/**
 * Unit tests for RedisQueue
 * Tests enqueue, claim, complete, fail, and retry functionality
 */

import RedisQueue from "../../src/queue/RedisQueue";
import {
  TaskPayload,
  TaskState,
  TaskStatus,
  calculateRetryDelay,
  serializeTask,
  deserializeTask,
} from "../../src/queue/Task";

// Mock ioredis
jest.mock("ioredis");

// Get the mocked Redis class
const MockedRedis = require("ioredis");

describe("RedisQueue", () => {
  let queue: RedisQueue;
  let mockRedis: any;

  beforeEach(() => {
    // Reset mocks
    jest.clearAllMocks();

    // Create mock Redis instance
    mockRedis = {
      hset: jest.fn().mockResolvedValue(1),
      hget: jest.fn().mockResolvedValue(null),
      hgetall: jest.fn().mockResolvedValue({}),
      expire: jest.fn().mockResolvedValue(1),
      zadd: jest.fn().mockResolvedValue(1),
      zrem: jest.fn().mockResolvedValue(1),
      zcard: jest.fn().mockResolvedValue(0),
      zrangebyscore: jest.fn().mockResolvedValue([]),
      xadd: jest.fn().mockResolvedValue("123-0"),
      xreadgroup: jest.fn().mockResolvedValue(null),
      xgroup: jest.fn().mockResolvedValue("OK"),
      xpending: jest.fn().mockResolvedValue([0, null, null, []]),
      xack: jest.fn().mockResolvedValue(1),
      xclaim: jest.fn().mockResolvedValue([]),
      xlen: jest.fn().mockResolvedValue(0),
      hlen: jest.fn().mockResolvedValue(0),
      hdel: jest.fn().mockResolvedValue(1),
      quit: jest.fn().mockResolvedValue("OK"),
    };

    MockedRedis.mockImplementation(() => mockRedis);

    queue = new RedisQueue({ redisUrl: "redis://localhost:6379/0" });
  });

  afterEach(async () => {
    await queue.close();
  });

  describe("initialize", () => {
    it("should create consumer group", async () => {
      await queue.initialize();
      expect(mockRedis.xgroup).toHaveBeenCalledWith(
        "CREATE",
        "ade:queue:tasks",
        "ade-workers",
        "$",
        "MKSTREAM"
      );
    });

    it("should not throw if group already exists", async () => {
      mockRedis.xgroup.mockRejectedValueOnce(new Error("BUSYGROUP Consumer Group name already exists"));
      await expect(queue.initialize()).resolves.not.toThrow();
    });
  });

  describe("enqueue", () => {
    const sampleTask: TaskPayload = {
      id: "test-task-1",
      kind: "task_notification",
      priority: 5,
      maxAttempts: 3,
      backoffMultiplier: 2,
      maxBackoffMs: 300000,
      enqueuedAt: Date.now(),
      source: "user",
      text: "Test task",
    };

    it("should enqueue a task successfully", async () => {
      const result = await queue.enqueue(sampleTask);

      expect(result.success).toBe(true);
      expect(result.taskId).toBe("test-task-1");
      expect(mockRedis.hset).toHaveBeenCalled();
      expect(mockRedis.expire).toHaveBeenCalled();
      expect(mockRedis.xadd).toHaveBeenCalled();
    });

    it("should handle delayed tasks", async () => {
      const delayedTask: TaskPayload = {
        ...sampleTask,
        runAfter: Date.now() + 60000, // 1 minute delay
      };

      const result = await queue.enqueue(delayedTask);

      expect(result.success).toBe(true);
      expect(mockRedis.zadd).toHaveBeenCalled();
      expect(mockRedis.xadd).not.toHaveBeenCalled();
    });

    it("should handle errors gracefully", async () => {
      mockRedis.hset.mockRejectedValueOnce(new Error("Redis error"));

      const result = await queue.enqueue(sampleTask);

      expect(result.success).toBe(false);
      expect(result.error).toBe("Redis error");
    });

    it("should generate task ID if not provided", async () => {
      const taskWithoutId: Omit<TaskPayload, "id"> = {
        kind: "message",
        priority: 5,
        maxAttempts: 3,
        backoffMultiplier: 2,
        maxBackoffMs: 300000,
        enqueuedAt: Date.now(),
        source: "system",
      };

      const result = await queue.enqueue(taskWithoutId as TaskPayload);

      expect(result.success).toBe(true);
      expect(result.taskId).toBeDefined();
      expect(result.taskId).not.toBe("");
    });
  });

