/**
 * 把 `claude -p --output-format stream-json --verbose` 吐出的每行 NDJSON
 * 压缩成人能看懂的进度短语，供长任务（如提交代码）实时展示。
 *
 * 只关心 assistant 消息里的 `tool_use` 和 `text` 块，其它行（system / user /
 * result / thinking 块 / 坏 JSON）一律返回空数组，调用方无需再做判断。
 */

import * as path from 'node:path'

const LABEL_MAX_CHARS = 60

interface ContentBlock {
  type?: unknown
  text?: unknown
  name?: unknown
  input?: unknown
}

function truncate(text: string): string {
  if (text.length <= LABEL_MAX_CHARS)
    return text
  return `${text.slice(0, LABEL_MAX_CHARS)}…`
}

function asString(value: unknown): string {
  return typeof value === 'string' ? value : ''
}

/** 一次工具调用写成人看得懂的短语：「读取 routes.py」「搜索 get_user」。 */
export function describeToolUse(name: string, input: Record<string, unknown>): string {
  switch (name) {
    case 'Bash':
      return `执行命令：${truncate(asString(input.description) || asString(input.command))}`
    case 'Read':
      return `读取 ${path.basename(asString(input.file_path))}`
    case 'Edit':
    case 'Write':
    case 'MultiEdit':
      return `修改 ${path.basename(asString(input.file_path))}`
    case 'Grep':
    case 'Glob':
      return `搜索 ${truncate(asString(input.pattern))}`
    default:
      return `调用 ${name}`
  }
}

function describeBlock(block: ContentBlock): string | null {
  if (block.type === 'tool_use' && typeof block.name === 'string') {
    const input = block.input && typeof block.input === 'object'
      ? block.input as Record<string, unknown>
      : {}
    return describeToolUse(block.name, input)
  }
  if (block.type === 'text' && typeof block.text === 'string') {
    const firstLine = block.text.split('\n').map(l => l.trim()).find(l => l.length > 0)
    return firstLine ? truncate(firstLine) : null
  }
  return null
}

export function summarizeClaudeStreamLine(line: string): string[] {
  let parsed: unknown
  try {
    parsed = JSON.parse(line)
  }
  catch {
    return []
  }
  if (!parsed || typeof parsed !== 'object')
    return []
  const obj = parsed as { type?: unknown, message?: { content?: unknown } }
  if (obj.type !== 'assistant' || !Array.isArray(obj.message?.content))
    return []

  const labels: string[] = []
  for (const block of obj.message.content as ContentBlock[]) {
    if (!block || typeof block !== 'object')
      continue
    const label = describeBlock(block)
    if (label)
      labels.push(label)
  }
  return labels
}