import { describe, it, expect, vi, beforeEach } from "vitest";
import { getCategoryOverTime, getHighlights } from "./reportService";

// Mock the db module
vi.mock("./db", () => ({
  getDb: vi.fn(),
}));

import { getDb } from "./db";

const mockSelect = vi.fn();
const mockDb = { select: mockSelect };

beforeEach(() => {
  vi.mocked(getDb).mockResolvedValue(mockDb as never);
  mockSelect.mockReset();
});

describe("getCategoryOverTime", () => {
  it("builds query without WHERE clause when no filters are provided", async () => {
    // First call: top categories, second call: monthly breakdown
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime();

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    // No WHERE clause should appear (no filters at all)
    expect(topCatSQL).not.toContain("WHERE");
  });

  it("applies typeFilter via category type when provided", async () => {
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime(undefined, undefined, 50, undefined, "expense");

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    const topCatParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(topCatSQL).toContain("COALESCE(c.type, 'expense')");
    expect(topCatSQL).toContain("WHERE");
    expect(topCatParams[0]).toBe("expense");
  });

  it("applies income typeFilter correctly", async () => {
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime("2025-01-01", "2025-06-30", 50, undefined, "income");

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    const topCatParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(topCatSQL).toContain("COALESCE(c.type, 'expense') = $1");
    expect(topCatParams[0]).toBe("income");
    // Date params follow
    expect(topCatParams[1]).toBe("2025-01-01");
    expect(topCatParams[2]).toBe("2025-06-30");
  });

  it("applies date range filters", async () => {
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime("2025-01-01", "2025-12-31");

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    const topCatParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(topCatSQL).toContain("t.date >= $1");
    expect(topCatSQL).toContain("t.date <= $2");
    expect(topCatParams).toEqual(["2025-01-01", "2025-12-31", 50]);
  });

  it("applies sourceId filter", async () => {
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime(undefined, undefined, 50, 3);

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    const topCatParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(topCatSQL).toContain("t.source_id");
    expect(topCatParams[0]).toBe(3);
  });

  it("combines typeFilter, date range, and sourceId", async () => {
    mockSelect
      .mockResolvedValueOnce([]) // topCategories
      .mockResolvedValueOnce([]); // monthlyRows

    await getCategoryOverTime("2025-01-01", "2025-06-30", 10, 2, "expense");

    const topCatSQL = mockSelect.mock.calls[0][0] as string;
    const topCatParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(topCatSQL).toContain("COALESCE(c.type, 'expense') = $1");
    expect(topCatSQL).toContain("t.date >= $2");
    expect(topCatSQL).toContain("t.date <= $3");
    expect(topCatSQL).toContain("t.source_id = $4");
    expect(topCatParams).toEqual(["expense", "2025-01-01", "2025-06-30", 2, 10]);
  });

  it("returns correct structure with categories, data, colors, and categoryIds", async () => {
    mockSelect
      .mockResolvedValueOnce([
        { category_id: 1, category_name: "Food", category_color: "#ff0000", total: 500 },
        { category_id: 2, category_name: "Transport", category_color: "#00ff00", total: 200 },
      ])
      .mockResolvedValueOnce([
        { month: "2025-01", category_id: 1, category_name: "Food", total: 300 },
        { month: "2025-01", category_id: 2, category_name: "Transport", total: 100 },
        { month: "2025-02", category_id: 1, category_name: "Food", total: 200 },
        { month: "2025-02", category_id: 2, category_name: "Transport", total: 100 },
      ]);

    const result = await getCategoryOverTime("2025-01-01", "2025-02-28", 50, undefined, "expense");

    expect(result.categories).toEqual(["Food", "Transport"]);
    expect(result.colors).toEqual({ Food: "#ff0000", Transport: "#00ff00" });
    expect(result.categoryIds).toEqual({ Food: 1, Transport: 2 });
    expect(result.data).toHaveLength(2);
    expect(result.data[0]).toEqual({ month: "2025-01", Food: 300, Transport: 100 });
    expect(result.data[1]).toEqual({ month: "2025-02", Food: 200, Transport: 100 });
  });

  it("groups non-top-N categories into Other", async () => {
    mockSelect
      .mockResolvedValueOnce([
        { category_id: 1, category_name: "Food", category_color: "#ff0000", total: 500 },
      ])
      .mockResolvedValueOnce([
        { month: "2025-01", category_id: 1, category_name: "Food", total: 300 },
        { month: "2025-01", category_id: 2, category_name: "Transport", total: 100 },
        { month: "2025-01", category_id: 3, category_name: "Entertainment", total: 50 },
      ]);

