// @vitest-environment jsdom
/**
 * AppFrame interaction spec under the four-share props form: real layout
 * store instance (createLayoutStore().create() — the test-sanctioned engine
 * path), a recording renderSlot stub, and a render-prop SessionProvider stub
 * (the real one is framework-wired to the renderer host; its own behavior is
 * web-react's spec territory). Drag sequences (pointer capture + rAF flush),
 * concession response to viewport change, and details staying mounted at
 * zero width are the preserved behavior assertions. jsdom has no layout
 * engine, so the frame width comes from a mocked getBoundingClientRect and
 * resizes are driven through the ResizeObserver stub.
 */
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
import { act, cleanup, render } from '@testing-library/react'
import { useSyncExternalStore } from 'react'
import { AppFrame } from '@deepseek-ai/dsh-client-ui-layout/src/client/AppFrame.tsx'
import type { AppFrameProps } from '@deepseek-ai/dsh-client-ui-layout/src/client/AppFrame.tsx'
import { SIDEBAR_COLLAPSED } from '@deepseek-ai/dsh-client-ui-layout/src/client/columns.ts'
import { createLayoutStore } from '@deepseek-ai/dsh-client-ui-layout/src/client/stores.ts'

// Session-mode switch for the SessionProvider stub prop.
const sessionMode = { current: true }

// Render-prop contract stub fed through the standard seat prop (the renderer
// injects the real one in production): session mode runs children(id), empty
// mode runs the empty branch — the frame must work against exactly this
// shape. Typed as the seat's own component type so the branded sessionId
// parameter stays contract-checked.
const SessionProviderStub: AppFrameProps['SessionProvider'] = ({ children, empty }) =>
  sessionMode.current ? <>{children('s-test' as Parameters<typeof children>[0])}</> : <>{empty?.() ?? null}</>


/** Observer stub: captures the callback so tests can fire resizes manually. */
let fireResize: (() => void) | null = null
class ResizeObserverStub {
  #cb: ResizeObserverCallback
  constructor(cb: ResizeObserverCallback) { this.#cb = cb }
  observe(): void { fireResize = () => { this.#cb([], this as unknown as ResizeObserver) } }
  unobserve(): void {}
  disconnect(): void { fireResize = null }
}

let frameWidth = 1920

/** Minimal selector hook over an engine instance (the engine carries no hook since the store migration; the renderer binds in production, the spec binds here). */
function hookOf<T>(inst: { subscribe: (fn: () => void) => () => void; getSnapshot: () => T }) {
  return <S,>(sel: (s: T) => S): S => sel(useSyncExternalStore(inst.subscribe, inst.getSnapshot))
}

function mountFrame() {
  window.innerWidth = frameWidth // first-render viewport source before the observer fires
  const instance = createLayoutStore().create()
  instance.actions.openDetails() // seed: sidebar at default 280, details open at default 360
  const slotCalls: { key: string; props: unknown }[] = []
  const renderSlot = ((key: string, owner: object) => {
    slotCalls.push({ key, props: owner })
    if (key === 'sidebar') return <div data-testid="sidebar-content" />
    if (key === 'conversation') return <div data-testid="center-content" />
    if (key === 'details') return <div data-testid="details-content" />
    return <div data-testid="empty-content" />
  }) as AppFrameProps['renderSlot']
  const useSessions = ((sel: (s: unknown) => unknown) => sel({ ids: [], byId: {} })) as never
  const utils = render(
    <AppFrame
      useStore={hookOf(instance) as never}
      actions={instance.actions}
      renderSlot={renderSlot}
      useSessions={useSessions}
      SessionProvider={SessionProviderStub}
    />,
  )
  const frame = utils.container.firstElementChild as HTMLElement
  return { instance, frame, slotCalls, ...utils }
}

function tracks(frame: HTMLElement): number[] {
  const m = /^(\d+)px minmax\(0, 1fr\) (\d+)px$/.exec(frame.style.gridTemplateColumns)
  if (m === null) throw new Error(`unexpected template: ${frame.style.gridTemplateColumns}`)
  return [Number(m[1]), Number(m[2])]
}

function drag(handle: Element, fromX: number, toX: number): void {
  const down = new PointerEvent('pointerdown', { pointerId: 1, clientX: fromX, bubbles: true })
  const move = new PointerEvent('pointermove', { pointerId: 1, clientX: toX, bubbles: true })
  const up = new PointerEvent('pointerup', { pointerId: 1, clientX: toX, bubbles: true })
  act(() => { handle.dispatchEvent(down) })
  act(() => { handle.dispatchEvent(move); vi.advanceTimersByTime(20) })
  act(() => { handle.dispatchEvent(up) })
}

