import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { textTokens } from "../estimate";
import { compactList } from "../format";
import type { Line, Section } from "../types";

/** Tool definitions breakdown, grouped by source (builtin / sdk / extension). */
export const toolsSection = (pi: ExtensionAPI): Section => {
	const tools = pi.getAllTools();
	const groups = new Map<string, { count: number; tokens: number; biggest: Line[] }>();

	for (const tool of tools) {
		let group: string;
		switch (tool.sourceInfo?.source) {
			case "builtin":
				group = "builtin";
				break;
			case "sdk":
				group = "sdk";
				break;
			default:
				// Extensions — incl. any MCP tools registered via an extension
				// (pi has no built-in MCP support).
				group = "extension (incl. MCP)";
		}
		const serialized = JSON.stringify({
			name: tool.name,
			description: tool.description,
			parameters: tool.parameters,
		});
		const t = textTokens(serialized);
		const g = groups.get(group) ?? { count: 0, tokens: 0, biggest: [] };
		g.count += 1;
		g.tokens += t;
		g.biggest.push({ label: tool.name, tokens: t });
		groups.set(group, g);
	}

	const lines: Line[] = [];
	let total = 0;
	for (const [group, g] of [...groups.entries()].sort((a, b) => b[1].tokens - a[1].tokens)) {
		total += g.tokens;
		lines.push({
			label: `${group} (${g.count})`,
			tokens: g.tokens,
			detail: compactList(g.biggest, 3),
		});
	}

	return { title: "Tools", total, lines };
};