import json
import hashlib
import datetime
from pathlib import Path
from openai import OpenAI
 
 
class EvidenceLogger:
    """包裝相容 OpenAI 的 client，記錄所有互動。"""
 
    def __init__(self, client: OpenAI, engagement_id: str, analyst: str,
                 evidence_dir: str = "./evidence"):
        self.client = client
        self.engagement_id = engagement_id
        self.analyst = analyst
        self.evidence_dir = Path(evidence_dir) / engagement_id
        self.evidence_dir.mkdir(parents=True, exist_ok=True)
        self.interaction_count = 0
 
    def chat(self, messages: list, model: str, **kwargs) -> dict:
        """送出 chat completion 並記錄完整互動。"""
        self.interaction_count += 1
        timestamp = datetime.datetime.now(datetime.timezone.utc).isoformat()
 
        # 發送 API 呼叫
        response = self.client.chat.completions.create(
            model=model, messages=messages, **kwargs
        )
 
        # 建構證據紀錄
        record = {
            "evidence_id": f"{self.engagement_id}-I{self.interaction_count:04d}",
            "timestamp": timestamp,
            "analyst": self.analyst,
            "request": {
                "model": model,
                "messages": messages,
                "parameters": kwargs,
            },
            "response": {
                "id": response.id,
                "content": response.choices[0].message.content,
                "finish_reason": response.choices[0].finish_reason,
                "usage": dict(response.usage) if response.usage else None,
            },
        }
 
        # 儲存並雜湊
        filepath = self.evidence_dir / f"interaction_{self.interaction_count:04d}.json"
        content = json.dumps(record, indent=2, ensure_ascii=False)
        filepath.write_text(content)
 
        record["integrity"] = {
            "sha256": hashlib.sha256(content.encode()).hexdigest()
        }
 
        return record