const ffmpeg = require('fluent-ffmpeg');
const ffmpegStatic = require('ffmpeg-static');
const fs = require('fs').promises;
const path = require('path');
const { spawn } = require('child_process');
const EventEmitter = require('events');

ffmpeg.setFfmpegPath(ffmpegStatic);

class RenderService extends EventEmitter {
  constructor() {
    super();
    this.tempDir = path.join(__dirname, '../../../temp');
    this.rendersDir = path.join(__dirname, '../../../renders');
    this.activeRenders = new Map();
  }

  async ensureDirs() {
    await fs.mkdir(this.tempDir, { recursive: true });
    await fs.mkdir(this.rendersDir, { recursive: true });
  }

  async renderEdit(editPlan, clipPaths, outputPath, audioPath = null) {
    console.log('🎬 Rendering video with edit plan...');
    await this.ensureDirs();
    
    const fullOutputPath = path.join(this.rendersDir, path.basename(outputPath));
    const renderId = path.basename(outputPath, '.mp4');
    
    return new Promise((resolve, reject) => {
      try {
        // Create complex filter for the edit
        const filterComplex = this.buildComplexFilter(editPlan, clipPaths.length);
        
        // Build FFmpeg command
        let command = ffmpeg();
        
        // Add all input clips
        clipPaths.forEach((clip, index) => {
          command = command.input(clip);
        });
        
        // Add audio if provided
        if (audioPath) {
          command = command.input(audioPath);
        }
        
        // Set up progress tracking
        let lastProgress = 0;
        
        command
          .on('start', (commandLine) => {
            console.log('FFmpeg command:', commandLine);
            this.activeRenders.set(renderId, { progress: 0, command: commandLine });
          })
          .on('progress', (progress) => {
            const percent = progress.percent || 0;
            if (percent - lastProgress > 5) {
              console.log(`Rendering: ${percent.toFixed(1)}%`);
              lastProgress = percent;
              this.activeRenders.set(renderId, { progress: percent });
              this.emit('progress', { renderId, progress: percent });
            }
          })
          .on('end', () => {
            console.log('✅ Rendering complete:', fullOutputPath);
            this.activeRenders.delete(renderId);
            resolve(fullOutputPath);
          })
          .on('error', (err) => {
            console.error('FFmpeg error:', err);
            this.activeRenders.delete(renderId);
            
            // If FFmpeg fails, try simple concatenation
            this.simpleConcat(clipPaths, fullOutputPath, audioPath)
              .then(resolve)
              .catch(reject);
          })
          .complexFilter(filterComplex.filter, filterComplex.outputs)
          .outputOptions([
            '-c:v libx264',
            '-preset medium',
            '-crf 23',
            '-pix_fmt yuv420p',
            '-movflags +faststart',
            '-metadata', 'title=TikVibe Creator Pro',
            '-metadata', 'artist=AI Editor',
            '-metadata', 'comment=Created with TikVibe AI'
          ])
          .save(fullOutputPath);
          
      } catch (error) {
        console.error('Render error:', error);
        
        // Fallback: simple concat
        this.simpleConcat(clipPaths, fullOutputPath, audioPath)
          .then(resolve)
          .catch(reject);
      }
    });
  }

  buildComplexFilter(editPlan, numClips) {
    const filters = [];
    const outputs = [];
    
    // Add trim and speed filters for each timeline segment
    editPlan.timeline.forEach((segment, index) => {
      const clipIndex = segment.clipIndex;
      const start = segment.startTime || 0;
      const duration = segment.duration || 2;
      const speed = segment.speed || 1.0;
      
      // Trim the clip
      const trimFilter = `[${clipIndex}:v]trim=start=${start}:duration=${duration},setpts=PTS-STARTPTS[trimmed${index}]`;
      filters.push(trimFilter);
      
      // Apply speed change
      if (speed !== 1.0) {
        const pts = 1 / speed;
        const speedFilter = `[trimmed${index}]setpts=${pts}*PTS[speed${index}]`;
        filters.push(speedFilter);
        outputs.push(`[speed${index}]`);
      } else {
        outputs.push(`[trimmed${index}]`);
      }
    });
    
    // Add effects
    if (editPlan.effects && editPlan.effects.length > 0) {
      editPlan.effects.forEach((effect, index) => {
        if (effect.type === 'flash' && effect.applyTo !== 'all') {
          const flashFilter = `[${outputs[effect.time ? 0 : index]}]eq=brightness=0.2:enable='between(t,${effect.time},${effect.time + effect.duration})'[flash${index}]`;
          filters.push(flashFilter);
          outputs[index] = `[flash${index}]`;
        }
        if (effect.type === 'glitch') {
          const glitchFilter = `[${outputs[index]}]geq=if(eq(mod(X,10),0),Y,lum(X,Y)):if(eq(mod(X,10),0),cb(X,Y),cb(X,Y)):if(eq(mod(X,10),0),cr(X,Y),cr(X,Y)):enable='between(t,${effect.time},${effect.time + effect.duration})'[glitch${index}]`;
          filters.push(glitchFilter);
          outputs[index] = `[glitch${index}]`;
        }
      });
    }
    
