#!/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=23ce50919b933b89b0dd4b0d5ba07d2dd6e4201a2f06b00de5388c0a4209b09c
        path=1qcc15z77jqpdqsp5k0k6rjmkw7f4zfb/nix-2.25.2-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=3ce95b7ad138bebaaac2be79a44d5c2b43a3e2483e36bc1c0821a6a9fc0e15bf
        path=lxb16gfx6bmnqdmy21c879pz8havz5bx/nix-2.25.2-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=8744e31c075c31272e7bab6995d5f15623a5de94f935a7a7420026d36f9cc90e
        path=idfaklsf96dbi7xy42a0bbmynvv4czsk/nix-2.25.2-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=6fcf943f47e5b0af0285720ee9e0a83ed8770ca4315c20589e23d334b6eeba80
        path=39lnsjhvr8lh2vwfhicb2rr5cyjmbb77/nix-2.25.2-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=e72bb87a8c78bc4d96710b742dfa841f342b038350ca265809df7a3eb50b2398
        path=b71slfhcs6i11q8zr15891j0ss7r4dv4/nix-2.25.2-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=6d17a3c543ec14df59af59eeeb0ba89b02411754128f5a276ff70a6d3dca25b2
        path=cbpn7058y7m1v3xlal4i6qy212ddyffb/nix-2.25.2-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=94b601f9f6195d100da48b29cca21d0d81ab77c0fa3060554c3e46a07cabb179
        path=z8brwk78bgzvs56hbz77rgkvkv28h1nd/nix-2.25.2-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=82355d662cae1f23ed1e22225203dca70c9012a2627b6a1c15bcfd3761849eb4
        path=pzpn97w5kgas9xfh4rir0b9rgh5v7j6w/nix-2.25.2-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-2.25.2/nix-2.25.2-$system.tar.xz
fi

tarball=$tmpDir/nix-2.25.2-$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 2.25.2 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