<?php

namespace WP_CLI;

use Exception;
use WP_CLI;
use WP_CLI_Command;
use WP_CLI\Traverser\RecursiveDataStructureTraverser;
use WP_CLI\Utils;

/**
 * Base class for WP-CLI commands that deal with metadata
 *
 * @package wp-cli
 */
abstract class CommandWithMeta extends WP_CLI_Command {

    protected $meta_type;

    /**
     * List all metadata associated with an object.
     *
     * ## OPTIONS
     *
     * <id>
     * : ID for the object.
     *
     * [--keys=<keys>]
     * : Limit output to metadata of specific keys.
     *
     * [--fields=<fields>]
     * : Limit the output to specific row fields. Defaults to id,meta_key,meta_value.
     *
     * [--format=<format>]
     * : Render output in a particular format.
     * ---
     * default: table
     * options:
     *   - table
     *   - csv
     *   - json
     *   - yaml
     *   - count
     * ---
     *
     * [--orderby=<fields>]
     * : Set orderby which field.
     * ---
     * default: id
     * options:
     *  - id
     *  - meta_key
     *  - meta_value
     * ---
     *
     * [--order=<order>]
     * : Set ascending or descending order.
     * ---
     * default: asc
     * options:
     *  - asc
     *  - desc
     * ---
     *
     * [--unserialize]
     * : Unserialize meta_value output.
     *
     * @subcommand list
     */
    public function list_( $args, $assoc_args ) {

        list( $object_id ) = $args;

        $keys = ! empty( $assoc_args['keys'] ) ? explode( ',', $assoc_args['keys'] ) : [];

        $object_id = $this->check_object_id( $object_id );

        $metadata = $this->get_metadata( $object_id );
        if ( ! $metadata ) {
            $metadata = [];
        }

        $items = [];
        foreach ( $metadata as $key => $values ) {

            // Skip if not requested
            if ( ! empty( $keys ) && ! in_array( $key, $keys, true ) ) {
                continue;
            }

            foreach ( $values as $item_value ) {

                if ( Utils\get_flag_value( $assoc_args, 'unserialize' ) ) {
                    $item_value = maybe_unserialize( $item_value );
                }

                $items[] = (object) [
                    "{$this->meta_type}_id" => $object_id,
                    'meta_key'              => $key,
                    'meta_value'            => $item_value,
                ];
            }
        }

        $order   = Utils\get_flag_value( $assoc_args, 'order' );
        $orderby = Utils\get_flag_value( $assoc_args, 'orderby' );

        if ( 'id' !== $orderby ) {

            usort(
                $items,
                function ( $a, $b ) use ( $orderby, $order ) {
                    // Sort array.
                    return 'asc' === $order
                        ? $a->$orderby > $b->$orderby
                        : $a->$orderby < $b->$orderby;
                }
            );

        } elseif ( 'id' === $orderby && 'desc' === $order ) { // Sort by default descending.
            krsort( $items );
        }

        if ( ! empty( $assoc_args['fields'] ) ) {
            $fields = explode( ',', $assoc_args['fields'] );
        } else {
            $fields = $this->get_fields();
        }

        $formatter = new Formatter( $assoc_args, $fields, $this->meta_type );
        $formatter->display_items( $items );
    }

    /**
     * Get meta field value.
     *
     * ## OPTIONS
     *
     * <id>
     * : The ID of the object.
     *
     * <key>
     * : The name of the meta field to get.
     *
     * [--single]
     * : Whether to return a single value.
     *
     * [--format=<format>]
     * : Get value in a particular format.
     * ---
     * default: var_export
     * options:
     *   - var_export
     *   - json
     *   - yaml
     * ---
     */
    public function get( $args, $assoc_args ) {
        list( $object_id, $meta_key ) = $args;

        $object_id = $this->check_object_id( $object_id );
        $single    = Utils\get_flag_value( $assoc_args, 'single', true );

