/**
 * DashScope (阿里云百炼) search provider.
 *
 * Uses the `enable_search` extension in the Chat Completions API to perform
 * web searches. This is NOT standard OpenAI protocol — DashScope adds
 * `enable_search` and `search_options` fields that other providers don't support.
 *
 * Supported models: qwen-plus, qwen-max, qwen-flash, qwen-turbo, qwen3-max, etc.
 *
 * @module @kamitobi/dsh-multi-search/providers/dashscope
 */

import type {
  WebSearchProvider,
  WebSearchRequest,
  WebSearchResult,
  WebSearchSource,
} from '@deepseek-ai/dsh-web'
import type { BaseProviderConfig } from '../types.js'
import { callChatCompletions, type ChatCompletionResponse } from '../api.js'

// ─── Config ────────────────────────────────────────────────────────────────

/** DashScope-specific configuration options. */
export interface DashScopeProviderConfig extends BaseProviderConfig {
  /** Force web search even if the model thinks it's unnecessary. */
  forceSearch?: boolean
  /** Search strategy: 'turbo' (fastest), 'max' (most thorough), 'agent' (with extraction). */
  searchStrategy?: 'turbo' | 'max' | 'agent'
  /** Maximum number of search results to return. */
  maxResults?: number
}

const DEFAULTS: Required<Omit<DashScopeProviderConfig, 'apiKey' | 'apiKeyEnv' | 'baseURL'>> = {
  model: 'qwen3.7flash',
  forceSearch: false,
  searchStrategy: 'max',
  maxResults: 5,
}

const DEFAULT_BASE_URL = 'https://dashscope.aliyuncs.com/compatible-mode/v1'

// ─── Provider ──────────────────────────────────────────────────────────────

/** Response annotation shape from DashScope. */
interface DashScopeAnnotation {
  type?: string
  url?: string
  title?: string
  summary?: string
  site_name?: string
  publish_time?: string
}

export class DashScopeSearchProvider implements WebSearchProvider {
  readonly id = 'multi-search'

  private readonly apiKey: string
  private readonly baseURL: string
  private readonly model: string
  private readonly forceSearch: boolean
  private readonly searchStrategy: string
  private readonly maxResults: number

  constructor(config: DashScopeProviderConfig) {
    this.apiKey = config.apiKey || ''
    this.baseURL = config.baseURL || DEFAULT_BASE_URL
    this.model = config.model || DEFAULTS.model
    this.forceSearch = config.forceSearch ?? DEFAULTS.forceSearch
    this.searchStrategy = config.searchStrategy || DEFAULTS.searchStrategy
    this.maxResults = config.maxResults ?? DEFAULTS.maxResults
  }

  available(): boolean {
    return Boolean(this.apiKey)
  }

  async search(request: WebSearchRequest, signal?: AbortSignal): Promise<WebSearchResult> {
    const maxResults = request.maxResults ?? this.maxResults

    const body: Record<string, unknown> = {
      model: this.model,
      messages: [{ role: 'user', content: request.query }],
      max_tokens: 2048,
      stream: false,
      enable_search: true,
      search_options: {
        forced_search: this.forceSearch,
        search_strategy: this.searchStrategy,
        enable_source: true,
      },
    }

    const data = await callChatCompletions(this.baseURL, this.apiKey, body, signal)
    const sources = extractAnnotations(data)
    const content = data.choices?.[0]?.message?.content

    return {
      content,
      sources,
      truncated: sources.length > maxResults,
    }
  }
}

// ─── Annotation extraction ─────────────────────────────────────────────────

function extractAnnotations(data: ChatCompletionResponse): WebSearchSource[] {
  const sources: WebSearchSource[] = []
  const seen = new Set<string>()

  const annotations = data.choices?.[0]?.message?.annotations as DashScopeAnnotation[] | undefined
  if (annotations) {
    for (const a of annotations) {
      if (a.url && !seen.has(a.url)) {
        seen.add(a.url)
        sources.push({
          url: a.url,
          title: a.title || a.site_name,
          snippet: a.summary,
          publishedAt: a.publish_time,
        })
      }
    }
  }

  return sources
}