#!/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=ea568c6d0a6d75a64195d8d69ba51821751ba18d8b530a579aa962057137f57f
        path=39pbbypb46lf8m86mzca2yf0l2rn0xpg/nix-2.26.4-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=2fb234686a51fa0da116ef0142ac78fb9f3a7eeca5db8e59519215707464a728
        path=bwlr2pl84jbjlbh9ax6r5azvqg66yma6/nix-2.26.4-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=2b014677833723d473adc82d9a01728b73038483fed0e2119c980d940aaa0c77
        path=33bs770hbj3vrc6s4i8ryjlmd36n7lh2/nix-2.26.4-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=a82675891f6ff22d1662dd157cbcaa202c1b98c562db2b5c5c566d1119f8eb6c
        path=6phjzdhflnwbf9x7p925yknlvadf1f0z/nix-2.26.4-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=3670e3340d62182758fc785aa650ff8ab0f725cb32dc6602e941460db2945cff
        path=5np5d51cyar81inss6qqhpi2xqrhpn3x/nix-2.26.4-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=aa2762b83d5dfbde956856e5c1718e64b85873c115e52d47f5abc21f30981130
        path=1bcnpfi41wx7flpvq704840p1a744s7f/nix-2.26.4-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=51eeed131281b442f4ee8672d1c865fa6c3209f3fec538f67d8441261f2da059
        path=w1p6spws9mlvws52n0hb8brvrifpcbay/nix-2.26.4-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=d38edc453e35d216a34c8464430c727552fe8a4d3989875108f6012d8c8fd45a
        path=knmhcppl7hggbchifjlcn3291h9pgs3z/nix-2.26.4-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-2.26.4/nix-2.26.4-$system.tar.xz
fi

tarball=$tmpDir/nix-2.26.4-$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 2.26.4 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