import assert from "node:assert/strict";
import { readFileSync } from "node:fs";
import test from "node:test";

import {
  consultationHistoryCheckpointChars,
} from "../src/lib/consultation-session-history.ts";
import {
  buildSummaryPrompt,
  checkpointSessionContextSummary,
  generateSessionContextSummary,
  messagesForSummaryInput,
  resolveInheritedContextSummary,
  sanitizeSessionContextSummary,
  shouldCheckpoint,
  writeSessionContextSummary,
} from "../src/lib/session-context-summary.ts";

function overBudgetConversation() {
  return [
    { role: "user" as const, text: `问${"x".repeat(8_000)}`, requestId: "u1" },
    { role: "assistant" as const, text: `答${"y".repeat(8_000)}`, requestId: "a1" },
    { role: "user" as const, text: "追问应期", requestId: "u2" },
    { role: "assistant" as const, text: "2027 年", requestId: "a2" },
  ];
}

test("checkpoint triggers only when the tail exceeds the derived threshold", () => {
  // Former value: hard-coded CONSULTATION_HISTORY_TAIL_MAX_CHARS = 16_000.
  // 128k still checkpoints at 16_000 (0.4 × 40_000 budget).
  assert.equal(consultationHistoryCheckpointChars(128_000), 16_000);
  assert.equal(shouldCheckpoint([{ role: "user", text: "x".repeat(15_999) }], null), false);
  assert.equal(shouldCheckpoint([{ role: "user", text: "x".repeat(16_001) }], null), true);
  assert.equal(shouldCheckpoint([{ role: "user", text: "x".repeat(2_400) }], null, { contextWindow: 64_000 }), false);
  assert.equal(shouldCheckpoint([{ role: "user", text: "x".repeat(2_401) }], null, { contextWindow: 64_000 }), true);
});

test("checkpoint prompt omits the last question-answer pair", () => {
  const messages = overBudgetConversation();
  const input = messagesForSummaryInput(messages, null);
  assert.equal(input.length, 2);
  assert.equal(input[0]?.requestId, "u1");
  assert.equal(input[1]?.requestId, "a1");
  assert.equal(input.some((turn) => turn.text === "追问应期"), false);
  assert.equal(input.some((turn) => turn.text === "2027 年"), false);

  const prompt = buildSummaryPrompt(null, messages);
  assert.equal(prompt.includes("追问应期"), false);
  assert.equal(prompt.includes("2027 年"), false);
  assert.equal(prompt.includes("上一份摘要：无"), true);
});

test("summary sanitizer strips ISO dates, clock times, and emails", () => {
  const cleaned = sanitizeSessionContextSummary(
    "已问过的问题\n事业时机，邮箱 user@example.com，日期 1990-01-01 08:30\n已给出的结论\nblocked 项无",
  );
  assert.ok(cleaned);
  assert.equal(cleaned.includes("1990-01-01"), false);
  assert.equal(cleaned.includes("08:30"), false);
  assert.equal(cleaned.includes("user@example.com"), false);
  assert.equal(cleaned.includes("事业时机"), true);
});

test("generateSessionContextSummary times out to null and keeps the timer ref'd", async () => {
  const source = readFileSync(new URL("../src/lib/session-context-summary.ts", import.meta.url), "utf8");
  assert.doesNotMatch(source, /AbortSignal\.timeout\(/);
  assert.doesNotMatch(source, /\.unref\(/);
  assert.match(source, /clearTimeout/);

  const pending = new Set<unknown>();
  let created = 0;
  const realSetTimeout = globalThis.setTimeout;
  const realClearTimeout = globalThis.clearTimeout;
  globalThis.setTimeout = ((handler: TimerHandler, delay?: number, ...args: unknown[]) => {
    created += 1;
    const id = realSetTimeout(handler, delay, ...args);
    pending.add(id);
    return id;
  }) as typeof setTimeout;
  globalThis.clearTimeout = ((id?: ReturnType<typeof setTimeout>) => {
    pending.delete(id);
    realClearTimeout(id);
  }) as typeof clearTimeout;
  try {
    const text = await generateSessionContextSummary({
      previous: null,
      messages: overBudgetConversation(),
      timeoutMs: 20,
      generateText: () => new Promise(() => {}),
    });
    assert.equal(text, null);
    assert.ok(created >= 1);
    assert.equal(pending.size, 0);
  } finally {
    globalThis.setTimeout = realSetTimeout;
    globalThis.clearTimeout = realClearTimeout;
  }
});

test("writeSessionContextSummary abandons when updatedAt does not match", async () => {
  const result = await writeSessionContextSummary({
    seenUpdatedAt: "2026-09-06T00:00:00.000Z",
    summary: {
      version: 1,
      text: "新摘要",
      throughRequestId: "a1",
      throughMessageIndex: 1,
      messageCount: 2,
      updatedAt: "2026-09-06T01:00:00.000Z",
    },
    update: async () => false,
  });
  assert.equal(result, "abandoned");
});

test("inherited context summary copies owned text and skips foreign or empty sources", async () => {
  const source = {
    version: 1 as const,
    text: "已问过的问题\n事业时机",
    throughRequestId: "a1",
    throughMessageIndex: 3,
    messageCount: 4,
    updatedAt: "2026-09-15T00:00:00.000Z",
  };
  const copied = await resolveInheritedContextSummary({
    continuedFromSessionId: "11111111-1111-4111-8111-111111111111",
    loadOwnedSummary: async () => source,
  });
  assert.deepEqual(copied, source);

  const foreign = await resolveInheritedContextSummary({
    continuedFromSessionId: "22222222-2222-4222-8222-222222222222",
    loadOwnedSummary: async () => null,
  });
  assert.equal(foreign, null);

  const empty = await resolveInheritedContextSummary({
    continuedFromSessionId: "11111111-1111-4111-8111-111111111111",
    loadOwnedSummary: async () => ({ version: 1, text: "   " }),
  });
  assert.equal(empty, null);

  const skipped = await resolveInheritedContextSummary({
    loadOwnedSummary: async () => {
      throw new Error("should not load");
    },
  });
  assert.equal(skipped, null);
});

test("checkpoint writes a new summary when the tail is over budget", async () => {
  const result = await checkpointSessionContextSummary({
    messages: overBudgetConversation(),
    summary: null,
    generateText: async () => "已问过的问题\n事业\n已给出的结论\n应期 blocked\n用户补充的事实\n无\n未决与待追问\n继续",
    update: async () => true,
    now: () => new Date("2026-09-06T02:00:00.000Z"),
  });
  assert.equal(result, "written");
});