import type { Register } from 'claude-code'

import type { CharacterCode } from './characters'
import { resolveConfig } from './config'
import { indexPath, loadIndex } from './index-loader'
import { buildInjection } from './inject'
import type { IndexEntry } from './retrieval'
import { buildRules, SECTION_ID } from './rules'

// 規則段落（W8）加到系統提示最後；每則使用者訊息再依功能標籤檢索角色的對白當語氣參考（W7）。
// 對白索引在使用者資料目錄（dataDir，預設 ~/.claude/anime-companion/<角色>/index.jsonl）。
export const register: Register = (on, options) => {
  const config = resolveConfig(options)
  const showTiming = options.showTiming === true
  const dataDir = typeof options.dataDir === 'string' ? options.dataDir : ''
  let turn = 0
  // 只快取讀到內容的索引；沒讀到（還沒建置）下一輪會再試，建置完不必重開 session。
  const cache = new Map<CharacterCode, readonly IndexEntry[]>()

  on('prompt.compose', async ($, e, next) => {
    const result = await next(e)
    const text = buildRules(config)
    if (text === null) return result
    return { sections: [...result.sections, { id: SECTION_ID, text, scope: 'session' }] }
  })

  on('prompt.submit', async ($, e, next) => {
    if (e.command || e.isMeta) return next(e)
    const load = async (code: CharacterCode) => {
      const hit = cache.get(code)
      if (hit) return hit
      const path = indexPath(dataDir, await $.env.get('HOME'), code)
      const index = await loadIndex(p => $.fs.read(p), path)
      if (index.length > 0) cache.set(code, index)
      return index
    }
    const r = await buildInjection(
      { config, loadIndex: load, complete: req => $.model.complete(req), now: Date.now, turn: turn++ },
      e.text,
    )
    if (r === null) return next(e)
    if (showTiming) $.ui.status(`anime-companion 分類 ${r.ms}ms → ${r.fn ?? '失敗'}`)
    // 附加在使用者訊息之前，只增不改，不影響對話的快取。
    if (r.text !== null) await $.session.append({ message: { type: 'user', content: [{ type: 'text', text: r.text }] } })
    return next(e)
  })
}