#!/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=8d2775b15ff2fd43be859735796c7da25c9e98a20e72612caef3ff0109646590
        path=l1cc9xzfx9jjx5n2d3iavqlqhmsznm99/nix-2.18.9-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=1d40fcca399d2c4804d83ae25a48530551e1f088d01994eb3a86e994a791eea6
        path=m9pnan6f9qwm6y1y14vfar0lskv8yz3q/nix-2.18.9-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=d91cb607f0267038991825cc345f8deb415aac21716aba20615c7a8b51570fb6
        path=dn2m83dv39zph6b9cvvsbm14ji1p839l/nix-2.18.9-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=c111941b5e7174ead0466edc4e2b63e81e6e78614c071ca8b62543c936745013
        path=56nh07940cca19n9xv8x3p164c4a7bp7/nix-2.18.9-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=37e375cd858f5e7c38a9e716f0f110387f6385f4f22cd19849fbc2802157328e
        path=wrf7grzzwgmf8rhwa71yy4yfz9l578zf/nix-2.18.9-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=0d623282ac938d01fd474fac6d5a2ea57fec35d279b8611a1df814f439e8fc4d
        path=k127bdxmz5aidfbfg3czvjram15jx33z/nix-2.18.9-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=8e54ada7b18f923d872eac31fdabbbbfa46f12a138987a6a82964725c5907b02
        path=hi9js8svxw7i8m4vwz6q28f5s6v5z11z/nix-2.18.9-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-2.18.9/nix-2.18.9-$system.tar.xz
fi

tarball=$tmpDir/nix-2.18.9-$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 2.18.9 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