<?php

namespace WP_CLI;

use WP_CLI;

/**
 * Context manager to register_context and process different contexts that commands can
 * run within.
 */
final class ContextManager {

    /**
     * Associative array of context implementations.
     *
     * @var array<string, Context>
     */
    private $contexts = [];

    /**
     * Store the current context.
     *
     * @var string Current context.
     */
    private $current_context = Context::CLI;

    /**
     * Register a context with WP-CLI.
     *
     * @param string  $name           Name of the context.
     * @param Context $implementation Implementation of the context.
     */
    public function register_context( $name, Context $implementation ) {
        $this->contexts[ $name ] = $implementation;
    }

    /**
     * Switch the context in which to run WP-CLI.
     *
     * @param array $config Associative array of configuration data.
     * @return void
     *
     * @throws ExitException When an invalid context was requested.
     */
    public function switch_context( $config ) {
        $context = isset( $config['context'] )
            ? $config['context']
            : $this->current_context;

        if ( ! array_key_exists( $context, $this->contexts ) ) {
            WP_CLI::error( "Unknown context '{$context}'" );
        }

        WP_CLI::debug( "Using context '{$context}'", Context::DEBUG_GROUP );

        $this->current_context = $context;
        $this->contexts[ $context ]->process( $config );
    }

    /**
     * Return the current context.
     *
     * @return string Current context.
     */
    public function get_context() {
        return $this->current_context;
    }
}