        $value = $this->get_metadata( $object_id, $meta_key, $single );

        if ( '' === $value ) {
            die( 1 );
        }

        WP_CLI::print_value( $value, $assoc_args );
    }

    /**
     * Delete a meta field.
     *
     * ## OPTIONS
     *
     * <id>
     * : The ID of the object.
     *
     * [<key>]
     * : The name of the meta field to delete.
     *
     * [<value>]
     * : The value to delete. If omitted, all rows with key will deleted.
     *
     * [--all]
     * : Delete all meta for the object.
     */
    public function delete( $args, $assoc_args ) {
        list( $object_id ) = $args;

        $meta_key   = ! empty( $args[1] ) ? $args[1] : '';
        $meta_value = ! empty( $args[2] ) ? $args[2] : '';

        if ( empty( $meta_key ) && ! Utils\get_flag_value( $assoc_args, 'all' ) ) {
            WP_CLI::error( 'Please specify a meta key, or use the --all flag.' );
        }

        $object_id = $this->check_object_id( $object_id );

        if ( Utils\get_flag_value( $assoc_args, 'all' ) ) {
            $errors = false;
            foreach ( $this->get_metadata( $object_id ) as $meta_key => $values ) {
                $success = $this->delete_metadata( $object_id, $meta_key );
                if ( $success ) {
                    WP_CLI::log( "Deleted '{$meta_key}' custom field." );
                } else {
                    WP_CLI::warning( "Failed to delete '{$meta_key}' custom field." );
                    $errors = true;
                }
            }
            if ( $errors ) {
                WP_CLI::error( 'Failed to delete all custom fields.' );
            } else {
                WP_CLI::success( 'Deleted all custom fields.' );
            }
        } else {
            $success = $this->delete_metadata( $object_id, $meta_key, $meta_value );
            if ( $success ) {
                WP_CLI::success( 'Deleted custom field.' );
            } else {
                WP_CLI::error( 'Failed to delete custom field.' );
            }
        }
    }

    /**
     * Add a meta field.
     *
     * ## OPTIONS
     *
     * <id>
     * : The ID of the object.
     *
     * <key>
     * : The name of the meta field to create.
     *
     * [<value>]
     * : The value of the meta field. If omitted, the value is read from STDIN.
     *
     * [--format=<format>]
     * : The serialization format for the value.
     * ---
     * default: plaintext
     * options:
     *   - plaintext
     *   - json
     * ---
     */
    public function add( $args, $assoc_args ) {
        list( $object_id, $meta_key ) = $args;

        $meta_value = WP_CLI::get_value_from_arg_or_stdin( $args, 2 );
        $meta_value = WP_CLI::read_value( $meta_value, $assoc_args );

        $object_id = $this->check_object_id( $object_id );

        $meta_value = wp_slash( $meta_value );
        $success    = $this->add_metadata( $object_id, $meta_key, $meta_value );

        if ( $success ) {
            WP_CLI::success( 'Added custom field.' );
        } else {
            WP_CLI::error( 'Failed to add custom field.' );
        }
    }

    /**
     * Update a meta field.
     *
     * ## OPTIONS
     *
     * <id>
     * : The ID of the object.
     *
     * <key>
     * : The name of the meta field to update.
     *
     * [<value>]
     * : The new value. If omitted, the value is read from STDIN.
     *
     * [--format=<format>]
     * : The serialization format for the value.
     * ---
     * default: plaintext
     * options:
     *   - plaintext
     *   - json
     * ---
     *
     * @alias set
     */
    public function update( $args, $assoc_args ) {
        list( $object_id, $meta_key ) = $args;

        $meta_value = WP_CLI::get_value_from_arg_or_stdin( $args, 2 );
        $meta_value = WP_CLI::read_value( $meta_value, $assoc_args );

        $object_id = $this->check_object_id( $object_id );

