import { describe, it, expect, vi } from 'vitest'
import {
  createUniqueList,
  uniqueListUpdate,
  uniqueListGetElements,
  uniqueListById,
} from '../UniqueList'

interface Item {
  id: number
  name: string
}

describe('createUniqueList', () => {
  it('creates an empty list', () => {
    const list = createUniqueList<Item>()
    expect(list.elements).toEqual({})
    expect(uniqueListGetElements(list)).toEqual([])
  })
})

describe('uniqueListUpdate', () => {
  it('adds new elements', () => {
    const list = createUniqueList<Item>()
    const addCb = vi.fn()

    uniqueListUpdate(list, [{ id: 1, name: 'a' }, { id: 2, name: 'b' }], addCb)

    expect(addCb).toHaveBeenCalledTimes(2)
    expect(uniqueListGetElements(list)).toHaveLength(2)
    expect(uniqueListById(list, 1)).toEqual({ id: 1, name: 'a' })
    expect(uniqueListById(list, 2)).toEqual({ id: 2, name: 'b' })
  })

  it('removes elements no longer present', () => {
    const list = createUniqueList<Item>()
    const removeCb = vi.fn()

    uniqueListUpdate(list, [{ id: 1, name: 'a' }, { id: 2, name: 'b' }])
    uniqueListUpdate(list, [{ id: 1, name: 'a' }], undefined, removeCb)

    expect(removeCb).toHaveBeenCalledTimes(1)
    expect(removeCb).toHaveBeenCalledWith({ id: 2, name: 'b' })
    expect(uniqueListGetElements(list)).toHaveLength(1)
    expect(uniqueListById(list, 2)).toBeUndefined()
  })

  it('calls update callback for existing elements', () => {
    const list = createUniqueList<Item>()
    const updateCb = vi.fn()

    uniqueListUpdate(list, [{ id: 1, name: 'a' }])
    uniqueListUpdate(list, [{ id: 1, name: 'updated' }], undefined, undefined, updateCb)

    expect(updateCb).toHaveBeenCalledTimes(1)
    expect(updateCb).toHaveBeenCalledWith({ id: 1, name: 'a' }, { id: 1, name: 'updated' })
  })

  it('handles all callbacks together', () => {
    const list = createUniqueList<Item>()
    const addCb = vi.fn()
    const removeCb = vi.fn()
    const updateCb = vi.fn()

    uniqueListUpdate(list, [{ id: 1, name: 'keep' }, { id: 2, name: 'remove' }])

    uniqueListUpdate(
      list,
      [{ id: 1, name: 'kept' }, { id: 3, name: 'new' }],
      addCb,
      removeCb,
      updateCb,
    )

    expect(addCb).toHaveBeenCalledTimes(1)
    expect(addCb).toHaveBeenCalledWith({ id: 3, name: 'new' })
    expect(removeCb).toHaveBeenCalledTimes(1)
    expect(removeCb).toHaveBeenCalledWith({ id: 2, name: 'remove' })
    expect(updateCb).toHaveBeenCalledTimes(1)
    expect(updateCb).toHaveBeenCalledWith({ id: 1, name: 'keep' }, { id: 1, name: 'kept' })
  })

  it('works with string IDs', () => {
    interface StringItem {
      id: string
      label: string
    }
    const list = createUniqueList<StringItem>()
    uniqueListUpdate(list, [{ id: 'abc', label: 'first' }])
    expect(uniqueListById(list, 'abc')).toEqual({ id: 'abc', label: 'first' })
  })

  it('handles empty update', () => {
    const list = createUniqueList<Item>()
    uniqueListUpdate(list, [{ id: 1, name: 'a' }])

    const removeCb = vi.fn()
    uniqueListUpdate(list, [], undefined, removeCb)

    expect(removeCb).toHaveBeenCalledTimes(1)
    expect(uniqueListGetElements(list)).toHaveLength(0)
  })

  it('handles update with no callbacks', () => {
    const list = createUniqueList<Item>()
    uniqueListUpdate(list, [{ id: 1, name: 'a' }])
    uniqueListUpdate(list, [{ id: 2, name: 'b' }])
    expect(uniqueListGetElements(list)).toHaveLength(1)
    expect(uniqueListById(list, 2)).toEqual({ id: 2, name: 'b' })
  })
})

describe('uniqueListGetElements', () => {
  it('returns all elements as array', () => {
    const list = createUniqueList<Item>()
    uniqueListUpdate(list, [{ id: 1, name: 'a' }, { id: 2, name: 'b' }])
    const elements = uniqueListGetElements(list)
    expect(elements).toHaveLength(2)
    expect(elements.map(e => e.id).sort()).toEqual([1, 2])
  })
})

describe('uniqueListById', () => {
  it('finds element by id', () => {
    const list = createUniqueList<Item>()
    uniqueListUpdate(list, [{ id: 42, name: 'target' }])
    expect(uniqueListById(list, 42)?.name).toBe('target')
  })

  it('returns undefined for missing id', () => {
    const list = createUniqueList<Item>()
    expect(uniqueListById(list, 999)).toBeUndefined()
  })
})