SubMiner/src/media-generator.ts

/*
 * SubMiner - Subtitle mining overlay for mpv
 * Copyright (C) 2024 sudacode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

import { ExecFileException, execFile } from 'child_process';
import * as fs from 'fs';
import * as path from 'path';
import * as os from 'os';
import { createLogger } from './logger';

const log = createLogger('media');

export class MediaGenerator {
  private tempDir: string;
  private notifyIconDir: string;
  private av1EncoderPromise: Promise<string | null> | null = null;

  constructor(tempDir?: string) {
    this.tempDir = tempDir || path.join(os.tmpdir(), 'subminer-media');
    this.notifyIconDir = path.join(os.tmpdir(), 'subminer-notify');
    if (!fs.existsSync(this.tempDir)) {
      fs.mkdirSync(this.tempDir, { recursive: true });
    }
    if (!fs.existsSync(this.notifyIconDir)) {
      fs.mkdirSync(this.notifyIconDir, { recursive: true });
    }
    // Clean up old notification icons on startup (older than 1 hour)
    this.cleanupOldNotificationIcons();
  }

  /**
   * Clean up notification icons older than 1 hour.
   * Called on startup to prevent accumulation of temp files.
   */
  private cleanupOldNotificationIcons(): void {
    try {
      if (!fs.existsSync(this.notifyIconDir)) return;

      const files = fs.readdirSync(this.notifyIconDir);
      const oneHourAgo = Date.now() - 60 * 60 * 1000;

      for (const file of files) {
        if (!file.endsWith('.png')) continue;
        const filePath = path.join(this.notifyIconDir, file);
        try {
          const stat = fs.statSync(filePath);
          if (stat.mtimeMs < oneHourAgo) {
            fs.unlinkSync(filePath);
          }
        } catch (err) {
          log.debug(`Failed to clean up ${filePath}:`, (err as Error).message);
        }
      }
    } catch (err) {
      log.error('Failed to cleanup old notification icons:', err);
    }
  }

  /**
   * Write a notification icon buffer to a temp file and return the file path.
   * The file path can be passed directly to Electron Notification for better
   * compatibility with Linux/Wayland notification daemons.
   */
  writeNotificationIconToFile(iconBuffer: Buffer, noteId: number): string {
    const filename = `icon_${noteId}_${Date.now()}.png`;
    const filePath = path.join(this.notifyIconDir, filename);
    fs.writeFileSync(filePath, iconBuffer);
    return filePath;
  }

  scheduleNotificationIconCleanup(filePath: string, delayMs = 10000): void {
    setTimeout(() => {
      try {
        fs.unlinkSync(filePath);
      } catch {}
    }, delayMs);
  }

  private ffmpegError(label: string, error: ExecFileException): Error {
    if (error.code === 'ENOENT') {
      return new Error('FFmpeg not found. Install FFmpeg to enable media generation.');
    }
    return new Error(`FFmpeg ${label} failed: ${error.message}`);
  }

  private detectAv1Encoder(): Promise<string | null> {
    if (this.av1EncoderPromise) return this.av1EncoderPromise;

    this.av1EncoderPromise = new Promise((resolve) => {
      execFile(
        'ffmpeg',
        ['-hide_banner', '-encoders'],
        { timeout: 10000 },
        (error, stdout, stderr) => {
          if (error) {
            resolve(null);
            return;
          }

          const output = `${stdout || ''}\n${stderr || ''}`;
          const candidates = ['libaom-av1', 'libsvtav1', 'librav1e'];
          for (const encoder of candidates) {
            if (output.includes(encoder)) {
              resolve(encoder);
              return;
            }
          }
          resolve(null);
        },
      );
    });

    return this.av1EncoderPromise;
  }

  async generateAudio(
    videoPath: string,
    startTime: number,
    endTime: number,
    padding: number = 0.5,
    audioStreamIndex: number | null = null,
  ): Promise<Buffer> {
    const start = Math.max(0, startTime - padding);
    const duration = endTime - startTime + 2 * padding;

    return new Promise((resolve, reject) => {
      const outputPath = path.join(this.tempDir, `audio_${Date.now()}.mp3`);
      const args: string[] = ['-ss', start.toString(), '-t', duration.toString(), '-i', videoPath];

      if (
        typeof audioStreamIndex === 'number' &&
        Number.isInteger(audioStreamIndex) &&
        audioStreamIndex >= 0
      ) {
        args.push('-map', `0:${audioStreamIndex}`);
      }

      args.push('-vn', '-acodec', 'libmp3lame', '-q:a', '2', '-ar', '44100', '-y', outputPath);

      execFile('ffmpeg', args, { timeout: 30000 }, (error) => {
        if (error) {
          reject(this.ffmpegError('audio generation', error));
          return;
        }

        try {
          const data = fs.readFileSync(outputPath);
          fs.unlinkSync(outputPath);
          resolve(data);
        } catch (err) {
          reject(err);
        }
      });
    });
  }

  async generateScreenshot(
    videoPath: string,
    timestamp: number,
    options: {
      format: 'jpg' | 'png' | 'webp';
      quality?: number;
      maxWidth?: number;
      maxHeight?: number;
    },
  ): Promise<Buffer> {
    const { format, quality = 92, maxWidth, maxHeight } = options;
    const ext = format === 'webp' ? 'webp' : format === 'png' ? 'png' : 'jpg';
    const codecMap: Record<'jpg' | 'png' | 'webp', string> = {
      jpg: 'mjpeg',
      png: 'png',
      webp: 'webp',
    };

    const args: string[] = ['-ss', timestamp.toString(), '-i', videoPath, '-vframes', '1'];