        $meta_value = sanitize_meta( $meta_key, $meta_value, $this->meta_type );
        $old_value  = sanitize_meta( $meta_key, $this->get_metadata( $object_id, $meta_key, true ), $this->meta_type );

        if ( $meta_value === $old_value ) {
            WP_CLI::success( "Value passed for custom field '{$meta_key}' is unchanged." );
        } else {
            $meta_value = wp_slash( $meta_value );
            $success    = $this->update_metadata( $object_id, $meta_key, $meta_value );

            if ( $success ) {
                WP_CLI::success( "Updated custom field '{$meta_key}'." );
            } else {
                WP_CLI::error( "Failed to update custom field '{$meta_key}'." );
            }
        }
    }

    /**
     * Get a nested value from a meta field.
     *
     * ## OPTIONS
     *
     * <id>
     * : The ID of the object.
     *
     * <key>
     * : The name of the meta field to get.
     *
     * <key-path>...
     * : The name(s) of the keys within the value to locate the value to pluck.
     *
     * [--format=<format>]
     * : The output format of the value.
     * ---
     * default: plaintext
     * options:
     *   - plaintext
     *   - json
     *   - yaml
     */
    public function pluck( $args, $assoc_args ) {
        list( $object_id, $meta_key ) = $args;
        $object_id                    = $this->check_object_id( $object_id );
        $key_path                     = array_map(
            function ( $key ) {
                if ( is_numeric( $key ) && ( (string) intval( $key ) === $key ) ) {
                    return (int) $key;
                }
                return $key;
            },
            array_slice( $args, 2 )
        );

        $value = $this->get_metadata( $object_id, $meta_key, true );

        $traverser = new RecursiveDataStructureTraverser( $value );

        try {
            $value = $traverser->get( $key_path );
        } catch ( Exception $exception ) {
            die( 1 );
        }

        WP_CLI::print_value( $value, $assoc_args );
    }

    /**
     * Update a nested value for a meta field.
     *
     * ## OPTIONS
     *
     * <action>
     * : Patch action to perform.
     * ---
     * options:
     *   - insert
     *   - update
     *   - delete
     * ---
     *
     * <id>
     * : The ID of the object.
     *
     * <key>
     * : The name of the meta field to update.
     *
     * <key-path>...
     * : The name(s) of the keys within the value to locate the value to patch.
     *
     * [<value>]
     * : The new value. If omitted, the value is read from STDIN.
     *
     * [--format=<format>]
     * : The serialization format for the value.
     * ---
     * default: plaintext
     * options:
     *   - plaintext
     *   - json
     * ---
     */
    public function patch( $args, $assoc_args ) {
        list( $action, $object_id, $meta_key ) = $args;
        $object_id                             = $this->check_object_id( $object_id );
        $key_path                              = array_map(
            function ( $key ) {
                if ( is_numeric( $key ) && ( (string) intval( $key ) === $key ) ) {
                    return (int) $key;
                }
                    return $key;
            },
            array_slice( $args, 3 )
        );

        if ( 'delete' === $action ) {
            $patch_value = null;
        } else {
            $stdin_value = Utils\has_stdin()
                ? trim( WP_CLI::get_value_from_arg_or_stdin( $args, -1 ) )
                : null;
            $patch_value = ! empty( $stdin_value )
                ? WP_CLI::read_value( $stdin_value, $assoc_args )
                : WP_CLI::read_value( array_pop( $key_path ), $assoc_args );
        }

        /* Need to make a copy of $current_meta_value here as it is modified by reference */
        $current_meta_value = sanitize_meta( $meta_key, $this->get_metadata( $object_id, $meta_key, true ), $this->meta_type );
        $old_meta_value     = $current_meta_value;
        if ( is_object( $current_meta_value ) ) {
            $old_meta_value = clone $current_meta_value;
        }

        $traverser = new RecursiveDataStructureTraverser( $current_meta_value );

        try {
            $traverser->$action( $key_path, $patch_value );
        } catch ( Exception $exception ) {
            WP_CLI::error( $exception->getMessage() );
        }

