<?php

namespace WP_CLI\I18n;

use Gettext\Extractors\Extractor;
use Gettext\Translations;
use WP_CLI;
use WP_CLI\Utils;

class JsonSchemaExtractor extends Extractor {
    use IterableCodeExtractor;

    /**
     * Source URL from which to download the latest theme-i18n.json file.
     *
     * @var string
     */
    const THEME_JSON_SOURCE = 'https://develop.svn.wordpress.org/trunk/src/wp-includes/theme-i18n.json';

    /**
     * Fallback theme-18n.json file path.
     *
     * @var string
     */
    const THEME_JSON_FALLBACK = __DIR__ . '/../assets/theme-i18n.json';

    /**
     * Source URL from which to download the latest block-i18n.json file.
     *
     * @var string
     */
    const BLOCK_JSON_SOURCE = 'https://develop.svn.wordpress.org/trunk/src/wp-includes/block-i18n.json';

    /**
     * Fallback block-18n.json file path.
     *
     * @var string
     */
    const BLOCK_JSON_FALLBACK = __DIR__ . '/../assets/block-i18n.json';

    /**
     * Static cache for the remote schema files.
     *
     * @var array<string, string>
     */
    protected static $schema_cache = [];

    /**
     * Load the i18n from a remote URL or fall back to a local schema in case of an error.
     * @param string $schema i18n schema URL.
     * @param string $fallback Fallback i18n schema JSON file.
     * @return array|mixed
     */
    protected static function load_schema( $schema, $fallback ) {
        if ( ! empty( self::$schema_cache[ $schema ] ) ) {
            return self::$schema_cache[ $schema ];
        }

        $json = self::remote_get( $schema );

        if ( empty( $json ) ) {
            WP_CLI::debug( 'Remote file could not be accessed, will use local file as fallback', 'make-pot' );
            $json = file_get_contents( $fallback );
        }

        $file_structure = json_decode( $json, false );

        if ( JSON_ERROR_NONE !== json_last_error() ) {
            WP_CLI::debug( 'Error when decoding theme-i18n.json file', 'make-pot' );
            return [];
        }

        if ( ! is_object( $file_structure ) ) {
            return [];
        }

        self::$schema_cache[ $schema ] = $file_structure;

        return $file_structure;
    }

    /**
     * @inheritdoc
     */
    public static function fromString( $text, Translations $translations, array $options = [] ) {
        $file = $options['file'];
        WP_CLI::debug( "Parsing file {$file}", 'make-pot' );

        $schema = self::load_schema( $options['schema'], $options['schemaFallback'] );

        $json = json_decode( $text, true );

        if ( null === $json ) {
            WP_CLI::debug(
                sprintf(
                    'Could not parse file %1$s: error code %2$s',
                    $file,
                    json_last_error()
                ),
                'make-pot'
            );

            return;
        }

        self::extract_strings_using_i18n_schema(
            $translations,
            $options['addReferences'] ? $file : null,
            $schema,
            $json
        );
    }

    /**
     * Extract strings from a JSON file using its i18n schema.
     *
     * @param Translations                   $translations The translations instance to append the new translations.
     * @param string|null                    $file         JSON file name or null if no reference should be added.
     * @param string|string[]|array[]|object $i18n_schema  I18n schema for the setting.
     * @param string|string[]|array[]        $settings     Value for the settings.
     *
     * @return void
     */
    private static function extract_strings_using_i18n_schema( Translations $translations, $file, $i18n_schema, $settings ) {
        if ( empty( $i18n_schema ) || empty( $settings ) ) {
            return;
        }

        if ( is_string( $i18n_schema ) && is_string( $settings ) ) {
            $translation = $translations->insert( $i18n_schema, $settings );

            if ( $file ) {
                $translation->addReference( $file );
            }

            return;
        }

        if ( is_array( $i18n_schema ) && is_array( $settings ) ) {
            foreach ( $settings as $value ) {
                self::extract_strings_using_i18n_schema( $translations, $file, $i18n_schema[0], $value );
            }
        }
        if ( is_object( $i18n_schema ) && is_array( $settings ) ) {
            $group_key = '*';
            foreach ( $settings as $key => $value ) {
                if ( isset( $i18n_schema->$key ) ) {
                    self::extract_strings_using_i18n_schema( $translations, $file, $i18n_schema->$key, $value );
                } elseif ( isset( $i18n_schema->$group_key ) ) {
                    self::extract_strings_using_i18n_schema( $translations, $file, $i18n_schema->$group_key, $value );
                }
            }
        }
    }

    /**
     * Given a remote URL, fetches it remotely and returns its content.
     *
     * Returns an empty string in case of error.
     *
     * @param string $url URL of the file to fetch.
     *
     * @return string Contents of the file.
     */
    private static function remote_get( $url ) {
        if ( ! $url ) {
            return '';
        }

        $headers  = [ 'Content-type: application/json' ];
        $options  = [ 'halt_on_error' => false ];
        $response = Utils\http_request( 'GET', $url, null, $headers, $options );

        if (
            ! $response->success
            || 200 > (int) $response->status_code
            || 300 <= (int) $response->status_code
        ) {
            WP_CLI::debug( "Failed to download from URL {$url}", 'make-pot' );
            return '';
        }

        return trim( $response->body );
    }
}