/**
 * Gamemaster API Server
 * Provides endpoints for accessing processed gamemaster data
 * Allows other apps to fetch unmodified and modified pokemon data
 */

import express from 'express';
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const router = express.Router();
const DATA_DIR = path.join(__dirname, 'data', 'gamemaster');

/**
 * Ensure data directory exists
 */
function ensureDataDir() {
  if (!fs.existsSync(DATA_DIR)) {
    fs.mkdirSync(DATA_DIR, { recursive: true });
  }
}

/**
 * Get path to a gamemaster file
 * @param {string} filename
 * @returns {string} Full file path
 */
function getFilePath(filename) {
  return path.join(DATA_DIR, filename);
}

/**
 * Check if a file exists
 * @param {string} filename
 * @returns {boolean}
 */
function fileExists(filename) {
  return fs.existsSync(getFilePath(filename));
}

/**
 * Get file metadata (size, modified time)
 * @param {string} filename
 * @returns {Object|null} File info or null if doesn't exist
 */
function getFileInfo(filename) {
  const filepath = getFilePath(filename);
  if (!fs.existsSync(filepath)) return null;

  const stats = fs.statSync(filepath);
  return {
    filename,
    size: stats.size,
    sizeKb: (stats.size / 1024).toFixed(2),
    modified: stats.mtime.toISOString()
  };
}

/**
 * Save gamemaster data to file
 * @param {string} filename
 * @param {Object|Array} data
 */
function saveFile(filename, data) {
  ensureDataDir();
  const filepath = getFilePath(filename);
  fs.writeFileSync(filepath, JSON.stringify(data, null, 2));
  return getFileInfo(filename);
}

/**
 * Load gamemaster data from file
 * @param {string} filename
 * @returns {Object|Array|null}
 */
function loadFile(filename) {
  const filepath = getFilePath(filename);
  if (!fs.existsSync(filepath)) return null;
  const content = fs.readFileSync(filepath, 'utf-8');
  return JSON.parse(content);
}

// ============================================================================
// ROUTES
// ============================================================================

/**
 * GET /api/gamemaster/status
 * Get status of available gamemaster files
 */
router.get('/status', (req, res) => {
  ensureDataDir();

  const files = {
    pokemon: getFileInfo('pokemon.json'),
    pokemonAllForms: getFileInfo('pokemon-allFormsCostumes.json'),
    moves: getFileInfo('pokemon-moves.json'),
    raw: getFileInfo('latest-raw.json')
  };

  res.json({
    available: Object.values(files).filter(f => f !== null),
    lastUpdate: files.pokemon?.modified || 'Never',
    totalFiles: Object.values(files).filter(f => f !== null).length
  });
});

/**
 * GET /api/gamemaster/pokemon
 * Get filtered pokemon data (base forms + regional variants)
 */
router.get('/pokemon', (req, res) => {
  const data = loadFile('pokemon.json');
  if (!data) {
    return res.status(404).json({
      error: 'Pokemon data not available. Generate from GamemasterManager.'
    });
  }
  res.json(data);
});

/**
 * GET /api/gamemaster/pokemon/allForms
 * Get all pokemon forms including costumes
 */
router.get('/pokemon/allForms', (req, res) => {
  const data = loadFile('pokemon-allFormsCostumes.json');
  if (!data) {
    return res.status(404).json({
      error: 'All forms data not available. Generate from GamemasterManager.'
    });
  }
  res.json(data);
});

/**
 * GET /api/gamemaster/moves
 * Get all pokemon moves
 */
router.get('/moves', (req, res) => {
  const data = loadFile('pokemon-moves.json');
  if (!data) {
    return res.status(404).json({
      error: 'Moves data not available. Generate from GamemasterManager.'
    });
  }
  res.json(data);
});

/**
 * GET /api/gamemaster/raw
 * Get raw unmodified gamemaster data
 */
router.get('/raw', (req, res) => {
  const data = loadFile('latest-raw.json');
  if (!data) {
    return res.status(404).json({
      error: 'Raw gamemaster data not available. Fetch from GamemasterManager.'
    });
  }
  res.json(data);
});

