<?php
namespace JmesPath;

/**
* Compiles JMESPath expressions to PHP source code and executes it.
*
* JMESPath file names are stored in the cache directory using the following
* logic to determine the filename:
*
* 1. Start with the string "jmespath_"
* 2. Append the MD5 checksum of the expression.
* 3. Append ".php"
*/
class CompilerRuntime
{
private $parser;
private $compiler;
private $cacheDir;
private $interpreter;

/**
* @param string|null $dir Directory used to store compiled PHP files.
* @param Parser|null $parser JMESPath parser to utilize
* @throws \RuntimeException if the cache directory cannot be created
*/
public function __construct($dir = null, ?Parser $parser = null)
{
$this->parser = $parser ?: new Parser();
$this->compiler = new TreeCompiler();
$dir = $dir ?: sys_get_temp_dir();

if (!is_dir($dir) && !mkdir($dir, 0755, true)) {
throw new \RuntimeException("Unable to create cache directory: $dir");
}

$this->cacheDir = realpath($dir);
$this->interpreter = new TreeInterpreter();
}

/**
* Returns data from the provided input that matches a given JMESPath
* expression.
*
* @param string $expression JMESPath expression to evaluate
* @param mixed $data Data to search. This data should be data that
* is similar to data returned from json_decode
* using associative arrays rather than objects.
*
* @return mixed Returns the matching data or null
* @throws \RuntimeException
*/
public function __invoke($expression, $data)
{
$functionName = 'jmespath_' . md5($expression);

if (!function_exists($functionName)) {
$filename = "{$this->cacheDir}/{$functionName}.php";
if (!file_exists($filename)) {
$this->compile($filename, $expression, $functionName);
}
require $filename;
}

return $functionName($this->interpreter, $data);
}

private function compile($filename, $expression, $functionName)
{
$code = $this->compiler->visit(
$this->parser->parse($expression),
$functionName,
$expression
);

if (!file_put_contents($filename, $code)) {
throw new \RuntimeException(sprintf(
'Unable to write the compiled PHP code to: %s (%s)',
$filename,
var_export(error_get_last(), true)
));
}
}
}