#!/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=e948b0a1ef43b353fabd1308ccfa959c3ab8d75b830a08ae581a5e0d1a68ede8
        path=c4v1v4x11hfbjx48hd7lrdx6g4i6vynx/nix-2.19.7-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=0eddf483dbe2f81d487fab8ac2e21b1f39a0519febe1c368255532ccbe7885bc
        path=bdvgg55zgyxism5qs7ci09igy3l1v4xi/nix-2.19.7-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=e478da658352d0ac41cad119107286ea3469671f2d0b554222597299b524d307
        path=bb767kbrl33szl56rlkg0v3p3dh0rvkf/nix-2.19.7-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=5c4d85c968c802d914cb48f048d67bb3dd13110287f17ac16004eefe0c6de245
        path=1hvwjd278nc67iai43abfq0vxhpvv0qp/nix-2.19.7-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=c309f4f7ded9d866e70b7d4060563783bc20d8172ef77ed1407f5a49646af333
        path=r0nd7simmwhrrz65y47xbgiaaxs0za57/nix-2.19.7-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=35bc4210048e40ef1049ee468451bc04023fff54cbf7c5946b4678c308f75864
        path=dbphb8d2y8vd293zhqlwag24plaijqii/nix-2.19.7-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=5bb445078537fd8998b4c1452d0c3d89d8e9e4e7483ce0689a9dcfe431d9d609
        path=9q1mrijg82nyylkzfql3mnyky7dyxkfm/nix-2.19.7-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-2.19.7/nix-2.19.7-$system.tar.xz
fi

tarball=$tmpDir/nix-2.19.7-$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 2.19.7 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