/**
 * Node.js TypeScript wrapper for Soroban Flashcard Generator
 * Calls Python functions via child_process
 */

import { spawn, execSync } from 'child_process';
import * as path from 'path';
import * as fs from 'fs/promises';
import * as os from 'os';

export interface FlashcardConfig {
  range: string;
  step?: number;
  cardsPerPage?: number;
  paperSize?: 'us-letter' | 'a4' | 'a3' | 'a5';
  orientation?: 'portrait' | 'landscape';
  margins?: {
    top?: string;
    bottom?: string;
    left?: string;
    right?: string;
  };
  gutter?: string;
  shuffle?: boolean;
  seed?: number;
  showCutMarks?: boolean;
  showRegistration?: boolean;
  fontFamily?: string;
  fontSize?: string;
  columns?: string | number;
  showEmptyColumns?: boolean;
  hideInactiveBeads?: boolean;
  beadShape?: 'diamond' | 'circle' | 'square';
  colorScheme?: 'monochrome' | 'place-value' | 'heaven-earth' | 'alternating';
  coloredNumerals?: boolean;
  scaleFactor?: number;
}

export class SorobanGenerator {
  private pythonPath: string;
  private generatorPath: string;
  private projectRoot: string;

  constructor(projectRoot?: string) {
    // Find Python executable
    this.pythonPath = this.findPython();
    
    // Set project root (where the Python scripts are)
    this.projectRoot = projectRoot || path.join(__dirname, '../../');
    this.generatorPath = path.join(this.projectRoot, 'src', 'generate.py');
  }

  private findPython(): string {
    // Try common Python commands
    const pythonCommands = ['python3', 'python'];
    
    for (const cmd of pythonCommands) {
      try {
        const version = execSync(`${cmd} --version`, { encoding: 'utf8' });
        if (version.includes('Python 3')) {
          return cmd;
        }
      } catch {
        // Continue to next command
      }
    }
    
    throw new Error('Python 3 not found. Please install Python 3.');
  }

  /**
   * Generate flashcards and return PDF as Buffer
   */
  async generate(config: FlashcardConfig): Promise<Buffer> {
    // Create temp output file
    const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), 'soroban-'));
    const outputPath = path.join(tempDir, 'flashcards.pdf');

    try {
      // Build command line arguments
      const args = [
        this.generatorPath,
        '--output', outputPath,
        '--range', config.range,
      ];

      if (config.step) args.push('--step', config.step.toString());
      if (config.cardsPerPage) args.push('--cards-per-page', config.cardsPerPage.toString());
      if (config.paperSize) args.push('--paper-size', config.paperSize);
      if (config.orientation) args.push('--orientation', config.orientation);
      if (config.gutter) args.push('--gutter', config.gutter);
      if (config.shuffle) args.push('--shuffle');
      if (config.seed !== undefined) args.push('--seed', config.seed.toString());
      if (config.showCutMarks) args.push('--cut-marks');
      if (config.showRegistration) args.push('--registration');
      if (config.fontFamily) args.push('--font-family', config.fontFamily);
      if (config.fontSize) args.push('--font-size', config.fontSize);
      if (config.columns !== undefined) args.push('--columns', config.columns.toString());
      if (config.showEmptyColumns) args.push('--show-empty-columns');
      if (config.hideInactiveBeads) args.push('--hide-inactive-beads');
      if (config.beadShape) args.push('--bead-shape', config.beadShape);
      if (config.colorScheme) args.push('--color-scheme', config.colorScheme);
      if (config.coloredNumerals) args.push('--colored-numerals');
      if (config.scaleFactor !== undefined) args.push('--scale-factor', config.scaleFactor.toString());

      if (config.margins) {
        const m = config.margins;
        const marginStr = `${m.top || '0.5in'},${m.right || '0.5in'},${m.bottom || '0.5in'},${m.left || '0.5in'}`;
        args.push('--margins', marginStr);
      }

      // Execute Python script
      await this.executePython(args);

      // Read generated PDF
      const pdfBuffer = await fs.readFile(outputPath);
      return pdfBuffer;

    } finally {
      // Clean up temp directory
      await fs.rm(tempDir, { recursive: true, force: true });
    }
  }

  /**
   * Generate flashcards and save to file
   */
  async generateToFile(config: FlashcardConfig, outputPath: string): Promise<void> {
    const pdfBuffer = await this.generate(config);
    await fs.writeFile(outputPath, pdfBuffer);
  }

  /**
   * Generate flashcards and return as base64 string
   */
  async generateBase64(config: FlashcardConfig): Promise<string> {
    const pdfBuffer = await this.generate(config);
    return pdfBuffer.toString('base64');
  }

  private executePython(args: string[]): Promise<void> {
    return new Promise((resolve, reject) => {
      const process = spawn(this.pythonPath, args, {
        cwd: this.projectRoot,
        env: { ...process.env, PYTHONPATH: this.projectRoot }
      });

      let stderr = '';

      process.stderr.on('data', (data) => {
        stderr += data.toString();
      });

      process.on('close', (code) => {
        if (code !== 0) {
          reject(new Error(`Python process failed with code ${code}: ${stderr}`));
        } else {
          resolve();
        }
      });

      process.on('error', (err) => {
        reject(new Error(`Failed to start Python process: ${err.message}`));
      });
    });
  }

  /**
   * Check if all dependencies are installed
   */
  async checkDependencies(): Promise<{ python: boolean; typst: boolean; qpdf: boolean }> {
    const checks = {
      python: false,
      typst: false,
      qpdf: false
    };

    try {
      execSync(`${this.pythonPath} --version`);
      checks.python = true;
    } catch {}

    try {
      execSync('typst --version');
      checks.typst = true;
    } catch {}

    try {
      execSync('qpdf --version');
      checks.qpdf = true;
    } catch {}

    return checks;
  }
}

// Example usage for Express/Next.js/etc
export async function expressExample() {
  const generator = new SorobanGenerator();
  
  // In your Express route handler:
  // app.post('/api/generate', async (req, res) => {
  //   try {
  //     const pdfBuffer = await generator.generate(req.body);
  //     res.contentType('application/pdf');
  //     res.send(pdfBuffer);
  //   } catch (error) {
  //     res.status(500).json({ error: error.message });
  //   }
  // });
}