import type {
  ContentVariants,
  SearchFilters,
  SearchPage,
  SearchSort,
  ServiceStats,
  TorrentDetail,
} from '@/types/api'

interface SearchInput {
  query: string
  offset: number
  limit: number
  sort: SearchSort
  filters: SearchFilters
}

function optionalNumber(params: URLSearchParams, key: string, value: string, scale = 1) {
  if (value.trim() === '') return
  const parsed = Number(value)
  if (Number.isFinite(parsed) && parsed >= 0) params.set(key, String(Math.round(parsed * scale)))
}

function optionalDate(params: URLSearchParams, key: string, value: string) {
  if (!value) return
  const timestamp = new Date(value).getTime()
  if (Number.isFinite(timestamp)) {
    const endOfDay = key.endsWith('_before') ? 86_399 : 0
    params.set(key, String(Math.floor(timestamp / 1000) + endOfDay))
  }
}

async function request<T>(path: string, signal?: AbortSignal): Promise<T> {
  const response = await fetch(path, { headers: { Accept: 'application/json' }, signal })
  if (!response.ok) {
    let message = `请求失败 (${response.status})`
    try {
      const body = (await response.json()) as { error?: string }
      if (body.error) message = body.error
    } catch {
      // 保留包含状态码的稳定错误信息
    }
    throw new Error(message)
  }
  return response.json() as Promise<T>
}

export function search(input: SearchInput, signal?: AbortSignal): Promise<SearchPage> {
  const params = new URLSearchParams({
    q: input.query.trim(),
    offset: String(input.offset),
    limit: String(input.limit),
    sort: input.sort,
  })
  const { filters } = input
  optionalNumber(params, 'min_size', filters.minSizeMiB, 1024 * 1024)
  optionalNumber(params, 'max_size', filters.maxSizeMiB, 1024 * 1024)
  optionalNumber(params, 'min_files', filters.minFiles)
  optionalNumber(params, 'max_files', filters.maxFiles)
  optionalDate(params, 'first_seen_after', filters.firstSeenAfter)
  optionalDate(params, 'first_seen_before', filters.firstSeenBefore)
  optionalDate(params, 'last_seen_after', filters.lastSeenAfter)
  optionalDate(params, 'last_seen_before', filters.lastSeenBefore)
  if (filters.extension.trim()) params.set('extension', filters.extension.trim().replace(/^\./, ''))
  if (filters.availability) params.set('availability', filters.availability)
  if (filters.heat) params.set('heat', filters.heat)
  return request<SearchPage>(`/search?${params}`, signal)
}

export function getTorrent(infoHash: string, signal?: AbortSignal): Promise<TorrentDetail> {
  return request<TorrentDetail>(`/torrents/${encodeURIComponent(infoHash)}`, signal)
}

export function getVariants(contentKey: string, signal?: AbortSignal): Promise<ContentVariants> {
  return request<ContentVariants>(`/contents/${encodeURIComponent(contentKey)}?limit=100`, signal)
}

export function getStats(signal?: AbortSignal): Promise<ServiceStats> {
  return request<ServiceStats>('/stats', signal)
}