import { renderHook } from "@testing-library/react"
import { describe, expect, it, vi } from "vitest"
import { useOffsetPagination } from "./useOffsetPagination"

describe("useOffsetPagination", () => {
  const defaultProps = {
    currentPage: 1,
    totalPages: 10,
    totalItems: 100,
    pageSize: 10,
    onPageChange: vi.fn(),
    onPageSizeChange: vi.fn(),
  }

  describe("basic calculations", () => {
    it("should calculate start and end items correctly", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 3,
          pageSize: 20,
          totalItems: 100,
        }),
      )

      expect(result.current.startItem).toBe(41) // (3-1) * 20 + 1
      expect(result.current.endItem).toBe(60) // 3 * 20
    })

    it("should handle zero total items", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalItems: 0,
        }),
      )

      expect(result.current.startItem).toBe(0)
      expect(result.current.endItem).toBe(0)
      expect(result.current.hasResults).toBe(false)
      expect(result.current.resultsText).toBe("No results")
    })

    it("should handle last page correctly", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 10,
          totalItems: 95,
          pageSize: 10,
        }),
      )

      expect(result.current.startItem).toBe(91) // (10-1) * 10 + 1
      expect(result.current.endItem).toBe(95) // min(10 * 10, 95)
    })
  })

  describe("page numbers generation", () => {
    it("should show all pages when totalPages <= 7", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalPages: 5,
          currentPage: 3,
        }),
      )

      expect(result.current.pageNumbers).toEqual([1, 2, 3, 4, 5])
    })

    it("should show ellipsis pattern when current page is near beginning and also near the boundary", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalPages: 20,
          currentPage: 2,
        }),
      )

      expect(result.current.pageNumbers).toEqual([1, 2, 3, "ellipsis", 20])
    })

    it("should show ellipsis pattern when current page is near end", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalPages: 20,
          currentPage: 19,
        }),
      )

      expect(result.current.pageNumbers).toEqual([1, "ellipsis", 18, 19, 20])
    })

    it("should show ellipsis pattern when current page is in middle", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalPages: 20,
          currentPage: 10,
        }),
      )

      expect(result.current.pageNumbers).toEqual([1, "ellipsis", 9, 10, 11, "ellipsis", 20])
    })
  })

  describe("navigation handlers", () => {
    it("should call onPageChange when handlePageChange is called with valid page", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 3,
        }),
      )

      result.current.handlePageChange(5)
      expect(onPageChange).toHaveBeenCalledWith(5)
    })

    it("should not call onPageChange when handlePageChange is called with current page", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 3,
        }),
      )

      result.current.handlePageChange(3)
      expect(onPageChange).not.toHaveBeenCalled()
    })

    it("should not call onPageChange when handlePageChange is called with invalid page", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 3,
          totalPages: 10,
        }),
      )

      result.current.handlePageChange(0)
      result.current.handlePageChange(11)
      expect(onPageChange).not.toHaveBeenCalled()
    })

    it("should call onPageSizeChange when handlePageSizeChange is called", () => {
      const onPageSizeChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageSizeChange,
        }),
      )

      result.current.handlePageSizeChange(25)
      expect(onPageSizeChange).toHaveBeenCalledWith(25)
    })

    it("should not call onPageSizeChange when callback is not provided", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageSizeChange: undefined,
        }),
      )

      // Should not throw
      expect(() => result.current.handlePageSizeChange(25)).not.toThrow()
    })

    it("should handle previous page navigation", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 3,
        }),
      )

      result.current.handlePreviousPage()
      expect(onPageChange).toHaveBeenCalledWith(2)
    })

    it("should handle next page navigation", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 3,
        }),
      )

      result.current.handleNextPage()
      expect(onPageChange).toHaveBeenCalledWith(4)
    })

    it("should not navigate when at first page", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 1,
        }),
      )

      result.current.handlePreviousPage()
      expect(onPageChange).not.toHaveBeenCalled()
    })

    it("should not navigate when at last page", () => {
      const onPageChange = vi.fn()
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          onPageChange,
          currentPage: 10,
          totalPages: 10,
        }),
      )

      result.current.handleNextPage()
      expect(onPageChange).not.toHaveBeenCalled()
    })
  })

  describe("state checks", () => {
    it("should correctly identify disabled states", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 1,
          totalPages: 10,
        }),
      )

      expect(result.current.isPreviousDisabled).toBe(true)
      expect(result.current.isNextDisabled).toBe(false)
    })

    it("should correctly identify disabled states at last page", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 10,
          totalPages: 10,
        }),
      )

      expect(result.current.isPreviousDisabled).toBe(false)
      expect(result.current.isNextDisabled).toBe(true)
    })

    it("should correctly identify disabled states in middle", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 5,
          totalPages: 10,
        }),
      )

      expect(result.current.isPreviousDisabled).toBe(false)
      expect(result.current.isNextDisabled).toBe(false)
    })
  })

  describe("selection handling", () => {
    it("should show selection text when rows are selected", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          selectedRows: 5,
          totalRows: 100,
        }),
      )

      expect(result.current.hasSelection).toBe(true)
      expect(result.current.selectionText).toBe("5 of 100 row(s) selected.")
    })

    it("should not show selection text when no rows are selected", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          selectedRows: 0,
          totalRows: 0,
        }),
      )

      expect(result.current.hasSelection).toBe(false)
      expect(result.current.selectionText).toBe(null)
    })
  })

  describe("results text", () => {
    it("should format results text correctly", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          currentPage: 3,
          pageSize: 20,
          totalItems: 100,
        }),
      )

      expect(result.current.resultsText).toBe("Showing 41 to 60 of 100 results")
    })

    it("should show 'No results' when totalItems is 0", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          ...defaultProps,
          totalItems: 0,
        }),
      )

      expect(result.current.resultsText).toBe("No results")
    })
  })

  describe("default values", () => {
    it("should use default pageSizeOptions when not provided", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          currentPage: 1,
          totalPages: 10,
          totalItems: 100,
          pageSize: 10,
          onPageChange: vi.fn(),
        }),
      )

      // The hook should work without pageSizeOptions
      expect(result.current.pageNumbers).toBeDefined()
    })

    it("should use default selectedRows and totalRows when not provided", () => {
      const { result } = renderHook(() =>
        useOffsetPagination({
          currentPage: 1,
          totalPages: 10,
          totalItems: 100,
          pageSize: 10,
          onPageChange: vi.fn(),
        }),
      )

      expect(result.current.hasSelection).toBe(false)
      expect(result.current.selectionText).toBe(null)
    })
  })
})