import { MAX_LINE } from './examples'
import type { IndexEntry } from './retrieval'
import { isFunctionTag } from './tags'

const DEFAULT_DIR = '.claude/anime-companion'

// 對白索引由建置流水線產生，放在使用者資料目錄（不在插件裡、不入版本控制）。
// dataDir 留空時用 ~/.claude/anime-companion；找不到家目錄就回傳 null。
export function indexPath(dataDir: string, home: string | undefined, code: string): string | null {
  const base = dataDir.trim() !== '' ? dataDir.trim() : home ? `${home}/${DEFAULT_DIR}` : null
  return base === null ? null : `${base.replace(/\/+$/, '')}/${code}/index.jsonl`
}

// 一行一筆；格式不對的行略過，不讓壞掉的資料擋住載入。
export function parseIndex(text: string): IndexEntry[] {
  const out: IndexEntry[] = []
  for (const line of text.split('\n')) {
    if (line.trim() === '') continue
    try {
      const e = JSON.parse(line) as Record<string, unknown>
      if (
        typeof e.id === 'string' &&
        isFunctionTag(e.function) &&
        typeof e.emotion === 'string' &&
        (e.mode === null || typeof e.mode === 'string') &&
        typeof e.text === 'string' &&
        e.text.length > 0 &&
        e.text.length <= MAX_LINE
      ) {
        out.push({ id: e.id, function: e.function, emotion: e.emotion, mode: e.mode, text: e.text })
      }
    } catch {
      // 略過壞行
    }
  }
  return out
}

export async function loadIndex(read: (path: string) => Promise<string>, path: string | null): Promise<IndexEntry[]> {
  if (path === null) return []
  try {
    return parseIndex(await read(path))
  } catch {
    return []
  }
}