#!/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=691bbb14a5ec47df366d265838f385db346a0bfce992f360733829e54c5e3a9d
        path=54p0csi5726cjgajnmwkg91979sy7i07/nix-2.26.0-x86_64-linux.tar.xz
        system=x86_64-linux
        ;;
    Linux.i?86)
        hash=9322c1df61460241d24bc7922812a77f17dc6b8280a33714ec8ffe710a1e650c
        path=jmsgdhsj20xx7d41x74p1762ypn08vjh/nix-2.26.0-i686-linux.tar.xz
        system=i686-linux
        ;;
    Linux.aarch64)
        hash=e65d8041838b23a70bc0bb80e28f2c4d4e5d8657f29652e35e3e860ed09ff4a5
        path=iz2nj6471azl2ahwajxjh1famb5ll3q5/nix-2.26.0-aarch64-linux.tar.xz
        system=aarch64-linux
        ;;
    Linux.armv6l)
        hash=b8fa755ec71aba6f0730c967eda686afb0bc4a2bc7fbf5ed1b139633437215e2
        path=4f0nzy6w9qjz5ryav5qbfb742j70qq2k/nix-2.26.0-armv6l-linux.tar.xz
        system=armv6l-linux
        ;;
    Linux.armv7l)
        hash=670ca680a285ad3916674015f4efe4ed17e243e3df3e801ef84c3e1305fc16ab
        path=51vsgd1yk36gr2dbry5hz16igzz83cav/nix-2.26.0-armv7l-linux.tar.xz
        system=armv7l-linux
        ;;
    Linux.riscv64)
        hash=344272c491e5054683b13e6e4111a60ae3200a382c206b992ecf74d8452d3241
        path=my6ni1v8wi56ii6rgm1nrvr31ljny503/nix-2.26.0-riscv64-linux.tar.xz
        system=riscv64-linux
        ;;
    Darwin.x86_64)
        hash=a858d95ffb1241a52e52cfc2c862b23394304fb0d4e3ff671156f84c3e2c3896
        path=8pbrl58lf6xp9mcbi60810a6sp2115dv/nix-2.26.0-x86_64-darwin.tar.xz
        system=x86_64-darwin
        ;;
    Darwin.arm64|Darwin.aarch64)
        hash=f777b01aee89964ecf3ea4b2aba82a1a3d817e400076facca508fb2020e628a2
        path=ncwpnc1lakvs1q19n7x64fry4cxsb3ji/nix-2.26.0-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-2.26.0/nix-2.26.0-$system.tar.xz
fi

tarball=$tmpDir/nix-2.26.0-$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 2.26.0 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