<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

final class MenuAbilities
{
    /** @return array<int,Ability> */
    public static function abilities(): array
    {
        $allowed = static fn (array $args): bool => current_user_can('edit_theme_options');
        $itemFields = [
            'objectId' => ['description' => 'The page or post id the item links to (sets a page link instead of a custom url)', 'minimum' => 1, 'type' => 'integer'],
            'parent' => ['description' => 'The parent menu item id, 0 for top level', 'minimum' => 0, 'type' => 'integer'],
            'position' => ['minimum' => 1, 'type' => 'integer'],
            'title' => ['maxLength' => 200, 'type' => 'string'],
            'url' => ['maxLength' => 2000, 'type' => 'string'],
        ];
        return [
            new Ability(
                'sarcio/menus-list',
                __('Look at the menus', 'sarcio'),
                Ability::READ,
                'Every navigation menu with its items (id, title, url, parent item id, order, what it links to) and which theme location each menu is assigned to.',
                ['properties' => [], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::list(),
            ),
            new Ability(
                'sarcio/menu-item-add',
                __('Add a menu item', 'sarcio'),
                Ability::WRITE,
                'Add an item to a navigation menu: a link to a page or post (objectId) or a custom url, with a title, optional parent item and position.',
                [
                    'properties' => ['menuId' => ['minimum' => 1, 'type' => 'integer']] + $itemFields,
                    'required' => ['menuId', 'title'],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::add($args),
                null,
                static fn (array $before, array $after): array => self::delete((int) ($after['id'] ?? 0)),
                false,
                static fn (array $args, Overlay $overlay): array => self::stageAdd($args, $overlay),
            ),
            new Ability(
                'sarcio/menu-item-update',
                __('Change a menu item', 'sarcio'),
                Ability::WRITE,
                'Change a navigation menu item’s title, url or linked page, parent or position, by its item id from menus-list (an item added in the preview has a negative id). Only the fields given change.',
                [
                    'properties' => ['id' => ['type' => 'integer']] + $itemFields,
                    'required' => ['id'],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::update($args),
                null,
                static fn (array $before, array $after): array => self::save((int) $before['menuId'], (int) $before['id'], $before) + ['restored' => true],
                false,
                static fn (array $args, Overlay $overlay): array => self::stageUpdate($args, $overlay),
            ),
            new Ability(
                'sarcio/menu-item-remove',
                __('Remove a menu item', 'sarcio'),
                Ability::WRITE,
                'Remove an item from a navigation menu by its item id from menus-list (an item added in the preview has a negative id). The page it linked to is not touched.',
                ['properties' => ['id' => ['type' => 'integer']], 'required' => ['id'], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::remove((int) $args['id']),
                null,
                static fn (array $before, array $after): array => self::save((int) $before['menuId'], 0, $before) + ['restored' => true],
                false,
                static fn (array $args, Overlay $overlay): array => self::stageRemove((int) $args['id'], $overlay),
            ),
        ];
    }

    /** @return array<string,mixed> */
    public static function snapshot(object $item, int $menuId): array
    {
        return [
            'id' => (int) $item->ID,
            'menuId' => $menuId,
            'object' => (string) ($item->object ?? ''),
            'objectId' => (int) ($item->object_id ?? 0),
            'parent' => (int) ($item->menu_item_parent ?? 0),
            'position' => (int) ($item->menu_order ?? 0),
            'title' => (string) ($item->title ?? ''),
            'type' => (string) ($item->type ?? 'custom'),
            'url' => (string) ($item->url ?? ''),
        ];
    }

    /** @param array<string,mixed> $fields */
    public static function save(int $menuId, int $itemId, array $fields): array
    {
        $isPost = (int) ($fields['objectId'] ?? 0) > 0;
        $data = [
            'menu-item-object' => $isPost ? (string) ($fields['object'] ?: get_post_type((int) $fields['objectId']) ?: 'page') : 'custom',
            'menu-item-object-id' => $isPost ? (int) $fields['objectId'] : 0,
            'menu-item-parent-id' => (int) ($fields['parent'] ?? 0),
            'menu-item-position' => (int) ($fields['position'] ?? 0),
            'menu-item-status' => 'publish',
            'menu-item-title' => sanitize_text_field((string) ($fields['title'] ?? '')),
            'menu-item-type' => $isPost ? 'post_type' : 'custom',
            'menu-item-url' => $isPost ? '' : esc_url_raw((string) ($fields['url'] ?? '')),
        ];
        $result = wp_update_nav_menu_item($menuId, $itemId, $data);
        if (is_wp_error($result) || (int) $result <= 0) {
            return ['error' => __('WordPress could not save the menu item.', 'sarcio')];
        }
        return ['id' => (int) $result, 'menuId' => $menuId];
    }

