import json
import urllib.request
import urllib.error

class LLMClient:
    class Message:
        def __init__(self, msg):
            self.content = msg.get('content', '')
            self.tool_calls = msg.get('tool_calls', None)
            self.warning = None

    def __init__(self, base_url, model, api_key, timeout=600):
        self.base_url = base_url.rstrip('/')
        self.model = model
        self.api_key = api_key
        self.timeout = timeout

    def chat(self, messages, tools=None):
        url = f"{self.base_url}/chat/completions"
        payload = {
            "model": self.model,
            "messages": messages
        }
        if tools:
            payload["tools"] = tools
            payload["tool_choice"] = "auto"

        data = json.dumps(payload).encode('utf-8')
        req = urllib.request.Request(url, data=data, method='POST')
        req.add_header('Content-Type', 'application/json')
        req.add_header('Authorization', f'Bearer {self.api_key}')

        try:
            with urllib.request.urlopen(req, timeout=self.timeout) as resp:
                response = json.loads(resp.read().decode('utf-8'))
            message = response['choices'][0]['message']
            return self.Message(message)
        except urllib.error.HTTPError as e:
            body_text = ""
            try:
                body_text = e.read().decode('utf-8', errors='replace')
            except Exception:
                pass
            if tools and e.code == 404:
                try:
                    body = json.loads(body_text) if body_text else {}
                    if 'tool use' in body.get('error', {}).get('message', '').lower():
                        result = self.chat(messages, tools=None)
                        result.warning = "Tool calling not supported by this model. Running in chat-only mode."
                        return result
                except Exception:
                    pass
            detail = f" - {body_text[:500]}" if body_text else ""
            return self.Message({'content': f"HTTP Error: {e.code} {e.reason}{detail}", 'tool_calls': None})
        except Exception as e:
            return self.Message({'content': f"Error: {str(e)}", 'tool_calls': None})