/**
 * Tests for streaming reply logic.
 */

import { describe, it, expect, vi } from "vitest";
import { StreamingReply } from "../src/streaming-reply.js";
import type { TelegramAPI } from "../src/telegram-api.js";

describe("streaming-reply", () => {
  it("should throttle edits", async () => {
    const sent: Array<{ type: string; text: string }> = [];
    const mockApi = {
      sendMessage: vi.fn(async (_chatId: string, text: string) => {
        sent.push({ type: "send", text });
        return { message_id: 1 };
      }),
      editMessageText: vi.fn(async (_chatId: string, _msgId: number, text: string) => {
        sent.push({ type: "edit", text });
      }),
    } as unknown as TelegramAPI;

    const streaming = new StreamingReply(mockApi, "123", 1, {
      throttleMs: 100,
      minInitialChars: 10,
    });

    streaming.update("Hello");
    streaming.update("Hello world");
    streaming.update("Hello world!!!");

    // Wait for throttle + initial char check
    await new Promise((resolve) => setTimeout(resolve, 150));

    expect(sent.length).toBeGreaterThan(0);
    expect(sent[0]?.type).toBe("send");
    expect(sent[0]?.text).toContain("Hello");

    await streaming.stop();
  });

  it("should track generation to prevent clobbering", () => {
    const mockApi = {
      sendMessage: vi.fn(async () => ({ message_id: 1 })),
      editMessageText: vi.fn(),
    } as unknown as TelegramAPI;

    const streaming1 = new StreamingReply(mockApi, "123", 1, { throttleMs: 1000 });
    const streaming2 = new StreamingReply(mockApi, "123", 2, { throttleMs: 1000 });

    expect(streaming1.getGeneration()).toBe(1);
    expect(streaming2.getGeneration()).toBe(2);
    expect(streaming1.getGeneration()).not.toBe(streaming2.getGeneration());
  });

  it("should truncate text exceeding 4096 chars", async () => {
    const sent: string[] = [];
    const mockApi = {
      sendMessage: vi.fn(async (_chatId: string, text: string) => {
        sent.push(text);
        return { message_id: 1 };
      }),
      editMessageText: vi.fn(),
    } as unknown as TelegramAPI;

    const streaming = new StreamingReply(mockApi, "123", 1, {
      throttleMs: 50,
      minInitialChars: 0,
    });

    streaming.update("x".repeat(5000));
    await streaming.flush();

    expect(sent.length).toBe(1);
    expect(sent[0]!.length).toBe(4096);

    await streaming.stop();
  });

  it("should debounce first send based on minInitialChars", async () => {
    const sent: string[] = [];
    const mockApi = {
      sendMessage: vi.fn(async (_chatId: string, text: string) => {
        sent.push(text);
        return { message_id: 1 };
      }),
      editMessageText: vi.fn(),
    } as unknown as TelegramAPI;

    const streaming = new StreamingReply(mockApi, "123", 1, {
      throttleMs: 50,
      minInitialChars: 20,
    });

    streaming.update("Short");
    await streaming.flush();

    // Should not send yet
    expect(sent.length).toBe(0);

    streaming.update("This is now long enough to send");
    await streaming.flush();

    expect(sent.length).toBe(1);

    await streaming.stop();
  });
});