/**
 * Contract: `createSettingsAwareStreamFn` layers session provider settings
 * (`providers.openrouterVariant`, `providers.antigravityEndpoint`,
 * `providers.maxInFlightRequests`, `model.loopGuard.*`, `textVerbosity` for
 * Responses-family requests) onto every call while letting caller-supplied
 * options win — the same wiring the main agent and the advisor agent share so
 * OpenRouter sticky-routing / response caching behaves the same on advisor turns
 * (can1357/oh-my-pi#3639).
 */
import { describe, expect, it } from "bun:test";
import type { StreamFn } from "@oh-my-pi/pi-agent-core";
import type { Context, Model, SimpleStreamOptions } from "@oh-my-pi/pi-ai";
import { AssistantMessageEventStream } from "@oh-my-pi/pi-ai/utils/event-stream";
import { Settings } from "@oh-my-pi/pi-coding-agent/config/settings";
import { createSettingsAwareStreamFn } from "@oh-my-pi/pi-coding-agent/session/settings-stream-fn";

function captureBase(): { fn: StreamFn; calls: Array<{ options?: SimpleStreamOptions }> } {
	const calls: Array<{ options?: SimpleStreamOptions }> = [];
	const fn: StreamFn = (_model, _context, options) => {
		calls.push({ options });
		return new AssistantMessageEventStream();
	};
	return { fn, calls };
}

const stubModel = {} as unknown as Model;
const stubCodexModel = { api: "openai-codex-responses" } as unknown as Model;
const stubResponsesModel = { api: "openai-responses" } as unknown as Model;
const stubContext = { messages: [], tools: [], systemPrompt: [] } as unknown as Context;

describe("createSettingsAwareStreamFn", () => {
	it("applies provider settings to the forwarded options when caller omits them", () => {
		const settings = Settings.isolated({
			"providers.openrouterVariant": "floor",
			"providers.antigravityEndpoint": "sandbox",
			"providers.maxInFlightRequests": { openrouter: 4 },
			"model.loopGuard.enabled": true,
			"model.loopGuard.checkAssistantContent": true,
		});
		const { fn: base, calls } = captureBase();
		const wrapped = createSettingsAwareStreamFn(settings, base);

		wrapped(stubModel, stubContext, { apiKey: "k" });

		const options = calls[0]?.options;
		expect(options?.openrouterVariant).toBe("floor");
		expect(options?.antigravityEndpointMode).toBe("sandbox");
		expect(options?.maxInFlightRequests).toEqual({ openrouter: 4 });
		expect(options?.loopGuard).toEqual({ enabled: true, checkAssistantContent: true });
		// caller's own option is preserved
		expect(options?.apiKey).toBe("k");
	});

	it("applies Responses-family text verbosity from settings while preserving caller overrides", () => {
		const settings = Settings.isolated({ textVerbosity: "low" });
		const { fn: base, calls } = captureBase();
		const wrapped = createSettingsAwareStreamFn(settings, base);

		wrapped(stubCodexModel, stubContext, undefined);
		wrapped(stubResponsesModel, stubContext, undefined);
		wrapped(stubResponsesModel, stubContext, { textVerbosity: "medium" });

		expect(calls[0]?.options?.textVerbosity).toBe("low");
		expect(calls[1]?.options?.textVerbosity).toBe("low");
		expect(calls[2]?.options?.textVerbosity).toBe("medium");
	});

	it("treats the default openrouterVariant as absent so the base call carries no variant", () => {
		const settings = Settings.isolated({ "providers.openrouterVariant": "default" });
		const { fn: base, calls } = captureBase();
		const wrapped = createSettingsAwareStreamFn(settings, base);

		wrapped(stubModel, stubContext, undefined);

		expect(calls[0]?.options?.openrouterVariant).toBeUndefined();
	});

	it("lets caller-supplied options override the session settings", () => {
		const settings = Settings.isolated({
			"providers.openrouterVariant": "floor",
			"providers.antigravityEndpoint": "sandbox",
			"providers.maxInFlightRequests": { openrouter: 4 },
			"model.loopGuard.enabled": true,
		});
		const { fn: base, calls } = captureBase();
		const wrapped = createSettingsAwareStreamFn(settings, base);

		wrapped(stubModel, stubContext, {
			openrouterVariant: "nitro",
			antigravityEndpointMode: "production",
			maxInFlightRequests: { openrouter: 1 },
			loopGuard: { enabled: false },
		});

		const options = calls[0]?.options;
		expect(options?.openrouterVariant).toBe("nitro");
		expect(options?.antigravityEndpointMode).toBe("production");
		expect(options?.maxInFlightRequests).toEqual({ openrouter: 1 });
		// Loop guard merges per-field: caller wins on `enabled`, settings fill
		// the rest (the inline closure the main agent used has the same shape).
		expect(options?.loopGuard?.enabled).toBe(false);
		expect(options?.loopGuard?.checkAssistantContent).toBe(true);
	});
});