<?php

namespace EE_CLI\Dispatcher;

/**
 * A leaf node in the command tree.
 *
 * @package EE_CLI
 */
class Subcommand extends CompositeCommand {

	private $alias;

	private $when_invoked;

	function __construct( $parent, $name, $docparser, $when_invoked ) {
		parent::__construct( $parent, $name, $docparser );

		$this->when_invoked = $when_invoked;

		$this->alias = $docparser->get_tag( 'alias' );

		$this->synopsis = $docparser->get_synopsis();
		if ( !$this->synopsis && $this->longdesc ) {
			$this->synopsis = self::extract_synopsis( $this->longdesc );
		}
	}

	/**
	 * Extract the synopsis from PHPdoc string.
	 *
	 * @param string $longdesc Command docs via PHPdoc
	 * @return string
	 */
	private static function extract_synopsis( $longdesc ) {
		preg_match_all( '/(.+?)[\r\n]+:/', $longdesc, $matches );
		return implode( ' ', $matches[1] );
	}

	/**
	 * Subcommands can't have subcommands because they
	 * represent code to be executed.
	 *
	 * @return bool
	 */
	function can_have_subcommands() {
		return false;
	}

	/**
	 * Get the synopsis string for this subcommand.
	 * A synopsis defines what runtime arguments are
	 * expected, useful to humans and argument validation.
	 *
	 * @return string
	 */
	function get_synopsis() {
		return $this->synopsis;
	}

	/**
	 * If an alias is set, grant access to it.
	 * Aliases permit subcommands to be instantiated
	 * with a secondary identity.
	 *
	 * @return string
	 */
	function get_alias() {
		return $this->alias;
	}

	/**
	 * Print the usage details to the end user.
	 *
	 * @param string $prefix
	 */
	function show_usage( $prefix = 'usage: ' ) {
		\EE_CLI::line( $this->get_usage( $prefix ) );
	}

	/**
	 * Get the usage of the subcommand as a formatted string.
	 *
	 * @param string $prefix
	 * @return string
	 */
	function get_usage( $prefix ) {
		return sprintf( "%s%s %s",
			$prefix,
			implode( ' ', get_path( $this ) ),
			$this->get_synopsis()
		);
	}

	/**
	 * Wrapper for CLI Tools' prompt() method.
	 *
	 * @param string $question
	 * @param string $default
	 * @return string|false
	 */
	private function prompt( $question, $default ) {

		try {
			$response = \cli\prompt( $question, $default );
		} catch( \Exception $e ) {
			\EE_CLI::line();
			return false;
		}

		return $response;
	}

	/**
	 * Interactively prompt the user for input
	 * based on defined synopsis and passed arguments.
	 *
	 * @param array $args
	 * @param array $assoc_args
	 * @return array
	 */
	private function prompt_args( $args, $assoc_args ) {

		$synopsis = $this->get_synopsis();

		if ( ! $synopsis )
			return array( $args, $assoc_args );

		$spec = array_filter( \EE_CLI\SynopsisParser::parse( $synopsis ), function( $spec_arg ) {
			return in_array( $spec_arg['type'], array( 'generic', 'positional', 'assoc', 'flag' ) );
		});

		$spec = array_values( $spec );

		// 'positional' arguments are positional (aka zero-indexed)
		// so $args needs to be reset before prompting for new arguments
		$args = array();
		foreach( $spec as $key => $spec_arg ) {

			$current_prompt = ( $key + 1 ) . '/' . count( $spec ) . ' ';
			$default = ( $spec_arg['optional'] ) ? '' : false;

			// 'generic' permits arbitrary key=value (e.g. [--<field>=<value>] )
			if ( 'generic' == $spec_arg['type'] ) {

				list( $key_token, $value_token ) = explode( '=', $spec_arg['token'] );

				$repeat = false;
				do {
					if ( ! $repeat )
						$key_prompt = $current_prompt . $key_token;
					else
						$key_prompt = str_repeat( " ", strlen( $current_prompt ) ) . $key_token;

					$key = $this->prompt( $key_prompt, $default );
					if ( false === $key )
						return array( $args, $assoc_args );

					if ( $key ) {
						$key_prompt_count = strlen( $key_prompt ) - strlen( $value_token ) - 1;
						$value_prompt = str_repeat( " ", $key_prompt_count ) . '=' . $value_token;

