#!/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=2b7e9fda8e17e2143c302a700908e86698c265b5862fc7e6b805942aceef6668
        path=w3nh2qyi8vcyrsfwwzy8rigq4flyagw9/nix-2.28.5-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=71ae7ea811a454ee31a5cb7ab0f7dea63d1163d4e211fccd1f8b28c0f408bec5
        path=lnby8ys538v72n8qva5vlfvf1g4a7x3x/nix-2.28.5-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=a7d20e2897de8044ed35a481d455e88130b6d70e40f2470d1b7c26727f6c8d8c
        path=z15c2r6bv6dg2myxz3zjy1k1mz3mykl1/nix-2.28.5-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=c7a7e61afe14c6c8f5cea0f6cbe649b0252f2254203d40c4ccd293f9ffc97280
        path=70gs3n6p1sh3pj1h23y7zs4c1vi9myf8/nix-2.28.5-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=e5f06609481fc63adfa871c5d910bffdb2d91940562be1ad32645ca60524d774
        path=234xz8znv5641wc1vzk1k8nyl14pz7bp/nix-2.28.5-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=2271adb9f922748493e74de147e914705eae5eb41bd193004ddc86a6636c79b0
        path=z1nakp1nbidk3c4l34xaic9c6ygl8z12/nix-2.28.5-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=f79d6f8d3506fb2c960755386a54b11de44a4a740d8dbba8dfb08ff7ea21b3c7
        path=zs91zbc4vi6ckpf4hc23cfxj91z8bbnd/nix-2.28.5-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=656de28d687213b15297a9d109fece8ae454a265a4bc1b3af57c8777d46bfd2c
        path=nr6i420kz66zxcjgv36djqyygmy4fc6g/nix-2.28.5-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-2.28.5/nix-2.28.5-$system.tar.xz
fi

tarball=$tmpDir/nix-2.28.5-$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 2.28.5 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