# backend/workflow.py
import dashscope
from http import HTTPStatus
from firecrawl import FirecrawlApp
from langchain_text_splitters import RecursiveCharacterTextSplitter
from .config import settings
from .service import crawler_sql_service

# 初始化配置
dashscope.api_key = settings.DASHSCOPE_API_KEY

class AutomatedCrawler:
    def __init__(self):
        self.firecrawl = FirecrawlApp(api_key=settings.FIRECRAWL_API_KEY)
        # 文本切分器：每块500字符，重叠100字符，保证语义连贯
        self.splitter = RecursiveCharacterTextSplitter(
            chunk_size=500, 
            chunk_overlap=100,
            separators=["\n\n", "\n", "。", "！", "？", " ", ""]
        )

    def _get_embedding(self, text: str):
        """调用 Dashscope 生成向量"""
        try:
            resp = dashscope.TextEmbedding.call(
                model=dashscope.TextEmbedding.Models.text_embedding_v4,
                input=text,
                dimension=1536
            )
            if resp.status_code == HTTPStatus.OK:
                # 阿里 text-embedding-v3 默认维度是 1024，v2 是 1536
                # 如果你的数据库是 1536 维，请使用 text_embedding_v2 或调整参数
                return resp.output['embeddings'][0]['embedding']
            else:
                print(f"Embedding API Error: {resp}")
                return None
        except Exception as e:
            print(f"Embedding Exception: {e}")
            return None

    def map_and_ingest(self, start_url: str):
        """
        V2 步骤1: 地图式扫描并入库
        """
        print(f"[WorkFlow] Start mapping: {start_url}")
        
        # 1. 在数据库注册任务
        task_info = crawler_sql_service.register_task(start_url)
        task_id = task_info['task_id']
        
        try:
            # 2. 调用 Firecrawl Map
            map_result = self.firecrawl.map(start_url)
            
            urls=[]
            for link in map_result.links:
                urls.append(link.url)

            print(f"[WorkFlow] Found {len(urls)} links")
            
            # 3. 批量入库 (状态为 pending)
            if urls:
                res = crawler_sql_service.add_urls(task_id, urls)
                
            return {
                "task_id": task_id,
                "map_result": res
            }
        except Exception as e:
            print(f"[WorkFlow] Map Error: {e}")
            raise e

    def process_task_queue(self, task_id: int, limit: int = 10):
        """
        V2 步骤2: 消费队列 -> 抓取 -> 切片 -> 向量化 -> 存储
        """
        # 1. 获取待处理 URL
        pending = crawler_sql_service.get_pending_urls(task_id, limit)
        urls = pending['urls']
        
        if not urls:
            return {"msg": "No pending urls", "count": 0}
        
        processed_count = 0
        
        for url in urls:
            try:
                print(f"[WorkFlow] Processing: {url}")
                # 2. 单页抓取 (Markdown)
                scrape_res = self.firecrawl.scrape(url, formats=['markdown'], only_main_content=True)
                
                content = scrape_res.markdown

                metadata = scrape_res.metadata_dict
                title = metadata.get('title', url)
                
                if not content:
                    print(f"[WorkFlow] Skip empty content: {url}")
                    continue

                # 3. 切片
                chunks = self.splitter.split_text(content)
                
                results_to_save = []
                
                # 4. 逐个切片向量化 (可以优化为批量调用 embedding API)
                for idx, chunk_text in enumerate(chunks):
                    vector = self._get_embedding(chunk_text)
                    if vector:
                        results_to_save.append({
                            "source_url": url,
                            "chunk_index": idx,
                            "title": title,
                            "content": chunk_text,
                            "embedding": vector
                        })
                
                # 5. 保存结果
                if results_to_save:
                    crawler_sql_service.save_results(task_id, results_to_save)
                    processed_count += 1
                    
            except Exception as e:
                print(f"[WorkFlow] Error processing {url}: {e}")
                # 实际生产中这里应该把 URL 状态改为 'failed'
                
        return {"processed_urls": processed_count, "total_chunks": "dynamic"}

    def search_with_embedding(self, query_text: str, task_id: int = None, limit: int = 5):
        """
        V2 搜索: 输入文本 -> 自动转向量 -> 搜索数据库
        """
        vector = self._get_embedding(query_text)
        if not vector:
            raise Exception("Failed to generate embedding for query")
            
        return crawler_sql_service.search_knowledge(vector, task_id, limit)

# 单例模式
workflow = AutomatedCrawler()