import type { CodeModeToolDefinition, CodeModeToolIdentity } from "./types.ts";

const DEFAULT_TOOL_NAMESPACE = "functions";

export function codeModeGlobalName(toolKey: string): string {
	let identifier = "";
	let index = 0;
	for (const character of toolKey) {
		const valid = character === "_" || character === "$" ||
			(index === 0
				? /[A-Za-z]/.test(character)
				: /[A-Za-z0-9]/.test(character));
		identifier += valid ? character : "_";
		index += 1;
	}
	return identifier || "_";
}

export function translateCodeModeUsage(
	usage: string,
	toolName: string,
): string {
	return translateCodeModeToolReferences(usage, toolName);
}

export function translateCodeModeToolReferences(
	text: string,
	toolName: string,
): string {
	const globalName = codeModeGlobalName(toolName);
	if (globalName === toolName) return text;
	const replacement = () => `tools.${globalName}`;
	const escapedName = escapeRegExp(toolName);
	let translated = text.replace(
		new RegExp(
			`\\btools\\s*\\.\\s*${escapedName}(?![A-Za-z0-9_$-])`,
			"g",
		),
		replacement,
	);
	for (const literal of [
		JSON.stringify(toolName),
		`'${toolName.replaceAll("\\", "\\\\").replaceAll("'", "\\'")}'`,
	]) {
		translated = translated.replace(
			new RegExp(
				`\\btools\\s*\\[\\s*${escapeRegExp(literal)}\\s*\\]`,
				"g",
			),
			replacement,
		);
	}
	return translated;
}

export function translateCodeModeGuideline(
	guideline: string,
	toolName: string,
): string {
	const globalName = codeModeGlobalName(toolName);
	const translated = translateCodeModeToolReferences(guideline, toolName);
	return globalName !== toolName && translated.startsWith(`${toolName}:`)
		? `${globalName}${translated.slice(toolName.length)}`
		: translated;
}

export function resolveCodeModeToolIdentity(tool: CodeModeToolDefinition): CodeModeToolIdentity {
	return tool.toolName ?? { name: tool.name };
}

export function codeModeNameForToolIdentity(identity: CodeModeToolIdentity): string {
	const namespace = identity.namespace;
	if (!namespace || namespace === DEFAULT_TOOL_NAMESPACE) return identity.name;
	return namespace.endsWith("_") || identity.name.startsWith("_")
		? `${namespace}${identity.name}`
		: `${namespace}__${identity.name}`;
}

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