#!/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=fb6faa5d497bfa711eb59a970e894c1a850848d86355be1e18517cf3cf34eb15
        path=aqilnsjd2z11gzzhbcwswxhcrzjwqaf7/nix-2.26.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=0f115964aa6930ff9c70f7ddc6064f30131b189266dada3711f1e234682e46ad
        path=bxcff0yasfk2ydhdj6qdcdp5g8jczq1z/nix-2.26.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=fb69e7fed7bc4521a3c3068206637a6b914bc1e31540a44a862e06e3927750e7
        path=ar46mvn481wpqvkrr6ylk9nwdh5ld7wj/nix-2.26.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=850870453268abad0b0aded4820c48b6bb47400267e07d919ebb8eddcf2f44f6
        path=xrmq0nzddxl17a01wwcj8pf0z7dwi0y9/nix-2.26.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=c6c91a62db57a72f4597fbbbbf215915830548c9844acf5719268a25bb5d7278
        path=7y5gvbm9ygcj4aa70rmcaqg1fik4yrlw/nix-2.26.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=ddc6b364996a0b29a20a2499a1ed5ba7adb3102dc28f13a5ded921d1acf44b56
        path=6xgcdjzfrzq9jqqdfr5qxzsfxhv4zj30/nix-2.26.1-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=2ef008b4978c9628d7e5eae75cdaef4106485d393f71de0a18c24d09620252db
        path=0h33w31b89wssyc19l5bxx7jfx530p2q/nix-2.26.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=366bdb937bb9df4f39fc185ea9b2ebfa9edacfa798af98e977dd1145ef1e5d36
        path=lwn6ivba8zjf7k63v48vpj9s0dvnrvzj/nix-2.26.1-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-2.26.1/nix-2.26.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.26.1-$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 2.26.1 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