/**
 * 分销站点首页轮播配置。
 * 与主站 mobile.home_banners 共用 pc / mobile 双端结构，历史扁平数据在读取时自动升级。
 */

export const HOME_BANNER_PC_RATIO = { width: 1600, height: 400 }
export const HOME_BANNER_MOBILE_RATIO = { width: 750, height: 375 }

export type BannerActionType = 'none' | 'route' | 'link' | 'preview'

export interface BannerAction {
  type: BannerActionType
  target: string
  open_new_tab: boolean
}

export interface BannerHotspot {
  id: string
  label: string
  x: number
  y: number
  width: number
  height: number
  image_url: string
  hover_scale: number
  action: BannerAction
}

export interface BannerVisual {
  image_url: string
  alt: string
  action: BannerAction
  hotspots: BannerHotspot[]
}

export interface DistributionBannerConfig {
  eyebrow: string
  title: string
  badge: string
  pill: string
  tone: string
  enabled: boolean
  pc: BannerVisual
  mobile: BannerVisual
}

export const bannerActionOptions: { value: BannerActionType; label: string }[] = [
  { value: 'none', label: '不跳转' },
  { value: 'route', label: '站内路径' },
  { value: 'link', label: '外部链接' },
  { value: 'preview', label: '查看大图' },
]

export const bannerActionHints: Record<BannerActionType, string> = {
  none: '点击无动作；未配置热区时仍可点击查看大图',
  route: '站内路径，如 /listings、/m/announcements',
  link: '外部链接，需以 http:// 或 https:// 开头',
  preview: '点击放大查看原图',
}

const ACTION_TYPES: BannerActionType[] = ['none', 'route', 'link', 'preview']
const BANNER_TONES = ['blue', 'green', 'orange', 'gold']
export const BANNER_HOTSPOT_DEFAULT_HOVER_SCALE = 1.06
const BANNER_HOTSPOT_MAX_HOVER_SCALE = 1.5

export function createEmptyBannerAction(): BannerAction {
  return { type: 'none', target: '', open_new_tab: false }
}

export function createEmptyBannerVisual(): BannerVisual {
  return { image_url: '', alt: '', action: createEmptyBannerAction(), hotspots: [] }
}

export function createBannerHotspot(partial: Partial<BannerHotspot> = {}): BannerHotspot {
  return {
    id: `hotspot-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 7)}`,
    label: '',
    x: 6,
    y: 20,
    width: 24,
    height: 24,
    image_url: '',
    hover_scale: BANNER_HOTSPOT_DEFAULT_HOVER_SCALE,
    action: createEmptyBannerAction(),
    ...partial,
  }
}

export function createEmptyDistributionBanner(): DistributionBannerConfig {
  return {
    eyebrow: '',
    title: '',
    badge: '本店精选',
    pill: '',
    tone: 'gold',
    enabled: true,
    pc: createEmptyBannerVisual(),
    mobile: createEmptyBannerVisual(),
  }
}

export function normalizeBannerAction(raw: unknown): BannerAction {
  const source = isRecord(raw) ? raw : {}
  const rawType = typeof source.type === 'string' ? source.type.trim() : ''
  const type = ACTION_TYPES.find(item => item === rawType) ?? 'none'
  const target = text(source.target)
  if ((type === 'route' || type === 'link') && !target) {
    return createEmptyBannerAction()
  }
  return { type, target, open_new_tab: source.open_new_tab === true }
}

export function normalizeBannerHotspot(raw: unknown, index: number): BannerHotspot | null {
  if (!isRecord(raw)) return null
  const width = clampPercent(raw.width)
  const height = clampPercent(raw.height)
  if (width <= 0 || height <= 0) return null
  return {
    id: typeof raw.id === 'string' && raw.id.trim() ? raw.id.trim() : `hotspot-${index + 1}`,
    label: text(raw.label),
    x: clampPercent(raw.x, 100 - width),
    y: clampPercent(raw.y, 100 - height),
    width,
    height,
    image_url: text(raw.image_url),
    hover_scale: normalizeHotspotHoverScale(raw.hover_scale),
    action: normalizeBannerAction(raw.action),
  }
}

export function normalizeBannerVisual(
  raw: unknown,
  legacy: { imageUrl?: string; action?: BannerAction } = {}
): BannerVisual {
  const source = isRecord(raw) ? raw : {}
  const imageUrl = text(source.image_url) || text(legacy.imageUrl)
  const action = normalizeBannerAction(source.action)
  const rawHotspots = Array.isArray(source.hotspots) ? source.hotspots : []
  return {
    image_url: imageUrl,
    alt: text(source.alt),
    action: action.type === 'none' && legacy.action ? legacy.action : action,
    hotspots: rawHotspots
      .map((item, index) => normalizeBannerHotspot(item, index))
      .filter((item): item is BannerHotspot => item !== null),
  }
}