/**
 * POST /api/gamemaster/process
 * Fetch and process gamemaster data on the server
 * This avoids sending large payloads from the frontend
 */
router.post('/process', async (req, res) => {
  try {
    const POKEMINERS_URL =
      'https://raw.githubusercontent.com/PokeMiners/game_masters/master/latest/latest.json';

    console.log('🔄 Fetching gamemaster from PokeMiners...');
    const response = await fetch(POKEMINERS_URL);
    if (!response.ok) {
      throw new Error(`Failed to fetch: ${response.statusText}`);
    }

    const raw = await response.json();
    console.log(`✅ Fetched ${raw.length} items from PokeMiners`);

    // Break up the data server-side
    console.log('⚙️  Processing gamemaster data...');
    const processed = breakUpGamemaster(raw);

    // Save all files
    console.log('💾 Saving files to disk...');
    const results = {
      pokemon: saveFile('pokemon.json', processed.pokemon),
      pokemonAllForms: saveFile(
        'pokemon-allFormsCostumes.json',
        processed.pokemonAllForms
      ),
      moves: saveFile('pokemon-moves.json', processed.moves),
      raw: saveFile('latest-raw.json', raw)
    };

    console.log('✅ All files saved successfully');

    res.json({
      message: 'Gamemaster processed and saved successfully',
      files: results,
      stats: {
        pokemon: processed.pokemon.length,
        pokemonAllForms: processed.pokemonAllForms.length,
        moves: processed.moves.length,
        raw: raw.length
      },
      timestamp: new Date().toISOString()
    });
  } catch (error) {
    console.error('Error processing gamemaster:', error);
    res.status(500).json({
      error: 'Failed to process gamemaster',
      details: error.message
    });
  }
});

/**
 * POST /api/gamemaster/save
 * Save processed gamemaster data (called by GamemasterManager)
 * Body: {pokemon, pokemonAllForms, moves, raw}
 */
router.post('/save', express.json({ limit: '50mb' }), (req, res) => {
  try {
    const { pokemon, pokemonAllForms, moves, raw } = req.body;

    if (!pokemon || !pokemonAllForms || !moves) {
      return res.status(400).json({
        error: 'Missing required data: pokemon, pokemonAllForms, moves'
      });
    }

    const results = {};

    if (pokemon) {
      results.pokemon = saveFile('pokemon.json', pokemon);
    }
    if (pokemonAllForms) {
      results.pokemonAllForms = saveFile(
        'pokemon-allFormsCostumes.json',
        pokemonAllForms
      );
    }
    if (moves) {
      results.moves = saveFile('pokemon-moves.json', moves);
    }
    if (raw) {
      results.raw = saveFile('latest-raw.json', raw);
    }

    res.json({
      message: 'Files saved successfully',
      files: results,
      timestamp: new Date().toISOString()
    });
  } catch (error) {
    console.error('Error saving gamemaster data:', error);
    res.status(500).json({
      error: 'Failed to save files',
      details: error.message
    });
  }
});

/**
 * GET /api/gamemaster/download/:filename
 * Download a specific gamemaster file
 */
router.get('/download/:filename', (req, res) => {
  const filename = req.params.filename;

  // Validate filename to prevent path traversal
  const allowedFiles = [
    'pokemon.json',
    'pokemon-allFormsCostumes.json',
    'pokemon-moves.json',
    'latest-raw.json'
  ];

  if (!allowedFiles.includes(filename)) {
    return res.status(400).json({ error: 'Invalid filename' });
  }

  const filepath = getFilePath(filename);
  if (!fs.existsSync(filepath)) {
    return res.status(404).json({ error: 'File not found' });
  }

  res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
  res.setHeader('Content-Type', 'application/json');
  res.sendFile(filepath);
});

// ============================================================================
// INITIALIZATION
// ============================================================================

ensureDataDir();

export default router;