"""
Dialogue Video Generator Module

This module extracts dialogue from video files, segments audio, 
and generates render props for dialogue-style videos with speech bubbles.

Usage:
    python backend/dialogue_video_generator.py --video path/to/video.mp4
    python backend/dialogue_video_generator.py  # Auto-detect from assets/0_input/
"""

import argparse
import json
import os
import subprocess
from pathlib import Path
from typing import Dict, Any, List

from dotenv import load_dotenv
from backend.extractor import VideoExtractor


class DialogueVideoGenerator:
    """Generate dialogue video assets from interview recordings"""
    
    def __init__(self, video_path: str = None):
        """
        Initialize the generator
        
        Args:
            video_path: Path to video file. If None, auto-detect from assets/0_input/
        """
        load_dotenv()
        self.project_root = Path(__file__).parent.parent
        self.video_path = self._resolve_video_path(video_path)
        self.segments_output = self.project_root / "assets/1_processed/video_segments.json"
        self.script_output = self.project_root / "assets/1_processed/dialogue_script.json"
        self.props_output = self.project_root / "assets/1_processed/render_props_dialogue.json"
        self.audio_output_dir = self.project_root / "public/dialogue"
        
    def _resolve_video_path(self, video_path: str = None) -> Path:
        """Resolve video path from input or auto-detect"""
        if video_path:
            return Path(video_path)
        
        # Auto-detect from assets/0_input/
        input_dir = self.project_root / "assets/0_input"
        video_extensions = ["*.mp4", "*.mov", "*.avi", "*.mkv"]
        
        for ext in video_extensions:
            video_files = list(input_dir.glob(ext))
            if video_files:
                print(f"✓ Auto-detected video: {video_files[0].name}")
                return video_files[0]
        
        raise FileNotFoundError("No video file found. Please provide --video path or place video in assets/0_input/")
    
    def extract_segments(self) -> Dict[str, Any]:
        """
        Extract audio transcription and timestamps from video
        
        Returns:
            Dictionary with transcription, segments, and metadata
        """
        print(f"📹 Extracting segments from: {self.video_path.name}")
        
        if not self.video_path.exists():
            raise FileNotFoundError(f"Video file not found: {self.video_path}")
        
        extractor = VideoExtractor()
        result = extractor.extract(str(self.video_path))
        
        # Save segments
        with open(self.segments_output, "w", encoding="utf-8") as f:
            json.dump(result, f, ensure_ascii=False, indent=2)
        
        print(f"✓ Saved {len(result['segments'])} segments to {self.segments_output.name}")
        return result
    
    def slice_audio(self, input_path: str, start: float, end: float, output_path: str):
        """Slice audio segment using ffmpeg"""
        duration = end - start
        cmd = [
            "ffmpeg", "-y",
            "-ss", str(start),
            "-t", str(duration),
            "-i", str(input_path),
            "-c:a", "libmp3lame", "-b:a", "128k",
            str(output_path)
        ]
        subprocess.run(cmd, check=True, capture_output=True)
    
    def identify_speaker(self, text: str, last_speaker: str) -> str:
        """
        Identify speaker based on text content
        
        Args:
            text: Dialogue text
            last_speaker: Previous segment's speaker (for alternation)
            
        Returns:
            Speaker label: "FP" or "家族代表様"
        """
        # FP (Financial Planner) keywords
        fp_keywords = [
            "?", "お願いいたします", "でしょうか", 
            "教えていただけますか", "ありがとうございます", 
            "いらっしゃいますか", "そうですか"
        ]
        
        is_fp = any(kw in text for kw in fp_keywords)
        
        # Short confirmations alternate between speakers
        if text in ["はい。", "そうですね。"]:
            return "FP" if last_speaker == "家族代表様" else "家族代表様"
        
        return "FP" if is_fp else "家族代表様"
    
    def generate_audio_clips(self, segments: List[Dict]) -> List[Dict]:
        """
        Generate individual audio clips for each dialogue segment
        
        Args:
            segments: List of segment dictionaries with text and timestamps
            
        Returns:
            List of processed segments with speaker labels and audio paths
        """
        print(f"🎙️ Generating {len(segments)} audio clips...")
        
