#!/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=4dc7deb3979b999599daf0f1a5dd9e4a62835cbc26b87ca8624b8fefe8242f53
        path=ii1i205sxgp18b5ggcvq0i65g7slxavf/nix-2.25.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=ec99374d4cc3c4d4ea15a742885f0f9917d0c154373468c88a023b1f6d557126
        path=65lcqncq40xa3f745xqlbyz6s3s3z266/nix-2.25.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=e2db1af8842f6a55a4499127ffac364c69b12f31463520dee594f9dff1e807ce
        path=fsqiv8aaj2dvcfkk50aa4pg8syywc2p0/nix-2.25.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=8585205b429b3e914fcbfa50bcebd7336dde0314d1b89f58a8f8a6dd61cd97c5
        path=kw5hqj1ayrq1s6mv99j96nwndy98xf1y/nix-2.25.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=d5cc30b85729b810c7dad3deb5fbd3371b1f94f0447e78d69acfd282e9a39822
        path=5vkpn7q7fgh5q24xj9n5dzyq5v91akr3/nix-2.25.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=42e601f06a0e16064784fbd68ac8d6601d9e065dee62b22da0eec777506d8418
        path=fxz2a4jwq37y68qlpxg2pqcf49a7p1k6/nix-2.25.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=4d3d0f6ae39d01d4d6aacb8ce6d276bbd94b71bd2d582b15286a9c84004d53ec
        path=70v7zagfk134cgvpm94lh1rqbhak9nlw/nix-2.25.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=8c6b4b57581173003ba5c44aeb142d9e1f8030cc613cae58aadaf442e4feee39
        path=84f4g5l61sxip952n09q7ddwb2lf1jqv/nix-2.25.0-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://releases.nixos.org/nix/nix-2.25.0/nix-2.25.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.25.0-$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 2.25.0 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