#!/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=34fe86212dbca0854f687c868e95602067d297a09acfe6447f7cddf1735717b2
        path=2ivijq81yp4901p4yhzmxlay2gfr9jbq/nix-2.31.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=1ae6c7a6a42b834e67650551f1d18184d263b4a29f246cae7a314915525e5d1a
        path=c0c447bb4qjyns99ra49cksqk3gfby80/nix-2.31.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=e1a68f6d9976cc8797febd8bb9e3253e17602e0d664a777c6d286541d5db07c4
        path=dzr827qk5fgflfwsh0qhk6rbbk1k5pq5/nix-2.31.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=8e911f14a4b88915ada07ec811f2738788bd1be2ccc2a589825a3250e11b5b00
        path=chpzz1nvfdh9j7vz521px923ykldij0l/nix-2.31.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=6c5b6ae2593595a3af6723bed76f33a86fcbd9cc664fbc584149c4dfac6b41b2
        path=f24fh5maypifg0b4w61dhdrf7aj3yn51/nix-2.31.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=3298370ee32de2474920ab328f0bc04426610968406289eea8972be4ca2f93ea
        path=q15jxfdpgjvpsl8zjdy1ib2m29mc2k41/nix-2.31.6-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=35e1ffa61643659f0f92ee6b12eb9ff1a22e199cecda0266e9c1d507c4b16852
        path=w8rf7s02wask14vlg0m4ymb1bpnlpkp1/nix-2.31.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=0e77bdf1f8412554dee1c2d76c7024c79911f65b75007f7e44eb24916bdb340b
        path=za045clsgx7amjj5gjzdk9zssh4jnhsy/nix-2.31.6-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-2.31.6/nix-2.31.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.31.6-$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 2.31.6 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