<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

final class WooAbilities
{
    public const SETTINGS = [
        'woocommerce_calc_taxes',
        'woocommerce_currency',
        'woocommerce_currency_pos',
        'woocommerce_default_country',
        'woocommerce_enable_coupons',
        'woocommerce_price_decimal_sep',
        'woocommerce_price_num_decimals',
        'woocommerce_price_thousand_sep',
        'woocommerce_prices_include_tax',
        'woocommerce_store_address',
        'woocommerce_store_address_2',
        'woocommerce_store_city',
        'woocommerce_store_postcode',
    ];

    public const COUPON_TYPES = ['percent', 'fixed_cart', 'fixed_product'];
    public const STOCK_STATUSES = ['instock', 'outofstock', 'onbackorder'];

    /** @return array<int,Ability> */
    public static function abilities(): array
    {
        if (!SiteAbilities::woocommerceActive()) {
            return [];
        }
        $allowed = static fn (array $args): bool => current_user_can('manage_woocommerce');
        $idSchema = ['minimum' => 1, 'type' => 'integer'];
        $settingsProperties = [];
        foreach (self::SETTINGS as $key) {
            $settingsProperties[$key] = ['maxLength' => 500, 'type' => 'string'];
        }
        return [
            new Ability(
                'sarcio/woo-settings-get',
                __('Look at the shop settings', 'sarcio'),
                Ability::READ,
                'The WooCommerce store settings: address, currency and its format, whether prices include tax and taxes are calculated, whether coupons are enabled, and the shipping zones with their methods.',
                ['properties' => [], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::settings(),
            ),
            new Ability(
                'sarcio/woo-settings-update',
                __('Change the shop settings', 'sarcio'),
                Ability::WRITE,
                'Change WooCommerce store settings. Keys are the woocommerce_* option names from woo-settings-get; yes/no settings take "yes" or "no". Only the keys given change.',
                ['properties' => $settingsProperties, 'required' => [], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::updateSettings($args),
                null,
                static fn (array $before, array $after): array => self::writeSettings($before) + ['restored' => true],
                false,
                static fn (array $args, Overlay $overlay): array => self::stageSettings($args, $overlay),
            ),
            new Ability(
                'sarcio/woo-products-search',
                __('Look for products', 'sarcio'),
                Ability::READ,
                'Search products by name or SKU. Returns id, name, sku, price, sale price, stock status and url.',
                [
                    'properties' => [
                        'limit' => ['maximum' => 20, 'minimum' => 1, 'type' => 'integer'],
                        'query' => ['maxLength' => 200, 'type' => 'string'],
                        'status' => ['enum' => ['any', 'publish', 'draft', 'pending', 'private'], 'type' => 'string'],
                    ],
                    'required' => [],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::searchProducts($args),
            ),
            new Ability(
                'sarcio/woo-product-get',
                __('Read a product', 'sarcio'),
                Ability::READ,
                'Read one product by id: name, sku, prices, sale dates, stock, status, descriptions, categories and url.',
                ['properties' => ['id' => $idSchema], 'required' => ['id'], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::product((int) $args['id']),