beforeEach(() => {
  frameWidth = 1920
  sessionMode.current = true
  localStorage.clear() // the layout store persists; instances must not bleed across tests
  vi.useFakeTimers()
  vi.stubGlobal('ResizeObserver', ResizeObserverStub)
  vi.stubGlobal('requestAnimationFrame', (cb: FrameRequestCallback) => setTimeout(() => { cb(0) }, 16) as unknown as number)
  vi.stubGlobal('cancelAnimationFrame', (h: number) => { clearTimeout(h) })
  window.innerWidth = frameWidth
  Element.prototype.getBoundingClientRect = function () {
    return { width: frameWidth, height: 1080, top: 0, left: 0, right: frameWidth, bottom: 1080, x: 0, y: 0, toJSON: () => ({}) } as DOMRect
  }
  // jsdom lacks pointer capture: emulate per-element so hasPointerCapture gates pass.
  const captured = new WeakSet<Element>()
  Element.prototype.setPointerCapture = function () { captured.add(this) }
  Element.prototype.releasePointerCapture = function () { captured.delete(this) }
  Element.prototype.hasPointerCapture = function () { return captured.has(this) }
})

afterEach(() => {
  cleanup()
  vi.useRealTimers()
  vi.unstubAllGlobals()
})

describe('AppFrame', () => {
  it('renders three tracks from store state', () => {
    const { frame } = mountFrame()
    expect(tracks(frame)).toEqual([280, 360])
  })

  it('renders the session pair with empty owner shares (sessionId is framework-standard)', () => {
    const { slotCalls, getByTestId } = mountFrame()
    expect(getByTestId('center-content')).toBeTruthy()
    expect(getByTestId('details-content')).toBeTruthy()
    const keys = slotCalls.map((c) => c.key)
    expect(keys).toContain('conversation')
    expect(keys).toContain('details')
    expect(keys).not.toContain('conversation.empty')
    expect(slotCalls.find((c) => c.key === 'conversation')!.props).toEqual({})
    expect(slotCalls.find((c) => c.key === 'details')!.props).toEqual({})
  })

  it('renders the empty branch through conversation.empty when no session is current', () => {
    sessionMode.current = false
    const { slotCalls, getByTestId, queryByTestId } = mountFrame()
    expect(getByTestId('empty-content')).toBeTruthy()
    expect(queryByTestId('center-content')).toBeNull()
    expect(slotCalls.map((c) => c.key)).toContain('conversation.empty')
    expect(slotCalls.map((c) => c.key)).not.toContain('conversation')
  })

  it('sidebar slot receives live concession output as owner props', () => {
    const { slotCalls } = mountFrame()
    expect(slotCalls.find((c) => c.key === 'sidebar')!.props).toEqual({ collapsed: false, width: 280 })
  })

  it('sidebar drag widens through rAF-batched pointer moves', () => {
    const { frame } = mountFrame()
    const handles = frame.querySelectorAll('[class*="handle"]')
    drag(handles[0]!, 280, 350)
    expect(tracks(frame)[0]).toBe(350)
  })

  it('details drag widens leftward (negative dx grows the panel)', () => {
    const { frame } = mountFrame()
    const handles = frame.querySelectorAll('[class*="handle"]')
    drag(handles[1]!, 1560, 1500)
    expect(tracks(frame)[1]).toBe(420)
  })

  it('drag base is the rendered (concession-clamped) width, not the preference', () => {
    frameWidth = 1250 // step-2 squeeze: details renders 330 while preference is 360
    const { frame, instance } = mountFrame()
    expect(tracks(frame)).toEqual([280, 330])
    const handles = frame.querySelectorAll('[class*="handle"]')
    drag(handles[1]!, 920, 930) // shrink by 10 from the rendered width
    expect(instance.getSnapshot().details).toBe(320)
  })

  it('details column stays mounted at zero width', () => {
    const { frame, instance, getByTestId } = mountFrame()
    act(() => { instance.actions.closeDetails() })
    expect(tracks(frame)).toEqual([280, 0])
    expect(getByTestId('details-content')).toBeTruthy()
    expect(frame.hasAttribute('data-details-collapsed')).toBe(true)
  })

  it('closed sidebar keeps its compact rail with mounted slot content and collapsed owner props', () => {
    const { frame, instance, slotCalls, getByTestId } = mountFrame()
    act(() => { instance.actions.toggleSidebar() })
    expect(tracks(frame)).toEqual([SIDEBAR_COLLAPSED, 360])
    expect(getByTestId('sidebar-content')).toBeTruthy()
    expect(frame.hasAttribute('data-sidebar-collapsed')).toBe(true)
    const lastSidebarCall = slotCalls.filter((c) => c.key === 'sidebar').at(-1)!
    expect(lastSidebarCall.props).toEqual({ collapsed: true, width: SIDEBAR_COLLAPSED })
  })

