#!/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=e72114e4858b01e1b44048408ec1c21a988f4aad10559f1a821664dcc4e5b27d
        path=xhnmj5qfvy016acwbvfzvynx444hmz45/nix-2.5.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=72b73f7f6b757ed45bce3c4fd22e6117aa6dcc9c36083462dd59e9a1258aeba5
        path=s6k7m8ki8jrk8k8gakrs6zqm88z7b7a0/nix-2.5.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=5cd83ba4f4e8c7f9350ad392acc24940d7ddf0be12503d5719a5ae943306792d
        path=facx9jfwad60lr6vlhh71jgy7x09kg2w/nix-2.5.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l_linux)
        hash=1b3bdc3e5c67855365e9dd9f91fee127d45aa36e03386852742c8a6e4f31963c
        path=zz8pnbv5kaz3yr4jx0c20pa0x29viw71/nix-2.5.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l_linux)
        hash=4bde07a9adf7d59f432f117b9cd5db7612e6e479594c5023bd4fdd38e63e2e5d
        path=b35i9mlniigb11ddr5vc11r0rz044m9x/nix-2.5.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=b84f6acba7ad0e27c46b87151d4ed4810af29595c76f5af33c6dedf28559aa4a
        path=fh7dr2g1c6aldwb1jkdgb9nzqaabfqxs/nix-2.5.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=911ba8bdc4852451117bc5609588ad22043b68a4f7c4495d89c80289a83b1e3c
        path=7wzj75450x4c9sg7aai8p9pq19xlf03j/nix-2.5.1-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-2.5.1/nix-2.5.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.5.1-$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 -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 2.5.1 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