/**
 * Simple data API for Weight Tracker
 * This script handles data storage operations when deployed in Docker
 * Includes authentication for password protection
 */

const fs = require('fs');
const path = require('path');
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const { initAuth, generateHash } = require('./auth-middleware');

// Create Express app
const app = express();
const port = process.env.PORT || 3000;

// Data file path in the Docker volume
const DATA_DIR = process.env.DATA_DIR || '/data';
const DATA_FILE = path.join(DATA_DIR, 'weight-tracker-data.json');

// Print data file path for debugging
console.log(`[STARTUP] Data directory: ${DATA_DIR}`);
console.log(`[STARTUP] Data file path: ${DATA_FILE}`);

// List files in data directory if it exists
if (fs.existsSync(DATA_DIR)) {
  try {
    const files = fs.readdirSync(DATA_DIR);
    console.log(`[STARTUP] Files in ${DATA_DIR}:`, files);
    
    // If data file exists, log its size and content preview
    if (fs.existsSync(DATA_FILE)) {
      const stats = fs.statSync(DATA_FILE);
      console.log(`[STARTUP] Data file exists: ${DATA_FILE}, size: ${stats.size} bytes`);
      
      if (stats.size > 0) {
        const preview = fs.readFileSync(DATA_FILE, 'utf8').substring(0, 200);
        console.log(`[STARTUP] Data file content preview: ${preview}...`);
      } else {
        console.log(`[STARTUP] Data file is empty`);
      }
    } else {
      console.log(`[STARTUP] Data file does not exist: ${DATA_FILE}`);
    }
  } catch (error) {
    console.error(`[STARTUP] Error reading data directory: ${error.message}`);
  }
} else {
  console.log(`[STARTUP] Data directory does not exist: ${DATA_DIR}`);
}

// Middleware
app.use(cors());
app.use(bodyParser.json({ limit: '5mb' }));
app.use(bodyParser.urlencoded({ extended: true })); // For parsing form data
app.use(express.static('public')); // Serve static files

// Copy login.html to the correct location for serving
const loginHtmlPath = path.join(__dirname, 'login.html');
if (fs.existsSync(loginHtmlPath)) {
  // Ensure public directory exists
  const publicDir = path.join(__dirname, 'public');
  if (!fs.existsSync(publicDir)) {
    fs.mkdirSync(publicDir, { recursive: true });
  }
  
  // Copy login.html to public directory
  fs.copyFileSync(loginHtmlPath, path.join(publicDir, 'login.html'));
  console.log('Login page copied to public directory');
}

// Initialize authentication middleware
initAuth(app);

// Ensure data directory exists
if (!fs.existsSync(DATA_DIR)) {
  fs.mkdirSync(DATA_DIR, { recursive: true });
  console.log(`Created data directory: ${DATA_DIR}`);
}

// Initialize data file if it doesn't exist
if (!fs.existsSync(DATA_FILE)) {
  const defaultData = {
    weights: [],
    meals: [],
    version: '1.0.0'
  };
  
  fs.writeFileSync(DATA_FILE, JSON.stringify(defaultData, null, 2));
  console.log(`Created initial data file: ${DATA_FILE}`);
}

// GET endpoint to retrieve data
app.get('/data/weight-tracker-data.json', (req, res) => {
  try {
    console.log(`[DEBUG] GET request received for ${DATA_FILE}`);
    console.log(`[DEBUG] File exists: ${fs.existsSync(DATA_FILE)}`);
    
    if (fs.existsSync(DATA_FILE)) {
      const data = fs.readFileSync(DATA_FILE, 'utf8');
      console.log(`[DEBUG] Data read from file: ${data.substring(0, 100)}...`);
      res.setHeader('Content-Type', 'application/json');
      res.send(data);
      console.log(`[DEBUG] Data sent to client`);
    } else {
      console.log(`[DEBUG] Data file not found at ${DATA_FILE}`);
      res.status(404).send({ error: 'Data file not found' });
    }
  } catch (error) {
    console.error('[DEBUG] Error reading data file:', error);
    res.status(500).send({ error: 'Failed to read data file' });
  }
});

// PUT endpoint to update data
app.put('/data/weight-tracker-data.json', (req, res) => {
  try {
    console.log(`[DEBUG] PUT request received for ${DATA_FILE}`);
    const data = req.body;
    
    // Log request body summary
    console.log(`[DEBUG] Request body received:`, {
      hasData: !!data,
      hasWeights: data && !!data.weights,
      weightCount: data && data.weights ? data.weights.length : 0,
      hasMeals: data && !!data.meals,
      mealCount: data && data.meals ? data.meals.length : 0
    });
    
    // Validate data structure
    if (!data || !data.weights || !data.meals) {
      console.log(`[DEBUG] Invalid data structure received`);
      return res.status(400).send({ error: 'Invalid data structure' });
    }
    
    // Ensure data directory exists
    if (!fs.existsSync(DATA_DIR)) {
      console.log(`[DEBUG] Creating data directory: ${DATA_DIR}`);
      fs.mkdirSync(DATA_DIR, { recursive: true });
    }
    
    // Write to file
    console.log(`[DEBUG] Writing data to file: ${DATA_FILE}`);
    fs.writeFileSync(DATA_FILE, JSON.stringify(data, null, 2));
    
    // Verify file was written
    const fileExists = fs.existsSync(DATA_FILE);
    console.log(`[DEBUG] File exists after write: ${fileExists}`);
    if (fileExists) {
      const stats = fs.statSync(DATA_FILE);
      console.log(`[DEBUG] File size after write: ${stats.size} bytes`);
    }
    
    res.send({ success: true, message: 'Data saved successfully' });
    console.log(`[DEBUG] Data updated: ${new Date().toISOString()}`);
  } catch (error) {
    console.error('[DEBUG] Error writing data file:', error);
    res.status(500).send({ error: 'Failed to write data file' });
  }
});

// Start server
app.listen(port, () => {
  console.log(`Data API server running on port ${port}`);
  console.log(`Data directory: ${DATA_DIR}`);
  console.log(`Data file: ${DATA_FILE}`);
});