#!/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=e070ea82a01889f491484279de452dd445dd155f395e49afe01086847c0f5330
        path=wy7lj0f3cskpxb2gq5rh0b5d4650r8hm/nix-2.20.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=855d9b5e18e38f86131a6c8b1e12a832f704bf3909715435f9e6d5984d52f37c
        path=1xl3hvd29lk3kwf69hlsl6m149hn9yi5/nix-2.20.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=e9603a5b5fecb3bd9616e88855bbc03d13306440ffcf7efb52929a13bf059f6c
        path=cy7vqgmx13jad36n6f527vbxlijqdvyj/nix-2.20.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=573e9c595e274abfc621ec3c688cbe2f9e106aaa6eff5b3c09d0cdd2f89589d9
        path=jhclh0mny9gmwxb83nngd2cn37993m2x/nix-2.20.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=c32b677edaf31df40a696d22a6a96d9f1885c8beb2452c36592182cebdda145b
        path=qn3mbz7n0xl58f4qiakkyj1c46cdkqzw/nix-2.20.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=6659138e9aaf1181fe21323fcd1e3d29f0b0e0ea2c06a794092c2d6184caa7c8
        path=pkzg0d5bmxa04xiggcszzj4l2n2lifai/nix-2.20.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=f247e84f3a93f02809954802b3fd049a0885739e9e22acf689692e71e6663bfd
        path=7ialpqd81gy0pwyy366s9fk7652rwx10/nix-2.20.0-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-2.20.0/nix-2.20.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.20.0-$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 2.20.0 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