export function findTomlSection(config, header) {
	const headerLine = `[${header}]`;
	const lines = config.match(/[^\n]*\n?|$/g) ?? [];
	let offset = 0;
	let start = -1;
	for (const line of lines) {
		if (line.length === 0) break;
		const trimmed = line.trim();
		if (start === -1) {
			if (trimmed === headerLine) start = offset;
		} else if (trimmed.startsWith("[") && trimmed.endsWith("]")) {
			return { start, end: offset, text: config.slice(start, offset) };
		}
		offset += line.length;
	}
	if (start === -1) return null;
	return { start, end: config.length, text: config.slice(start) };
}

export function replaceOrInsertSetting(config, section, key, value) {
	const linePattern = new RegExp(`^${escapeRegExp(key)}\\s*=.*$`, "m");
	const replacement = linePattern.test(section.text)
		? section.text.replace(linePattern, `${key} = ${value}`)
		: insertSetting(section.text, key, value);
	return config.slice(0, section.start) + replacement + config.slice(section.end);
}

export function removeSetting(config, section, key) {
	const linePattern = new RegExp(`^${escapeRegExp(key)}\\s*=.*(?:\\n|$)`, "m");
	const replacement = section.text.replace(linePattern, "");
	return config.slice(0, section.start) + replacement + config.slice(section.end);
}

export function appendBlock(config, block) {
	const prefix = config.trimEnd();
	return `${prefix}${prefix.length > 0 ? "\n\n" : ""}${block.trimEnd()}\n`;
}

function insertSetting(sectionText, key, value) {
	const lines = sectionText.split("\n");
	lines.splice(1, 0, `${key} = ${value}`);
	return lines.join("\n");
}

function escapeRegExp(value) {
	return value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}