import {
  BRAND_KNOWLEDGE_MAX_PREVIEW_IMAGE_BYTES,
  BRAND_KNOWLEDGE_MAX_PREVIEW_SLICE_BYTES,
  BRAND_KNOWLEDGE_MAX_PREVIEW_SLICE_COUNT,
} from '@/lib/brand-knowledge-file-types'
import {
  preparePerformanceSurveyImagesInBrowser,
  type PerformanceSurveyBrowserProcessedImage,
} from '@/lib/performance-survey-image-browser'
import {
  BRAND_KNOWLEDGE_LEGACY_SERVER_MAX_PIXELS,
  PERFORMANCE_SURVEY_BROWSER_SOURCE_LIMITS,
  readPerformanceSurveySourceImageDimensions,
} from '@/lib/performance-survey-image-source-guard'

export type BrandKnowledgeBrowserPreviewSlice = PerformanceSurveyBrowserProcessedImage & {
  kind: 'slice'
}

export async function prepareBrandKnowledgePreviewInBrowser(
  file: File,
  onProgress?: (label: string) => void,
  options: { signal?: AbortSignal; timeoutMs?: number } = {},
): Promise<BrandKnowledgeBrowserPreviewSlice[]> {
  const processed = await preparePerformanceSurveyImagesInBrowser(
    [file],
    onProgress,
    {
      profile: 'brand_knowledge_preview',
      signal: options.signal,
      timeoutMs: options.timeoutMs,
    },
  )
  const slices = processed.filter(
    (item): item is BrandKnowledgeBrowserPreviewSlice => item.kind === 'slice',
  )
  if (slices.length === 0) throw new Error('浏览器未生成品牌知识预览切片')
  if (slices.length > BRAND_KNOWLEDGE_MAX_PREVIEW_SLICE_COUNT) {
    throw new Error(`预览图处理后超过 ${BRAND_KNOWLEDGE_MAX_PREVIEW_SLICE_COUNT} 个切片`)
  }
  if (slices.some((slice) => slice.file.size <= 0 || slice.file.size > BRAND_KNOWLEDGE_MAX_PREVIEW_SLICE_BYTES)) {
    throw new Error('预览图处理后的单个切片过大，请先压缩图片后重试')
  }
  const totalBytes = slices.reduce((sum, slice) => sum + slice.file.size, 0)
  if (totalBytes > BRAND_KNOWLEDGE_MAX_PREVIEW_IMAGE_BYTES) {
    throw new Error('预览图处理后的切片总大小超过 50MB，请先压缩图片后重试')
  }
  return slices
}

export async function canUseBrandKnowledgeLegacyServerPreview(file: File) {
  let bytes = new Uint8Array(
    await file.slice(0, PERFORMANCE_SURVEY_BROWSER_SOURCE_LIMITS.headerReadBytes).arrayBuffer(),
  )
  let dimensions = readPerformanceSurveySourceImageDimensions(bytes)
  if (!dimensions && file.size > bytes.byteLength) {
    bytes = new Uint8Array(
      await file.slice(0, PERFORMANCE_SURVEY_BROWSER_SOURCE_LIMITS.extendedHeaderReadBytes).arrayBuffer(),
    )
    dimensions = readPerformanceSurveySourceImageDimensions(bytes)
  }
  if (!dimensions) return false
  return dimensions.width <= PERFORMANCE_SURVEY_BROWSER_SOURCE_LIMITS.maxWidth
    && dimensions.height <= 90_000
    && dimensions.width * dimensions.height <= BRAND_KNOWLEDGE_LEGACY_SERVER_MAX_PIXELS
}