项目重命名: ReelForge => Pixelle-Video

pixelle_video/services/title_generator.py

@@ -0,0 +1,138 @@
+"""
+Title Generator Service
+
+Service for generating video titles from content.
+"""
+
+from typing import Literal
+
+from loguru import logger
+
+
+# Title generation constants
+AUTO_LENGTH_THRESHOLD = 15
+MAX_TITLE_LENGTH = 15
+
+
+class TitleGeneratorService:
+    """
+    Title generation service
+    
+    Generates video titles from content using different strategies:
+    - auto: Automatically decide based on content length
+    - direct: Use content directly as title
+    - llm: Always use LLM to generate title
+    """
+    
+    def __init__(self, pixelle_video_core):
+        """
+        Initialize title generator service
+        
+        Args:
+            pixelle_video_core: PixelleVideoCore instance
+        """
+        self.core = pixelle_video_core
+    
+    async def __call__(
+        self,
+        content: str,
+        strategy: Literal["auto", "direct", "llm"] = "auto",
+        max_length: int = MAX_TITLE_LENGTH
+    ) -> str:
+        """
+        Generate title from content
+        
+        Args:
+            content: Source content (topic or script)
+            strategy: Generation strategy
+                - "auto": Auto-decide based on content length (default)
+                    * If content <= AUTO_LENGTH_THRESHOLD chars: use directly
+                    * If content > AUTO_LENGTH_THRESHOLD chars: use LLM
+                - "direct": Use content directly (truncated to max_length if needed)
+                - "llm": Always use LLM to generate title
+            max_length: Maximum title length (default: MAX_TITLE_LENGTH)
+        
+        Returns:
+            Generated title
+        
+        Examples:
+            # Auto strategy (default)
+            >>> title = await title_generator("AI技术")  # Short, use directly
+            >>> # Returns: "AI技术"
+            
+            >>> title = await title_generator("如何在信息爆炸时代保持深度思考")  # Long, use LLM
+            >>> # Returns: "信息时代的深度思考" (LLM generated)
+            
+            # Direct strategy
+            >>> title = await title_generator("Very long content...", strategy="direct")
+            >>> # Returns: "Very long content..." (truncated to max_length)
+            
+            # LLM strategy
+            >>> title = await title_generator("AI", strategy="llm")  # Force LLM even for short content
+            >>> # Returns: "人工智能技术" (LLM generated)
+        """
+        if strategy == "direct":
+            return self._use_directly(content, max_length)
+        elif strategy == "llm":
+            return await self._generate_by_llm(content, max_length)
+        else:  # auto
+            if len(content.strip()) <= AUTO_LENGTH_THRESHOLD:
+                return content.strip()
+            return await self._generate_by_llm(content, max_length)
+    
+    def _use_directly(self, content: str, max_length: int) -> str:
+        """
+        Use content directly as title (with truncation if needed)
+        
+        Args:
+            content: Source content
+            max_length: Maximum title length
+            
+        Returns:
+            Truncated or original content
+        """
+        content = content.strip()
+        if len(content) <= max_length:
+            return content
+        return content[:max_length]
+    
+    async def _generate_by_llm(self, content: str, max_length: int) -> str:
+        """
+        Generate title using LLM
+        
+        Args:
+            content: Source content (topic or script)
+            max_length: Maximum title length
+            
+        Returns:
+            LLM-generated title
+        """
+        from pixelle_video.prompts import build_title_generation_prompt
+        
+        # Build prompt using template
+        prompt = build_title_generation_prompt(content, max_length=500)
+        
+        # Call LLM to generate title
+        response = await self.core.llm(
+            prompt=prompt,
+            temperature=0.7,
+            max_tokens=50
+        )
+        
+        # Clean up response
+        title = response.strip()
+        
+        # Remove quotes if present
+        if title.startswith('"') and title.endswith('"'):
+            title = title[1:-1]
+        if title.startswith("'") and title.endswith("'"):
+            title = title[1:-1]
+        
+        # Limit to max_length (safety)
+        if len(title) > max_length:
+            title = title[:max_length]
+        
+        logger.debug(f"Generated title: '{title}' (length: {len(title)})")
+        
+        return title
+