import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";

import { describe, expect, it } from "vitest";

import type { ClawdbotConfig } from "../../config/config.js";
import { saveSessionStore } from "../../config/sessions.js";
import { initSessionState } from "./session.js";

describe("initSessionState thread forking", () => {
  it("forks a new session from the parent session file", async () => {
    const root = await fs.mkdtemp(
      path.join(os.tmpdir(), "clawdbot-thread-session-"),
    );
    const sessionsDir = path.join(root, "sessions");
    await fs.mkdir(sessionsDir, { recursive: true });

    const parentSessionId = "parent-session";
    const parentSessionFile = path.join(sessionsDir, "parent.jsonl");
    const header = {
      type: "session",
      version: 3,
      id: parentSessionId,
      timestamp: new Date().toISOString(),
      cwd: process.cwd(),
    };
    const message = {
      type: "message",
      id: "m1",
      parentId: null,
      timestamp: new Date().toISOString(),
      message: { role: "user", content: "Parent prompt" },
    };
    await fs.writeFile(
      parentSessionFile,
      `${JSON.stringify(header)}\n${JSON.stringify(message)}\n`,
      "utf-8",
    );

    const storePath = path.join(root, "sessions.json");
    const parentSessionKey = "agent:main:slack:channel:C1";
    await saveSessionStore(storePath, {
      [parentSessionKey]: {
        sessionId: parentSessionId,
        sessionFile: parentSessionFile,
        updatedAt: Date.now(),
      },
    });

    const cfg = {
      session: { store: storePath },
    } as ClawdbotConfig;

    const threadSessionKey = "agent:main:slack:channel:C1:thread:123";
    const threadLabel = "Slack thread #general: starter";
    const result = await initSessionState({
      ctx: {
        Body: "Thread reply",
        SessionKey: threadSessionKey,
        ParentSessionKey: parentSessionKey,
        ThreadLabel: threadLabel,
      },
      cfg,
      commandAuthorized: true,
    });

    expect(result.sessionKey).toBe(threadSessionKey);
    expect(result.sessionEntry.sessionId).not.toBe(parentSessionId);
    expect(result.sessionEntry.sessionFile).toBeTruthy();
    expect(result.sessionEntry.displayName).toBe(threadLabel);

    const newSessionFile = result.sessionEntry.sessionFile;
    if (!newSessionFile) {
      throw new Error("Missing session file for forked thread");
    }
    const [headerLine] = (await fs.readFile(newSessionFile, "utf-8"))
      .split(/\r?\n/)
      .filter((line) => line.trim().length > 0);
    const parsedHeader = JSON.parse(headerLine) as {
      parentSession?: string;
    };
    expect(parsedHeader.parentSession).toBe(parentSessionFile);
  });

  it("records topic-specific session files when MessageThreadId is present", async () => {
    const root = await fs.mkdtemp(
      path.join(os.tmpdir(), "clawdbot-topic-session-"),
    );
    const storePath = path.join(root, "sessions.json");

    const cfg = {
      session: { store: storePath },
    } as ClawdbotConfig;

    const result = await initSessionState({
      ctx: {
        Body: "Hello topic",
        SessionKey: "agent:main:telegram:group:123:topic:456",
        MessageThreadId: 456,
      },
      cfg,
      commandAuthorized: true,
    });

    const sessionFile = result.sessionEntry.sessionFile;
    expect(sessionFile).toBeTruthy();
    expect(path.basename(sessionFile ?? "")).toBe(
      `${result.sessionEntry.sessionId}-topic-456.jsonl`,
    );
  });
});