import fs from "node:fs/promises";
import path from "node:path";
import { beforeAll, describe, expect, it, vi } from "vitest";
import type { OpenClawConfig } from "../../../config/config.js";
import type { HookHandler } from "../../hooks.js";
import { makeTempWorkspace, writeWorkspaceFile } from "../../../test-helpers/workspace.js";
import { createHookEvent } from "../../hooks.js";

// Avoid calling the embedded Pi agent (global command lane); keep this unit test deterministic.
vi.mock("../../llm-slug-generator.js", () => ({
  generateSlugViaLLM: vi.fn().mockResolvedValue("simple-math"),
}));

let handler: HookHandler;

beforeAll(async () => {
  ({ default: handler } = await import("./handler.js"));
});

/**
 * Create a mock session JSONL file with various entry types
 */
function createMockSessionContent(
  entries: Array<{ role: string; content: string } | { type: string }>,
): string {
  return entries
    .map((entry) => {
      if ("role" in entry) {
        return JSON.stringify({
          type: "message",
          message: {
            role: entry.role,
            content: entry.content,
          },
        });
      }
      // Non-message entry (tool call, system, etc.)
      return JSON.stringify(entry);
    })
    .join("\n");
}

async function runNewWithPreviousSession(params: {
  sessionContent: string;
  cfg?: (tempDir: string) => OpenClawConfig;
}): Promise<{ tempDir: string; files: string[]; memoryContent: string }> {
  const tempDir = await makeTempWorkspace("openclaw-session-memory-");
  const sessionsDir = path.join(tempDir, "sessions");
  await fs.mkdir(sessionsDir, { recursive: true });

  const sessionFile = await writeWorkspaceFile({
    dir: sessionsDir,
    name: "test-session.jsonl",
    content: params.sessionContent,
  });

  const cfg =
    params.cfg?.(tempDir) ??
    ({
      agents: { defaults: { workspace: tempDir } },
    } satisfies OpenClawConfig);

  const event = createHookEvent("command", "new", "agent:main:main", {
    cfg,
    previousSessionEntry: {
      sessionId: "test-123",
      sessionFile,
    },
  });

  await handler(event);

  const memoryDir = path.join(tempDir, "memory");
  const files = await fs.readdir(memoryDir);
  const memoryContent =
    files.length > 0 ? await fs.readFile(path.join(memoryDir, files[0]), "utf-8") : "";

  return { tempDir, files, memoryContent };
}

describe("session-memory hook", () => {
  it("skips non-command events", async () => {
    const tempDir = await makeTempWorkspace("openclaw-session-memory-");

    const event = createHookEvent("agent", "bootstrap", "agent:main:main", {
      workspaceDir: tempDir,
    });

    await handler(event);

    // Memory directory should not be created for non-command events
    const memoryDir = path.join(tempDir, "memory");
    await expect(fs.access(memoryDir)).rejects.toThrow();
  });

  it("skips commands other than new", async () => {
    const tempDir = await makeTempWorkspace("openclaw-session-memory-");

    const event = createHookEvent("command", "help", "agent:main:main", {
      workspaceDir: tempDir,
    });

    await handler(event);

    // Memory directory should not be created for other commands
    const memoryDir = path.join(tempDir, "memory");
    await expect(fs.access(memoryDir)).rejects.toThrow();
  });

  it("creates memory file with session content on /new command", async () => {
    // Create a mock session file with user/assistant messages
    const sessionContent = createMockSessionContent([
      { role: "user", content: "Hello there" },
      { role: "assistant", content: "Hi! How can I help?" },
      { role: "user", content: "What is 2+2?" },
      { role: "assistant", content: "2+2 equals 4" },
    ]);
    const { files, memoryContent } = await runNewWithPreviousSession({ sessionContent });
    expect(files.length).toBe(1);

    // Read the memory file and verify content
    expect(memoryContent).toContain("user: Hello there");
    expect(memoryContent).toContain("assistant: Hi! How can I help?");
    expect(memoryContent).toContain("user: What is 2+2?");
    expect(memoryContent).toContain("assistant: 2+2 equals 4");
  });

  it("filters out non-message entries (tool calls, system)", async () => {
    // Create session with mixed entry types
    const sessionContent = createMockSessionContent([
      { role: "user", content: "Hello" },
      { type: "tool_use", tool: "search", input: "test" },
      { role: "assistant", content: "World" },
      { type: "tool_result", result: "found it" },
      { role: "user", content: "Thanks" },
    ]);
    const { memoryContent } = await runNewWithPreviousSession({ sessionContent });

