#!/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=9b1ce0cabe4c315e0e65029d3e111f741b911a3362e452f487d6c15757b9b605
        path=m4pz8pvpvqp35kxvd95pfd45ya1cv91w/nix-2.20.7-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=d931a05c076ca0684827ba7fad57bb72e6142cd3b0f118ea8a029b41ec9eecf3
        path=g0prddqlvb245dy2jr2qs2zsmcqhwksn/nix-2.20.7-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=cc88fb9df164d1d04cc3bfa3a1de4878280270fcd2da939ab63a732bece61a28
        path=jzbpxpw6bmcbd44qw19rrbajwxm9pk95/nix-2.20.7-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=827105e4c12367c07db9642d4f1857d2ba4a97851eb9dbada6ff2ad165de999a
        path=bxf25rmdh3fmwis0fdlz4y1qvf9y2mh5/nix-2.20.7-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=d3d2abaafb23e74ea9fe03eaddc9d1de8c02edad85c321559c8895c6f356f40c
        path=3vh07a3j900fzyds8vwdf5azwfw25xim/nix-2.20.7-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=80cc6635f23f016d4e78f51d59016b996e11b61cb8ff75e48e602a49ac51d0df
        path=afhmiwz1wifyd6xg48mksdphi72lvhaa/nix-2.20.7-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=3249e9e9f03d135b974c24d031e98dd2c9a57655f7395883fc302ad193dd6c48
        path=fhgkaap3ykwg3ixdvnzdr2xn764klapp/nix-2.20.7-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-2.20.7/nix-2.20.7-$system.tar.xz
fi

tarball=$tmpDir/nix-2.20.7-$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 2.20.7 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