#!/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=94430a343cd7b27b533683afce4807644bb9a10865d27514841dfe14ce0dec5e
        path=p6cwzaxlpiv1115cvkb7f4pgl6mla849/nix-2.24.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=83718a26134548b52d7a7160c3aba56b777b605e8634539b8db2ce9559486b1d
        path=3qxxinl481zlkf7zjgjw3g45vpavdrpz/nix-2.24.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=0bc62aacbe66e9c84c1152269f56e135ace894aae1111555ab799dd3f9c9e998
        path=0853izsk1mzvklr06myzvgz67jq1hdj4/nix-2.24.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=2e2f47acbb992452d6b189d367cd1f39eaf8164a57b8f4c38df926f921e57950
        path=3jz4ail8s3pp7262p9kqdgk2wyq1g5n3/nix-2.24.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=e673dc55932f50953a313ceff4bb7c6e559de53f964ea4dcbfadef7ff6d8af4e
        path=1ssaja0p6x0grajidm387vvzvw2jjkky/nix-2.24.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=0f938f5581a79f1312bea2e3f7aa898cb0a73962f6e79f1f700f279c6ef984a0
        path=kji1yp3ap9pv181fz2xxr8f2ll6ip05l/nix-2.24.1-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=7eacfc4e0a2d3793bed2fa3e41c5a94216f7f55faba2def3f7d7c9fbb206c92c
        path=cll5b3cql1p9jcyndby47x1wa132irsg/nix-2.24.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=03e0185f28088194850d8724981cc14be54c303f3c169d323f55710a8a94c978
        path=aa13b9j9q7mx24x6gp4si82hzfacamxa/nix-2.24.1-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-2.24.1/nix-2.24.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.24.1-$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 --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 2.24.1 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