#!/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=089323a7b9cbfdbb9e20d9f504b251e0b3416d2921da587b8c3a4c9f9261a648
        path=r14fmgzmhcbfhs02bmy1zswwhvpnvjsw/nix-2.25.1-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=34ce90acd902bd7c2f53a3a095b4fbc96de8f0ec9bf7f67353c9c1d5d99bcae4
        path=d495xj44wzxahwjbcsyfq18nz4gpqffb/nix-2.25.1-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=177f15710b1ce778875d8ac76648adc721d3d07b1e10bea8a62f708caadaad3c
        path=h0sd2yji4dl0j3is3zahivqmzmd8z28n/nix-2.25.1-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=89ff9ed116f85e5694cdca9daf7393ee33145459fc2523935a3e17c4db18f6d8
        path=0s8pivvffar53mkyaw50z85qdd38v2dy/nix-2.25.1-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=de412a7e2d6d9d44ebdbd1fdc1646a7b81cfbd76f1e5d3add325939ce0878aae
        path=jqa7b0s8jmb8723dxgzjfxa22368znd7/nix-2.25.1-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=986c246a4eb7dc927210359762bd71cbadd5922b211d182638386a3e13552a28
        path=0230j7vmvlci7ppqx4acway10g6vljka/nix-2.25.1-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=5449d3941db1732fe234a98f2484b1f34c99109b1d7211179a5ab13b2a6a849e
        path=jg7n909qc2j2v6hkm9g8w08l7pxagz5x/nix-2.25.1-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=ee122149e736a7becc8cb6d79859e646a208b462dff889ad4adb8de1d3674d3e
        path=jjz3d3a975l53lj079sga0lk61wx7ama/nix-2.25.1-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-2.25.1/nix-2.25.1-$system.tar.xz
fi

tarball=$tmpDir/nix-2.25.1-$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 2.25.1 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