            ),
            new Ability(
                'sarcio/woo-product-update',
                __('Change a product', 'sarcio'),
                Ability::WRITE,
                'Change a product’s regular price, sale price and sale dates (YYYY-MM-DD), stock status or quantity, descriptions or status. Only the fields given change. Prices are plain numbers as text, e.g. "24.50".',
                [
                    'properties' => [
                        'description' => ['type' => 'string'],
                        'id' => $idSchema,
                        'regularPrice' => ['maxLength' => 20, 'type' => 'string'],
                        'saleFrom' => ['maxLength' => 10, 'type' => 'string'],
                        'salePrice' => ['maxLength' => 20, 'type' => 'string'],
                        'saleTo' => ['maxLength' => 10, 'type' => 'string'],
                        'shortDescription' => ['type' => 'string'],
                        'status' => ['enum' => ['publish', 'draft', 'pending', 'private'], 'type' => 'string'],
                        'stockQuantity' => ['minimum' => 0, 'type' => 'integer'],
                        'stockStatus' => ['enum' => self::STOCK_STATUSES, 'type' => 'string'],
                    ],
                    'required' => ['id'],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::updateProduct($args),
                null,
                static fn (array $before, array $after): array => self::writeProduct($before) + ['restored' => true],
                false,
                static fn (array $args, Overlay $overlay): array => self::stageProduct($args, $overlay),
            ),
            new Ability(
                'sarcio/woo-coupons-list',
                __('Look at the coupons', 'sarcio'),
                Ability::READ,
                'Every coupon: id, code, type, amount, expiry, usage limit and count, free shipping, minimum spend.',
                ['properties' => [], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => self::coupons(),
            ),
            new Ability(
                'sarcio/woo-coupon-save',
                __('Create or change a coupon', 'sarcio'),
                Ability::WRITE,
                'Create a coupon, or change the one with the given code. type is percent, fixed_cart or fixed_product; amount is a number as text; expiry is YYYY-MM-DD or empty for none; usageLimit caps uses in total, usageLimitPerUser caps uses per customer (0 = no cap).',
                [
                    'properties' => [
                        'amount' => ['maxLength' => 20, 'type' => 'string'],
                        'code' => ['maxLength' => 100, 'minLength' => 1, 'type' => 'string'],
                        'description' => ['maxLength' => 1000, 'type' => 'string'],
                        'expiry' => ['maxLength' => 10, 'type' => 'string'],
                        'freeShipping' => ['type' => 'boolean'],
                        'minimumSpend' => ['maxLength' => 20, 'type' => 'string'],
                        'type' => ['enum' => self::COUPON_TYPES, 'type' => 'string'],
                        'usageLimit' => ['minimum' => 0, 'type' => 'integer'],
                        'usageLimitPerUser' => ['minimum' => 0, 'type' => 'integer'],
                    ],
                    'required' => ['code'],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::saveCoupon($args),
                static fn (array $args): array => self::saveCouponPreview($args),
                static fn (array $before, array $after): array => self::undoCoupon($before, $after),
            ),
        ];
    }

