// Inspired by https://github.com/remanufacturing/react-truncate/blob/0ed69b87021e937c7768dcfee29c0289b2153788/tsup.config.ts

import { type Options } from 'tsup';

type ESBuildPlugin = NonNullable<Options['esbuildPlugins']>[number];

export const NAMESPACE = '@preserves/iifeExternalPlugin';

// NB. Make sure the keys of `Externals` do not contain any RegExp metacharacters!
// RegExp.escape() is missing in node.js as of this writing :-(
//
// Keys are module import paths, values are global variable names.
//
export type Externals = Record<string, string>;

export function withIifeExternalPlugin(externals: Externals, options: Options): Options {
    return {
        ... options,
        esbuildOptions(inner, context) {
            options.esbuildOptions?.(inner, context);
            (inner.external ??= []).push(... Object.keys(externals));
        },
        esbuildPlugins: [... (options.esbuildPlugins ?? []), iifeExternalPlugin(externals)],
    };
}

export function iifeExternalPlugin(externals: Externals): ESBuildPlugin {
    const filter = new RegExp(`^(${Object.keys(externals).join('|')})$`);
    return {
        name: NAMESPACE,
        setup(build) {
            build.onResolve({ filter }, args => ({ path: args.path, namespace: NAMESPACE }));
            build.onLoad({ filter: /.*/, namespace: NAMESPACE }, args => ({
                contents: `module.exports = ${externals[args.path]}`
            }));
        },
    };
}