import { stripVTControlCharacters } from "node:util";
import type { StatuslineInspection } from "./modules/inspection.js";

export function formatFooterExplanation(inspection: StatuslineInspection | undefined): string {
	if (!inspection) {
		return safeLines([
			"Footer inspection is unavailable until the TUI footer is ready.",
			"No collection work was started.",
		]);
	}
	if (inspection.showing.length === 0) {
		return safeLines([
			"No modules are currently showing.",
			"Open Modules to inspect empty, disabled, or unreachable modules.",
		]);
	}
	return safeLines(
		inspection.showing.flatMap((module, index) => [
			...(index > 0 ? [""] : []),
			module.name,
			...previewLines(module.preview),
			module.description,
		]),
	);
}

function previewLines(preview: string): string[] {
	const lines = preview ? preview.split("\n") : ["(no text)"];
	return lines.map((line, index) => `${index === 0 ? "Value: " : "       "}${line}`);
}

function safeLines(lines: readonly string[]): string {
	return lines.map(safeDisplayText).join("\n");
}

function safeDisplayText(value: string): string {
	return Array.from(stripVTControlCharacters(value), (character) => {
		const codePoint = character.codePointAt(0) ?? 0;
		return codePoint <= 0x1f || (codePoint >= 0x7f && codePoint <= 0x9f) ? "" : character;
	}).join("");
}