    private static function settings(): array
    {
        $out = [];
        foreach (self::SETTINGS as $key) {
            $out[$key] = (string) Stage::option($key, '');
        }
        $zones = [];
        if (class_exists('WC_Shipping_Zones')) {
            foreach ((array) \WC_Shipping_Zones::get_zones() as $zone) {
                $methods = [];
                foreach ((array) ($zone['shipping_methods'] ?? []) as $method) {
                    $methods[] = [
                        'enabled' => (string) ($method->enabled ?? 'yes') === 'yes',
                        'title' => (string) $method->get_title(),
                        'type' => (string) $method->id,
                    ];
                }
                $zones[] = [
                    'id' => (int) ($zone['id'] ?? $zone['zone_id'] ?? 0),
                    'methods' => $methods,
                    'name' => (string) ($zone['zone_name'] ?? ''),
                    'regions' => (string) ($zone['formatted_zone_location'] ?? ''),
                ];
            }
        }
        return ['settings' => $out, 'shippingZones' => $zones];
    }

    /** @param array<string,mixed> $args */
    private static function updateSettings(array $args): array
    {
        $before = [];
        $after = [];
        foreach (self::SETTINGS as $key) {
            if (array_key_exists($key, $args)) {
                $current = (string) get_option($key, '');
                if ($current !== (string) $args[$key]) {
                    $before[$key] = $current;
                    $after[$key] = (string) $args[$key];
                }
            }
        }
        if ($after === []) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        self::writeSettings($after);
        return [
            'changed' => array_keys($after),
            'journal' => [
                'after' => $after,
                'before' => $before,
                'summary' => sprintf(
                    /* translators: %s: the settings changed. */
                    __('Changed the shop settings: %s', 'sarcio'),
                    implode(', ', array_map(static fn (string $key): string => str_replace(['woocommerce_', '_'], ['', ' '], $key), array_keys($after))),
                ),
                'target' => 'woocommerce_settings',
            ],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function stageSettings(array $args, Overlay $overlay): array
    {
        $before = [];
        $after = [];
        foreach (self::SETTINGS as $key) {
            if (array_key_exists($key, $args) && (string) $overlay->option($key, '') !== (string) $args[$key]) {
                $label = str_replace(['woocommerce_', '_'], ['', ' '], $key);
                $before[] = $label . ': ' . (string) $overlay->option($key, '');
                $after[] = $label . ': ' . (string) $args[$key];
                $overlay->options[$key] = (string) $args[$key];
            }
        }
        if ($after === []) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        return ['after' => implode("\n", $after), 'before' => implode("\n", $before), 'summary' => __('Change the shop settings', 'sarcio')];
    }

    /** @param array<string,string> $values */
    private static function writeSettings(array $values): array
    {
        foreach ($values as $key => $value) {
            if (in_array($key, self::SETTINGS, true)) {
                update_option($key, (string) $value);
            }
        }
        return ['changed' => array_keys($values)];
    }

    private static function summarizeProduct(object $product): array
    {
        return [
            'id' => (int) $product->get_id(),
            'name' => (string) $product->get_name(),
            'price' => (string) $product->get_price(),
            'regularPrice' => (string) $product->get_regular_price(),
            'salePrice' => (string) $product->get_sale_price(),
            'sku' => (string) $product->get_sku(),
            'status' => (string) $product->get_status(),
            'stockStatus' => (string) $product->get_stock_status(),
            'url' => (string) $product->get_permalink(),
        ];
    }

    /** @param array<string,mixed> $args */
    private static function searchProducts(array $args): array
    {
        $query = (string) ($args['query'] ?? '');
        $products = wc_get_products([
            'limit' => (int) ($args['limit'] ?? 10),
            'orderby' => 'date',
            's' => $query,
            'status' => (string) ($args['status'] ?? 'any'),
        ]);
        $out = array_map([self::class, 'summarizeProduct'], is_array($products) ? $products : []);
        if ($query !== '' && function_exists('wc_get_product_id_by_sku')) {
            $bySku = (int) wc_get_product_id_by_sku($query);
            if ($bySku > 0 && !in_array($bySku, array_column($out, 'id'), true)) {
                $product = wc_get_product($bySku);
                if ($product) {
                    array_unshift($out, self::summarizeProduct($product));
                }
            }
        }
        return ['results' => $out];
    }

    /** @return array<string,mixed> */
    private static function snapshotProduct(object $product): array
    {
        $from = $product->get_date_on_sale_from();
        $to = $product->get_date_on_sale_to();
        return [
            'description' => (string) $product->get_description(),
            'id' => (int) $product->get_id(),
            'regularPrice' => (string) $product->get_regular_price(),
            'saleFrom' => $from ? $from->date('Y-m-d') : '',
            'salePrice' => (string) $product->get_sale_price(),
            'saleTo' => $to ? $to->date('Y-m-d') : '',
            'shortDescription' => (string) $product->get_short_description(),
            'status' => (string) $product->get_status(),
            'stockQuantity' => $product->get_stock_quantity() === null ? null : (int) $product->get_stock_quantity(),
            'stockStatus' => (string) $product->get_stock_status(),
        ];
    }

    private static function product(int $id): array
    {
        $product = wc_get_product($id);
        if (!$product) {
            return ['error' => __('There is no product with that id.', 'sarcio')];
        }
        $categories = [];
        foreach ((array) get_the_terms($id, 'product_cat') as $term) {
            if (is_object($term)) {
                $categories[] = (string) $term->name;
            }
        }
        $snapshot = self::snapshotProduct($product);
        if (Stage::active()) {
            $snapshot = Stage::overlay()->applyToProduct($id, $snapshot);
        }
        return $snapshot + [
            'categories' => $categories,
            'name' => (string) $product->get_name(),
            'sku' => (string) $product->get_sku(),
            'url' => (string) $product->get_permalink(),
        ];
    }

