4511534d3c617a7e6bc1f72485e465c80fd6aba89a1a7b25d83aa
        path=52mi7kj3qnpwj2yxl2ahy245s2173za1/nix-2.28.7-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=e5469b10b9c7da0840e25f98cc8cdf2cf1798b730d041acee0c3e07b73fceb70
        path=7vivb49h6i0zk9icm75kvv8406480rdc/nix-2.28.7-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=f41b0b783b62fed4f39e0d37e7745493a36d6581c83d78483fd3c9271b8cf492
        path=9b79m4z8mqw5fpasc9hv1x6rxvjix51x/nix-2.28.7-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=3c5c5811fdb5720a9bc9a59128eed96f86e263235eed8fbe0b2ec22ede74a69b
        path=2zqm764hc23ys5znm68jvp1niisdcs5p/nix-2.28.7-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=8aa1f35e00990ba15200ca6199ccd34ff7056ec0316afd10f0ae20b73b6024f4
        path=qq8qcl87awycd2adilsg9mwvnrm9gin5/nix-2.28.7-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=104dd609c99509bb16d5c6af0899797f2ef946140ec33b3bcf9e83500df6271f
        path=var4ngaq67j20rwi418mw53nw2iarhya/nix-2.28.7-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=b5447a9cfa070e05f472696455a73e0d23e40876078726ecb66f093ede692c85
        path=387bdyrdpfj13gvjmzwzas39znv2nhm2/nix-2.28.7-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=61691c5125eba90e13310f04fc7e9bd3e6a8b80c40a85f841967fe7f33f64530
        path=4vmbpsd7hlck041ixbnv9y3krnw9g22k/nix-2.28.7-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-2.28.7/nix-2.28.7-$system.tar.xz
fi

tarball=$tmpDir/nix-2.28.7-$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 2.28.7 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