  describe("claimTasks", () => {
    const sampleTaskData: TaskState = {
      id: "test-task-1",
      kind: "task_notification",
      status: "pending",
      priority: 5,
      maxAttempts: 3,
      backoffMultiplier: 2,
      maxBackoffMs: 300000,
      enqueuedAt: Date.now(),
      source: "user",
      attemptCount: 0,
    };

    it("should claim tasks from the queue", async () => {
      mockRedis.xreadgroup.mockResolvedValueOnce([
        ["ade:queue:tasks", [
          ["123-0", ["taskId", "test-task-1", "payload", "{}", "priority", "5"]]
        ]]
      ]);

      mockRedis.hgetall.mockResolvedValueOnce({
        id: "test-task-1",
        kind: "task_notification",
        status: "pending",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "0",
      });

      const tasks = await queue.claimTasks("worker-1", { batchSize: 5 });

      expect(tasks.length).toBeGreaterThan(0);
      expect(tasks[0].id).toBe("test-task-1");
      expect(tasks[0].status).toBe("claimed");
      expect(tasks[0].workerId).toBe("worker-1");
    });

    it("should return empty array when no tasks available", async () => {
      mockRedis.xreadgroup.mockResolvedValueOnce(null);

      const tasks = await queue.claimTasks("worker-1");

      expect(tasks).toEqual([]);
    });

    it("should skip tasks not found in hash", async () => {
      mockRedis.xreadgroup.mockResolvedValueOnce([
        ["ade:queue:tasks", [
          ["123-0", ["taskId", "missing-task", "payload", "{}", "priority", "5"]]
        ]]
      ]);

      mockRedis.hgetall.mockResolvedValueOnce({}); // Empty = not found

      const tasks = await queue.claimTasks("worker-1");

      expect(tasks).toEqual([]);
    });
  });

  describe("completeTask", () => {
    it("should mark task as completed", async () => {
      const taskId = "test-task-1";
      const result = { success: true, data: "completed" };

      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "claimed",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "0",
      });

      const success = await queue.completeTask(taskId, result);

      expect(success).toBe(true);
      expect(mockRedis.hset).toHaveBeenCalled();
    });

    it("should return false for non-existent task", async () => {
      mockRedis.hgetall.mockResolvedValueOnce({});

      const success = await queue.completeTask("missing-task");

      expect(success).toBe(false);
    });
  });

  describe("failTask", () => {
    it("should mark task as failed on final attempt", async () => {
      const taskId = "test-task-1";

      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "claimed",
        priority: "5",
        maxAttempts: "2",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "1", // Will become 2, which equals maxAttempts
      });

      const success = await queue.failTask(taskId, "Task failed");

      expect(success).toBe(true);
      expect(mockRedis.hset).toHaveBeenCalled();
      // Should set status to failed
      const hsetCall = mockRedis.hset.mock.calls[0];
      expect(hsetCall[1].status).toBe("failed");
    });

    it("should schedule retry on non-final failure", async () => {
      const taskId = "test-task-1";

      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "claimed",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "0", // Will become 1, retry allowed
      });

      const success = await queue.failTask(taskId, "Temporary error");

      expect(success).toBe(true);
      // Should add to delayed queue for retry
      expect(mockRedis.zadd).toHaveBeenCalled();
      expect(mockRedis.hset).toHaveBeenCalled();
      // Should set status back to pending
      const hsetCall = mockRedis.hset.mock.calls[0];
      expect(hsetCall[1].status).toBe("pending");
    });
  });

  describe("promoteDelayedTasks", () => {
    it("should promote due delayed tasks", async () => {
      const taskId = "delayed-task-1";

      mockRedis.zrangebyscore.mockResolvedValueOnce([taskId]);
      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "pending",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "1",
      });

      const count = await queue.promoteDelayedTasks(10);

      expect(count).toBe(1);
      expect(mockRedis.zrem).toHaveBeenCalled();
      expect(mockRedis.xadd).toHaveBeenCalled();
    });

    it("should return 0 when no delayed tasks", async () => {
      mockRedis.zrangebyscore.mockResolvedValueOnce([]);

      const count = await queue.promoteDelayedTasks();

      expect(count).toBe(0);
      expect(mockRedis.xadd).not.toHaveBeenCalled();
    });
  });

  describe("worker registration", () => {
    it("should register worker", async () => {
      await queue.registerWorker("worker-1", {
        hostname: "test-host",
        pid: 12345,
        version: "1.0.0",
      });

      expect(mockRedis.hset).toHaveBeenCalled();
      expect(mockRedis.zadd).toHaveBeenCalled();
    });

    it("should update heartbeat", async () => {
      await queue.updateHeartbeat("worker-1");

