#!/usr/bin/env nu
# SPDX-License-Identifier: AGPL-3.0-only
# Copyright (c) 2026 MatrixFurry <matrix@matrixfurry.com>

# Replace content between `<a data-tag>` elements in a markdown file
#
# Allows you to directly edit the static parts of your markdown files without
# using templates, while also being able to update the content that is
# auto-generated by your CI scripts.
#
# This is useful, for example, to keep package lists and descriptions
# up to date, and is used in this repo (see [`meta/update-readme.nu`](./meta/update-readme.nu))!
export def main [
    tag: string
    body: string
    path?: path
]: [
  nothing -> nothing
  string -> string
] {
    let pipeline = $in != null
    let input = $in

    if not $pipeline and not ($path | path exists) {
        error make -u {
            msg: $"Could not open the specified file: `($path)`"
        }
    }

    if $pipeline {
        $input
    } else {
        open $path --raw
    }
    | str replace --regex $"\(?s\)\(?<=<a data-tag=\"($tag)\">\).*?\(?=</a>\)" $body
    | if $pipeline {
        $in
    } else {
        collect
        | save -f $path
    }
}