        # Create output directory
        self.audio_output_dir.mkdir(parents=True, exist_ok=True)
        
        # Find audio file
        audio_path = self.video_path.parent / f"{self.video_path.stem}_audio.wav"
        if not audio_path.exists():
            raise FileNotFoundError(f"Audio file not found: {audio_path}")
        
        processed_segments = []
        last_speaker = "家族代表様"
        
        for i, seg in enumerate(segments):
            text = seg["text"]
            speaker = self.identify_speaker(text, last_speaker)
            last_speaker = speaker
            
            # Generate audio clip
            segment_filename = f"dialogue_seg_{i:03d}.mp3"
            segment_path = self.audio_output_dir / segment_filename
            
            print(f"  [{i+1}/{len(segments)}] {text[:30]}...")
            self.slice_audio(str(audio_path), seg["start"], seg["end"], str(segment_path))
            
            processed_segments.append({
                "id": i + 1,
                "text": text,
                "duration": seg["end"] - seg["start"],
                "type": "dialogue",
                "visualType": "dialogue",
                "speaker": speaker,
                "audioPath": f"public/dialogue/{segment_filename}",
                "brollKeyword": "Japanese interview"
            })
        
        # Save dialogue script
        with open(self.script_output, "w", encoding="utf-8") as f:
            json.dump(processed_segments, f, ensure_ascii=False, indent=2)
        
        print(f"✓ Generated {len(processed_segments)} dialogue segments")
        return processed_segments
    
    def create_render_props(self, dialogue_script: List[Dict]) -> Dict[str, Any]:
        """
        Create render_props.json for dialogue video
        
        Args:
            dialogue_script: List of dialogue segments
            
        Returns:
            Complete render props dictionary
        """
        print("📝 Creating render props for dialogue video...")
        
        # Load original render_props for meta and charts
        original_props_path = self.project_root / "assets/1_processed/render_props.json"
        
        if original_props_path.exists():
            with open(original_props_path, "r", encoding="utf-8") as f:
                original_props = json.load(f)
        else:
            # Minimal fallback structure
            original_props = {
                "meta": {"title": "対話動画", "currencyUnit": "万円", "duration": 180},
                "charts": {},
                "assets": {"broll": {}, "videoClips": [], "slides": []}
            }
        
        # Construct new props
        new_props = {
            "meta": original_props.get("meta", {}),
            "charts": original_props.get("charts", {}),
            "script": dialogue_script,
            "assets": original_props.get("assets", {})
        }
        
        # Update title
        if "title" in new_props["meta"]:
            new_props["meta"]["title"] = "【対話版】" + new_props["meta"]["title"]
        
        # Save render props
        with open(self.props_output, "w", encoding="utf-8") as f:
            json.dump(new_props, f, ensure_ascii=False, indent=2)
        
        print(f"✓ Saved render props to {self.props_output.name}")
        return new_props
    
    def run(self) -> str:
        """
        Execute full dialogue video generation pipeline
        
        Returns:
            Path to generated render_props.json
        """
        print("🚀 Starting Dialogue Video Generation Pipeline...")
        print()
        
        # Step 1: Extract segments
        result = self.extract_segments()
        segments = result["segments"]
        print()
        
        # Step 2: Generate audio clips
        processed_segments = self.generate_audio_clips(segments)
        print()
        
        # Step 3: Create render props
        self.create_render_props(processed_segments)
        print()
        
        print(f"✅ Pipeline complete! Use the following command to render:")
        print(f"   npx remotion render MainVideo assets/2_output/dialogue_video.mp4 \\")
        print(f"       --props=\"{self.props_output.relative_to(self.project_root)}\"")
        
        return str(self.props_output)


def main():
    """CLI entry point"""
    parser = argparse.ArgumentParser(
        description="Dialogue Video Generator - Extract and render interview dialogues",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  python backend/dialogue_video_generator.py
  python backend/dialogue_video_generator.py --video assets/0_input/interview.mp4
        """
    )
    
    parser.add_argument(
        "--video",
        type=str,
        help="Path to video file (auto-detect from assets/0_input/ if not provided)",
    )
    
    args = parser.parse_args()
    
    try:
        generator = DialogueVideoGenerator(video_path=args.video)
        generator.run()
    except Exception as e:
        print(f"\n❌ Generation failed: {e}")
        import traceback
        traceback.print_exc()
        return 1
    
    return 0


if __name__ == "__main__":
    exit(main())