#!/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=75f18f5d567bb8c7b5d62155f8c852e62ffac0c81acda02f52b998281e3603ce
        path=acdc8v68p4v4l24bkjmf64g7x2rq3anf/nix-2.31.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=962ac24cade53bbef458b49679de8570e144f10d4a28f699d47ff6ae381023c2
        path=gcl2ya2lww0hnnxzxqxbn3ylzw608y2b/nix-2.31.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=4ae8cb26dada33765f3068d185b36dcfe23efba2ba678048b70d36d8b1553850
        path=xnzhs89y5if60z2319z4zw7vgz2ikxwx/nix-2.31.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=6b6596272644df1accdd2db49036291d822c83253f3c1fa22a5ed10ad82d50d9
        path=ijabzak4wxmwfzkkb8w4zkzmzip4y56h/nix-2.31.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=5fc40605b2d223afa2cafff6ee6f1463fa1d12079a0241b40228bc900f27295a
        path=9zfbgah32giikw94a37xawvh2r6piq98/nix-2.31.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=2249831144ae7e4616933e45eeec8d2aeffc834c9fc247842b125c3d053c19ed
        path=rx392w64rnj7whw1hlqcg5hkxpbzrsqk/nix-2.31.1-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=db8a87a920f59dd2cffef9def40bb7a3f64e3150fbadc889ca0b15ed70235652
        path=m5m81qjizs2id4f6c8x79nnc09ib1zxi/nix-2.31.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=497c487ec73ce6fe027f4ef76a04dde8b6774ba14e479fd5ec96c45cf5e4164c
        path=v6jy7h0gkrvihrq7qdcpn312jan0mckv/nix-2.31.1-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-2.31.1/nix-2.31.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.31.1-$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 2.31.1 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