#!/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=5c8080b8cc7913a8c6f584aa619ca0b3326ff944b7676dbbd6a1bee498a866bb
        path=l36vikzvl05z6npajd64ipkv3y95vzy1/nix-2.18.7-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=5424eb5a4e96baac50adb2e490f343f04f52a8db869d6656326188b0d751be43
        path=cl8naiqhzy9gr45pr2sad1x96lrg078i/nix-2.18.7-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=596c4db55294a4f802389f822355aba1a271059daaf171b1eec02da5be3c8eaa
        path=1ww9n8bqmqfxz3f00h7rrji8i90h1hg5/nix-2.18.7-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=19ae56ce56541445469f1fb4a7c5abab2587968999f02a67a43fe200bfcd2721
        path=6h944fwn2sdmafgkfzbyb055r5n3836c/nix-2.18.7-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=3a9b5ef1277963ae7f30be2b46e75de0b79bbbe6a293431a7a0c9923b5125bf1
        path=m6r98n1l6kqdgv2jgb9mbk9gxl0ywvda/nix-2.18.7-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=012650df6a2df413850e27d1c5fca60a0923943b8528b8a3606131a71d8d6727
        path=fgkr2hs9wjck95rfs92ry35xilrdcdpb/nix-2.18.7-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=ff6b0f81555c6024990c2420bbcc5589230f14c6a48dd4833031c8f74e463848
        path=zlmhimqf985ki05mf7n8w8q9l8hn0i9f/nix-2.18.7-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-2.18.7/nix-2.18.7-$system.tar.xz
fi

tarball=$tmpDir/nix-2.18.7-$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 2.18.7 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