// ABOUTME: Unit tests for period logging API route.
// ABOUTME: Tests POST /api/cycle/period for period start date logging.
import type { NextRequest } from "next/server";
import { NextResponse } from "next/server";
import { beforeEach, describe, expect, it, vi } from "vitest";

import type { User } from "@/types";

// Module-level variable to control mock user in tests
let currentMockUser: User | null = null;

// Mock PocketBase client for database operations
const mockPbUpdate = vi.fn();
const mockPbCreate = vi.fn();

vi.mock("@/lib/pocketbase", () => ({
  createPocketBaseClient: vi.fn(() => ({
    collection: vi.fn((_name: string) => ({
      update: mockPbUpdate,
      create: mockPbCreate,
    })),
  })),
  loadAuthFromCookies: vi.fn(),
  isAuthenticated: vi.fn(() => currentMockUser !== null),
  getCurrentUser: vi.fn(() => currentMockUser),
}));

// Mock the auth-middleware module
vi.mock("@/lib/auth-middleware", () => ({
  withAuth: vi.fn((handler) => {
    return async (request: NextRequest) => {
      if (!currentMockUser) {
        return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
      }
      return handler(request, currentMockUser);
    };
  }),
}));

import { POST } from "./route";

describe("POST /api/cycle/period", () => {
  const mockUser: User = {
    id: "user123",
    email: "test@example.com",
    garminConnected: false,
    garminOauth1Token: "",
    garminOauth2Token: "",
    garminTokenExpiresAt: new Date("2025-06-01"),
    calendarToken: "cal-secret-token",
    lastPeriodDate: new Date("2024-12-15"),
    cycleLength: 28,
    notificationTime: "07:00",
    timezone: "America/New_York",
    activeOverrides: [],
    created: new Date("2024-01-01"),
    updated: new Date("2025-01-10"),
  };

  beforeEach(() => {
    vi.clearAllMocks();
    currentMockUser = null;
    mockPbUpdate.mockResolvedValue({});
    mockPbCreate.mockResolvedValue({ id: "periodlog123" });
  });

  it("returns 401 when not authenticated", async () => {
    currentMockUser = null;

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(401);
    const body = await response.json();
    expect(body.error).toBe("Unauthorized");
  });

  it("returns 400 when startDate is missing", async () => {
    currentMockUser = mockUser;

    const mockRequest = {
      json: vi.fn().mockResolvedValue({}),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(400);
    const body = await response.json();
    expect(body.error).toContain("startDate");
  });

  it("returns 400 when startDate is invalid format", async () => {
    currentMockUser = mockUser;

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: "invalid-date" }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(400);
    const body = await response.json();
    expect(body.error).toContain("Invalid");
  });

  it("returns 400 when startDate is in the future", async () => {
    currentMockUser = mockUser;

    // Set a date far in the future
    const futureDate = new Date();
    futureDate.setFullYear(futureDate.getFullYear() + 1);
    const futureDateStr = futureDate.toISOString().split("T")[0];

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: futureDateStr }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(400);
    const body = await response.json();
    expect(body.error).toContain("future");
  });

  it("updates user lastPeriodDate and creates PeriodLog", async () => {
    currentMockUser = mockUser;

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(200);

    // Verify user record was updated
    expect(mockPbUpdate).toHaveBeenCalledWith(
      "user123",
      expect.objectContaining({
        lastPeriodDate: "2025-01-10",
      }),
    );

    // Verify PeriodLog was created
    expect(mockPbCreate).toHaveBeenCalledWith(
      expect.objectContaining({
        user: "user123",
        startDate: "2025-01-10",
      }),
    );
  });

  it("returns updated cycle information", async () => {
    currentMockUser = mockUser;

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(200);
    const body = await response.json();

    // Should return cycle info
    expect(body.lastPeriodDate).toBe("2025-01-10");
    expect(body.cycleDay).toBeTypeOf("number");
    expect(body.phase).toBeTypeOf("string");
    expect(body.message).toBe("Period start date logged successfully");
  });

  it("calculates correct cycle day for new period", async () => {
    currentMockUser = mockUser;

    // If period started today, cycle day should be 1
    const today = new Date().toISOString().split("T")[0];

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: today }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(200);
    const body = await response.json();

    expect(body.cycleDay).toBe(1);
    expect(body.phase).toBe("MENSTRUAL");
  });

  it("handles database update errors gracefully", async () => {
    currentMockUser = mockUser;
    mockPbUpdate.mockRejectedValue(new Error("Database error"));

    const mockRequest = {
      json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
    } as unknown as NextRequest;

    const response = await POST(mockRequest);

    expect(response.status).toBe(500);
    const body = await response.json();
    expect(body.error).toBe("Failed to update period date");
  });

  describe("prediction accuracy tracking", () => {
    it("calculates and stores predictedDate based on previous cycle", async () => {
      // User's last period was 2024-12-15 with 28-day cycle
      // Predicted next period: 2024-12-15 + 28 days = 2025-01-12
      currentMockUser = mockUser;

      const mockRequest = {
        json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
      } as unknown as NextRequest;

      const response = await POST(mockRequest);

      expect(response.status).toBe(200);

      // Verify PeriodLog was created with predictedDate
      expect(mockPbCreate).toHaveBeenCalledWith(
        expect.objectContaining({
          user: "user123",
          startDate: "2025-01-10",
          predictedDate: "2025-01-12", // lastPeriodDate (Dec 15) + cycleLength (28)
        }),
      );
    });

    it("returns prediction accuracy information in response", async () => {
      currentMockUser = mockUser;

      const mockRequest = {
        json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
      } as unknown as NextRequest;

      const response = await POST(mockRequest);

      expect(response.status).toBe(200);
      const body = await response.json();

      expect(body.predictedDate).toBe("2025-01-12");
      expect(body.daysEarly).toBe(2); // Arrived 2 days early
    });

    it("handles period arriving late (positive daysLate)", async () => {
      currentMockUser = mockUser;

      // Period arrives 3 days after predicted (2025-01-15 instead of 2025-01-12)
      const mockRequest = {
        json: vi.fn().mockResolvedValue({ startDate: "2025-01-15" }),
      } as unknown as NextRequest;

      const response = await POST(mockRequest);

      expect(response.status).toBe(200);
      const body = await response.json();

      expect(body.predictedDate).toBe("2025-01-12");
      expect(body.daysLate).toBe(3);
    });

    it("sets predictedDate to null when user has no previous lastPeriodDate", async () => {
      // First period log - no previous cycle data
      currentMockUser = {
        ...mockUser,
        lastPeriodDate: null as unknown as Date,
      };

      const mockRequest = {
        json: vi.fn().mockResolvedValue({ startDate: "2025-01-10" }),
      } as unknown as NextRequest;

      const response = await POST(mockRequest);

      expect(response.status).toBe(200);

      // Should not include predictedDate for first log
      expect(mockPbCreate).toHaveBeenCalledWith(
        expect.objectContaining({
          user: "user123",
          startDate: "2025-01-10",
          predictedDate: null,
        }),
      );
    });

    it("handles period arriving on predicted date exactly", async () => {
      currentMockUser = mockUser;

      // Period arrives exactly on predicted date (2025-01-12)
      const mockRequest = {
        json: vi.fn().mockResolvedValue({ startDate: "2025-01-12" }),
      } as unknown as NextRequest;

      const response = await POST(mockRequest);

      expect(response.status).toBe(200);
      const body = await response.json();

      expect(body.predictedDate).toBe("2025-01-12");
      expect(body.daysEarly).toBeUndefined();
      expect(body.daysLate).toBeUndefined();
    });
  });
});