#!/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=b471fab14335c6fb5a2c8f76d115af9cec6b726af040306e76af8be39b1d080e
        path=140a10yylxyvw2i6cw6b9x72p3dqz89i/nix-2.19.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=fc88eeb1a779a3968b0a7ff7ca78afc70cbc85473f2b5f19799603ac78f14ee5
        path=bcwcjahk3hiqqbps9bjd1n8mw8ssghms/nix-2.19.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=5e591f4923e081a770adb212f1e136a435c9d53c8da2935963243d1fd369735d
        path=5kcjml5dyp429nkiq7bbmf4n9rcc0ypv/nix-2.19.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=76514d1493c842691f74e3d165d9abd8bdbc674b68f71348bce8d8420786ffbb
        path=kljrlgbzz5yq8qxl7ppijsy9pgf4iqby/nix-2.19.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=c891370067eb0fd28a66dccac2f6ef1fdbffd309ee89affb5cd364e5568f7e20
        path=d7ilixzshd9grskngs23hmv6zi24vd0v/nix-2.19.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=fb5b49bab3b57e5a91f3504d050df26fcea5e269650cbdedd50490271fc50b4f
        path=6psabfq9kv9sjkjgb0y4imk5f39ia81y/nix-2.19.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=f2527db932b8079d2c3df74090d02646af5164a5716dd9f38a6c5ba40e7aab80
        path=y71sy1ncm61wwpxd4sl5da7lchlck9g9/nix-2.19.6-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-2.19.6/nix-2.19.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.19.6-$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 2.19.6 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