      expect(mockRedis.zadd).toHaveBeenCalled();
    });

    it("should deregister worker", async () => {
      await queue.deregisterWorker("worker-1");

      expect(mockRedis.hdel).toHaveBeenCalled();
      expect(mockRedis.zrem).toHaveBeenCalled();
    });
  });

  describe("getStats", () => {
    it("should return queue statistics", async () => {
      mockRedis.xpending.mockResolvedValue([5, null, null, []]);
      mockRedis.zcard.mockResolvedValue(3);
      mockRedis.xlen.mockResolvedValue(100);
      mockRedis.hlen.mockResolvedValue(2);

      const stats = await queue.getStats();

      expect(stats.pending).toBe(5);
      expect(stats.delayed).toBe(3);
      expect(stats.streamLength).toBe(100);
      expect(stats.activeWorkers).toBe(2);
    });
  });

  describe("getTask", () => {
    it("should return task by ID", async () => {
      const taskId = "test-task-1";

      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "pending",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: "1234567890",
        source: "user",
        attemptCount: "0",
      });

      const task = await queue.getTask(taskId);

      expect(task).not.toBeNull();
      expect(task?.id).toBe(taskId);
      expect(task?.kind).toBe("task_notification");
    });

    it("should return null for non-existent task", async () => {
      mockRedis.hgetall.mockResolvedValueOnce({});

      const task = await queue.getTask("missing-task");

      expect(task).toBeNull();
    });
  });

  describe("cancelTask", () => {
    it("should cancel a pending task", async () => {
      const taskId = "test-task-1";

      mockRedis.hgetall.mockResolvedValueOnce({
        id: taskId,
        kind: "task_notification",
        status: "pending",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "0",
      });

      const success = await queue.cancelTask(taskId);

      expect(success).toBe(true);
      const hsetCall = mockRedis.hset.mock.calls[0];
      expect(hsetCall[1].status).toBe("cancelled");
    });

    it("should not cancel completed tasks", async () => {
      mockRedis.hgetall.mockResolvedValueOnce({
        id: "test-task-1",
        kind: "task_notification",
        status: "completed",
        priority: "5",
        maxAttempts: "3",
        backoffMultiplier: "2",
        maxBackoffMs: "300000",
        enqueuedAt: Date.now().toString(),
        source: "user",
        attemptCount: "0",
        completedAt: Date.now().toString(),
      });

      const success = await queue.cancelTask("test-task-1");

      expect(success).toBe(false);
    });
  });
});

describe("Task utilities", () => {
  describe("calculateRetryDelay", () => {
    it("should calculate exponential backoff", () => {
      const delay0 = calculateRetryDelay({ attempt: 0, baseDelayMs: 1000 });
      const delay1 = calculateRetryDelay({ attempt: 1, baseDelayMs: 1000 });
      const delay2 = calculateRetryDelay({ attempt: 2, baseDelayMs: 1000 });

      expect(delay0).toBeGreaterThanOrEqual(900); // With jitter
      expect(delay0).toBeLessThanOrEqual(1100);
      expect(delay1).toBeGreaterThanOrEqual(1800);
      expect(delay1).toBeLessThanOrEqual(2200);
      expect(delay2).toBeGreaterThanOrEqual(3600);
      expect(delay2).toBeLessThanOrEqual(4400);
    });

    it("should cap at maxDelayMs", () => {
      const delay = calculateRetryDelay({
        attempt: 10,
        baseDelayMs: 1000,
        maxDelayMs: 5000,
        jitterFactor: 0, // Disable jitter for this test
      });

      expect(delay).toBeLessThanOrEqual(5000);
    });
  });

  describe("serializeTask / deserializeTask", () => {
    it("should serialize and deserialize task state", () => {
      const task: TaskState = {
        id: "test-task",
        kind: "task_notification",
        status: "pending",
        priority: 5,
        maxAttempts: 3,
        backoffMultiplier: 2,
        maxBackoffMs: 300000,
        enqueuedAt: 1234567890,
        source: "user",
        attemptCount: 0,
        text: "Test task",
        content: { key: "value" },
        isCoalescable: true,
      };

      const serialized = serializeTask(task);
      expect(serialized.id).toBe("test-task");
      expect(serialized.content).toBe('{"key":"value"}');
      expect(serialized.isCoalescable).toBe("1");

      const deserialized = deserializeTask(serialized);
      expect(deserialized.id).toBe(task.id);
      expect(deserialized.kind).toBe(task.kind);
      expect(deserialized.status).toBe(task.status);
      expect(deserialized.content).toEqual(task.content);
      expect(deserialized.isCoalescable).toBe(true);
    });
  });
});