    private static function list(): array
    {
        $locations = function_exists('get_nav_menu_locations') ? (array) get_nav_menu_locations() : [];
        $registered = function_exists('get_registered_nav_menus') ? (array) get_registered_nav_menus() : [];
        $menus = [];
        foreach ((array) wp_get_nav_menus() as $menu) {
            $items = [];
            foreach (Stage::menuItems((int) $menu->term_id) as $item) {
                $items[] = self::snapshot($item, (int) $menu->term_id);
            }
            $assigned = [];
            foreach ($locations as $location => $menuId) {
                if ((int) $menuId === (int) $menu->term_id) {
                    $assigned[] = ['location' => (string) $location, 'name' => (string) ($registered[$location] ?? $location)];
                }
            }
            $menus[] = ['id' => (int) $menu->term_id, 'items' => $items, 'locations' => $assigned, 'name' => (string) $menu->name];
        }
        return ['menus' => $menus];
    }

    /** @return array{item?:array<string,mixed>,error?:string} */
    private static function find(int $itemId): array
    {
        $post = get_post($itemId);
        if ($post === null || (string) $post->post_type !== 'nav_menu_item') {
            return ['error' => __('There is no menu item with that id.', 'sarcio')];
        }
        $terms = wp_get_post_terms($itemId, 'nav_menu');
        $menuId = is_array($terms) && isset($terms[0]) ? (int) $terms[0]->term_id : 0;
        if ($menuId <= 0) {
            return ['error' => __('That menu item is not in any menu.', 'sarcio')];
        }
        return ['item' => self::snapshot(wp_setup_nav_menu_item($post), $menuId)];
    }

    /**
     * The item as the preview shows it: one the preview added (a negative id),
     * or a real one with the preview's edits, unless the preview removed it.
     *
     * @return array{item?:array<string,mixed>,error?:string}
     */
    private static function locate(int $itemId, Overlay $overlay): array
    {
        if ($itemId < 0) {
            foreach ($overlay->menus as $menuId => $edits) {
                foreach ($edits['added'] as $added) {
                    if ((int) $added['ID'] === $itemId) {
                        return ['item' => self::snapshot((object) $added, (int) $menuId)];
                    }
                }
            }
            return ['error' => __('There is no menu item with that id.', 'sarcio')];
        }
        $found = self::find($itemId);
        if (isset($found['error'])) {
            return $found;
        }
        $edits = $overlay->menus[(int) $found['item']['menuId']] ?? null;
        if ($edits !== null && in_array($itemId, $edits['removed'], true)) {
            return ['error' => __('That menu item is removed in the preview.', 'sarcio')];
        }
        if ($edits !== null && isset($edits['updated'][$itemId])) {
            $post = get_post($itemId);
            $item = wp_setup_nav_menu_item($post);
            foreach ($edits['updated'][$itemId] as $key => $value) {
                $item->$key = $value;
            }
            return ['item' => self::snapshot($item, (int) $found['item']['menuId'])];
        }
        return $found;
    }

    /**
     * @param array<string,mixed> $item the snapshot shape
     * @return array<string,mixed> nav menu item object fields
     */
    private static function itemFields(array $item): array
    {
        return [
            'menu_item_parent' => (int) $item['parent'],
            'menu_order' => (int) $item['position'],
            'object' => (string) $item['object'],
            'object_id' => (int) $item['objectId'],
            'post_title' => (string) $item['title'],
            'title' => (string) $item['title'],
            'type' => (string) $item['type'],
            'url' => (string) $item['url'],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function add(array $args): array
    {
        $menu = wp_get_nav_menu_object((int) $args['menuId']);
        if (!$menu) {
            return ['error' => __('There is no menu with that id.', 'sarcio')];
        }
        $saved = self::save((int) $args['menuId'], 0, $args);
        if (isset($saved['error'])) {
            return $saved;
        }
        $after = self::find((int) $saved['id'])['item'] ?? ['id' => $saved['id'], 'menuId' => (int) $args['menuId']] + $args;
        return [
            'id' => (int) $saved['id'],
            'journal' => [
                'after' => $after,
                'before' => [],
                'summary' => sprintf(
                    /* translators: 1: the item title, 2: the menu name. */
                    __('Added “%1$s” to the %2$s menu', 'sarcio'),
                    (string) $args['title'],
                    (string) $menu->name,
                ),
                'target' => 'menu:' . $args['menuId'],
            ],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function stageAdd(array $args, Overlay $overlay): array
    {
        $menu = wp_get_nav_menu_object((int) $args['menuId']);
        if (!$menu) {
            return ['error' => __('There is no menu with that id.', 'sarcio')];
        }
        $link = (int) ($args['objectId'] ?? 0) > 0 ? get_the_title((int) $args['objectId']) : (string) ($args['url'] ?? '');
        $id = $overlay->addMenuItem((int) $args['menuId'], $args);
        return [
            'after' => (string) $args['title'] . ($link !== '' ? ' → ' . $link : ''),
            'id' => $id,
            'before' => '',
            'summary' => sprintf(
                /* translators: 1: the item title, 2: the menu name. */
                __('Add “%1$s” to the %2$s menu', 'sarcio'),
                (string) $args['title'],
                (string) $menu->name,
            ),
        ];
    }

