import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
import { CronScheduler, type CronJob } from "../../src/cron-scheduler.js";
import type { Event } from "../../src/event-queue.js";

// Mock node-cron
vi.mock("node-cron", () => {
  const tasks: Array<{ expression: string; callback: () => void; stopped: boolean }> = [];

  return {
    default: {
      validate: (expr: string) => {
        // Simple validation: reject obviously invalid expressions
        if (expr === "invalid" || expr === "bad-cron" || expr === "not a cron") return false;
        // Accept standard 5-field cron expressions
        const parts = expr.trim().split(/\s+/);
        return parts.length === 5 || parts.length === 6;
      },
      schedule: (expression: string, callback: () => void) => {
        const task = { expression, callback, stopped: false };
        tasks.push(task);
        return {
          stop: () => { task.stopped = true; },
          start: () => { task.stopped = false; },
        };
      },
      // Helper to get tasks for testing
      _getTasks: () => tasks,
      _clearTasks: () => { tasks.length = 0; },
      _fireLast: () => {
        const last = tasks[tasks.length - 1];
        if (last && !last.stopped) last.callback();
      },
      _fireAll: () => {
        for (const t of tasks) {
          if (!t.stopped) t.callback();
        }
      },
    },
  };
});

// Import the mock to access helpers
import cron from "node-cron";
const mockCron = cron as unknown as {
  validate: (expr: string) => boolean;
  schedule: (expression: string, callback: () => void) => { stop: () => void };
  _getTasks: () => Array<{ expression: string; callback: () => void; stopped: boolean }>;
  _clearTasks: () => void;
  _fireLast: () => void;
  _fireAll: () => void;
};

type EnqueueFn = (event: Omit<Event, "id" | "timestamp">) => Event | null;

describe("CronScheduler", () => {
  let scheduler: CronScheduler;

  beforeEach(() => {
    mockCron._clearTasks();
    scheduler = new CronScheduler();
  });

  afterEach(() => {
    scheduler.stop();
  });

  describe("parseConfig", () => {
    it("parses a single cron job from agents.md content", () => {
      const content = `## Cron Jobs

### daily-email-check
Cron: 0 9 * * *
Instruction: Check email and flag anything urgent`;

      const jobs = scheduler.parseConfig(content);
      expect(jobs).toEqual([
        { name: "daily-email-check", expression: "0 9 * * *", instruction: "Check email and flag anything urgent" },
      ]);
    });

    it("parses multiple cron jobs", () => {
      const content = `## Cron Jobs

### daily-email-check
Cron: 0 9 * * *
Instruction: Check email and flag anything urgent

### weekly-review
Cron: 0 15 * * 1
Instruction: Review calendar for the week`;

      const jobs = scheduler.parseConfig(content);
      expect(jobs).toHaveLength(2);
      expect(jobs[0]).toEqual({
        name: "daily-email-check",
        expression: "0 9 * * *",
        instruction: "Check email and flag anything urgent",
      });
      expect(jobs[1]).toEqual({
        name: "weekly-review",
        expression: "0 15 * * 1",
        instruction: "Review calendar for the week",
      });
    });

    it("returns empty array when no Cron Jobs section exists", () => {
      const content = `## Hooks

### startup
Instruction: Say hello`;

      expect(scheduler.parseConfig(content)).toEqual([]);
    });

    it("returns empty array for empty content", () => {
      expect(scheduler.parseConfig("")).toEqual([]);
    });

    it("skips incomplete job definitions (missing instruction)", () => {
      const content = `## Cron Jobs

### incomplete-job
Cron: 0 9 * * *`;

      expect(scheduler.parseConfig(content)).toEqual([]);
    });

    it("skips incomplete job definitions (missing cron expression)", () => {
      const content = `## Cron Jobs

### incomplete-job
Instruction: Do something`;

      expect(scheduler.parseConfig(content)).toEqual([]);
    });

    it("only parses jobs within the Cron Jobs section", () => {
      const content = `## Hooks