        $patched_meta_value = sanitize_meta( $meta_key, $traverser->value(), $this->meta_type );

        if ( $patched_meta_value === $old_meta_value ) {
            WP_CLI::success( "Value passed for custom field '{$meta_key}' is unchanged." );
        } else {
            $slashed = wp_slash( $patched_meta_value );
            $success = $this->update_metadata( $object_id, $meta_key, $slashed );

            if ( $success ) {
                WP_CLI::success( "Updated custom field '{$meta_key}'." );
            } else {
                WP_CLI::error( "Failed to update custom field '{$meta_key}'." );
            }
        }
    }

    /**
     * Wrapper method for add_metadata that can be overridden in sub classes.
     *
     * @param int    $object_id  ID of the object the metadata is for.
     * @param string $meta_key   Metadata key to use.
     * @param mixed  $meta_value Metadata value. Must be serializable if
     *                           non-scalar.
     * @param bool   $unique     Optional, default is false. Whether the
     *                           specified metadata key should be unique for the
     *                           object. If true, and the object already has a
     *                           value for the specified metadata key, no change
     *                           will be made.
     *
     * @return int|false The meta ID on success, false on failure.
     */
    protected function add_metadata( $object_id, $meta_key, $meta_value, $unique = false ) {
        return add_metadata( $this->meta_type, $object_id, $meta_key, $meta_value, $unique );
    }

    /**
     * Wrapper method for update_metadata that can be overridden in sub classes.
     *
     * @param int    $object_id  ID of the object the metadata is for.
     * @param string $meta_key   Metadata key to use.
     * @param mixed  $meta_value Metadata value. Must be serializable if
     *                           non-scalar.
     * @param mixed  $prev_value Optional. If specified, only update existing
     *                           metadata entries with the specified value.
     *                           Otherwise, update all entries.
     *
     * @return int|bool Meta ID if the key didn't exist, true on successful
     *                  update, false on failure.
     */
    protected function update_metadata( $object_id, $meta_key, $meta_value, $prev_value = '' ) {
        return update_metadata( $this->meta_type, $object_id, $meta_key, $meta_value, $prev_value );
    }

    /**
     * Wrapper method for get_metadata that can be overridden in sub classes.
     *
     * @param int    $object_id ID of the object the metadata is for.
     * @param string $meta_key  Optional. Metadata key. If not specified,
     *                          retrieve all metadata for the specified object.
     * @param bool   $single    Optional, default is false. If true, return only
     *                          the first value of the specified meta_key. This
     *                          parameter has no effect if meta_key is not
     *                          specified.
     *
     * @return mixed Single metadata value, or array of values.
     */
    protected function get_metadata( $object_id, $meta_key = '', $single = false ) {
        return get_metadata( $this->meta_type, $object_id, $meta_key, $single );
    }

    /**
     * Wrapper method for delete_metadata that can be overridden in sub classes.
     *
     * @param int    $object_id  ID of the object metadata is for
     * @param string $meta_key   Metadata key
     * @param mixed $meta_value  Optional. Metadata value. Must be serializable
     *                           if non-scalar. If specified, only delete
     *                           metadata entries with this value. Otherwise,
     *                           delete all entries with the specified meta_key.
     *                           Pass `null, `false`, or an empty string to skip
     *                           this check. For backward compatibility, it is
     *                           not possible to pass an empty string to delete
     *                           those entries with an empty string for a value.
     *
     * @return bool True on successful delete, false on failure.
     */
    protected function delete_metadata( $object_id, $meta_key, $meta_value = '' ) {
        return delete_metadata( $this->meta_type, $object_id, $meta_key, $meta_value, false );
    }

    /**
     * Get the fields for this object's meta
     *
     * @return array
     */
    private function get_fields() {
        return [
            "{$this->meta_type}_id",
            'meta_key',
            'meta_value',
        ];
    }

    /**
     * Check that the object ID exists
     *
     * @param int
     */
    protected function check_object_id( $object_id ) {
        // Needs to be set in subclass
        return $object_id;
    }
}