#!/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=3969ba872becad10f8631981006b8f708de6fea892aa6fe3b09f9070c9dde414
        path=b9hrxhhbl5hxiniqcagnp6kazi92fv53/nix-2.13.4-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=388a24f1258f48cc4606b931a5fc02d31562c18c58dc8f4d6f2a0dc30ef1aa07
        path=nipl1hx397br5x8km6111qj1mzr559c9/nix-2.13.4-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=bb453d230c02998df0bd79c6350b2eca1340834542551ca0104d599be73b66f8
        path=jls30622apjsnj57m8v5vqgzkmvqssxh/nix-2.13.4-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=bb1ada265197cb005ebbac9148da147ac06bfed4e86a34747bd5f0fb269cfcb3
        path=q27q5y2zyl77ds653n876wj0bpv0k9in/nix-2.13.4-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=6b146aa39cf654d3ade1ba51bfccbe23da8266fcfa6814442bfc1eb87f2c77b6
        path=jn0h1s8qdy1l7081661grcy4w8wgybzf/nix-2.13.4-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=9ad7d56e9d83b1da1eaa8e1d1e5f4645435d6b12e0cc2e0ef8194f20e9467bf7
        path=v68cnx2cp4y6mzy8b517am4h5jwp9468/nix-2.13.4-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=6f6683940dad447e0f6f43d2851c8dc417e0ed63b35e84e4117084fe78858388
        path=jkkpna5nynhzj7z5n39hqzr1qz7valbp/nix-2.13.4-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-2.13.4/nix-2.13.4-$system.tar.xz
fi

tarball=$tmpDir/nix-2.13.4-$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 2.13.4 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