import { defineTool, type ToolDefinition } from "@earendil-works/pi-coding-agent";
import { Type } from "typebox";

/**
 * Captures the arguments of the single structured_output tool call a schema
 * agent is required to make. The captured value becomes agent()'s return value.
 */
export interface StructuredOutputCapture<T = unknown> {
	called: boolean;
	value: T | undefined;
}

/**
 * Build a one-shot `structured_output` tool whose parameters ARE the workflow
 * author's JSON Schema (wrapped with Type.Unsafe so TypeBox passes it through to
 * the model unchanged). When the subagent calls it, we capture the args — that
 * IS the agent's return value. This mirrors Claude Code's StructuredOutput tool:
 * validation/retry happens at the tool-call layer, not via prose parsing.
 */
export function createStructuredOutputTool<T = unknown>(opts: {
	schema: object;
	capture: StructuredOutputCapture<T>;
}): ToolDefinition {
	const parameters = Type.Unsafe<T>(opts.schema as Record<string, unknown>);
	return defineTool({
		name: "structured_output",
		label: "Structured Output",
		description:
			"Return the final structured result of this task. The arguments you pass ARE the return value — call this exactly once, as your final action, with every required field filled in. Do not write a prose answer instead.",
		parameters,
		// biome-ignore lint/suspicious/noExplicitAny: schema is dynamic per call
		async execute(_id: string, params: any) {
			opts.capture.called = true;
			opts.capture.value = params as T;
			// terminate: true lets the agent end on this tool call without paying for
			// an extra follow-up LLM turn (per the SDK's structured-output example).
			return { content: [{ type: "text", text: "structured_output recorded." }], terminate: true };
		},
	}) as unknown as ToolDefinition;
}