#!/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=c46141848c51fd889e5e04601e7598782fd7a7b3a9be708d9b78dcf07662b240
        path=n5gp4kz5gk0by8y3jwxyn298n6v6vpvl/nix-2.18.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=894e88545775863078d041024552d8b5a739f043305615c22a6284bc95f9b8ec
        path=ha9ycrr4dd6jpxsr4l2ahxaxrma0p9p5/nix-2.18.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=968619f408d2d54ce3c15b2773a17061ed7cb5d385e953381a4323252842ecd2
        path=59i2nxsia8mxnn3ndcaq185h5hbgprhk/nix-2.18.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=3aa30d14323314024d6f1d4758c13b99d2b957fffd5218d49a089248f4d8a7ef
        path=bi5csad3ah5xj7m5qa62d8k0n1zarnwq/nix-2.18.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=6b453460bbd57338bf91409e97f3729d12548e853812803b2ef6f4ec91c78585
        path=88r02llhn3i5jm8gdj5amxy1a8ap48kr/nix-2.18.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=ba07323047adb1b995016cfd595f3a55498cc85b92405a84933b111604b3af57
        path=7013y0v3dqv9r16ms6hyxj0f9794llgv/nix-2.18.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=81afb16f063a213b935a5916e41c68453387cf35f4d13b6826aa5ae501556749
        path=fgkwspwz1d5iqhsh6lxm53b8461qd3ch/nix-2.18.6-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://mirrors.tuna.tsinghua.edu.cn/nix//nix-2.18.6/nix-2.18.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.18.6-$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 2.18.6 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