    /**
     * @param array<string,mixed> $args
     * @return array{before:array<string,mixed>,after:array<string,mixed>,name:string}|array{error:string}
     */
    private static function productChanges(array $args, ?Overlay $overlay = null): array
    {
        $product = wc_get_product((int) $args['id']);
        if (!$product) {
            return ['error' => __('There is no product with that id.', 'sarcio')];
        }
        $before = self::snapshotProduct($product);
        if ($overlay !== null) {
            $before = $overlay->applyToProduct((int) $args['id'], $before);
        }
        $after = $before;
        foreach (['description', 'regularPrice', 'saleFrom', 'salePrice', 'saleTo', 'shortDescription', 'status', 'stockQuantity', 'stockStatus'] as $field) {
            if (array_key_exists($field, $args)) {
                $after[$field] = in_array($field, ['description', 'shortDescription'], true) ? wp_kses_post((string) $args[$field]) : $args[$field];
            }
        }
        if ($after === $before) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        return ['after' => $after, 'before' => $before, 'name' => (string) $product->get_name()];
    }

    /** @param array<string,mixed> $args */
    private static function updateProduct(array $args): array
    {
        $changes = self::productChanges($args);
        if (isset($changes['error'])) {
            return $changes;
        }
        $written = self::writeProduct($changes['after']);
        if (isset($written['error'])) {
            return $written;
        }
        $changed = array_keys(array_filter($changes['after'], static fn ($value, $key) => $changes['before'][$key] !== $value, ARRAY_FILTER_USE_BOTH));
        return [
            'changed' => $changed,
            'id' => (int) $args['id'],
            'journal' => [
                'after' => $changes['after'],
                'before' => $changes['before'],
                'summary' => sprintf(
                    /* translators: 1: the fields changed, 2: the product name. */
                    __('Changed %1$s of “%2$s”', 'sarcio'),
                    implode(', ', $changed),
                    $changes['name'],
                ),
                'target' => 'product:' . $args['id'],
            ],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function stageProduct(array $args, Overlay $overlay): array
    {
        $changes = self::productChanges($args, $overlay);
        if (isset($changes['error'])) {
            return $changes;
        }
        $before = [];
        $after = [];
        $staged = [];
        foreach ($changes['after'] as $field => $value) {
            if ($changes['before'][$field] !== $value) {
                $before[] = $field . ': ' . (string) $changes['before'][$field];
                $after[] = $field . ': ' . (string) $value;
                $staged[$field] = $value;
            }
        }
        $overlay->setProduct((int) $args['id'], $staged);
        $postFields = array_filter([
            'post_content' => $staged['description'] ?? null,
            'post_excerpt' => $staged['shortDescription'] ?? null,
            'post_status' => $staged['status'] ?? null,
        ], static fn ($value): bool => $value !== null);
        if ($postFields !== []) {
            $overlay->setPost((int) $args['id'], $postFields);
        }
        return [
            'after' => implode("\n", $after),
            'before' => implode("\n", $before),
            'summary' => sprintf(
                /* translators: %s: the product name. */
                __('Change “%s”', 'sarcio'),
                $changes['name'],
            ),
        ];
    }

    /** @param array<string,mixed> $fields */
    private static function writeProduct(array $fields): array
    {
        $product = wc_get_product((int) $fields['id']);
        if (!$product) {
            return ['error' => __('There is no product with that id.', 'sarcio')];
        }
        $product->set_regular_price((string) $fields['regularPrice']);
        $product->set_sale_price((string) $fields['salePrice']);
        $product->set_date_on_sale_from($fields['saleFrom'] !== '' ? (string) $fields['saleFrom'] : null);
        $product->set_date_on_sale_to($fields['saleTo'] !== '' ? (string) $fields['saleTo'] : null);
        $product->set_description((string) $fields['description']);
        $product->set_short_description((string) $fields['shortDescription']);
        $product->set_status((string) $fields['status']);
        if ($fields['stockQuantity'] !== null) {
            $product->set_manage_stock(true);
            $product->set_stock_quantity((int) $fields['stockQuantity']);
        } else {
            $product->set_stock_status((string) $fields['stockStatus']);
        }
        $product->save();
        return ['id' => (int) $fields['id']];
    }