    const vfParts: string[] = [];
    if (maxWidth && maxWidth > 0 && maxHeight && maxHeight > 0) {
      vfParts.push(`scale=w=${maxWidth}:h=${maxHeight}:force_original_aspect_ratio=decrease`);
    } else if (maxWidth && maxWidth > 0) {
      vfParts.push(`scale=w=${maxWidth}:h=-2`);
    } else if (maxHeight && maxHeight > 0) {
      vfParts.push(`scale=w=-2:h=${maxHeight}`);
    }
    if (vfParts.length > 0) {
      args.push('-vf', vfParts.join(','));
    }

    args.push('-c:v', codecMap[format]);

    if (format !== 'png') {
      const clampedQuality = Math.max(1, Math.min(100, quality));
      if (format === 'jpg') {
        const qv = Math.round(2 + (100 - clampedQuality) * (29 / 99));
        args.push('-q:v', qv.toString());
      } else {
        args.push('-q:v', clampedQuality.toString());
      }
    }

    args.push('-y');

    return new Promise((resolve, reject) => {
      const outputPath = path.join(this.tempDir, `screenshot_${Date.now()}.${ext}`);
      args.push(outputPath);

      execFile('ffmpeg', args, { timeout: 30000 }, (error) => {
        if (error) {
          reject(this.ffmpegError('screenshot generation', error));
          return;
        }

        try {
          const data = fs.readFileSync(outputPath);
          fs.unlinkSync(outputPath);
          resolve(data);
        } catch (err) {
          reject(err);
        }
      });
    });
  }

  /**
   * Generate a small PNG icon suitable for desktop notifications.
   * Always outputs PNG format (known-good for Electron + Linux notification daemons).
   * Scaled to 256px width for fast encoding and small file size.
   */
  async generateNotificationIcon(videoPath: string, timestamp: number): Promise<Buffer> {
    return new Promise((resolve, reject) => {
      const outputPath = path.join(this.tempDir, `notify_icon_${Date.now()}.png`);

      execFile(
        'ffmpeg',
        [
          '-ss',
          timestamp.toString(),
          '-i',
          videoPath,
          '-vframes',
          '1',
          '-vf',
          'scale=256:256:force_original_aspect_ratio=decrease,pad=256:256:(ow-iw)/2:(oh-ih)/2:black',
          '-c:v',
          'png',
          '-y',
          outputPath,
        ],
        { timeout: 30000 },
        (error) => {
          if (error) {
            reject(this.ffmpegError('notification icon generation', error));
            return;
          }

          try {
            const data = fs.readFileSync(outputPath);
            fs.unlinkSync(outputPath);
            resolve(data);
          } catch (err) {
            reject(err);
          }
        },
      );
    });
  }

  async generateAnimatedImage(
    videoPath: string,
    startTime: number,
    endTime: number,
    padding: number = 0.5,
    options: {
      fps?: number;
      maxWidth?: number;
      maxHeight?: number;
      crf?: number;
    } = {},
  ): Promise<Buffer> {
    const start = Math.max(0, startTime - padding);
    const duration = endTime - startTime + 2 * padding;
    const { fps = 10, maxWidth = 640, maxHeight, crf = 35 } = options;

    const clampedFps = Math.max(1, Math.min(60, fps));
    const clampedCrf = Math.max(0, Math.min(63, crf));

    const vfParts: string[] = [];
    vfParts.push(`fps=${clampedFps}`);
    if (maxWidth && maxWidth > 0 && maxHeight && maxHeight > 0) {
      vfParts.push(`scale=w=${maxWidth}:h=${maxHeight}:force_original_aspect_ratio=decrease`);
    } else if (maxWidth && maxWidth > 0) {
      vfParts.push(`scale=w=${maxWidth}:h=-2`);
    } else if (maxHeight && maxHeight > 0) {
      vfParts.push(`scale=w=-2:h=${maxHeight}`);
    }

    const av1Encoder = await this.detectAv1Encoder();
    if (!av1Encoder) {
      throw new Error(
        'No supported AV1 encoder found for animated AVIF (tried libaom-av1, libsvtav1, librav1e).',
      );
    }

    return new Promise((resolve, reject) => {
      const outputPath = path.join(this.tempDir, `animation_${Date.now()}.avif`);

      const encoderArgs: string[] = ['-c:v', av1Encoder];
      if (av1Encoder === 'libaom-av1') {
        encoderArgs.push('-crf', clampedCrf.toString(), '-b:v', '0', '-cpu-used', '8');
      } else if (av1Encoder === 'libsvtav1') {
        encoderArgs.push('-crf', clampedCrf.toString(), '-preset', '8');
      } else {
        // librav1e
        encoderArgs.push('-qp', clampedCrf.toString(), '-speed', '8');
      }

      execFile(
        'ffmpeg',
        [
          '-ss',
          start.toString(),
          '-t',
          duration.toString(),
          '-i',
          videoPath,
          '-vf',
          vfParts.join(','),
          ...encoderArgs,
          '-y',
          outputPath,
        ],
        { timeout: 60000 },
        (error) => {
          if (error) {
            reject(this.ffmpegError('animation generation', error));
            return;
          }

          try {
            const data = fs.readFileSync(outputPath);
            fs.unlinkSync(outputPath);
            resolve(data);
          } catch (err) {
            reject(err);
          }
        },
      );
    });
  }

  cleanup(): void {
    try {
      if (fs.existsSync(this.tempDir)) {
        fs.rmSync(this.tempDir, { recursive: true, force: true });
      }
    } catch (err) {
      log.error('Failed to cleanup media generator temp directory:', err);
    }
  }
}