#!/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=04f5b870bac909de8139b4667697ec46a1e440f7e423d70848e355ff40ba2cb7
        path=rkcbhprwbp5sd1dh3pspwq3iyw0ydd96/nix-2.19.3-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=4ade2ca7f108b65c9c96eb6d9a96870a01ac86a9d486671dfe4a4ba6d329dad2
        path=ifkmc16s6hy79pi8f28jcx72nkzqs1ry/nix-2.19.3-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=4fd70d4831b8a5c2879c850fe5c592a9d658053032ba7a0b890ab78c37cf1dae
        path=zl41fzf1pq1fcwg2a5ynbys9r71k5vs4/nix-2.19.3-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=47258a60b3f84d7f501504d65aa4ce958a4533252cf1f4c8b599672207ea4259
        path=cvd3kdbw89ddrji7ms3hz12bwsmxiwiz/nix-2.19.3-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=6a92d1d0918617a4f06173e90e47bbfe2cbdbf48da3730238192c3ad181796e6
        path=hcr780f54ly6yw53lpacvw72dmmffb61/nix-2.19.3-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=2b3957772118fb6ecba1fc470629dad6d5bb624558c5115800c3bc6ee2580330
        path=2xb76lyznim3z8la2hb2lvvkajfdjjbm/nix-2.19.3-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=411aab848b38360526fbbdb4469a6cca2119c6fc626ba0f087c6acfe34a57c1c
        path=0pivfjkcf68j271x5fbagbmvx3ynv5wd/nix-2.19.3-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-2.19.3/nix-2.19.3-$system.tar.xz
fi

tarball=$tmpDir/nix-2.19.3-$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 2.19.3 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