						$value = $this->prompt( $value_prompt, $default );
						if ( false === $value )
							return array( $args, $assoc_args );

						$assoc_args[$key] = $value;

						$repeat = true;
						$required = false;
					} else {
						$repeat = false;
					}

				} while( $required || $repeat );

			} else {

				$prompt = $current_prompt . $spec_arg['token'];
				if ( 'flag' == $spec_arg['type'] )
					$prompt .= ' (Y/n)';

				$response = $this->prompt( $prompt, $default );
				if ( false === $response )
					return array( $args, $assoc_args );

				if ( $response ) {
					switch ( $spec_arg['type'] ) {
						case 'positional':
							if ( $spec_arg['repeating'] )
								$response = explode( ' ', $response );
							else
								$response = array( $response );
							$args = array_merge( $args, $response );
							break;
						case 'assoc':
							$assoc_args[$spec_arg['name']] = $response;
							break;
						case 'flag':
							if ( 'Y' == $response )
								$assoc_args[$spec_arg['name']] = true;
							break;
					}
				}
			}
		}

		return array( $args, $assoc_args );
	}

	/**
	 * Validate the supplied arguments to the command.
	 * Throws warnings or errors if arguments are missing
	 * or invalid.
	 *
	 * @param array $args
	 * @param array $assoc_args
	 * @param array $extra_args
	 * @return array list of invalid $assoc_args keys to unset
	 */
	private function validate_args( $args, $assoc_args, $extra_args ) {
		$synopsis = $this->get_synopsis();
		if ( !$synopsis )
			return array();

		$validator = new \EE_CLI\SynopsisValidator( $synopsis );

		$cmd_path = implode( ' ', get_path( $this ) );
		foreach ( $validator->get_unknown() as $token ) {
			\EE_CLI::warning( sprintf(
				"The `%s` command has an invalid synopsis part: %s",
				$cmd_path, $token
			) );
		}

		if ( !$validator->enough_positionals( $args ) ) {
			$this->show_usage();
			exit(1);
		}

		$unknown_positionals = $validator->unknown_positionals( $args );
		if ( !empty( $unknown_positionals ) ) {
			\EE_CLI::error( 'Too many positional arguments: ' .
				implode( ' ', $unknown_positionals ) );
		}

		list( $errors, $to_unset ) = $validator->validate_assoc(
			array_merge( \EE_CLI::get_config(), $extra_args, $assoc_args )
		);

		if ( $this->name != 'help' ) {
			foreach ( $validator->unknown_assoc( $assoc_args ) as $key ) {
				$errors['fatal'][] = "unknown --$key parameter";
			}
		}

		if ( !empty( $errors['fatal'] ) ) {
			$out = 'Parameter errors:';
			foreach ( $errors['fatal'] as $key => $error ) {
				$out .= "\n {$error}";
				if ( $desc = $this->docparser->get_param_desc( $key ) ) {
					$out .= " ({$desc})";
				}
			}

			\EE_CLI::error( $out );
		}

		array_map( '\\EE_CLI::warning', $errors['warning'] );

		return $to_unset;
	}

	/**
	 * Invoke the subcommand with the supplied arguments.
	 * Given a --prompt argument, interactively request input
	 * from the end user.
	 *
	 * @param array $args
	 * @param array $assoc_args
	 */
	public function invoke( $args, $assoc_args, $extra_args ) {
		if ( \EE_CLI::get_config( 'prompt' ) )
			list( $args, $assoc_args ) = $this->prompt_args( $args, $assoc_args );

		$to_unset = $this->validate_args( $args, $assoc_args, $extra_args );

		foreach ( $to_unset as $key ) {
			unset( $assoc_args[ $key ] );
		}

		$path = get_path( $this->get_parent() );
		\EE_CLI::do_hook( 'before_invoke:' . implode( ' ', array_slice( $path, 1 ) ) );

		call_user_func( $this->when_invoked, $args, array_merge( $extra_args, $assoc_args ) );

		\EE_CLI::do_hook( 'after_invoke:' . implode( ' ', array_slice( $path, 1 ) ) );
	}
}