import { afterEach, describe, expect, it, vi } from 'vitest'
import {
  clearSftpDragEntry,
  hasSftpDragEntry,
  isCrossPaneSftpDrag,
  peekSftpDragEntry,
  peekSftpDragEntries,
  primeSftpDragEntries,
  readSftpDragEntry,
  readSftpDragEntries,
  resolveSftpDragEntries,
  scheduleClearSftpDragEntry,
  SFTP_ENTRY_TEXT_PREFIX,
  writeSftpDragEntry,
  writeSftpDragEntries,
} from '../../../src/components/sftp/dragDrop'

function mockDataTransfer(initialTypes: string[] = []): DataTransfer {
  const store = new Map<string, string>()
  const types = [...initialTypes]
  return {
    effectAllowed: 'none',
    dropEffect: 'none',
    files: [] as unknown as FileList,
    items: [] as unknown as DataTransferItemList,
    types,
    setData(format: string, data: string) {
      store.set(format, data)
      if (!types.includes(format)) types.push(format)
    },
    getData(format: string) {
      return store.get(format) || ''
    },
    clearData() {
      store.clear()
      types.length = 0
    },
    setDragImage() {},
  } as DataTransfer
}

describe('sftp dragDrop', () => {
  afterEach(() => {
    clearSftpDragEntry()
    vi.useRealTimers()
  })

  it('mirrors entry for dragover when getData is empty', () => {
    const dt = mockDataTransfer()
    writeSftpDragEntry(dt, {
      source: 'local',
      name: 'a.txt',
      path: '/tmp/a.txt',
      type: 'file',
      size: 12,
    })

    // Simulate WebView dragover: types may be present but getData returns empty
    const over = mockDataTransfer([...(dt.types as string[])])
    expect(hasSftpDragEntry(over)).toBe(true)
    expect(peekSftpDragEntry()?.name).toBe('a.txt')
    expect(readSftpDragEntry(over)?.source).toBe('local')

    clearSftpDragEntry()
    expect(peekSftpDragEntry()).toBeNull()
  })

  it('writes text/plain prefix for WebKit-compatible drop payloads', () => {
    const dt = mockDataTransfer()
    writeSftpDragEntry(dt, {
      source: 'remote',
      name: 'b.txt',
      path: '/home/u/b.txt',
      type: 'file',
      size: 3,
    })

    const plain = dt.getData('text/plain')
    expect(plain.startsWith(SFTP_ENTRY_TEXT_PREFIX)).toBe(true)

    clearSftpDragEntry()
    // Drop path without mirror: parse text/plain
    expect(readSftpDragEntry(dt)?.path).toBe('/home/u/b.txt')
  })

  it('only accepts cross-pane drops', () => {
    const dt = mockDataTransfer()
    writeSftpDragEntry(dt, {
      source: 'local',
      name: 'a.txt',
      path: '/tmp/a.txt',
      type: 'file',
      size: 1,
    })

    expect(isCrossPaneSftpDrag(dt, false)).toBe(true) // remote pane
    expect(isCrossPaneSftpDrag(dt, true)).toBe(false) // local pane
  })

  it('uses the pre-drag mirror when WebKit has not exposed DataTransfer data', () => {
    primeSftpDragEntries([
      { source: 'remote', name: 'server.log', path: '/var/log/server.log', type: 'file', size: 9 },
    ])

    const hiddenWebKitTransfer = mockDataTransfer()
    expect(isCrossPaneSftpDrag(hiddenWebKitTransfer, true)).toBe(true)
    expect(resolveSftpDragEntries(hiddenWebKitTransfer).entries[0]?.name).toBe('server.log')
  })

  it('keeps mirror readable until scheduled clear runs (drop/dragend race)', () => {
    vi.useFakeTimers()
    const dt = mockDataTransfer()
    writeSftpDragEntry(dt, {
      source: 'remote',
      name: 'b.txt',
      path: '/home/u/b.txt',
      type: 'file',
      size: 3,
    })

    scheduleClearSftpDragEntry(50)
    expect(peekSftpDragEntry()?.name).toBe('b.txt')
    expect(readSftpDragEntry(mockDataTransfer())?.path).toBe('/home/u/b.txt')

    vi.advanceTimersByTime(50)
    expect(peekSftpDragEntry()).toBeNull()
  })

  it('ignores stale clear timers after a new drag starts', () => {
    vi.useFakeTimers()
    const dt = mockDataTransfer()
    writeSftpDragEntry(dt, {
      source: 'local',
      name: 'old.txt',
      path: '/tmp/old.txt',
      type: 'file',
      size: 1,
    })
    scheduleClearSftpDragEntry(100)

    writeSftpDragEntry(dt, {
      source: 'remote',
      name: 'new.txt',
      path: '/r/new.txt',
      type: 'file',
      size: 2,
    })

    vi.advanceTimersByTime(100)
    expect(peekSftpDragEntry()?.name).toBe('new.txt')
  })

  it('keeps multi-selection batch in the drag mirror', () => {
    const dt = mockDataTransfer()
    writeSftpDragEntries(dt, [
      { source: 'local', name: 'a.txt', path: '/tmp/a.txt', type: 'file', size: 1 },
      { source: 'local', name: 'b.txt', path: '/tmp/b.txt', type: 'file', size: 2 },
    ])
    expect(peekSftpDragEntries().map((e) => e.name)).toEqual(['a.txt', 'b.txt'])
    clearSftpDragEntry()
    expect(readSftpDragEntries(dt).map((e) => e.name)).toEqual(['a.txt', 'b.txt'])
  })

  it('resolves drop payload via mirror or text/plain', () => {
    const dt = mockDataTransfer()
    writeSftpDragEntries(dt, [
      { source: 'local', name: 'a.txt', path: '/tmp/a.txt', type: 'file', size: 1 },
      { source: 'local', name: 'b.txt', path: '/tmp/b.txt', type: 'file', size: 2 },
    ])
    expect(resolveSftpDragEntries(dt).via).toBe('mirror')
    expect(resolveSftpDragEntries(dt).entries).toHaveLength(2)

    clearSftpDragEntry()
    expect(resolveSftpDragEntries(dt).via).toBe('text/plain')
    expect(resolveSftpDragEntries(dt).entries.map((e) => e.name)).toEqual(['a.txt', 'b.txt'])
  })
})