/**
 * Dependency checking utilities for pandoc, LaTeX, and related tools
 */

import { execSync } from 'child_process';

/**
 * Check if a command is available by running it silently
 */
function commandExists(cmd: string): boolean {
  try {
    execSync(cmd, { stdio: 'ignore' });
    return true;
  } catch {
    return false;
  }
}

/**
 * Check if pandoc-crossref is available
 */
export function hasPandocCrossref(): boolean {
  return commandExists('pandoc-crossref --version');
}

/**
 * Check if pandoc is available
 */
export function hasPandoc(): boolean {
  return commandExists('pandoc --version');
}

/**
 * Check if LaTeX is available (for PDF generation)
 */
export function hasLatex(): boolean {
  return commandExists('pdflatex --version') || commandExists('xelatex --version');
}

/**
 * Get installation instructions for missing dependencies
 */
export function getInstallInstructions(dependency: string): string {
  const platform = process.platform;
  const instructions: Record<string, Record<string, string>> = {
    pandoc: {
      darwin: 'brew install pandoc',
      win32: 'winget install JohnMacFarlane.Pandoc',
      linux: 'sudo apt install pandoc',
    },
    latex: {
      darwin: 'brew install --cask mactex-no-gui',
      win32: 'Install MiKTeX from https://miktex.org/download',
      linux: 'sudo apt install texlive-latex-base texlive-fonts-recommended',
    },
    'pandoc-crossref': {
      darwin: 'brew install pandoc-crossref',
      win32: 'Download from https://github.com/lierdakil/pandoc-crossref/releases',
      linux: 'Download from https://github.com/lierdakil/pandoc-crossref/releases',
    },
  };

  const platformInstructions = instructions[dependency];
  if (!platformInstructions) return '';

  return platformInstructions[platform] || platformInstructions.linux || '';
}

export interface DependencyStatus {
  pandoc: boolean;
  latex: boolean;
  crossref: boolean;
  messages: string[];
}

/**
 * Check dependencies and return status
 */
export function checkDependencies(): DependencyStatus {
  const status: DependencyStatus = {
    pandoc: hasPandoc(),
    latex: hasLatex(),
    crossref: hasPandocCrossref(),
    messages: [],
  };

  if (!status.pandoc) {
    status.messages.push(`Pandoc not found. Install with: ${getInstallInstructions('pandoc')}`);
  }
  if (!status.latex) {
    status.messages.push(`LaTeX not found (required for PDF). Install with: ${getInstallInstructions('latex')}`);
  }
  if (!status.crossref) {
    status.messages.push(`pandoc-crossref not found (optional, for figure/table refs). Install with: ${getInstallInstructions('pandoc-crossref')}`);
  }

  return status;
}