import type { ContextMenuBindings } from '@deepseek-ai/dsh-client-ui-context-menu/client'
import { useCallback, useEffect, useMemo, useState } from 'react'
import type { ImageAttachmentRef } from '@deepseek-ai/dsh-attachment'
import { IconLoadingOutlineRegular, IconRefreshOutlineRegular, DraggableImage, ImageLightbox, type FileDragActions } from '@deepseek-ai/dsh-client-ui-primitives'
import type { MessageImageLabels } from '@deepseek-ai/dsh-client-ui-conversation/client'
import css from './MessageImage.module.css'

export type { MessageImageLabels } from '@deepseek-ai/dsh-client-ui-conversation/client'

/** Loads a Gateway-authorized durable image URL and may expose a cached URL synchronously. */
export type ImageLoader = ((attachment: ImageAttachmentRef) => Promise<string>) & {
  peek?: (attachment: ImageAttachmentRef) => string | undefined
}

/** One gallery entry: a durable admitted reference, or a submission echo's local preview. */
export type MessageImageSpec =
  | {
    readonly attachment: ImageAttachmentRef
    /** Presentation-only name for the thumbnail and lightbox; loading uses the original reference. */
    readonly label?: string
  }
  | {
    readonly preview: {
      readonly url: string
      readonly name?: string
      readonly width?: number
      readonly height?: number
    }
  }

/** Display box for a lone image (DeepSeek Chat rule): long edge 240px with
 * the rendered aspect ratio clamped to [0.25, 4] — the overflow is cropped by
 * `object-fit: cover` — and never upscaled past the image's natural size. The
 * crop anchor keeps the top of very tall images and the left of very wide
 * ones, where the informative content usually starts. */
function singleFit(
  dimensions: { readonly width: number; readonly height: number },
): { width: number; height: number; objectPosition: string } {
  const natural = dimensions.width / dimensions.height
  const ratio = Math.min(4, Math.max(0.25, natural))
  const box = ratio >= 1 ? { width: 240, height: 240 / ratio } : { width: 240 * ratio, height: 240 }
  const scale = Math.min(1, dimensions.width / box.width, dimensions.height / box.height)
  return {
    width: Math.max(1, Math.round(box.width * scale)),
    height: Math.max(1, Math.round(box.height * scale)),
    objectPosition: natural < 0.25 ? 'center top' : natural > 4 ? 'left center' : 'center',
  }
}

/** Intrinsic dimensions of one gallery entry; a preview's stay unknown until its intake probe resolved. */
function dimensionsOf(image: MessageImageSpec): { readonly width: number; readonly height: number } | undefined {
  if ('attachment' in image) return image.attachment
  return image.preview.width !== undefined && image.preview.height !== undefined
    ? { width: image.preview.width, height: image.preview.height }
    : undefined
}

/**
 * Compact history renderer with retryable loading and click-to-open original
 * preview. A lone image renders at its `singleFit` size; an image among
 * several renders as a fixed 64px square tile. The preview arm displays its
 * local URL directly — no loader round-trip, no failure/retry surface.
 * List thumbnails use status icons with localized tooltips and accessible names.
 *
 * @param props.image - the durable reference to load, or the local preview to display.
 * @param props.load - Gateway-authorized URL loader for the durable arm.
 * @param props.variant - lone image, cropped gallery tile, or uncropped list thumbnail.
 * @param props.labels - resolved strings (tooltip, loading, retry, lightbox).
 * @returns the bounded thumbnail button, or the retry control on failure.
 */
export function MessageImage({ image, load, variant, labels, fileDrag, getTriggerProps }: {
  image: MessageImageSpec
  load: ImageLoader
  variant: 'single' | 'tile' | 'thumbnail'
  fileDrag: FileDragActions
  labels: MessageImageLabels
  getTriggerProps: ContextMenuBindings['getTriggerProps']
}) {
  const preview = 'preview' in image ? image.preview : undefined
  const attachment = 'attachment' in image ? image.attachment : undefined
  const [loaded, setLoaded] = useState<string | null>(() =>
    attachment === undefined ? null : (load.peek?.(attachment) ?? null))
  const [error, setError] = useState(false)
  const [open, setOpen] = useState(false)
  // Retry re-arms the one load effect below, so every attempt — first load or
  // retry — runs under the same liveness guard and the same reset.
  const [attempt, setAttempt] = useState(0)
  const request = useCallback(() => { setAttempt(a => a + 1) }, [])
  const close = useCallback(() => { setOpen(false) }, [])
  const dimensions = useMemo(() => dimensionsOf(image), [image])
  const fit = useMemo(
    () => {
      if (variant !== 'single') return undefined
      // A preview whose intake probe has not resolved sizes as a square crop;
      // the durable replacement restores the exact fit.
      return dimensions === undefined
        ? { width: 240, height: 240, objectPosition: 'center' }
        : singleFit(dimensions)
    },
    [dimensions, variant],
  )

