/**
 * Stack Observer Service
 * Reads divergences from observer.db (SQLite)
 * @author Descomplicar® | @link descomplicar.pt | @copyright 2026
 */
import sqlite3 from 'sqlite3'
import { open } from 'sqlite'
import path from 'path'
import { fileURLToPath } from 'url'
import os from 'os'

const __dirname = path.dirname(fileURLToPath(import.meta.url))

interface Evaluation {
  id: number
  source: string
  entity_id: string
  site_sig: string
  result_real: string
  result_nominal: string
  tokens: number
  reincidence_count: number
  judge_method: string
  confidence: number
  evaluated_at: number
  category: string
}

interface DivergenceStats {
  total_divergences: number
  by_category: Record<string, number>
  by_judge: Record<string, number>
  recent_24h: number
  high_confidence: number
}

/**
 * Open observer.db connection
 * DB is located at ~/Dados/Dev/stack-observer/observer.db
 */
async function openObserverDb() {
  const dbPath = path.join(
    os.homedir(),
    'Dados/Dev/stack-observer/observer.db'
  )
  
  return open({
    filename: dbPath,
    driver: sqlite3.Database
  })
}

/**
 * Get all divergences (evaluations)
 * Filters for result_real != result_nominal
 */
export async function getDivergences() {
  const db = await openObserverDb()
  
  try {
    // Get divergences with divergence flag
    const divergences = await db.all<Evaluation[]>(`
      SELECT 
        id, source, entity_id, site_sig,
        result_real, result_nominal,
        tokens, reincidence_count,
        judge_method, confidence, evaluated_at, category
      FROM evaluations
      WHERE result_real IS NOT NULL 
        AND category IN ('automation-liveness', 'automation-failure')
      ORDER BY evaluated_at DESC
      LIMIT 100
    `)
    
    // Calculate stats
    const now = Math.floor(Date.now() / 1000)
    const day_ago = now - 86400
    
    const stats: DivergenceStats = {
      total_divergences: 0,
      by_category: {},
      by_judge: {},
      recent_24h: 0,
      high_confidence: 0
    }
    
    if (divergences) {
      stats.total_divergences = divergences.length
      
      for (const div of divergences) {
        // Count by category
        stats.by_category[div.category] = (stats.by_category[div.category] ?? 0) + 1
        
        // Count by judge method
        stats.by_judge[div.judge_method] = (stats.by_judge[div.judge_method] ?? 0) + 1
        
        // Count recent
        if (div.evaluated_at >= day_ago) {
          stats.recent_24h++
        }
        
        // Count high confidence
        if (div.confidence >= 0.9) {
          stats.high_confidence++
        }
      }
    }
    
    return {
      divergences: divergences ?? [],
      stats,
      generated_at: new Date().toISOString()
    }
  } finally {
    await db.close()
  }
}

/**
 * Get single divergence by ID
 */
export async function getDivergenceById(id: string) {
  const db = await openObserverDb()
  
  try {
    const evaluation = await db.get<Evaluation>(`
      SELECT * FROM evaluations
      WHERE id = ?
    `, [id])
    
    return evaluation ?? null
  } finally {
    await db.close()
  }
}

/**
 * Get divergence trend (last 7 days)
 */
export async function getDivergenceTrend() {
  const db = await openObserverDb()
  
  try {
    interface TrendRow {
      date: string
      count: number
    }
    
    const trend = await db.all<TrendRow[]>(`
      SELECT 
        DATE(evaluated_at, 'unixepoch') as date,
        COUNT(*) as count
      FROM evaluations
      WHERE result_real IS NOT NULL
        AND category IN ('automation-liveness', 'automation-failure')
        AND evaluated_at >= (unixepoch() - 604800)
      GROUP BY date
      ORDER BY date DESC
    `)
    
    return trend ?? []
  } finally {
    await db.close()
  }
}

/**
 * Get list of automations (hermes_jobs)
 * F1b: Colector lê de ~/.hermes/data/action-log.db
 */
export async function getAutomations() {
  const db = await openObserverDb()
  
  try {
    const automations = await db.all(`
      SELECT 
        action_id, who, what, where_field, when_ts,
        result, result_real, why, how, detail, session_id, created_at,
        ingested_at
      FROM hermes_jobs
      ORDER BY created_at DESC
      LIMIT 100
    `)
    
    return automations ?? []
  } finally {
    await db.close()
  }
}

/**
 * Get list of gate events
 * F1a: Colector lê de /tmp/stack-observer/gate-events.queue
 */
export async function getGateEvents() {
  const db = await openObserverDb()
  
  try {
    const events = await db.all(`
      SELECT 
        id, gate_id, event_type, payload, timestamp, ingested_at
      FROM gate_events
      ORDER BY timestamp DESC
      LIMIT 100
    `)
    
    return events ?? []
  } finally {
    await db.close()
  }
}