#!/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=2ead868a2d1fbbafedd7ebf1b53d08ad896ce654bdb0d7dde55385738d96593a
        path=c2vn3nsl97a3lgmdhxhjxdcy9bsm38rp/nix-2.25.4-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=e0ff5718e185996e3020384838489b0b6c4c64f3bf75773308c18e7851676eaa
        path=dazn76ayfnkf56wv175bp1kh0l80img2/nix-2.25.4-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=113e583a0118d3155a8264c33497cd12266402dee5c8dc92289f86c7d52af1eb
        path=xfff3vabqb7mk8rm4dwmsi48mpd8k4wq/nix-2.25.4-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=c0fd6bb42cf362b89366906b561f008c9996fc5a2a6890e63142791c37f5dc64
        path=rlngj1l9g07p8421gklaz22faqn5a49j/nix-2.25.4-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=cbd671889ac8fd27e85ef566d82b9096356f79b2aeb9c4941a38d9914a4b5032
        path=kz0id5br1pph4xq15d4bdks3q62xgmja/nix-2.25.4-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=6284600fd6c8c4ccd33edb576034a64c01c441a1704a4125bd6649a472ccb934
        path=r8azn0bcv87cw090k2v99s2imzakpvz6/nix-2.25.4-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=7b69ddef20dc7ecb6eab5efa2deeea7715f8899d071b5a038f7ff0c936072b9c
        path=7yjc7bf2xmdr0jfsdpyx9rlrhmg2af03/nix-2.25.4-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=9b5e6db5ff8c45c8450601a0c43dcc526bf9d8858976b52b8a7118f6d7562868
        path=iqa6mda240klb3ymfp4l7kgm0d5l7wlc/nix-2.25.4-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-2.25.4/nix-2.25.4-$system.tar.xz
fi

tarball=$tmpDir/nix-2.25.4-$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 2.25.4 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