#!/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=65cf7fe9e7e7011cf3732c7f9a51d379d69241017b356b6ab354572b038ccfd7
        path=k51vv8b59cbjgf61l1klx6lqsa8mb0s1/nix-2.21.2-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=a7242f470d2d2f8bf39aded6b02b2735477ecd4ebda2d0df08d65be793820686
        path=ghjnipjmah78ryh6j5bm0znv46cjbz21/nix-2.21.2-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=ea53dc4b101add1a2e31f6b3216ef2541541b5a180533a614df885a43542fa6a
        path=q5kxiskn9m26ajjp8q0aqjwmjiqr3byz/nix-2.21.2-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=1791ee504d1711994fcb1cc4de20677bf683a4f5ebf33e666f5d6b59c7eb9f7d
        path=6crzg8j3ya1g4rq5fizbqdjp7fwds8dj/nix-2.21.2-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=5818beb5e93686949476d3e847f3dd71b2003ee073554c47bf5b154226559ab4
        path=arwzs2z8qcsl45392k7hpqr7qyb2mf68/nix-2.21.2-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=d4ba797ec4061e84b3c54bffd7ae6645f5199a991d0888a8adcbe686dad9edb1
        path=s0wa36rn6xxj15vc2g5pvcgn0q5ki78f/nix-2.21.2-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=4d22218df861a574afcd4008be7b0a47c50b8cd14eed65eda0c72cc5918357da
        path=xsmwdm9d3br9mhi14msbf346zfv7v56l/nix-2.21.2-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-2.21.2/nix-2.21.2-$system.tar.xz
fi

tarball=$tmpDir/nix-2.21.2-$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 2.21.2 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