import { describe, it, expect } from "vitest";
import { discoverSessions } from "../../src/server/services/session-discovery.js";
import path from "path";
import fs from "fs/promises";
import os from "os";

/** Helper to write a sessions-index.json in the real { version, entries } format */
function makeIndex(entries: Record<string, unknown>[]) {
  return JSON.stringify({ version: 1, entries });
}

describe("session-discovery", () => {
  it("discovers sessions from { version, entries } format", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-${Date.now()}`);
    const projectDir = path.join(tmpDir, "test-project");
    await fs.mkdir(projectDir, { recursive: true });

    const sessionPath = path.join(projectDir, "sess-001.jsonl");
    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      makeIndex([
        {
          sessionId: "sess-001",
          fullPath: sessionPath,
          summary: "Test session",
          firstPrompt: "Hello",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
          messageCount: 5,
        },
      ])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toHaveLength(1);
    expect(sessions[0].id).toBe("sess-001");
    expect(sessions[0].summary).toBe("Test session");
    expect(sessions[0].project).toBe("test-project");
    expect(sessions[0].messageCount).toBe(5);
    expect(sessions[0].path).toBe(sessionPath);

    await fs.rm(tmpDir, { recursive: true });
  });

  it("also handles legacy raw array format", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-legacy-${Date.now()}`);
    const projectDir = path.join(tmpDir, "legacy-project");
    await fs.mkdir(projectDir, { recursive: true });

    // Raw array (not wrapped in { version, entries })
    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      JSON.stringify([
        {
          sessionId: "legacy-001",
          summary: "Legacy format",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
      ])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toHaveLength(1);
    expect(sessions[0].id).toBe("legacy-001");

    await fs.rm(tmpDir, { recursive: true });
  });

  it("handles missing projects directory gracefully", async () => {
    const sessions = await discoverSessions("/nonexistent/path");
    expect(sessions).toEqual([]);
  });

  it("handles corrupt index files gracefully", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-corrupt-${Date.now()}`);
    const projectDir = path.join(tmpDir, "corrupt-project");
    await fs.mkdir(projectDir, { recursive: true });
    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      "not valid json {"
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toEqual([]);

    await fs.rm(tmpDir, { recursive: true });
  });

  it("aggregates across multiple project directories", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-multi-${Date.now()}`);
    const proj1 = path.join(tmpDir, "project-a");
    const proj2 = path.join(tmpDir, "project-b");
    await fs.mkdir(proj1, { recursive: true });
    await fs.mkdir(proj2, { recursive: true });

    await fs.writeFile(
      path.join(proj1, "sessions-index.json"),
      makeIndex([{ sessionId: "a-001", created: "2025-01-01T00:00:00Z", modified: "2025-01-01T00:00:00Z" }])
    );
    await fs.writeFile(
      path.join(proj2, "sessions-index.json"),
      makeIndex([{ sessionId: "b-001", created: "2025-01-02T00:00:00Z", modified: "2025-01-02T00:00:00Z" }])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toHaveLength(2);
    const ids = sessions.map((s) => s.id);
    expect(ids).toContain("a-001");
    expect(ids).toContain("b-001");

    await fs.rm(tmpDir, { recursive: true });
  });

  it("rejects paths with traversal segments", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-traversal-${Date.now()}`);
    const projectDir = path.join(tmpDir, "traversal-project");
    await fs.mkdir(projectDir, { recursive: true });

    const goodPath = path.join(projectDir, "good-001.jsonl");
    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      makeIndex([
        {
          sessionId: "evil-001",
          fullPath: "/home/ubuntu/../../../etc/passwd",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
        {
          sessionId: "evil-002",
          fullPath: "/home/ubuntu/sessions/not-a-jsonl.txt",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
        {
          sessionId: "good-001",
          fullPath: goodPath,
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
      ])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toHaveLength(1);
    expect(sessions[0].id).toBe("good-001");

    await fs.rm(tmpDir, { recursive: true });
  });

  it("rejects absolute paths outside the projects directory", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-containment-${Date.now()}`);
    const projectDir = path.join(tmpDir, "contained-project");
    await fs.mkdir(projectDir, { recursive: true });

    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      makeIndex([
        {
          sessionId: "escaped-001",
          fullPath: "/etc/shadow.jsonl",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
        {
          sessionId: "escaped-002",
          fullPath: "/tmp/other-dir/secret.jsonl",
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
      ])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions).toHaveLength(0);

    await fs.rm(tmpDir, { recursive: true });
  });

  it("uses fullPath from index entry", async () => {
    const tmpDir = path.join(os.tmpdir(), `sv-test-fp-${Date.now()}`);
    const projectDir = path.join(tmpDir, "fp-project");
    await fs.mkdir(projectDir, { recursive: true });

    const sessionPath = path.join(projectDir, "fp-001.jsonl");
    await fs.writeFile(
      path.join(projectDir, "sessions-index.json"),
      makeIndex([
        {
          sessionId: "fp-001",
          fullPath: sessionPath,
          created: "2025-10-15T10:00:00Z",
          modified: "2025-10-15T11:00:00Z",
        },
      ])
    );

    const sessions = await discoverSessions(tmpDir);
    expect(sessions[0].path).toBe(sessionPath);

    await fs.rm(tmpDir, { recursive: true });
  });
});