/**
 * Contract: the anchored subagent HUD (rendered above the editor, next to the
 * Todos block) lists exactly the running *detached* subagents as
 * `Id: description` rows and yields no output once nothing qualifies, so the
 * block self-clears. Sync task spawns and eval `agent()` spawns are excluded:
 * their progress is already rendered inline (tool block / eval cell).
 */
import { beforeAll, describe, expect, it } from "bun:test";
import { renderSubagentHudLines } from "@oh-my-pi/pi-coding-agent/modes/interactive-mode";
import {
	type ObservableSession,
	SessionObserverRegistry,
} from "@oh-my-pi/pi-coding-agent/modes/session-observer-registry";
import { initTheme } from "@oh-my-pi/pi-coding-agent/modes/theme/theme";
import {
	type AgentProgress,
	type SubagentLifecyclePayload,
	type SubagentProgressPayload,
	TASK_SUBAGENT_LIFECYCLE_CHANNEL,
	TASK_SUBAGENT_PROGRESS_CHANNEL,
} from "@oh-my-pi/pi-coding-agent/task";
import { EventBus } from "@oh-my-pi/pi-coding-agent/utils/event-bus";

function makeSession(overrides: Partial<ObservableSession> & { id: string }): ObservableSession {
	return {
		kind: "subagent",
		label: overrides.id,
		status: "active",
		detached: true,
		lastUpdate: Date.now(),
		...overrides,
	};
}

function makeProgress(overrides: Partial<AgentProgress> & { id: string }): AgentProgress {
	return {
		index: 0,
		agent: "task",
		agentSource: "bundled",
		status: "running",
		task: "",
		recentTools: [],
		recentOutput: [],
		toolCount: 0,
		requests: 0,
		tokens: 0,
		cost: 0,
		durationMs: 0,
		...overrides,
	};
}

function makeLifecycle(id: string, index: number, description: string, detached?: boolean): SubagentLifecyclePayload {
	return {
		id,
		index,
		agent: "task",
		agentSource: "bundled",
		description,
		status: "started",
		parentToolCallId: "tool-call",
		detached,
	};
}

function makeProgressPayload(
	id: string,
	index: number,
	description: string,
	detached?: boolean,
): SubagentProgressPayload {
	return {
		index,
		agent: "task",
		agentSource: "bundled",
		task: description,
		parentToolCallId: "tool-call",
		detached,
		progress: makeProgress({ id, index, description, task: description }),
	};
}

function render(sessions: ObservableSession[], columns = 120): string {
	return Bun.stripANSI(renderSubagentHudLines(sessions, columns).join("\n"));
}

describe("subagent HUD lines", () => {
	beforeAll(async () => {
		await initTheme();
	});

	it("renders running subagents as Id: description under a Subagents header", () => {
		const out = render([
			makeSession({ id: "AuthLoader", description: "Refactoring the auth flow" }),
			makeSession({ id: "SchemaMigrator", description: "Migrating the users table" }),
		]);
		expect(out).toContain("Subagents");
		expect(out).toContain("AuthLoader: Refactoring the auth flow");
		expect(out).toContain("SchemaMigrator: Migrating the users table");
	});

	it("only shows active subagents and clears once everything finished", () => {
		const finishedStates = ["completed", "failed", "aborted"] as const;
		const sessions: ObservableSession[] = [
			{ id: "main", kind: "main", label: "Main Session", status: "active", lastUpdate: Date.now() },
			...finishedStates.map(status => makeSession({ id: `Done-${status}`, status, description: "old work" })),
		];
		expect(renderSubagentHudLines(sessions, 120)).toEqual([]);

		const out = render([...sessions, makeSession({ id: "StillRunning", description: "live work" })]);
		expect(out).toContain("StillRunning: live work");
		expect(out).not.toContain("Done-");
		expect(out).not.toContain("Main Session");
	});

	it("falls back to the description and task carried by progress snapshots", () => {
		const fromProgressDesc = render([
			makeSession({ id: "Worker", progress: makeProgress({ id: "Worker", description: "From progress" }) }),
		]);
		expect(fromProgressDesc).toContain("Worker: From progress");

