#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Elephant Alpha AI 服務模組
負責與 OpenRouter / Elephant Alpha API 互動，提供高效率、長上下文的 Worker AI 功能
"""

import os
import time
import json
import logging
import requests
from typing import Optional, Dict, Any, List
from dataclasses import dataclass

logger = logging.getLogger(__name__)

# Elephant Alpha 設定
OPENROUTER_API_KEY = os.getenv('OPENROUTER_API_KEY', '')
ELEPHANT_ALPHA_URL = "https://openrouter.ai/api/v1/chat/completions"
DEFAULT_ELEPHANT_MODEL = "openrouter/elephant-alpha"
ELEPHANT_TIMEOUT = int(os.getenv('ELEPHANT_TIMEOUT', '120'))  # 預設 2 分鐘

# Elephant Alpha 定價 (USD per 1M tokens) - 預估效能型定價
ELEPHANT_PRICING = {
    'openrouter/elephant-alpha': {'input': 0.10, 'output': 0.40},
}

@dataclass
class ElephantResponse:
    """Elephant Alpha 回應結構"""
    success: bool
    content: str
    model: str
    error: Optional[str] = None
    total_duration: Optional[float] = None
    input_tokens: int = 0
    output_tokens: int = 0
    total_tokens: int = 0
    input_cost: float = 0.0
    output_cost: float = 0.0
    total_cost: float = 0.0

class ElephantService:
    """Elephant Alpha AI 服務 - 100B 效率型 Worker"""

    def __init__(self, api_key: str = None, model: str = None):
        """
        初始化 Elephant 服務
        """
        self.api_key = api_key or OPENROUTER_API_KEY
        self.model = model or DEFAULT_ELEPHANT_MODEL

    # W3-A: 護欄 2 — 斷線降級 cache (300s TTL，不每次 ping OpenRouter)
    _connection_cache: Dict[str, Any] = {"ok": False, "checked_at": 0.0}

    def check_connection(self, cache_seconds: int = 300) -> bool:
        """
        檢查 API 是否可用（結果快取 300s）。
        cache_seconds=300 與 Anthropic prompt cache TTL 對齊，避免每分鐘 EA loop 都打 API。
        """
        if not self.api_key:
            return False

        now = time.time()
        cache = ElephantService._connection_cache
        if cache["checked_at"] and (now - cache["checked_at"]) < cache_seconds:
            return cache["ok"]

        try:
            response = self.generate("hi", timeout=10)
            result = response.success
        except Exception:
            result = False

        ElephantService._connection_cache = {"ok": result, "checked_at": now}
        return result

    @staticmethod
    def calculate_cost(model: str, input_tokens: int, output_tokens: int) -> Dict[str, float]:
        """計算費用"""
        pricing = ELEPHANT_PRICING.get(model, ELEPHANT_PRICING['openrouter/elephant-alpha'])
        input_cost = (input_tokens / 1_000_000) * pricing['input']
        output_cost = (output_tokens / 1_000_000) * pricing['output']
        return {
            'input_cost': round(input_cost, 6),
            'output_cost': round(output_cost, 6),
            'total_cost': round(input_cost + output_cost, 6)
        }

    def generate(self, prompt: str, model: str = None, 
                 system_prompt: str = None, temperature: float = 0.3,
                 json_mode: bool = False, timeout: int = None) -> ElephantResponse:
        """
        生成文字（主介面）
        """
        model_name = model or self.model
        request_timeout = timeout or ELEPHANT_TIMEOUT

        if not self.api_key:
            return ElephantResponse(success=False, content='', model=model_name, error="API Key 未設定")

        headers = {
            "Authorization": f"Bearer {self.api_key}",
            "Content-Type": "application/json"
        }

        messages = []
        if system_prompt:
            messages.append({"role": "system", "content": system_prompt})
        messages.append({"role": "user", "content": prompt})

        payload = {
            "model": model_name,
            "messages": messages,
            "temperature": temperature,
            "max_tokens": 8000
        }

        if json_mode:
            payload["response_format"] = {"type": "json_object"}

        try:
            start_time = time.time()
            response = requests.post(
                ELEPHANT_ALPHA_URL,
                json=payload,
                headers=headers,
                timeout=request_timeout
            )
            response.raise_for_status()
            end_time = time.time()
            
            data = response.json()
            content = data["choices"][0]["message"]["content"]
            
            # Token 用量
            usage = data.get("usage", {})
            input_tokens = usage.get("prompt_tokens", 0)
            output_tokens = usage.get("completion_tokens", 0)
            
            costs = self.calculate_cost(model_name, input_tokens, output_tokens)
            
            return ElephantResponse(
                success=True,
                content=content,
                model=model_name,
                total_duration=end_time - start_time,
                input_tokens=input_tokens,
                output_tokens=output_tokens,
                total_tokens=input_tokens + output_tokens,
                input_cost=costs['input_cost'],
                output_cost=costs['output_cost'],
                total_cost=costs['total_cost']
            )

        except Exception as e:
            logger.error(f"[Elephant] 生成失敗: {e}")
            return ElephantResponse(success=False, content='', model=model_name, error=str(e))

# 單例實例
elephant_service = ElephantService()