// src/main/services/HistoryService.ts
// SQLite 기반 전사/명령 이력 저장. 설계서 01/03 IHistoryService 구현.

import { eq, desc, like, and, sql, count } from 'drizzle-orm'
import { getDatabase } from '../db'
import { history, stats } from '../db/schema'
import type { History, NewHistory } from '../db/schema'
import { getLogger } from './LoggerService'
import type {
  HistoryEntry,
  HistoryQueryParams,
  HistoryPage,
  HistorySearchParams,
  StatsSummary
} from '@d3ro/core/types'

const logger = getLogger('HistoryService')

class HistoryService {
  create(input: Omit<NewHistory, 'id' | 'createdAt' | 'updatedAt'>): HistoryEntry {
    const db = getDatabase()
    const now = Date.now()
    const id = crypto.randomUUID()

    const entry: NewHistory = {
      id,
      ...input,
      createdAt: now,
      updatedAt: now
    }

    db.insert(history).values(entry).run()

    // stats 싱글톤 업데이트
    this._updateStats(input.duration, input.wordCount)

    logger.info(`History entry created: ${id}`)

    // 비동기로 LLM 타이틀 자동 생성 (fire-and-forget)
    this.generateTitle(id).catch(() => { /* ignore */ })

    return this._toEntry(entry as History)
  }

  getById(id: string): HistoryEntry | null {
    const db = getDatabase()
    const row = db.select().from(history).where(eq(history.id, id)).get()
    return row ? this._toEntry(row) : null
  }

  list(params: HistoryQueryParams): HistoryPage {
    const db = getDatabase()
    const { page, pageSize } = params

    const totalResult = db.select({ count: count() }).from(history).get()
    const total = totalResult?.count ?? 0

    const entries = db
      .select()
      .from(history)
      .orderBy(desc(history.createdAt))
      .limit(pageSize)
      .offset(page * pageSize)
      .all()

    return {
      entries: entries.map((e) => this._toEntry(e)),
      total,
      page,
      pageSize,
      totalPages: Math.ceil(total / pageSize)
    }
  }

  search(params: HistorySearchParams): HistoryPage {
    const db = getDatabase()
    const { query, page, pageSize } = params
    const pattern = `%${query}%`

    const conditions = and(
      like(history.originalText, pattern)
    )

    const totalResult = db
      .select({ count: count() })
      .from(history)
      .where(conditions)
      .get()
    const total = totalResult?.count ?? 0

    const entries = db
      .select()
      .from(history)
      .where(conditions)
      .orderBy(desc(history.createdAt))
      .limit(pageSize)
      .offset(page * pageSize)
      .all()

    return {
      entries: entries.map((e) => this._toEntry(e)),
      total,
      page,
      pageSize,
      totalPages: Math.ceil(total / pageSize)
    }
  }

  delete(id: string): boolean {
    const db = getDatabase()
    const result = db.delete(history).where(eq(history.id, id)).run()
    return result.changes > 0
  }

  deleteAll(): void {
    const db = getDatabase()
    db.delete(history).run()
    logger.info('All history entries deleted')
  }

  getStats(): StatsSummary {
    const db = getDatabase()
    const row = db.select().from(stats).where(eq(stats.id, 1)).get()

    const todayStart = new Date()
    todayStart.setHours(0, 0, 0, 0)
    const todayMs = todayStart.getTime()

    const todayResult = db
      .select({
        sessions: count(),
        duration: sql<number>`COALESCE(SUM(duration), 0)`,
        words: sql<number>`COALESCE(SUM(word_count), 0)`
      })
      .from(history)
      .where(
        and(
          sql`created_at >= ${todayMs}`,
          eq(history.status, 'completed')
        )
      )
      .get()

    return {
      totalRecordingTimeMs: (row?.totalDuration ?? 0) * 1000,
      totalWordCount: row?.totalWords ?? 0,
      totalSessionCount: row?.sessionCount ?? 0,
      todayRecordingTimeMs: (todayResult?.duration ?? 0) * 1000,
      todayWordCount: todayResult?.words ?? 0,
      todaySessionCount: todayResult?.sessions ?? 0,
      streakDays: row?.streakDays ?? 0
    }
  }

  /**
   * 보존 정책에 따라 오래된 항목 정리 (30일 초과)
   */
  runRetentionCleanup(): number {
    const db = getDatabase()
    const cutoff = Date.now() - 30 * 24 * 60 * 60 * 1000
    const result = db.delete(history).where(sql`created_at < ${cutoff}`).run()
    if (result.changes > 0) {
      logger.info(`Retention cleanup: ${result.changes} old entries removed`)
    }
    return result.changes
  }

  dispose(): void {
    logger.info('HistoryService disposed')
  }

  private _updateStats(duration: number, wordCount: number): void {
    const db = getDatabase()
    const now = Date.now()

    db.update(stats)
      .set({
        totalDuration: sql`total_duration + ${duration}`,
        totalWords: sql`total_words + ${wordCount}`,
        sessionCount: sql`session_count + 1`,
        lastSessionAt: now,
        lastUpdated: now
      })
      .where(eq(stats.id, 1))
      .run()
  }

  /** 전사 완료 후 LLM으로 자동 타이틀 생성 */
  async generateTitle(id: string): Promise<string | null> {
    const entry = this.getById(id)
    if (!entry) return null

    const text = entry.polishedText || entry.originalText
    if (!text || text.length < 10) return null

    try {
      const { getLocalLLMService } = await import('./LocalLLMService')
      const llm = getLocalLLMService()
      const result = await llm.generate(
        text.slice(0, 2000),
        {
          systemPrompt: '다음 텍스트의 핵심 내용을 10단어 이내의 짧은 제목으로 만들어주세요. 제목만 출력하세요. 따옴표나 마침표를 붙이지 마세요.',
          temperature: 0.3,
          maxTokens: 50,
        },
      )
      const title = result.text.trim().replace(/^["']|["']$/g, '').slice(0, 80)
      if (title) {
        const db = getDatabase()
        db.update(history).set({ title, updatedAt: Date.now() }).where(eq(history.id, id)).run()
        logger.info(`Auto title generated: ${id} → "${title}"`)
        return title
      }
    } catch (err) {
      logger.warn(`Auto title generation failed: ${err instanceof Error ? err.message : String(err)}`)
    }
    return null
  }

  private _toEntry(row: History): HistoryEntry {
    return {
      id: row.id,
      title: row.title ?? null,
      originalText: row.originalText,
      polishedText: row.polishedText,
      focusedApp: row.focusedApp,
      focusedAppName: row.focusedAppName,
      focusedAppWindowTitle: row.focusedAppWindowTitle,
      mode: row.mode as HistoryEntry['mode'],
      status: row.status as HistoryEntry['status'],
      errorCode: row.errorCode,
      audioLocalPath: row.audioLocalPath,
      duration: row.duration,
      detectedLanguage: row.detectedLanguage,
      micDevice: row.micDevice,
      wordCount: row.wordCount,
      sttModel: row.sttModel,
      llmModel: row.llmModel,
      sttLatencyMs: row.sttLatencyMs,
      llmLatencyMs: row.llmLatencyMs,
      createdAt: row.createdAt,
      updatedAt: row.updatedAt,
      appVersion: row.appVersion,
      summaryText: row.summaryText ?? null,
    }
  }
}

let instance: HistoryService | null = null

export function getHistoryService(): HistoryService {
  if (!instance) {
    instance = new HistoryService()
  }
  return instance
}