		const fromTask = render([
			makeSession({ id: "Worker", progress: makeProgress({ id: "Worker", task: "Investigate flaky CI on macOS" }) }),
		]);
		expect(fromTask).toContain("Worker Investigate flaky CI on macOS");
	});

	it("hides non-detached spawns: sync task calls and eval agent() helpers", () => {
		// Sync task spawn (parent blocked on the call) and eval `agent()` spawn
		// (no detached flag at all) both stay off the HUD.
		const sessions = [
			makeSession({ id: "SyncSpawn", description: "inline task work", detached: false }),
			makeSession({ id: "EvalSpawn", description: "eval cell work", detached: undefined }),
		];
		expect(renderSubagentHudLines(sessions, 120)).toEqual([]);

		const out = render([...sessions, makeSession({ id: "BackgroundSpawn", description: "detached work" })]);
		expect(out).toContain("BackgroundSpawn: detached work");
		expect(out).not.toContain("SyncSpawn");
		expect(out).not.toContain("EvalSpawn");
	});

	it("threads the detached flag from lifecycle and progress payloads", () => {
		const eventBus = new EventBus();
		const registry = new SessionObserverRegistry();
		registry.subscribeToEventBus(eventBus);

		eventBus.emit(TASK_SUBAGENT_LIFECYCLE_CHANNEL, makeLifecycle("Detached", 0, "background work", true));
		eventBus.emit(TASK_SUBAGENT_LIFECYCLE_CHANNEL, makeLifecycle("Inline", 1, "sync work"));
		eventBus.emit(TASK_SUBAGENT_PROGRESS_CHANNEL, makeProgressPayload("FromProgress", 2, "background work", true));

		const out = render(registry.getSessions());
		expect(out).toContain("Detached: background work");
		expect(out).toContain("FromProgress: background work");
		expect(out).not.toContain("Inline");
	});

	it("renders nested ids as a breadcrumb and truncates long descriptions to the viewport", () => {
		const out = render([makeSession({ id: "Anna.Bob", description: `start ${"x".repeat(300)} end` })], 60);
		expect(out).toContain("Anna>Bob:");
		expect(out).not.toContain("end");
		for (const line of out.split("\n")) {
			expect(Bun.stringWidth(line)).toBeLessThanOrEqual(60);
		}
	});

	it("keeps subagent registry order stable while progress arrives out of order", () => {
		const eventBus = new EventBus();
		const registry = new SessionObserverRegistry();
		registry.subscribeToEventBus(eventBus);
		const activeIds = () =>
			registry
				.getSessions()
				.filter(session => session.kind === "subagent" && session.status === "active")
				.map(session => session.id);

		eventBus.emit(
			TASK_SUBAGENT_LIFECYCLE_CHANNEL,
			makeLifecycle("BlastRadius", 1, "Survey id-keyed downstream consumers"),
		);
		eventBus.emit(
			TASK_SUBAGENT_LIFECYCLE_CHANNEL,
			makeLifecycle("SelectorSurfaces", 0, "Map model-selector resolution surfaces"),
		);
		eventBus.emit(
			TASK_SUBAGENT_LIFECYCLE_CHANNEL,
			makeLifecycle("VariantsSurvey", 2, "Survey tier-variant ids across catalog"),
		);

		expect(activeIds()).toEqual(["SelectorSurfaces", "BlastRadius", "VariantsSurvey"]);

		eventBus.emit(
			TASK_SUBAGENT_PROGRESS_CHANNEL,
			makeProgressPayload("VariantsSurvey", 2, "Survey tier-variant ids across catalog"),
		);
		eventBus.emit(
			TASK_SUBAGENT_PROGRESS_CHANNEL,
			makeProgressPayload("BlastRadius", 1, "Survey id-keyed downstream consumers"),
		);

		expect(activeIds()).toEqual(["SelectorSurfaces", "BlastRadius", "VariantsSurvey"]);
	});
});