/** 读取后台 JSON：新结构原样归一化，旧扁平结构自动升级为两端共图。 */
export function parseDistributionBanners(
  raw: string | undefined,
  siteName = ''
): DistributionBannerConfig[] {
  const parsed = safeParseJSON(raw)
  if (!Array.isArray(parsed)) return []
  return parsed.map(item => normalizeDistributionBanner(item, siteName))
}

export function normalizeDistributionBanner(
  raw: unknown,
  siteName = ''
): DistributionBannerConfig {
  const source = isRecord(raw) ? raw : {}
  const legacyImageUrl = text(source.image_url)
  const legacyAction = resolveLegacyBannerAction(source.link_url || source.link)
  const structured = isRecord(source.pc) || isRecord(source.mobile)
  const sharedLegacy = { imageUrl: legacyImageUrl, action: legacyAction }

  const banner: DistributionBannerConfig = {
    eyebrow: text(source.eyebrow),
    title: text(source.title),
    badge: text(source.badge),
    pill: text(source.pill),
    tone: normalizeBannerTone(source.tone),
    enabled: source.enabled !== false,
    pc: normalizeBannerVisual(source.pc, sharedLegacy),
    mobile: normalizeBannerVisual(source.mobile, sharedLegacy),
  }

  if (!structured) {
    const hasImage = Boolean(legacyImageUrl)
    banner.eyebrow = hasImage ? '' : text(source.eyebrow) || siteName
    banner.title = hasImage ? '' : text(source.title) || '精选游戏账号 · 随租随玩'
    banner.badge = text(source.badge) || '本店精选'
    banner.pill = hasImage ? '' : text(source.pill) || '官方保障'
    banner.tone = 'gold'
  } else if (!banner.badge) {
    banner.badge = ''
  }

  return banner
}

/** 保存前过滤完全空白的卡片，序列化为与主站一致的 JSON 结构。 */
export function serializeDistributionBanners(banners: DistributionBannerConfig[]): string {
  return JSON.stringify(banners.filter(hasBannerContent))
}

export function hasBannerContent(banner: DistributionBannerConfig): boolean {
  return Boolean(
    banner.eyebrow.trim() ||
      banner.title.trim() ||
      banner.pill.trim() ||
      banner.pc.image_url.trim() ||
      banner.mobile.image_url.trim() ||
      banner.pc.hotspots.length ||
      banner.mobile.hotspots.length
  )
}

function resolveLegacyBannerAction(raw: unknown): BannerAction {
  const target = text(raw)
  if (!target) return createEmptyBannerAction()
  if (/^https?:\/\//i.test(target)) return { type: 'link', target, open_new_tab: true }
  if (target.startsWith('/')) return { type: 'route', target, open_new_tab: false }
  return createEmptyBannerAction()
}

function normalizeHotspotHoverScale(value: unknown): number {
  const num = typeof value === 'number' ? value : Number(value)
  if (!Number.isFinite(num) || num <= 0) return BANNER_HOTSPOT_DEFAULT_HOVER_SCALE
  const clamped = Math.min(Math.max(num, 1), BANNER_HOTSPOT_MAX_HOVER_SCALE)
  return Math.round(clamped * 100) / 100
}

function normalizeBannerTone(value: unknown): string {
  const tone = text(value)
  return BANNER_TONES.includes(tone) ? tone : 'gold'
}

function clampPercent(value: unknown, max = 100): number {
  const num = typeof value === 'number' ? value : Number(value)
  if (!Number.isFinite(num)) return 0
  const clamped = Math.min(Math.max(num, 0), max)
  return Math.round(clamped * 100) / 100
}

function text(value: unknown): string {
  return typeof value === 'string' ? value.trim() : ''
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === 'object' && value !== null
}

function safeParseJSON(raw: string | undefined): unknown {
  const value = (raw || '').trim()
  if (!value) return []
  try {
    return JSON.parse(value)
  } catch {
    return []
  }
}