    const result = await getCategoryOverTime("2025-01-01", "2025-01-31", 1, undefined, "expense");

    expect(result.categories).toEqual(["Food", "Other"]);
    expect(result.colors["Other"]).toBe("#9ca3af");
    expect(result.data[0]).toEqual({ month: "2025-01", Food: 300, Other: 150 });
  });
});

describe("getHighlights", () => {
  const REF = "2026-04-14";

  function queueEmpty(n: number) {
    for (let i = 0; i < n; i++) {
      mockSelect.mockResolvedValueOnce([]);
    }
  }

  it("computes windows and returns zeroed data on an empty profile", async () => {
    queueEmpty(5); // currentBalance, ytd, series, movers, recent

    const result = await getHighlights(30, REF);

    expect(result.currentMonth).toBe("2026-04");
    expect(result.netBalanceCurrent).toBe(0);
    expect(result.netBalanceYtd).toBe(0);
    expect(result.monthlyBalanceSeries).toHaveLength(12);
    expect(result.monthlyBalanceSeries[11].month).toBe("2026-04");
    expect(result.monthlyBalanceSeries[0].month).toBe("2025-05");
    expect(result.topMovers).toEqual([]);
    expect(result.topTransactions).toEqual([]);
  });

  it("parameterises every query with no inlined strings", async () => {
    queueEmpty(5);

    await getHighlights(60, REF);

    for (const call of mockSelect.mock.calls) {
      const sql = call[0] as string;
      const params = call[1] as unknown[];
      expect(sql).not.toContain(`'${REF}'`);
      expect(Array.isArray(params)).toBe(true);
    }
    // First call uses current month range parameters
    const firstParams = mockSelect.mock.calls[0][1] as unknown[];
    expect(firstParams[0]).toBe("2026-04-01");
    expect(firstParams[1]).toBe("2026-04-30");
    // YTD call uses year start
    const ytdParams = mockSelect.mock.calls[1][1] as unknown[];
    expect(ytdParams[0]).toBe("2026-01-01");
    expect(ytdParams[1]).toBe(REF);
  });

  it("uses a 60-day window for top transactions when requested", async () => {
    queueEmpty(5);

    await getHighlights(60, REF);

    const recentParams = mockSelect.mock.calls[4][1] as unknown[];
    // 60-day window ending at REF: start = 2026-04-14 - 59 days = 2026-02-14
    expect(recentParams[0]).toBe("2026-02-14");
    expect(recentParams[1]).toBe(REF);
    expect(recentParams[2]).toBe(10);
  });

  it("computes deltaAbs and deltaPct from movers rows", async () => {
    mockSelect
      .mockResolvedValueOnce([{ net: -500 }]) // current balance
      .mockResolvedValueOnce([{ net: -1800 }]) // ytd
      .mockResolvedValueOnce([
        { month: "2026-04", net: -500 },
        { month: "2026-03", net: -400 },
      ]) // series
      .mockResolvedValueOnce([
        {
          category_id: 1,
          category_name: "Restaurants",
          category_color: "#f97316",
          current_total: 240,
          previous_total: 200,
        },
        {
          category_id: 2,
          category_name: "Groceries",
          category_color: "#10b981",
          current_total: 85,
          previous_total: 170,
        },
      ])
      .mockResolvedValueOnce([]); // recent

    const result = await getHighlights(30, REF);

    expect(result.netBalanceCurrent).toBe(-500);
    expect(result.netBalanceYtd).toBe(-1800);
    expect(result.topMovers).toHaveLength(2);
    expect(result.topMovers[0]).toMatchObject({
      categoryName: "Restaurants",
      currentAmount: 240,
      previousAmount: 200,
      deltaAbs: 40,
    });
    expect(result.topMovers[0].deltaPct).toBeCloseTo(20, 4);
    expect(result.topMovers[1].deltaAbs).toBe(-85);
    expect(result.topMovers[1].deltaPct).toBeCloseTo(-50, 4);
  });

  it("returns deltaPct=null when previous month total is zero", async () => {
    mockSelect
      .mockResolvedValueOnce([{ net: 0 }])
      .mockResolvedValueOnce([{ net: 0 }])
      .mockResolvedValueOnce([])
      .mockResolvedValueOnce([
        {
          category_id: 3,
          category_name: "New expense",
          category_color: "#3b82f6",
          current_total: 120,
          previous_total: 0,
        },
      ])
      .mockResolvedValueOnce([]);

    const result = await getHighlights(30, REF);

    expect(result.topMovers[0].deltaPct).toBeNull();
    expect(result.topMovers[0].deltaAbs).toBe(120);
  });
});