import type { Message } from "../agent/conversation"

/**
 * Microcompact: reduce token usage by stripping verbose tool results
 * and compressing old messages. Ported from Clawd-Code compact_service/microcompact.py.
 */

export function microcompactMessages(messages: Message[]): {
  compacted: Message[]
  tokensSaved: number
} {
  let tokensSaved = 0
  const compacted: Message[] = []

  for (const msg of messages) {
    if (msg.role === "tool") {
      const text = typeof msg.content === "string" ? msg.content : JSON.stringify(msg.content)
      if (text.length > 2000) {
        const compressed = compressToolResult(text)
        tokensSaved += Math.ceil((text.length - compressed.length) / 4)
        compacted.push({ ...msg, content: compressed })
        continue
      }
    }

    if (msg.role === "assistant" && msg.content) {
      const text = typeof msg.content === "string" ? msg.content : JSON.stringify(msg.content)
      if (text.length > 10000) {
        const truncated = text.slice(0, 5000) + "\n... [truncated for compaction]"
        tokensSaved += Math.ceil((text.length - truncated.length) / 4)
        compacted.push({ ...msg, content: truncated })
        continue
      }
    }

    compacted.push(msg)
  }

  return { compacted, tokensSaved }
}

function compressToolResult(text: string): string {
  // Keep first 500 chars and last 500 chars of large tool results
  if (text.length <= 2000) return text
  const head = text.slice(0, 500)
  const tail = text.slice(-500)
  const lines = text.split("\n").length
  return `${head}\n\n... [${lines} lines compressed, ${text.length} chars total] ...\n\n${tail}`
}