  useEffect(() => {
    if (attachment === undefined) return
    let live = true
    setError(false)
    setLoaded(load.peek?.(attachment) ?? null)
    void load(attachment).then((url) => { if (live) setLoaded(url) }).catch(() => { if (live) setError(true) })
    return () => { live = false }
  }, [attachment, load, attempt])

  const src = preview?.url ?? loaded
  const label = ('attachment' in image ? image.label : undefined)
    ?? preview?.name ?? attachment?.name ?? labels.image
  const contextMenuProps = getTriggerProps(src === null ? undefined : { kind: 'image', value: {
    url: src, name: label, ...(attachment === undefined ? {} : { mediaType: attachment.mediaType }),
  } })
  const loadingThumbnail = variant === 'thumbnail' && src === null
  if (error) return (
    <button
      type="button"
      className={css.error}
      data-variant={variant}
      title={variant === 'thumbnail' ? labels.loadFailed : undefined}
      aria-label={variant === 'thumbnail' ? labels.loadFailed : undefined}
      onClick={request}
    >
      {variant === 'thumbnail'
        ? <span aria-hidden="true"><IconRefreshOutlineRegular /></span>
        : labels.loadFailed}
    </button>
  )
  return (
    <>
      <button
        type="button"
        className={css.frame}
        data-variant={variant}
        style={fit === undefined ? undefined : { width: fit.width, height: fit.height }}
        title={loadingThumbnail ? labels.loading : labels.open}
        aria-label={loadingThumbnail ? labels.loading : labels.openNamed(label)}
        aria-busy={loadingThumbnail || undefined}
        {...contextMenuProps}
        onClick={() => { if (src !== null) setOpen(true) }}
      >
        {src === null
          ? (
            <span className={css.loading} aria-hidden={loadingThumbnail || undefined}>
              {loadingThumbnail ? <IconLoadingOutlineRegular className={css.spinner} /> : labels.loading}
            </span>
          )
          : <DraggableImage fileDrag={fileDrag} src={src} alt={label} name={preview?.name ?? attachment?.name ?? 'image'}
            style={fit === undefined ? undefined : { objectPosition: fit.objectPosition }} />}
      </button>
      {open && src !== null && <ImageLightbox src={src} alt={label} labels={labels.lightbox} onClose={close}
        contextMenuProps={contextMenuProps} />}
    </>
  )
}

/** Wrapping image group shared by user and assistant history: a lone image
 * renders large unless its owner requests compact tiles or contained list thumbnails. */
export function ImageGallery({ images, load, align, compact = false, thumbnail = false, labels, fileDrag, getTriggerProps }: {
  images: readonly MessageImageSpec[]
  load: ImageLoader
  align: 'start' | 'end'
  compact?: boolean
  thumbnail?: boolean
  fileDrag: FileDragActions
  labels: MessageImageLabels
  getTriggerProps: ContextMenuBindings['getTriggerProps']
}) {
  if (images.length === 0) return null
  const variant = thumbnail ? 'thumbnail' : compact || images.length > 1 ? 'tile' : 'single'
  return (
    <div className={css.gallery} data-align={align}>
      {images.map((image, index) => (
        <MessageImage
          key={`${'attachment' in image ? image.attachment.attachmentId : image.preview.url}:${index}`}
          image={image}
          load={load}
          variant={variant}
          fileDrag={fileDrag}
          labels={labels}
          getTriggerProps={getTriggerProps}
        />
      ))}
    </div>
  )
}