  it('viewport shrink triggers the concession chain via ResizeObserver', () => {
    const { frame } = mountFrame()
    frameWidth = 1250
    act(() => { fireResize?.(); vi.advanceTimersByTime(20) })
    expect(tracks(frame)).toEqual([280, 330])
    frameWidth = 1920
    act(() => { fireResize?.(); vi.advanceTimersByTime(20) })
    expect(tracks(frame)).toEqual([280, 360])
  })

  it('drag handles disappear for collapsed columns', () => {
    const { frame, instance } = mountFrame()
    expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(2)
    act(() => { instance.actions.closeDetails() })
    expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(1)
    act(() => { instance.actions.toggleSidebar() })
    expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(0)
  })
})

describe('AppFrame — guard branches', () => {
  it('pointer moves without capture are ignored (no width write)', () => {
    const { frame, instance } = mountFrame()
    const handle = frame.querySelectorAll('[class*="handle"]')[0]!
    const before = instance.getSnapshot().sidebar
    // Move + up without a preceding pointerdown: hasPointerCapture is false.
    act(() => {
      handle.dispatchEvent(new PointerEvent('pointermove', { pointerId: 9, clientX: 500, bubbles: true }))
      vi.advanceTimersByTime(20)
      handle.dispatchEvent(new PointerEvent('pointerup', { pointerId: 9, clientX: 500, bubbles: true }))
    })
    expect(instance.getSnapshot().sidebar).toBe(before)
  })

  it('two moves inside one frame coalesce through the pending rAF', () => {
    const { frame, instance } = mountFrame()
    const handle = frame.querySelectorAll('[class*="handle"]')[0]!
    act(() => { handle.dispatchEvent(new PointerEvent('pointerdown', { pointerId: 1, clientX: 280, bubbles: true })) })
    act(() => {
      // Two moves before the frame flushes: the second must ride the pending
      // rAF (frame.current ??= guard), and the flush sees the latest x.
      handle.dispatchEvent(new PointerEvent('pointermove', { pointerId: 1, clientX: 320, bubbles: true }))
      handle.dispatchEvent(new PointerEvent('pointermove', { pointerId: 1, clientX: 340, bubbles: true }))
      vi.advanceTimersByTime(20)
    })
    act(() => { handle.dispatchEvent(new PointerEvent('pointerup', { pointerId: 1, clientX: 340, bubbles: true })) })
    expect(instance.getSnapshot().sidebar).toBe(340)
  })

  it('pointerup with a pending rAF cancels it and commits the final position', () => {
    const { frame, instance } = mountFrame()
    const handle = frame.querySelectorAll('[class*="handle"]')[0]!
    act(() => { handle.dispatchEvent(new PointerEvent('pointerdown', { pointerId: 1, clientX: 280, bubbles: true })) })
    act(() => {
      handle.dispatchEvent(new PointerEvent('pointermove', { pointerId: 1, clientX: 360, bubbles: true }))
      // No timer advance: the rAF is still pending when pointerup arrives.
      handle.dispatchEvent(new PointerEvent('pointerup', { pointerId: 1, clientX: 360, bubbles: true }))
    })
    expect(instance.getSnapshot().sidebar).toBe(360)
  })

  it('zero-width resize reports are ignored (display:none window)', () => {
    const { frame } = mountFrame()
    frameWidth = 0
    act(() => { fireResize?.(); vi.advanceTimersByTime(20) })
    // Track template still reflects the last non-zero viewport.
    expect(tracks(frame)).toEqual([280, 360])
  })
})

describe('AppFrame — unmount with an in-flight resize frame', () => {
  it('cancels the pending rAF on unmount (no post-unmount setState)', () => {
    const { unmount } = mountFrame()
    frameWidth = 800
    act(() => { fireResize?.() }) // rAF scheduled, NOT flushed
    unmount()
    // Flushing after unmount must be a no-op (the frame was cancelled).
    expect(() => { vi.advanceTimersByTime(20) }).not.toThrow()
  })

  it('double resize inside one frame rides the pending rAF (??= guard)', () => {
    const { frame } = mountFrame()
    frameWidth = 1250
    act(() => { fireResize?.(); fireResize?.(); vi.advanceTimersByTime(20) })
    expect(tracks(frame)).toEqual([280, 330])
  })
})