#!/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=3715d7812c6c959dccffc5d532f7eea68640d6e1c0cc25d14b20af4b0a365215
        path=v7vz586by5r34jfdp1bdj2yxfs3bdjxs/nix-2.15.2-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=feda0682332c6683acd9ef8fb07ae82c4450f8fad1c304c69657a696a46c7eb8
        path=rm83r2d5j3zcff9z177z5an2gx46ynd5/nix-2.15.2-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=5d7c110498fb541e4d332000d5de4ebfe710e699f104d64c7413b6590ea8352f
        path=asdah0jjq30i40spyip4imf7y5ram6br/nix-2.15.2-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=4415f1432a46bbaccece0ed5e66a1df9e300df7666890516e57fa98b5fd42c06
        path=zcsr8c6liqrl55z7kbl1k8sbaa8lfvbv/nix-2.15.2-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=a89eb3f6d250f8b9d76b1be7277dd2e1886d73f9c21d2e49756db1dae900beb5
        path=mbg62gyh283y9lc77gvhq5bj4nrxn034/nix-2.15.2-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Darwin.x86_64)
        hash=03f0c880505c888a7b3587c454c31d427406599adc700bf7ce61eaa15d5d3871
        path=5rq3b80k45wk1f87whkrpavvn945dnis/nix-2.15.2-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=23ca6d4c3e2b3f4a0efc998077ed57402120ec1cbbc03beb380eb31036814f75
        path=f9rbmg2i5i42d3b6myliadb9hx5pd1r0/nix-2.15.2-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-2.15.2/nix-2.15.2-$system.tar.xz
fi

tarball=$tmpDir/nix-2.15.2-$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 2.15.2 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