#!/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=a7fba65eb659ef9293e3ffb5a40131f592353b4433f378814e202278ead25261
        path=vxjl3dxzf3hpwvbjlsa8ph94qvzw12jp/nix-2.24.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=297663df8db4edcddf07e4b2312a1b1461c766b780f2ff8f24d06ccfcd4cbc9c
        path=03wz5qi2fnp8mlckxs7yv90ajdrmbpnw/nix-2.24.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=ed5bb9433e1dcf9000ab78e93719f099855f9cc8bb6a07eb44f6b6eb12f4d775
        path=hmb6rinsrciqxlwbjf8f1936w5ziq1d8/nix-2.24.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=525cc8a0a56feab8d4a8b337ca82c82a6524147d308798ffd14ecdc2aa2cc35c
        path=7fqmydva2hm5q36ck4xnxs45vwjw3868/nix-2.24.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=d6729276ecbd94e00fa13fe43e6512bf7accb0040c863da9a7d76742fb9d76d0
        path=7vidl51sn6nilmg3ivwyw1y14w73b5r4/nix-2.24.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=c4663509131c4f63b8415d36f724d3253d2f9edb0736a3e758ae811c0c28b860
        path=mlp1cz5s9sa9j50hl3jhc5rw6ddlrc6g/nix-2.24.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=d5392ec6146d5f33f1006f2bc1110613aa59d2a608822ec655cf675861f9ee5a
        path=qqzqjdvjsnrfdk7kn2yh5y28jvsv91q2/nix-2.24.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=400fde355951202beab1fb1386c9710f3cbdf67501ceccd39f419fd218235b00
        path=rmmmlylkhhwb4y6a7baxh9fj84318nxb/nix-2.24.0-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-2.24.0/nix-2.24.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.24.0-$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 2.24.0 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