#!/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=08a2f069480392d88a1fa05c39add7647980e48692157dadda85ba200e18e13e
        path=vnnmc2ffh43k30qayv7fb90p9ml3vrmv/nix-2.19.5-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=7ebf65f8551bd3dd13357abadaf9898fe52a335263d7c4d61895e5b96f4f961b
        path=vzrq3jq0d7k5jyy2nldadda5ka8nka9y/nix-2.19.5-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=23423406c5e7bdba20ec2228d3729b52be65e6961656afcc8237653f9460c24d
        path=qqs7m7fw7si7vclys8f31y2w4bd8snvp/nix-2.19.5-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=7ad1d8cde47ca6970ad762c591b62cfe7aafbc8478c7a8d15f2d94748ea13b49
        path=s4h11h6aprsvdkx03c3lwgfqha0l39ls/nix-2.19.5-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=bf99d64bbf03ee213c81d6d665ae2f8c7e4fe74ecf01cd232fb55fb7eb087063
        path=nxwgm6a39pnbj8dgsp3zbnn0yy21pxdy/nix-2.19.5-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=409fcc99300c0a9e2b4a15939e4470f0e0ecf468a4863ebc02013678b10b5186
        path=yj44b6vlki3s12x9ial46zhmjmkcs4m2/nix-2.19.5-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=bf827fec29fb12731ec3fb845bb93def0a12305832809ce53c7feb82af9013ab
        path=bn9337nh9b6v1fvcfhz8alh17qbaimb1/nix-2.19.5-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-2.19.5/nix-2.19.5-$system.tar.xz
fi

tarball=$tmpDir/nix-2.19.5-$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 2.19.5 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