#!/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=d2da118cd2dff31562fddd576a81d3ea216f4eff967a371e0224fd4bc045dd29
        path=2lijvrvqawzpn89c1f848a5hzkj51sfc/nix-2.15.3-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=c6574fff78652e941afc8c4219509e65948cf7052f425e4e0e977fde5686a328
        path=qd3qkwmlxq597w5hpk07v9y2njv4p9cm/nix-2.15.3-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=98a2490dc77e4601cf2ab2d79336b3aea0f98f93ed72d9b13ba2e856337115da
        path=zfvcii2p3r5q9l2x70kv0g2c4q425h53/nix-2.15.3-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=670f7ea3cbce95c906f25d2e3d1feeae85d5d176840a93c097a5dbf5e7dcd484
        path=lfn8x2kfiz46p4pc5xvbxq96xlmybf5a/nix-2.15.3-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=6e52bf37e9ba2cbdef7e47cc5cfb19b62c37cc1840fd87fa2eb9eb6e19085236
        path=abpz913jjjfw19lkpl7b30mwdgdypkjf/nix-2.15.3-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=191e5cb18bdd378c10890600ff5e90a73825f5dedf07fd7a4ee5a5a01007de90
        path=l62w5pg3fg8czaj51w5j0hfrh0ib5gfp/nix-2.15.3-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=f991c09fcb9aa79a10e08930dd5134bd4d7f2838efbed6d772330bfa6efd4fd8
        path=cb5j6yc670fzjka4an2s1kk1c2v9zqrp/nix-2.15.3-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-2.15.3/nix-2.15.3-$system.tar.xz
fi

tarball=$tmpDir/nix-2.15.3-$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 2.15.3 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