#!/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=207f510adf83950c718eb880f7adfc9ea2e9fecd9c90ca3ffb0f39d87f0deb3e
        path=6i6m15mq0wwyz8d214rvqbr4i1p9nqhq/nix-2.28.6-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=efcdf8b40121083c2dc1f1045787c745073ce3e47966dceba8c982658b25edbe
        path=42bwsdqhim8a4jdws7hcv3mkw3jzk18j/nix-2.28.6-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=fe68bb38f6ab822e598cac2cf6a7d7f26feb9e012ad062df6a3809c4ea0faece
        path=zd15sf8r794f9r3ma1n8v98ff07dmb96/nix-2.28.6-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=5ab9b820aebdee5eeea7badf6e1f2100e56865a8f70ffa290089afecf2cb2b4e
        path=6iyvc6dxas8rg0la3lyzmf4hp23vivwn/nix-2.28.6-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=05e1439fe591442474e5dd21bbd117133cc75adc8e4aadf0edb624bac29f8e43
        path=f7v1qgki9xvglss5kvb4y9wf0jvhq3b3/nix-2.28.6-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=4f80449b08989a6594440386b0d29052352ad87ce5c6c5a712a66fe13c80446b
        path=aw49yg0iiailqx7gaf3j66a9k4cpkz2d/nix-2.28.6-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=96f49c610415ac1abf14143b8930762dd55cdf0e1eaa46641a91b0b49c0898ed
        path=5bp8v9dwsyyrk95n870fh44cdq77fsnj/nix-2.28.6-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=a031b75ea6a470aca6ab75669052b34b4fcaf945a46413d7309c5bc22206a04c
        path=ilhd4m88xk71bzzjkvril6d7zgaspygc/nix-2.28.6-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-2.28.6/nix-2.28.6-$system.tar.xz
fi

tarball=$tmpDir/nix-2.28.6-$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 2.28.6 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