### startup
Cron: 0 0 * * *
Instruction: This should not be parsed

## Cron Jobs

### real-job
Cron: 0 9 * * *
Instruction: This should be parsed

## Other Section

### not-a-job
Cron: 0 0 * * *
Instruction: This should not be parsed either`;

      const jobs = scheduler.parseConfig(content);
      expect(jobs).toHaveLength(1);
      expect(jobs[0].name).toBe("real-job");
    });
  });

  describe("start", () => {
    it("schedules valid cron jobs and enqueues events on trigger", () => {
      const enqueued: Omit<Event, "id" | "timestamp">[] = [];
      const enqueue: EnqueueFn = (event) => {
        enqueued.push(event);
        return { ...event, id: enqueued.length, timestamp: new Date() } as Event;
      };

      const jobs: CronJob[] = [
        { name: "daily-check", expression: "0 9 * * *", instruction: "Check email" },
      ];

      scheduler.start(jobs, enqueue);

      // Simulate cron trigger
      mockCron._fireAll();

      expect(enqueued).toHaveLength(1);
      expect(enqueued[0]).toEqual({
        type: "cron",
        payload: { instruction: "Check email", jobName: "daily-check" },
        source: "cron-scheduler",
      });
    });

    it("skips jobs with invalid cron expressions and logs a warning", () => {
      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
      const enqueue: EnqueueFn = (event) =>
        ({ ...event, id: 1, timestamp: new Date() }) as Event;

      const jobs: CronJob[] = [
        { name: "bad-job", expression: "invalid", instruction: "Do something" },
      ];

      scheduler.start(jobs, enqueue);

      expect(warnSpy).toHaveBeenCalledWith(
        expect.stringContaining("bad-job")
      );
      expect(warnSpy).toHaveBeenCalledWith(
        expect.stringContaining("invalid cron expression")
      );

      warnSpy.mockRestore();
    });

    it("schedules valid jobs and skips invalid ones in the same batch", () => {
      const enqueued: Omit<Event, "id" | "timestamp">[] = [];
      const enqueue: EnqueueFn = (event) => {
        enqueued.push(event);
        return { ...event, id: enqueued.length, timestamp: new Date() } as Event;
      };
      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});

      const jobs: CronJob[] = [
        { name: "bad-job", expression: "invalid", instruction: "Bad" },
        { name: "good-job", expression: "0 9 * * *", instruction: "Good" },
      ];

      scheduler.start(jobs, enqueue);

      expect(warnSpy).toHaveBeenCalledTimes(1);

      // Only the valid job should have been scheduled — fire all
      mockCron._fireAll();
      expect(enqueued).toHaveLength(1);
      expect(enqueued[0].payload).toEqual({ instruction: "Good", jobName: "good-job" });

      warnSpy.mockRestore();
    });
  });

  describe("stop", () => {
    it("stops all scheduled cron tasks", () => {
      const enqueued: Omit<Event, "id" | "timestamp">[] = [];
      const enqueue: EnqueueFn = (event) => {
        enqueued.push(event);
        return { ...event, id: enqueued.length, timestamp: new Date() } as Event;
      };

      const jobs: CronJob[] = [
        { name: "job-a", expression: "0 9 * * *", instruction: "Do A" },
        { name: "job-b", expression: "0 15 * * 1", instruction: "Do B" },
      ];

      scheduler.start(jobs, enqueue);

      // Fire once before stopping
      mockCron._fireAll();
      expect(enqueued).toHaveLength(2);

      scheduler.stop();

      // After stop, firing should not enqueue (tasks are stopped)
      mockCron._fireAll();
      expect(enqueued).toHaveLength(2);
    });

    it("is safe to call stop when no tasks are scheduled", () => {
      expect(() => scheduler.stop()).not.toThrow();
    });
  });
});