#!/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=1ddc10c0f7799408c4d72db6eaad6fefbee6d07dfc1dbf05c242ae75d637966e
        path=x94v26mx2s6ypn9fqhp4cvnwgx1791v9/nix-2.13.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=4240ee96d518a0bff77888e982b3b3c19400b9bdd654fe677b1c31e650a94d09
        path=5znv76w0q1dqxaqqpswvl4maisf7dxhj/nix-2.13.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=ae12a43dcb04ca07cf93ef40e0890c7a00b49e62253c45419966c20083bf6f3c
        path=0ih6xrh95kw1mszfnnfbjhakd840sv00/nix-2.13.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=e2d268bb642c4f2e549f72c2e1e1a108c378797d0c66cfd22f3d2a0251dc9767
        path=hnl2w1cnpbcnhdkimbf5vff4m52mc1xj/nix-2.13.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=b0e16ee608dfa3b330552afae2563f39d86705b5c4a5956f07f550214335736b
        path=mg1xyrr0wzjr0avybsl073qz7fpg73s0/nix-2.13.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=af83026dbdce11969f2b77df02b637ee49ca68311deeab6b32a53e61505561ea
        path=caviip4a8rkzzmdd5kifbw5vwsycl2ka/nix-2.13.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=7974c9f40bef43339c50a513a0669b362e833221d87ac32c63496c6500668285
        path=3w4jy1f1mg2xngqxbv9hbw38aph040v3/nix-2.13.6-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-2.13.6/nix-2.13.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.13.6-$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 2.13.6 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