/**
 * NLP 查询模块
 * 提供词频统计等 NLP 相关查询功能
 */

import { openDatabase, buildTimeFilter, type TimeFilter } from '../core'
import { segment, batchSegmentWithFrequency, getPosTagDefinitions, collectPosTagStats } from '../../nlp'
import type {
  SupportedLocale,
  WordFrequencyResult,
  WordFrequencyParams,
  PosTagInfo,
  PosTagStat,
  DictType,
} from '../../nlp'

/**
 * 获取词频统计
 * 用于词云展示
 */
export function getWordFrequency(params: WordFrequencyParams): WordFrequencyResult {
  const {
    sessionId,
    locale,
    timeFilter,
    memberId,
    topN = 100,
    minWordLength,
    minCount = 2,
    posFilterMode = 'meaningful',
    customPosTags,
    enableStopwords = true,
    dictType = 'default',
    excludeWords,
  } = params

  const db = openDatabase(sessionId)
  if (!db) {
    return {
      words: [],
      totalWords: 0,
      totalMessages: 0,
      uniqueWords: 0,
    }
  }

  const filter: TimeFilter = {
    ...timeFilter,
    memberId,
  }
  const { clause, params: filterParams } = buildTimeFilter(filter, 'msg')

  let whereClause = clause
  if (whereClause.includes('WHERE')) {
    whereClause +=
      " AND COALESCE(m.account_name, '') != '系统消息' AND msg.type = 0 AND msg.content IS NOT NULL AND TRIM(msg.content) != ''"
  } else {
    whereClause =
      " WHERE COALESCE(m.account_name, '') != '系统消息' AND msg.type = 0 AND msg.content IS NOT NULL AND TRIM(msg.content) != ''"
  }

  const messages = db
    .prepare(
      `
      SELECT msg.content
      FROM message msg
      JOIN member m ON msg.sender_id = m.id
      ${whereClause}
      `
    )
    .all(...filterParams) as Array<{ content: string }>

  if (messages.length === 0) {
    return {
      words: [],
      totalWords: 0,
      totalMessages: 0,
      uniqueWords: 0,
    }
  }

  const texts = messages.map((m) => m.content)

  let posTagStats: PosTagStat[] | undefined
  if (typeof locale === 'string' && locale.startsWith('zh')) {
    const posStatsMap = collectPosTagStats(texts, minWordLength ?? 2, enableStopwords, dictType as DictType)
    posTagStats = [...posStatsMap.entries()].map(([tag, count]) => ({ tag, count }))
  }

  const result = batchSegmentWithFrequency(texts, locale as SupportedLocale, {
    minLength: minWordLength,
    minCount,
    topN,
    posFilterMode,
    customPosTags,
    enableStopwords,
    dictType: dictType as DictType,
    excludeWords,
  })

  let topNTotalWords = 0
  for (const count of result.words.values()) {
    topNTotalWords += count
  }

  const words = [...result.words.entries()].map(([word, count]) => ({
    word,
    count,
    percentage: topNTotalWords > 0 ? Math.round((count / topNTotalWords) * 10000) / 100 : 0,
  }))

  return {
    words,
    totalWords: result.totalWords,
    totalMessages: messages.length,
    uniqueWords: result.uniqueWords,
    posTagStats,
  }
}

/**
 * 单文本分词（用于调试或其他用途）
 */
export function segmentText(text: string, locale: SupportedLocale, minLength?: number): string[] {
  return segment(text, locale, { minLength })
}

/**
 * 获取词性标签定义
 */
export function getPosTags(): PosTagInfo[] {
  return getPosTagDefinitions()
}