#!/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=83c546c6f7a3f086be4eceabf1d9f14fa4e9518174c35303892d91554d944afc
        path=bfw6mdn9h7z0gfrrip6x5vxz9vmp1r77/nix-2.24.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=274c114ae717aa379599f13ef72e8668b6bca8f34a0ee2a5928701733bf04b90
        path=p565aq0jhlq5f2j2f7nkjc6nmf65rbza/nix-2.24.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=d56721185add6670337f74b7600b97f31ecaeada429cbce3e35b22cf10ffebc8
        path=c59mgaakl4ax844kp8q42zvbmrnp2ykz/nix-2.24.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=9fdfa57adb3713fe982db82be6ece1dcd53fde424feb3c606e0c0fa998ca4c0a
        path=fv8b9aiv75r4bcxh1iijlqrmr4qp2pr1/nix-2.24.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=32324241b30b3c81bf31bed95c21176c0c271de7299e70a3f2294eb1274c74fc
        path=312yklk7whk8d8f892241rq3zxxw8rgv/nix-2.24.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=ec5b3639b6f92f69874394a2e90a3b4e5e507dfb6145e57b924d73aabb48f84b
        path=lzlj820fjanixvzas8hy30q1xcjwkxb9/nix-2.24.6-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=ef71da85421c67be536ce07b9ce54a50c43b850b82fac42c199cf05259a53155
        path=bj4svx98q4hl3c7lf7v6avwrv76sm6bn/nix-2.24.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=0d10f245892f62055853ace3d073e4947a27fb6450a3b6d3570ab30726ff6371
        path=lgg5x8hfqji7r64z3s0g2iphbw7w0i4c/nix-2.24.6-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://releases.nixos.org/nix/nix-2.24.6/nix-2.24.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.24.6-$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 2.24.6 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