#!/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=fa2d848b0e155b144b6e5e312f04306b2136fa26ead168778909bc13dd9da4d9
        path=i2v9x6gicrw2hbbnsr3yxmfjmfqbx31p/nix-2.31.5-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=7334ac2a373168140ffba35d2f9d72eec20e0047b6f57fd76d209568dc1b351f
        path=szgr26jggbccsk815mff0b3d83qwlvvj/nix-2.31.5-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=57c9b68619dc623516189c2a306603d55da7e711efced1550fb1ec344a4375a1
        path=3ymfpysbfv3cra5azy1yh4ydwlqfx54b/nix-2.31.5-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=27676d2ccf28b85bd9fb8ec6a20781eae1b6803a7ba6c98ebdbaaec3c14d97a3
        path=mf6s9nm3xswzhm9y17zizix6gljgzf00/nix-2.31.5-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=77ed591d0c4085c1bd0e5249d78ad6c6a6cc22ad2e82e740545566c18c2e4d18
        path=fgyqkh89i8y8x7vc78yhfwhmadhry824/nix-2.31.5-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=b7fb6a07905d19a7075dae7eadca68e27c8e1329501b19c83374441c39c8bfc0
        path=jsw50zcxzk7iapgac62qabv1lwzsylpa/nix-2.31.5-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=696c079abef4da5cb3dce430dc4a57a4a695868ae2628bca62254e24d22feaab
        path=q7xcvhrh0gkdz830s7ngjyh08hdp1ycp/nix-2.31.5-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=e2b80dd40fd62cc7d4c2ee5e4d39e841cc7d113f91f7172007988fe17a394bb3
        path=xycvzx9s479kb4a6xx68h8aplg3clz5q/nix-2.31.5-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://mirror.nju.edu.cn/nix/nix-2.31.5/nix-2.31.5-$system.tar.xz
fi

tarball=$tmpDir/nix-2.31.5-$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 2.31.5 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