    // Only user/assistant messages should be present
    expect(memoryContent).toContain("user: Hello");
    expect(memoryContent).toContain("assistant: World");
    expect(memoryContent).toContain("user: Thanks");
    // Tool entries should not appear
    expect(memoryContent).not.toContain("tool_use");
    expect(memoryContent).not.toContain("tool_result");
    expect(memoryContent).not.toContain("search");
  });

  it("filters out inter-session user messages", async () => {
    const sessionContent = [
      JSON.stringify({
        type: "message",
        message: {
          role: "user",
          content: "Forwarded internal instruction",
          provenance: { kind: "inter_session", sourceTool: "sessions_send" },
        },
      }),
      JSON.stringify({
        type: "message",
        message: { role: "assistant", content: "Acknowledged" },
      }),
      JSON.stringify({
        type: "message",
        message: { role: "user", content: "External follow-up" },
      }),
    ].join("\n");
    const { memoryContent } = await runNewWithPreviousSession({ sessionContent });

    expect(memoryContent).not.toContain("Forwarded internal instruction");
    expect(memoryContent).toContain("assistant: Acknowledged");
    expect(memoryContent).toContain("user: External follow-up");
  });

  it("filters out command messages starting with /", async () => {
    const sessionContent = createMockSessionContent([
      { role: "user", content: "/help" },
      { role: "assistant", content: "Here is help info" },
      { role: "user", content: "Normal message" },
      { role: "user", content: "/new" },
    ]);
    const { memoryContent } = await runNewWithPreviousSession({ sessionContent });

    // Command messages should be filtered out
    expect(memoryContent).not.toContain("/help");
    expect(memoryContent).not.toContain("/new");
    // Normal messages should be present
    expect(memoryContent).toContain("assistant: Here is help info");
    expect(memoryContent).toContain("user: Normal message");
  });

  it("respects custom messages config (limits to N messages)", async () => {
    // Create 10 messages
    const entries = [];
    for (let i = 1; i <= 10; i++) {
      entries.push({ role: "user", content: `Message ${i}` });
    }
    const sessionContent = createMockSessionContent(entries);
    const { memoryContent } = await runNewWithPreviousSession({
      sessionContent,
      cfg: (tempDir) => ({
        agents: { defaults: { workspace: tempDir } },
        hooks: {
          internal: {
            entries: {
              "session-memory": { enabled: true, messages: 3 },
            },
          },
        },
      }),
    });

    // Only last 3 messages should be present
    expect(memoryContent).not.toContain("user: Message 1\n");
    expect(memoryContent).not.toContain("user: Message 7\n");
    expect(memoryContent).toContain("user: Message 8");
    expect(memoryContent).toContain("user: Message 9");
    expect(memoryContent).toContain("user: Message 10");
  });

  it("filters messages before slicing (fix for #2681)", async () => {
    // Create session with many tool entries interspersed with messages
    // This tests that we filter FIRST, then slice - not the other way around
    const entries = [
      { role: "user", content: "First message" },
      { type: "tool_use", tool: "test1" },
      { type: "tool_result", result: "result1" },
      { role: "assistant", content: "Second message" },
      { type: "tool_use", tool: "test2" },
      { type: "tool_result", result: "result2" },
      { role: "user", content: "Third message" },
      { type: "tool_use", tool: "test3" },
      { type: "tool_result", result: "result3" },
      { role: "assistant", content: "Fourth message" },
    ];
    const sessionContent = createMockSessionContent(entries);
    const { memoryContent } = await runNewWithPreviousSession({
      sessionContent,
      cfg: (tempDir) => ({
        agents: { defaults: { workspace: tempDir } },
        hooks: {
          internal: {
            entries: {
              "session-memory": { enabled: true, messages: 3 },
            },
          },
        },
      }),
    });

    // Should have exactly 3 user/assistant messages (the last 3)
    expect(memoryContent).not.toContain("First message");
    expect(memoryContent).toContain("user: Third message");
    expect(memoryContent).toContain("assistant: Second message");
    expect(memoryContent).toContain("assistant: Fourth message");
  });

  it("handles empty session files gracefully", async () => {
    // Should not throw
    const { files } = await runNewWithPreviousSession({ sessionContent: "" });
    expect(files.length).toBe(1);
  });

  it("handles session files with fewer messages than requested", async () => {
    // Only 2 messages but requesting 15 (default)
    const sessionContent = createMockSessionContent([
      { role: "user", content: "Only message 1" },
      { role: "assistant", content: "Only message 2" },
    ]);
    const { memoryContent } = await runNewWithPreviousSession({ sessionContent });

    // Both messages should be included
    expect(memoryContent).toContain("user: Only message 1");
    expect(memoryContent).toContain("assistant: Only message 2");
  });
});
