import { readdirSync, statSync } from 'fs'
import { homedir } from 'os'
import { join } from 'path'
import { parseSessionFile } from './parser.js'
import { openSessionsDb, type SessionsDb } from './db.js'
import type { SessionMeta } from '../../types/session.js'

export const PROJECTS_ROOT = join(homedir(), '.claude', 'projects')
export const DEFAULT_DB_PATH = join(homedir(), '.claude-work', 'sessions.db')

/**
 * Percorre a raiz de projectos Claude (profundidade 2) e devolve todos os .jsonl.
 * Estrutura: ~/.claude/projects/<project-slug>/<session-uuid>.jsonl
 */
export function findAllJsonl(root: string = PROJECTS_ROOT): string[] {
  const result: string[] = []
  let entries: string[]
  try {
    entries = readdirSync(root)
  } catch {
    return result
  }
  for (const entry of entries) {
    const projectDir = join(root, entry)
    let st
    try {
      st = statSync(projectDir)
    } catch {
      continue
    }
    if (!st.isDirectory()) continue
    let files: string[]
    try {
      files = readdirSync(projectDir)
    } catch {
      continue
    }
    for (const f of files) {
      if (f.endsWith('.jsonl')) result.push(join(projectDir, f))
    }
  }
  return result
}

/**
 * Indexa um único ficheiro (parse + upsert). Uso individual — útil para o watcher (Task 8).
 */
export async function indexFile(db: SessionsDb, path: string): Promise<void> {
  const { meta } = await parseSessionFile(path)
  db.upsertSession(meta)
}

export interface IndexAllOptions {
  dbPath?: string
  onProgress?: (done: number, total: number) => void
}

/**
 * Full scan: percorre todos os JSONL e faz upsert em lote (batch 50 via transacção).
 */
export async function indexAll(
  options: IndexAllOptions = {},
): Promise<{ indexed: number; failed: number }> {
  const db = openSessionsDb(options.dbPath ?? DEFAULT_DB_PATH)
  const files = findAllJsonl()
  const BATCH = 50
  let indexed = 0
  let failed = 0
  let batch: SessionMeta[] = []

  try {
    for (let i = 0; i < files.length; i++) {
      try {
        const { meta } = await parseSessionFile(files[i])
        batch.push(meta)
        if (batch.length >= BATCH) {
          db.upsertMany(batch)
          indexed += batch.length
          batch = []
        }
      } catch (err) {
        failed++
        console.error(`[indexer] erro em ${files[i]}:`, err)
      }
      if (options.onProgress) {
        options.onProgress(indexed + failed + batch.length, files.length)
      }
    }
    if (batch.length > 0) {
      db.upsertMany(batch)
      indexed += batch.length
    }
  } finally {
    db.close()
  }

  return { indexed, failed }
}