#!/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=eb745404810299c66ce215bb1f33a646da4e3426cd5e598d4042df927094c789
        path=s3178id9dh704rmwip9zkc53kgqzqkf3/nix-2.27.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=9fab02aae8815992a629f090f1037cbd2c7c1e9e8014833bf3c6ec45cacdc565
        path=9p4vvn0f0j6i9501wg4l7f4yw5d605nr/nix-2.27.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=49b98294c4797cbce52bb70012eb2d0a1dfef5ca7f7c51c5d9de5f1b4f92ff0f
        path=d7hzgskc2x8bwpiqn2l0s4v740z19zsc/nix-2.27.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=a010289458ea67cb286ad6301b66ef91a85cbd202d17e3fc00a6bb09c4368cfc
        path=kxk10cg4bkmznm3ra02xiw66q1b8k0h3/nix-2.27.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=3bf11f18e07b93ca5f2add87dca7b5d85bd9774ed1ed3db8997036e5449a4ce6
        path=g0f9b5qn66r56mifgsyxhd420gi1b07j/nix-2.27.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=577a4d1b45ea1af3b4e21f36566c3d8cf015a8f2d94d061267c1841295796b6e
        path=nimyi6xzj6d098g9djxr63rn74m65rzg/nix-2.27.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=db62e88a44d9f25c6433854f123930b62a3e3af0df91ea1fa9ba055a5171f07c
        path=303d2ddsbfd2gdwq0wkkcaa42lz9snj7/nix-2.27.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=9d7400a5c3bfc84893b1ed1ffa1a0d644bb84f44bb969d7da055f134ef468711
        path=4s43v1slz43pldsgmc7mb83knxw5gsx8/nix-2.27.0-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-2.27.0/nix-2.27.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.27.0-$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 2.27.0 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