    /** @param array<string,mixed> $args */
    private static function update(array $args): array
    {
        $found = self::find((int) $args['id']);
        if (isset($found['error'])) {
            return $found;
        }
        $before = $found['item'];
        $after = self::merge($before, $args);
        if ($after === $before) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        $saved = self::save((int) $before['menuId'], (int) $before['id'], $after);
        if (isset($saved['error'])) {
            return $saved;
        }
        return [
            'id' => (int) $before['id'],
            'journal' => [
                'after' => $after,
                'before' => $before,
                'summary' => sprintf(
                    /* translators: %s: the item title. */
                    __('Changed the menu item “%s”', 'sarcio'),
                    (string) $before['title'],
                ),
                'target' => 'menu:' . $before['menuId'],
            ],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function stageUpdate(array $args, Overlay $overlay): array
    {
        $found = self::locate((int) $args['id'], $overlay);
        if (isset($found['error'])) {
            return $found;
        }
        $before = $found['item'];
        $after = self::merge($before, $args);
        if ($after === $before) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        $overlay->updateMenuItem((int) $before['menuId'], (int) $before['id'], self::itemFields($after));
        return [
            'after' => self::describe($after),
            'before' => self::describe($before),
            'summary' => sprintf(
                /* translators: %s: the item title. */
                __('Change the menu item “%s”', 'sarcio'),
                (string) $before['title'],
            ),
        ];
    }

    private static function remove(int $itemId): array
    {
        $found = self::find($itemId);
        if (isset($found['error'])) {
            return $found;
        }
        $deleted = self::delete($itemId);
        if (isset($deleted['error'])) {
            return $deleted;
        }
        return [
            'id' => $itemId,
            'journal' => [
                'after' => [],
                'before' => $found['item'],
                'summary' => sprintf(
                    /* translators: %s: the item title. */
                    __('Removed the menu item “%s”', 'sarcio'),
                    (string) $found['item']['title'],
                ),
                'target' => 'menu:' . $found['item']['menuId'],
            ],
        ];
    }

    private static function stageRemove(int $itemId, Overlay $overlay): array
    {
        $found = self::locate($itemId, $overlay);
        if (isset($found['error'])) {
            return $found;
        }
        $overlay->removeMenuItem((int) $found['item']['menuId'], $itemId);
        return [
            'after' => '',
            'before' => self::describe($found['item']),
            'summary' => sprintf(
                /* translators: %s: the item title. */
                __('Remove the menu item “%s”', 'sarcio'),
                (string) $found['item']['title'],
            ),
        ];
    }

    private static function delete(int $itemId): array
    {
        if ($itemId <= 0 || get_post($itemId) === null) {
            return ['error' => __('That menu item no longer exists.', 'sarcio')];
        }
        if (!wp_delete_post($itemId, true)) {
            return ['error' => __('WordPress could not remove the menu item.', 'sarcio')];
        }
        return ['id' => $itemId, 'removed' => true];
    }

    /**
     * @param array<string,mixed> $before
     * @param array<string,mixed> $args
     */
    private static function merge(array $before, array $args): array
    {
        $after = $before;
        foreach (['title', 'url', 'objectId', 'parent', 'position'] as $field) {
            if (array_key_exists($field, $args)) {
                $after[$field] = $args[$field];
            }
        }
        if (array_key_exists('url', $args) && !array_key_exists('objectId', $args)) {
            $after['objectId'] = 0;
            $after['object'] = 'custom';
            $after['type'] = 'custom';
        }
        if (array_key_exists('objectId', $args)) {
            $after['object'] = (string) (get_post_type((int) $args['objectId']) ?: 'page');
            $after['type'] = 'post_type';
            $after['url'] = (string) get_permalink((int) $args['objectId']);
        }
        return $after;
    }

    /** @param array<string,mixed> $item */
    private static function describe(array $item): string
    {
        $parts = [(string) $item['title']];
        if ((int) $item['objectId'] > 0) {
            $parts[] = get_the_title((int) $item['objectId']);
        } elseif ((string) $item['url'] !== '') {
            $parts[] = (string) $item['url'];
        }
        if ((int) $item['parent'] > 0) {
            $parts[] = sprintf(
                /* translators: %s: the parent item title. */
                __('under %s', 'sarcio'),
                get_the_title((int) $item['parent']),
            );
        }
        return implode(' · ', $parts);
    }
}