import { describe, it, expect } from "vitest";
import { MemoSummarizer } from "../src/ai/memory/summarizer.js";
import {
  shouldSummarize,
  parseQueryList,
  MEMORY_KEY_SUMMARY,
} from "../src/ai/agent/agent.js";
import type { LlmProvider } from "../src/ai/providers/llm.js";
import { createLogger } from "../src/utils/logger.js";

class FakeLlm implements LlmProvider {
  smallCalls: { system: string; user: string }[] = [];
  result: string;
  fail = false;
  constructor(result = "Customer speaks Chinese and is interested in CDD01.") {
    this.result = result;
  }
  async chat(): Promise<string> {
    return "main reply";
  }
  async chatSmall(args: {
    system: string;
    messages: { role: "user" | "assistant"; content: string }[];
  }): Promise<string> {
    this.smallCalls.push({
      system: args.system,
      user: args.messages.map((m) => m.content).join("\n"),
    });
    if (this.fail) throw new Error("small model down");
    return this.result;
  }
}

const logger = createLogger("fatal");

describe("MemoSummarizer.extract", () => {
  it("returns the plain-text summary from the small model", async () => {
    const llm = new FakeLlm("Customer speaks Chinese, wants CDD01.");
    const s = new MemoSummarizer(llm, logger);

    const out = await s.extract({
      priorSummary: "old",
      priorQueries: ["what is CDD01?", "price of CDD01"],
      currentTurn: "I want to buy CDD01",
    });

    expect(out).toBe("Customer speaks Chinese, wants CDD01.");
    expect(llm.smallCalls).toHaveLength(1);
    expect(llm.smallCalls[0].system).toContain("plain-text");
    expect(llm.smallCalls[0].user).toContain("Prior summary: old");
    expect(llm.smallCalls[0].user).toContain("Latest customer message: I want to buy CDD01");
  });

  it("returns undefined when the small model throws (caller keeps old value)", async () => {
    const llm = new FakeLlm();
    llm.fail = true;
    const s = new MemoSummarizer(llm, logger);

    const out = await s.extract({
      priorSummary: "old",
      priorQueries: [],
      currentTurn: "hi",
    });

    expect(out).toBeUndefined();
  });

  it("returns undefined on empty model output", async () => {
    const llm = new FakeLlm("   ");
    const s = new MemoSummarizer(llm, logger);

    const out = await s.extract({
      priorQueries: [],
      currentTurn: "hi",
    });

    expect(out).toBeUndefined();
  });
});

describe("shouldSummarize", () => {
  const base = {
    langChanged: false,
    userText: "anything",
    mem: {},
    priorQueries: [] as string[],
    turn: 3,
    lastSummarizedAt: 0,
  };

  it("true when the language preference changed", () => {
    expect(shouldSummarize({ ...base, langChanged: true })).toBe(true);
  });

  it("true on a brand-new SKU token", () => {
    expect(shouldSummarize({ ...base, userText: "how about CDD01?" })).toBe(true);
  });

  it("false when the SKU was already seen in prior queries", () => {
    expect(
      shouldSummarize({
        ...base,
        userText: "how about CDD01 again?",
        priorQueries: ["is CDD01 good?"],
      }),
    ).toBe(false);
  });

  it("false when the SKU is already in the summary", () => {
    expect(
      shouldSummarize({
        ...base,
        userText: "CDD01 price?",
        mem: { [MEMORY_KEY_SUMMARY]: "likes CDD01" },
      }),
    ).toBe(false);
  });

  it("true on identity keywords", () => {
    expect(shouldSummarize({ ...base, userText: "我是 Hoelee，想买" })).toBe(true);
    expect(shouldSummarize({ ...base, userText: "I need a refund" })).toBe(true);
  });

  it("true when >=10 turns since last summary (fallback)", () => {
    expect(
      shouldSummarize({ ...base, turn: 10, lastSummarizedAt: 0 }),
    ).toBe(true);
    expect(
      shouldSummarize({ ...base, turn: 9, lastSummarizedAt: 0 }),
    ).toBe(false);
  });

  it("false when nothing matches", () => {
    expect(shouldSummarize({ ...base, userText: "thanks" })).toBe(false);
  });
});

describe("parseQueryList", () => {
  it("parses a valid JSON array", () => {
    expect(parseQueryList('["a","b"]')).toEqual(["a", "b"]);
  });
  it("returns [] for undefined, empty, or malformed", () => {
    expect(parseQueryList(undefined)).toEqual([]);
    expect(parseQueryList("")).toEqual([]);
    expect(parseQueryList("{not json")).toEqual([]);
  });
  it("drops non-string entries", () => {
    expect(parseQueryList('[1,"a",null]')).toEqual(["a"]);
  });
});