#!/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=2d71dfdaeb5969971beaf9e111c2b378f02ccab83fa8095d8a4465da00e676a5
        path=5vmkybdbxir3x6wnzxh5c1p663m5z6gz/nix-2.23.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=0204c03ddc8902901f70db062c09635c84ec4d78e4b37f6821ba0d669ccd2178
        path=r2k50l5zc5ywv7pd22xmwkf91q84p3hk/nix-2.23.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=8a7fda14a7b67606f4fd2cdac3cd7623defcbd4ff39ea2d4ad8f701079a991da
        path=bbgn2kaib9c2l0h5h8afckx13f1nvanc/nix-2.23.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=95371cb1a30a4ce2bbecdf4e4c6fe8e4e61a68ab17a81d74174778df3566da08
        path=2xjr5n7gjvys4zv0qy9ysvziy0kax8pp/nix-2.23.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=affc4a5e817e4f05b09e3b3961e9d40b3ec15df9aa0272490cb4496165e9ca79
        path=954x5wi6bxf1kgdwj9msv4wi6kicbgmn/nix-2.23.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=8305c0ee7aa66c6155b0e3bb02819affa4e352abd92f3343e280e92d5e1e8bac
        path=1f3wxkgmks961jc5pj2qqq8ldvzqzwkr/nix-2.23.1-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=3e87b5aba8826a5937451c3d6fa86491de08fa18cc67228828c51a8c247207de
        path=yfnp9mym23knv4hr4a35xzhwid3bimqc/nix-2.23.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=e8620f7f58c9a8f6a080adbe6d61e1933fdcaab5f65b3559f0a3a8fc179b61b4
        path=g6wp76qyqivjhblxfaz9sb2gnszijcbx/nix-2.23.1-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-2.23.1/nix-2.23.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.23.1-$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 2.23.1 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