oh-my-pi/packages/coding-agent/test/tool-args-reveal.test.ts

import { afterEach, describe, expect, it, vi } from "bun:test";
import { STREAMING_REVEAL_FRAME_MS } from "@oh-my-pi/pi-coding-agent/modes/controllers/streaming-reveal";
import { ToolArgsRevealController } from "@oh-my-pi/pi-coding-agent/modes/controllers/tool-args-reveal";
import { STREAMING_JSON_PARSE_MIN_GROWTH } from "@oh-my-pi/pi-utils";

class RecordingArgsComponent {
	frames: Array<Record<string, unknown>> = [];

	updateArgs(args: unknown): void {
		this.frames.push(args as Record<string, unknown>);
	}
}

function makeController(options: { smooth?: boolean; requestRender?: () => void } = {}) {
	const component = new RecordingArgsComponent();
	const controller = new ToolArgsRevealController({
		getSmoothStreaming: () => options.smooth ?? true,
		requestRender: options.requestRender ?? (() => {}),
	});
	return { component, controller };
}

function partialOf(frame: Record<string, unknown>): string {
	const partial = frame.__partialJson;
	if (typeof partial !== "string") {
		throw new Error("Expected __partialJson string on revealed frame");
	}
	return partial;
}

function drain(frames: number): void {
	for (let i = 0; i < frames; i++) {
		vi.advanceTimersByTime(STREAMING_REVEAL_FRAME_MS);
	}
}

function jsonTarget(options: { fullArgs?: Record<string, unknown>; exposeRawPartialJson?: boolean } = {}) {
	return {
		rawInput: false,
		exposeRawPartialJson: options.exposeRawPartialJson ?? false,
		fullArgs: options.fullArgs ?? {},
	};
}

function rawTarget(fullArgs: Record<string, unknown>) {
	return { rawInput: true, exposeRawPartialJson: true, fullArgs };
}

describe("tool args reveal", () => {
	afterEach(() => {
		vi.useRealTimers();
	});

	it("reveals what already arrived on the first setTarget call", () => {
		const { controller } = makeController();
		const target = `{"path":"a.ts","content":"abc"}`;

		const initial = controller.setTarget(
			"call-1",
			target,
			jsonTarget({ fullArgs: { path: "a.ts" }, exposeRawPartialJson: true }),
		);

		// The provider already delivered a complete partialJson chunk; the
		// controller MUST surface its parsed fields and raw prefix immediately —
		// pacing applies only to subsequent growth, never to bytes already in hand.
		expect(initial.path).toBe("a.ts");
		expect(initial.content).toBe("abc");
		expect(partialOf(initial)).toBe(target);
	});

	it("paces growth across successive setTarget calls for raw-prefix renderers", () => {
		vi.useFakeTimers();
		const { component, controller } = makeController();
		const content = "line one\\nline two\\nline three of a streamed write payload";
		const target = `{"path":"a.ts","content":"${content}"}`;
		const seed = target.slice(0, 12);

		const initial = controller.setTarget(
			"call-1",
			seed,
			jsonTarget({ fullArgs: { path: "a.ts" }, exposeRawPartialJson: true }),
		);
		// What arrived is exposed immediately, no empty initial frame.
		expect(partialOf(initial)).toBe(seed);
		controller.bind("call-1", component);

		// More bytes arrive later — the controller now paces the new backlog.
		controller.setTarget("call-1", target, jsonTarget({ fullArgs: { path: "a.ts" }, exposeRawPartialJson: true }));
		drain(100);

		const partials = component.frames.map(partialOf);
		expect(partials.length).toBeGreaterThan(0);
		expect(partials.at(-1)).toBe(target);
		let previous = seed.length;
		for (const partial of partials) {
			expect(partial.length).toBeGreaterThanOrEqual(previous);
			expect(target.startsWith(partial)).toBe(true);
			previous = partial.length;
		}
	});

	it("throttles JSON re-parses for renderers that do not read raw partial JSON", () => {
		vi.useFakeTimers();
		const requestRender = vi.fn();
		const { component, controller } = makeController({ requestRender });
		const target = `{"path":"a.ts","content":"${"x".repeat(1200)}"}`;
		const seed = target.slice(0, 10);

		// Seed: small initial slice, revealed immediately, sets parsedLen=seed.length.
		const initial = controller.setTarget("call-1", seed, jsonTarget());
		expect(partialOf(initial)).toBe(seed);
		controller.bind("call-1", component);

		// Full payload arrives; the controller paces the new growth.
		controller.setTarget("call-1", target, jsonTarget());
		expect(component.frames).toHaveLength(0);

