const pptxgen = require('pptxgenjs');
const fs = require('fs');

function normalizePosition(options) {
  if (!options || typeof options !== 'object') return options;
  ['x', 'y', 'w', 'h'].forEach(function(key) {
    if (options[key] === undefined) return;
    var val = options[key];
    if (typeof val === 'number' && !isNaN(val)) return;
    if (typeof val === 'string' && /^\d+(\.\d+)?%$/.test(val)) return;
    console.warn('Invalid position value for "' + key + '": got ' + JSON.stringify(val) + ', expected a number or percentage string (e.g. "50%")');
    delete options[key];
  });
  if ((options.x !== undefined || options.y !== undefined) && options.w === undefined) options.w = 4;
  if ((options.x !== undefined || options.y !== undefined) && options.h === undefined) options.h = 3;
  return options;
}

function normalizeColor(color) {
  if (color === undefined || color === null) return color;
  if (typeof color !== 'string') {
    console.warn('Invalid color value: expected a string, got ' + typeof color);
    return undefined;
  }
  var themeColors = ['tx1', 'tx2', 'bg1', 'bg2', 'accent1', 'accent2', 'accent3', 'accent4', 'accent5', 'accent6'];
  for (var i = 0; i < themeColors.length; i++) {
    if (color === themeColors[i]) return color;
  }
  var clean = color.replace(/^#/, '');
  if (/^[0-9A-Fa-f]{6}$/.test(clean)) return clean;
  console.warn('Invalid color value: "' + color + '" is not a valid color format (expected 6-digit hex or theme color)');
  return undefined;
}

function normalizeColorInOptions(options, key) {
  if (!options || options[key] === undefined) return;
  var nc = normalizeColor(options[key]);
  if (nc === undefined) delete options[key];
  else options[key] = nc;
}

function validateEnum(value, validValues, name) {
  if (value === undefined || value === null) return value;
  if (validValues.indexOf(value) === -1) {
    console.warn('Invalid value for ' + name + ': got "' + value + '", expected one of [' + validValues.join(', ') + ']');
  }
  return value;
}

function withDefaults(options, defaults) {
  if (!options || typeof options !== 'object') return options;
  for (var key in defaults) {
    if (defaults.hasOwnProperty(key) && options[key] === undefined) {
      options[key] = defaults[key];
    }
  }
  return options;
}

module.exports.normalizePosition = normalizePosition;
module.exports.normalizeColor = normalizeColor;
module.exports.normalizeColorInOptions = normalizeColorInOptions;
module.exports.validateEnum = validateEnum;
module.exports.withDefaults = withDefaults;

const { renderSlide } = require('./slide-renderer');

function render(pptxJson) {
  const pptx = new pptxgen();
  const data = typeof pptxJson === 'string' ? JSON.parse(pptxJson) : pptxJson;
  const pres = data.presentation || {};
  const slides = data.slides || [];

  if (pres.layout) pptx.layout = pres.layout;
  if (pres.author) pptx.author = pres.author;
  if (pres.title) pptx.title = pres.title;
  if (pres.subject) pptx.subject = pres.subject;
  if (pres.company) pptx.company = pres.company;
  if (pres.revision) pptx.revision = pres.revision;
  if (pres.rtlMode !== undefined) pptx.rtlMode = pres.rtlMode;
  if (pres.theme) pptx.theme = pres.theme;

  slides.forEach(slideData => renderSlide(pptx, slideData));

  return pptx;
}

async function renderFile(inputPath, outputPath) {
  const json = fs.readFileSync(inputPath, 'utf8');
  const pptx = render(json);

  // pptxgenjs v4 uses https.get() to download URL-based images but doesn't
  // handle connection errors on the request object (only on the response
  // stream). A failed TLS handshake emits an unhandled 'error' event on the
  // request that crashes Node.js, and the internal promise never resolves.
  // Patch to pipe request errors into a fake response that ends cleanly so
  // writeFile completes with an empty placeholder image.
  var https = require('https');
  var _origGet = https.get;
  var EventEmitter = require('events').EventEmitter;
  https.get = function() {
    var args = arguments;
    var cb = typeof args[args.length - 1] === 'function' ? args[args.length - 1] : null;
    var urlStr = typeof args[0] === 'string' ? args[0] : '';
    var req = _origGet.apply(this, args);
    req.on('error', function(err) {
      console.warn('Failed to load image: ' + (urlStr || err.hostname || err.host || 'unknown'));
      if (cb) {
        var fakeRes = new EventEmitter();
        fakeRes.setEncoding = function() {};
        cb(fakeRes);
        process.nextTick(function() {
          fakeRes.emit('data', '');
          fakeRes.emit('end');
        });
      }
    });
    return req;
  };

  try {
    return await pptx.writeFile({ fileName: outputPath });
  } finally {
    https.get = _origGet;
  }
}

module.exports.render = render;
module.exports.renderFile = renderFile;