<?php

/**
 * include_path
 * 
 * uses a partial url, eg '/foo' to locate a corresponding
 * php file, eg 'foo.php', and execute it.
 *
 * url_fragment - a key to locating php files, no extetension
                  letters and hyphens are ok
 */
function include_path($url_fragment) {
  if (preg_match('#^/([a-z-]+.php)$#', $url_fragment, $matches)) {
    $path = __DIR__ . '/../' . $matches[1];
  } else {
    $path = null;
  }

  if (file_exists($path)) {
    ob_start();
    include $path;
    $result = ob_get_clean();

    return $result;
  } else {
    # Hard bail
    http_response_code(404);
    echo "404: $path not found\n";
    exit;
  }
}

/**
 * snippet_include
 *
 * loads non_php file for parsing.
 * Uses {varname} to replace strings
 * 
 * filename
 * context - a keyed array for matching
 *           eg [ 'title'=>'Home Page', ... ]
 */
function snippet_include($filename, $context=[]) {
  $snippet = file_get_contents($filename);

  // Handle comments {* ... *}
  $snippet = preg_replace('/ *{\*(.*?)\*}\n*/s','',$snippet);

  // Use regex to find {placeholders} in the template
  // Note this uses a callback function to do the matches
  $snippet = preg_replace_callback('/\{\s*(\w+)\s*\}/', function($matches) use ($context) {
    $key = $matches[1];

    $value = isset($context[$key]) ? $context[$key] : $key;

    return $value;
  }, $snippet);

  return $snippet;
}