<?php

namespace Automattic\WooCommerce\Blueprint;

/**
 * Class ClassExtractor
 *
 * Provides functionality to manipulate PHP class files by replacing variables,
 * adding prefixes, and removing strict types declarations.
 *
 * This class is used to generate 'code' part for runPHP step from a template file.
 */
class ClassExtractor {
	/**
	 * Path to the PHP file being processed.
	 *
	 * @var string
	 */
	private string $file_path;

	/**
	 * Whether the file contains a strict types declaration.
	 *
	 * @var bool
	 */
	private bool $has_strict_types_declaration = false;

	/**
	 * PHP code to prefix to the final output.
	 *
	 * @var string
	 */
	private string $prefix = '';

	/**
	 * Replacements for class variables.
	 *
	 * @var array
	 */
	private array $class_variable_replacements = array();

	/**
	 * Replacements for method variables.
	 *
	 * @var array
	 */
	private array $method_variable_replacements = array();

	/**
	 * Constructor.
	 *
	 * @param string $file_path Path to the PHP file to process.
	 *
	 * @throws \InvalidArgumentException If the file does not exist.
	 */
	public function __construct( string $file_path ) {
		if ( ! file_exists( $file_path ) ) {
			throw new \InvalidArgumentException( "File not found: $file_path" );
		}
		$this->file_path = $file_path;
	}

	/**
	 * Adds a prefix to include the WordPress wp-load.php file.
	 *
	 * @return $this
	 */
	public function with_wp_load() {
		$this->prefix .= "<?php require_once 'wordpress/wp-load.php'; ";
		return $this;
	}

	/**
	 * Replaces a class variable with a new value.
	 *
	 * @param string $variable_name Name of the class variable.
	 * @param mixed  $new_value The new value to assign to the variable.
	 *
	 * @return $this
	 */
	public function replace_class_variable( $variable_name, $new_value ) {
		$this->class_variable_replacements[ $variable_name ] = $new_value;
		return $this;
	}

	/**
	 * Replaces a variable inside a method with a new value.
	 *
	 * @param string $method_name Name of the method.
	 * @param string $variable_name Name of the variable to replace.
	 * @param mixed  $new_value The new value to assign to the variable.
	 *
	 * @return $this
	 */
	public function replace_method_variable( $method_name, $variable_name, $new_value ) {
		$this->method_variable_replacements[] = array(
			'method'   => $method_name,
			'variable' => $variable_name,
			'value'    => $new_value,
		);
		return $this;
	}

	/**
	 * Generates the processed PHP code with applied replacements and prefixes.
	 *
	 * @return string The modified PHP code.
	 */
	public function get_code() {
		// Security check: Check if we can replace this with a more secure function.
		$file_content = file_get_contents( $this->file_path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

		$file_content = preg_replace( '/<\?php\s*/', '', $file_content );

		if ( preg_match( '/declare\s*\(\s*strict_types\s*=\s*1\s*\)\s*;/', $file_content ) ) {
			$this->has_strict_types_declaration = true;
			$file_content                       = preg_replace( '/declare\s*\(\s*strict_types\s*=\s*1\s*\)\s*;/', '', $file_content );
		}

		$file_content = preg_replace( '/\/\*.*?\*\/|\/\/.*?(?=\r?\n)/s', '', $file_content );

		foreach ( $this->class_variable_replacements as $variable => $value ) {
			$file_content = $this->apply_class_variable_replacement( $file_content, $variable, $value );
		}

		foreach ( $this->method_variable_replacements as $replacement ) {
			$file_content = $this->apply_variable_replacement(
				$file_content,
				$replacement['method'],
				$replacement['variable'],
				$replacement['value']
			);
		}

		return $this->prefix . trim( $file_content );
	}

	/**
	 * Applies a replacement to a class variable in the file content.
	 *
	 * @param string $file_content The content of the PHP file.
	 * @param string $variable_name The name of the variable to replace.
	 * @param mixed  $new_value The new value for the variable.
	 *
	 * @return string The updated file content.
	 */
	private function apply_class_variable_replacement( $file_content, $variable_name, $new_value ) {
		// Security check: Check if it's necessary to use var_export.
		$replacement_value = var_export( $new_value, true ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_var_export

		$pattern = '/(protected|private|public)\s+\$' . preg_quote( $variable_name, '/' ) . '\s*=\s*.*?;|'
			. '(protected|private|public)\s+\$' . preg_quote( $variable_name, '/' ) . '\s*;?/';

		$replacement = "$1 \$$variable_name = $replacement_value;";
		return preg_replace( $pattern, $replacement, $file_content, 1 );
	}

	/**
	 * Applies a replacement to a variable in a specific method.
	 *
	 * @param string $file_content The content of the PHP file.
	 * @param string $method_name The name of the method containing the variable.
	 * @param string $variable_name The name of the variable to replace.
	 * @param mixed  $new_value The new value for the variable.
	 *
	 * @return string The updated file content.
	 */
	private function apply_variable_replacement( $file_content, $method_name, $variable_name, $new_value ) {
		$pattern = '/function\s+' . preg_quote( $method_name, '/' ) . '\s*\([^)]*\)\s*\{\s*(.*?)\s*\}/s';
		if ( preg_match( $pattern, $file_content, $matches ) ) {
			$method_body = $matches[1];

			// Security check: Check if it's necessary to use var_export.
			$new_value_exported = var_export( $new_value, true ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_var_export
			$variable_pattern   = '/\$' . preg_quote( $variable_name, '/' ) . '\s*=\s*[^;]+;/';
			$replacement        = '$' . $variable_name . ' = ' . $new_value_exported . ';';

			$updated_method_body = preg_replace( $variable_pattern, $replacement, $method_body, 1 );

			if ( null !== $updated_method_body ) {
				$file_content = str_replace( $method_body, $updated_method_body, $file_content );
			}
		}

		return $file_content;
	}

	/**
	 * Checks if the file has a strict types declaration.
	 *
	 * @return bool True if the file has a strict types declaration, false otherwise.
	 */
	public function has_strict_type_declaration() {
		return $this->has_strict_types_declaration;
	}
}