#!/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=0956dfdd28f6ecaed23e905b11565a08cc574720c91765ac4be1c85135f3fd17
        path=d5n95m8b1qlbrjz4f26jpr223klsvkgf/nix-2.19.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=a9e2f153448a41a5b9f25c4d8d45d1511b285b6d3dbe78e7cf108c3add7e7c87
        path=skkwhhbvx80ycn9camr3wwabn0msrlmc/nix-2.19.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=ac533908df0fa82ddf9dd4ef09ffd2715b878f902bbe4700ba330ef823863333
        path=kd1jb59yysvlm2s7ywwqjnm5j2p1cy30/nix-2.19.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=985b1df1841e528cb47004ef9622ab857ca4f288e0d421e73280cdfb75605ce7
        path=mrgw6422k5n4zz3a0gh4c7wzg8iqjixq/nix-2.19.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=bba4bb3154af88d93179fe6cf2f91e8a6f7dd35cefe0bae339b807e2f38dc686
        path=l5xpnlkks1pmwlrap1807ixszh83wjy0/nix-2.19.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=c61c1a9bdef41a0e695a806e46aa482c9a0dd5fda6e01e2c922dd25488a84f31
        path=g0jiabyqcl0bp37s5ijgyimqg3z64969/nix-2.19.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=e1ae612b8241ce471d69bc0d9812336da1843db6538d1875ee714a31f3522ae5
        path=3vf21m50jicy2js53hawsqia80ay9w43/nix-2.19.0-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-2.19.0/nix-2.19.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.19.0-$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 2.19.0 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