#!/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=562ffcdf293ad178ce984858ce152915753cd1055fca6be35adcb41e58be2681
        path=gvpx43dd99gq0lxlhmlgpb1187w27lrz/nix-2.28.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=c90027a9280e827057eb2913cd732a44f924ff86d526674deb9f3154d2dd7f97
        path=dfgbq6m4lpm4jg54qdwxsh91745c1r9c/nix-2.28.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=6cb7bdc80ecbe90ebc105768769643afa537fcb1fdbdeb05dd4da320d5071e44
        path=873qm72xjycbz2h3jn331khgmn01m9ad/nix-2.28.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=d3213e73b3b91e3ebda866bfa5b5f8ad65f5340c1691f6afd57165632da29ce2
        path=cmjggyg3ai1p2k8lp5hvvp6s1qn3nvv9/nix-2.28.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=8a59b0cd34c2cc2f084d316e0fe623ef65d4392586a3dd2dae9c12979d3e889d
        path=d5lbyjba7sb0sidyc5pbadip3i4nksln/nix-2.28.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=ea81368f7490a414a2c19a5133332a61e48c5b747bfa90ce317dda409a46ae86
        path=15ifyjl6lppcxl4i7ckmb9clskk5kdy4/nix-2.28.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=f6d8adcf0b53b2a33db6e4f666793d98895d903485c5f9c57badcf66d5198426
        path=rfgd3q3wjjbi7vc5565h8ycm70wnrqnh/nix-2.28.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=f605763f1c02ea39de999e8545e488297c46efb2e67618bab9e31a5b6c0d7841
        path=q1r8f9kk8n6r87wbjv1ic545wl5yyzfi/nix-2.28.0-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-2.28.0/nix-2.28.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.28.0-$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 2.28.0 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