		// First paced tick lands inside the small-prefix window
		// (< STREAMING_JSON_PARSE_MIN_GROWTH), so a re-parse is forced and a
		// frame fires.
		drain(1);
		expect(component.frames).toHaveLength(1);
		expect(requestRender).toHaveBeenCalledTimes(1);
		const firstPartial = partialOf(component.frames[0]);

		// The next tick crosses into the throttled window: growth from the last
		// parse hasn't yet hit STREAMING_JSON_PARSE_MIN_GROWTH, so no frame fires.
		drain(1);
		expect(component.frames).toHaveLength(1);
		expect(requestRender).toHaveBeenCalledTimes(1);

		drain(3);
		expect(component.frames.length).toBeGreaterThan(1);
		const secondPartial = partialOf(component.frames[1]);
		expect(secondPartial.length - firstPartial.length).toBeGreaterThanOrEqual(STREAMING_JSON_PARSE_MIN_GROWTH);
	});

	it("passes the full target through untouched when smoothing is disabled", () => {
		vi.useFakeTimers();
		const requestRender = vi.fn();
		const { component, controller } = makeController({ smooth: false, requestRender });
		const target = `{"path":"a.ts","content":"abc"}`;
		const fullArgs = { path: "a.ts", content: "abc" };

		const renderArgs = controller.setTarget("call-1", target, jsonTarget({ fullArgs }));
		controller.bind("call-1", component);
		drain(10);

		expect(renderArgs).toEqual({ ...fullArgs, __partialJson: target });
		expect(component.frames).toHaveLength(0);
		expect(requestRender).not.toHaveBeenCalled();
	});

	it("finish drops the reveal so no further frames are pushed", () => {
		vi.useFakeTimers();
		const { component, controller } = makeController();
		const target = `{"path":"a.ts","content":"${"x".repeat(400)}"}`;
		const seed = target.slice(0, 5);

		controller.setTarget("call-1", seed, jsonTarget());
		controller.bind("call-1", component);
		// Backlog of new bytes for the reveal loop to advance through.
		controller.setTarget("call-1", target, jsonTarget());
		drain(1);
		const frames = component.frames.length;
		expect(frames).toBeGreaterThan(0);
		controller.finish("call-1");
		drain(10);

		expect(component.frames).toHaveLength(frames);
	});

	it("flushAll snaps live entries to the full received stream", () => {
		vi.useFakeTimers();
		const { component, controller } = makeController();
		const target = `{"path":"a.ts","content":"${"x".repeat(500)}"}`;
		const seed = target.slice(0, 5);

		controller.setTarget("call-1", seed, jsonTarget());
		controller.bind("call-1", component);
		controller.setTarget("call-1", target, jsonTarget());
		drain(1);
		expect(partialOf(component.frames.at(-1)!).length).toBeLessThan(target.length);
		controller.flushAll();

		expect(partialOf(component.frames.at(-1)!)).toBe(target);
		const frames = component.frames.length;
		drain(10);
		expect(component.frames).toHaveLength(frames);
	});

	it("never splits a surrogate pair at a frame boundary", () => {
		vi.useFakeTimers();
		const { component, controller } = makeController();
		const target = `{"content":"${"😀🎉".repeat(40)}"}`;
		const seed = target.slice(0, 12); // before any surrogate

		controller.setTarget("call-1", seed, jsonTarget({ exposeRawPartialJson: true }));
		controller.bind("call-1", component);
		controller.setTarget("call-1", target, jsonTarget({ exposeRawPartialJson: true }));
		drain(100);

		expect(partialOf(component.frames.at(-1)!)).toBe(target);
		for (const frame of component.frames) {
			expect(partialOf(frame).isWellFormed()).toBe(true);
		}
	});

	it("exposes custom raw-input streams as { input } without JSON parsing", () => {
		vi.useFakeTimers();
		const { component, controller } = makeController();
		const target = "*** Begin Patch\n*** Update File: a.ts\n-old\n+new\n*** End Patch";
		const seed = target.slice(0, 5);

		const initial = controller.setTarget("call-1", seed, rawTarget({ input: seed }));
		expect(initial.input).toBe(seed);
		expect(partialOf(initial)).toBe(seed);
		controller.bind("call-1", component);
		controller.setTarget("call-1", target, rawTarget({ input: target }));
		drain(100);

		expect(component.frames.length).toBeGreaterThan(0);
		for (const frame of component.frames) {
			expect(frame.input).toBe(partialOf(frame));
		}
		expect(component.frames.at(-1)!.input).toBe(target);
	});
});