    // Add color grading
    if (editPlan.colorGrading) {
      const grade = editPlan.colorGrading;
      const colorFilter = this.buildColorFilter(grade);
      filters.push(colorFilter);
    }
    
    // Add text overlays
    if (editPlan.textOverlays && editPlan.textOverlays.length > 0) {
      editPlan.textOverlays.forEach((overlay, index) => {
        // Check if we have a font file, otherwise use default
        const fontFile = '/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf';
        const yPos = overlay.position === 'bottom' ? 'h-text_h-50' : overlay.position === 'top' ? '50' : '(h-text_h)/2';
        
        const textFilter = `drawtext=text='${overlay.text}':fontcolor=${overlay.color || 'white'}:fontsize=${overlay.fontSize || 36}:fontfile=${fontFile}:x=(w-text_w)/2:y=${yPos}:enable='between(t,${overlay.time},${overlay.time + overlay.duration})'`;
        filters.push(textFilter);
      });
    }
    
    // Add audio processing if needed
    if (editPlan.soundDesign && editPlan.soundDesign.length > 0) {
      editPlan.soundDesign.forEach((sound, index) => {
        if (sound.type === 'whoosh') {
          // This would require external audio files - simplified for now
        }
      });
    }
    
    // Concatenate all segments
    if (outputs.length > 0) {
      const concatInput = outputs.join('');
      const concatFilter = `${concatInput}concat=n=${outputs.length}:v=1:a=0[finalv]`;
      filters.push(concatFilter);
      
      // Handle audio
      if (editPlan.timeline.length > 0) {
        // For now, just use audio from first clip or external audio
        filters.push(`[0:a]aresample=48000[finala]`);
        return {
          filter: filters.join(';'),
          outputs: ['[finalv]', '[finala]']
        };
      }
    }
    
    return {
      filter: filters.join(';'),
      outputs: ['[finalv]']
    };
  }

  buildColorFilter(grade) {
    const {
      saturation = 1.0,
      contrast = 1.0,
      brightness = 0.0
    } = grade;
    
    return `eq=saturation=${saturation}:contrast=${contrast}:brightness=${brightness}`;
  }

  async simpleConcat(clipPaths, outputPath, audioPath) {
    console.log('⚠️ Using simple concatenation fallback');
    
    return new Promise((resolve, reject) => {
      const command = ffmpeg();
      
      clipPaths.forEach(clip => command.input(clip));
      
      if (audioPath) {
        command.input(audioPath);
      }
      
      // Create concat file
      const concatContent = clipPaths.map(p => `file '${p}'`).join('\n');
      const concatFile = path.join(this.tempDir, `concat-${Date.now()}.txt`);
      
      fs.writeFile(concatFile, concatContent)
        .then(() => {
          const ffCommand = ffmpeg()
            .input(concatFile)
            .inputOptions(['-f', 'concat', '-safe', '0']);
          
          if (audioPath) {
            ffCommand
              .input(audioPath)
              .outputOptions([
                '-c:v copy',
                '-c:a aac',
                '-map 0:v',
                '-map 1:a',
                '-shortest'
              ]);
          } else {
            ffCommand.outputOptions(['-c copy']);
          }
          
          ffCommand
            .on('end', () => {
              fs.unlink(concatFile).catch(console.error);
              console.log('✅ Simple concat complete');
              resolve(outputPath);
            })
            .on('error', (err) => {
              fs.unlink(concatFile).catch(console.error);
              reject(err);
            })
            .save(outputPath);
        })
        .catch(reject);
    });
  }

  async getRenderProgress(renderId) {
    const render = this.activeRenders.get(renderId);
    return render ? render.progress : 0;
  }

  async cancelRender(renderId) {
    const render = this.activeRenders.get(renderId);
    if (render && render.process) {
      render.process.kill();
      this.activeRenders.delete(renderId);
      return true;
    }
    return false;
  }

  async cleanup() {
    const files = await fs.readdir(this.tempDir);
    const now = Date.now();
    
    for (const file of files) {
      const filePath = path.join(this.tempDir, file);
      const stats = await fs.stat(filePath);
      
      // Delete files older than 1 hour
      if (now - stats.mtimeMs > 3600000) {
        await fs.unlink(filePath);
        console.log('🧹 Cleaned up temp file:', file);
      }
    }
    
    // Also clean up old renders
    const renders = await fs.readdir(this.rendersDir);
    for (const file of renders) {
      const filePath = path.join(this.rendersDir, file);
      const stats = await fs.stat(filePath);
      
      // Delete renders older than 24 hours
      if (now - stats.mtimeMs > 86400000) {
        await fs.unlink(filePath);
        console.log('🧹 Cleaned up old render:', file);
      }
    }
  }
}

module.exports = RenderService;