import { afterEach, describe, expect, it, vi } from "bun:test";
import type { TextContent, UserMessage } from "@oh-my-pi/pi-ai";
import { EventController } from "@oh-my-pi/pi-coding-agent/modes/controllers/event-controller";
import type { InteractiveModeContext } from "@oh-my-pi/pi-coding-agent/modes/types";

function createUserMessage(text: string): UserMessage {
	return {
		role: "user",
		content: [{ type: "text", text }],
		attribution: "user",
		timestamp: Date.now(),
	};
}

function createContext(options: {
	editorText: string;
	optimisticSignature?: string;
	locallySubmittedSignatures?: string[];
}) {
	let currentEditorText = options.editorText;
	const setText = vi.fn((text: string) => {
		currentEditorText = text;
	});
	const editor = {
		setText,
		getText: () => currentEditorText,
	};
	const addMessageToChat = vi.fn();
	const updatePendingMessagesDisplay = vi.fn();
	const ctx = {
		isInitialized: true,
		statusLine: { invalidate: vi.fn() },
		updateEditorTopBorder: vi.fn(),
		ui: { requestRender: vi.fn() },
		editor,
		addMessageToChat,
		updatePendingMessagesDisplay,
		getUserMessageText: (message: UserMessage) =>
			typeof message.content === "string"
				? message.content
				: message.content
						.filter((c): c is TextContent => c.type === "text")
						.map(c => c.text)
						.join(""),
		optimisticUserMessageSignature: options.optimisticSignature,
		locallySubmittedUserSignatures: new Set<string>(options.locallySubmittedSignatures ?? []),
	} as unknown as InteractiveModeContext;
	return { ctx, editor, setText, addMessageToChat, updatePendingMessagesDisplay };
}

describe("EventController message_start (user role)", () => {
	afterEach(() => {
		vi.restoreAllMocks();
	});

	it("preserves an in-progress editor draft when delivering a queued submission", async () => {
		// Reproduces the bug: user sends a message during streaming (queued) and then
		// types a follow-up draft. When the queue drains and message_start fires,
		// the editor MUST keep the draft.
		const message = createUserMessage("queued during streaming");
		const signature = "queued during streaming\u00000";
		const { ctx, editor, setText, addMessageToChat, updatePendingMessagesDisplay } = createContext({
			editorText: "draft typed after queuing",
			locallySubmittedSignatures: [signature],
		});
		const controller = new EventController(ctx);

		await controller.handleEvent({ type: "message_start", message });

		expect(setText).not.toHaveBeenCalled();
		expect(editor.getText()).toBe("draft typed after queuing");
		// Queued message was not optimistically rendered, so it must still land in chat.
		expect(addMessageToChat).toHaveBeenCalledWith(message);
		// Pending list always refreshes so the dequeued entry disappears.
		expect(updatePendingMessagesDisplay).toHaveBeenCalledTimes(1);
		// Signature is consumed so a future external message with the same shape still clears.
		expect(ctx.locallySubmittedUserSignatures.has(signature)).toBe(false);
	});

	it("clears the editor for user messages that did not originate from this session", async () => {
		// Counter-case: an external/programmatic user message must still trigger the
		// defensive editor reset so the next prompt starts clean.
		const message = createUserMessage("external prompt");
		const { ctx, setText, addMessageToChat } = createContext({
			editorText: "stale text",
		});
		const controller = new EventController(ctx);

		await controller.handleEvent({ type: "message_start", message });

		expect(setText).toHaveBeenCalledWith("");
		expect(addMessageToChat).toHaveBeenCalledWith(message);
	});

	it("preserves the editor for an optimistic submission and skips the duplicate chat add", async () => {
		// Optimistic path already added the user message to chat and cleared the
		// editor at submit time. message_start must not re-add or re-clear.
		const message = createUserMessage("optimistic send");
		const signature = "optimistic send\u00000";
		const { ctx, setText, addMessageToChat } = createContext({
			editorText: "",
			optimisticSignature: signature,
			locallySubmittedSignatures: [signature],
		});
		const controller = new EventController(ctx);

		await controller.handleEvent({ type: "message_start", message });

		expect(addMessageToChat).not.toHaveBeenCalled();
		expect(setText).not.toHaveBeenCalled();
		expect(ctx.optimisticUserMessageSignature).toBeUndefined();
	});
});