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

describe("useDedupedItems", () => {
  it("should return the original array if it has no duplicates", () => {
    const items = [
      { id: 1, name: "Alice" },
      { id: 2, name: "Bob" },
      { id: 3, name: "Charlie" },
    ]

    const { result } = renderHook(() =>
      useDedupedItems(items, item => item?.id),
    )

    expect(result.current).toHaveLength(3)
    expect(result.current).toEqual(items)
  })

  it("should filter out duplicate items based on the key extractor", () => {
    const items = [
      { id: 1, name: "Alice" },
      { id: 2, name: "Bob" },
      { id: 1, name: "Alice (duplicate)" },
      { id: 3, name: "Charlie" },
      { id: 2, name: "Bob (duplicate)" },
    ]

    const { result } = renderHook(() =>
      useDedupedItems(items, item => item?.id),
    )

    expect(result.current).toHaveLength(3)
    expect(result.current).toEqual([
      { id: 1, name: "Alice" },
      { id: 2, name: "Bob" },
      { id: 3, name: "Charlie" },
    ])
  })

  it("should handle an empty array", () => {
    const { result } = renderHook(() => useDedupedItems([], () => undefined))

    expect(result.current).toEqual([])
  })

  it("should use index as fallback key if key extractor returns undefined", () => {
    const items = [
      { name: "Alice" },
      { name: "Bob" },
      { name: "Alice" }, // Same name but different index
    ]

    // Deliberately returning undefined to test fallback
    const { result } = renderHook(() =>
      useDedupedItems(items, () => undefined as unknown as number),
    )

    expect(result.current).toHaveLength(3)
    expect(result.current).toEqual(items)
  })
})