import { describe, expect, mock, test } from "bun:test";

mock.module("../persistence/conversation-crud.js", () => ({
  setConversationProcessingStartedAt: () => {},
  isConversationProcessing: () => false,
  getMessages: () => [],
  reserveMessage: mock(async () => ({ id: "msg-reserve" })),
}));

mock.module("../persistence/attachments-store.js", () => ({
  getAttachmentMetadataForMessage: () => [],
  getAttachmentContent: () => null,
}));

import { runAssistantDrivenCompaction } from "../context/compactor.js";
import type { Message, Provider } from "../providers/types.js";

const TAIL_TIMESTAMP =
  "2026-05-21 (Thursday) 10:00:00 -05:00 (America/Chicago)";

const compactionResponse = `
<compaction_result>
<summary>
Earlier turns summarized here.
</summary>

<key_state>
- Nothing critical pending.
</key_state>

<tail_start timestamp="${TAIL_TIMESTAMP}" preview="tail anchor message" />
</compaction_result>
`;

function makeProvider(): Provider {
  return {
    name: "mock-provider",
    sendMessage: async () => ({
      content: [{ type: "text", text: compactionResponse }],
      model: "mock-model",
      usage: { inputTokens: 100, outputTokens: 50 },
      stopReason: "end_turn",
    }),
  };
}

const userText = (text: string): Message => ({
  role: "user",
  content: [{ type: "text", text }],
});

const userTextWithTurnContext = (text: string, timestamp: string): Message => ({
  role: "user",
  content: [
    {
      type: "text",
      text: `<turn_context>\ncurrent_time: ${timestamp}\n</turn_context>\n${text}`,
    },
  ],
});

const assistantText = (text: string): Message => ({
  role: "assistant",
  content: [{ type: "text", text }],
});

describe("runAssistantDrivenCompaction — preservedTailMessages count", () => {
  test("reflects the pre-strip tail size so the reported cut point matches the user-visible split", async () => {
    const messages: Message[] = [
      userText("old user turn 1"),
      assistantText("old assistant reply 1"),
      userText("old user turn 2"),
      userTextWithTurnContext("tail anchor message", TAIL_TIMESTAMP),
      userText("<system_reminder>\nstale reminder\n</system_reminder>"),
      userText("<knowledge_base>\nstale pkb\n</knowledge_base>"),
      assistantText("most recent assistant reply"),
    ];

    const result = await runAssistantDrivenCompaction({
      conversationId: "conv-test",
      messages,
      provider: makeProvider(),
      systemPrompt: "system",
      compaction: { enabled: true, autoThreshold: 0.7 },
      maxInputTokens: 1000,
      previousEstimatedInputTokens: 900,
    });

    expect(result.compacted).toBe(true);
    expect(result.preservedTailMessages).toBe(4);
  });
});