    /** @return array<string,mixed> */
    private static function snapshotCoupon(object $coupon): array
    {
        $expiry = $coupon->get_date_expires();
        return [
            'amount' => (string) $coupon->get_amount(),
            'code' => (string) $coupon->get_code(),
            'description' => (string) $coupon->get_description(),
            'expiry' => $expiry ? $expiry->date('Y-m-d') : '',
            'freeShipping' => (bool) $coupon->get_free_shipping(),
            'id' => (int) $coupon->get_id(),
            'minimumSpend' => (string) $coupon->get_minimum_amount(),
            'type' => (string) $coupon->get_discount_type(),
            'usageCount' => (int) $coupon->get_usage_count(),
            'usageLimit' => (int) $coupon->get_usage_limit(),
            'usageLimitPerUser' => (int) $coupon->get_usage_limit_per_user(),
        ];
    }

    private static function coupons(): array
    {
        $posts = get_posts(['numberposts' => 100, 'post_status' => 'any', 'post_type' => 'shop_coupon']);
        $out = [];
        foreach (is_array($posts) ? $posts : [] as $post) {
            $out[] = self::snapshotCoupon(new \WC_Coupon((int) $post->ID));
        }
        return ['coupons' => $out];
    }

    private static function findCoupon(string $code): ?object
    {
        $id = function_exists('wc_get_coupon_id_by_code') ? (int) wc_get_coupon_id_by_code($code) : 0;
        return $id > 0 ? new \WC_Coupon($id) : null;
    }

    /**
     * @param array<string,mixed> $args
     * @return array{before:array<string,mixed>,after:array<string,mixed>}
     */
    private static function couponChanges(array $args, ?object $existing): array
    {
        $before = $existing !== null ? self::snapshotCoupon($existing) : [];
        $after = $existing !== null ? $before : [
            'amount' => '0',
            'code' => (string) $args['code'],
            'description' => '',
            'expiry' => '',
            'freeShipping' => false,
            'id' => 0,
            'minimumSpend' => '',
            'type' => 'percent',
            'usageCount' => 0,
            'usageLimit' => 0,
            'usageLimitPerUser' => 0,
        ];
        foreach (['amount', 'description', 'expiry', 'freeShipping', 'minimumSpend', 'type', 'usageLimit', 'usageLimitPerUser'] as $field) {
            if (array_key_exists($field, $args)) {
                $after[$field] = $args[$field];
            }
        }
        return ['after' => $after, 'before' => $before];
    }

    /** @param array<string,mixed> $args */
    private static function saveCoupon(array $args): array
    {
        $existing = self::findCoupon((string) $args['code']);
        $changes = self::couponChanges($args, $existing);
        if ($existing !== null && $changes['after'] === $changes['before']) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        $written = self::writeCoupon($changes['after']);
        if (isset($written['error'])) {
            return $written;
        }
        $changes['after']['id'] = $written['id'];
        return [
            'id' => $written['id'],
            'journal' => [
                'after' => $changes['after'],
                'before' => $changes['before'],
                'summary' => sprintf(
                    $existing !== null
                        /* translators: %s: the coupon code. */
                        ? __('Changed the coupon %s', 'sarcio')
                        /* translators: %s: the coupon code. */
                        : __('Created the coupon %s', 'sarcio'),
                    (string) $args['code'],
                ),
                'target' => 'coupon:' . $args['code'],
            ],
        ];
    }

    /** @param array<string,mixed> $args */
    private static function saveCouponPreview(array $args): array
    {
        $existing = self::findCoupon((string) $args['code']);
        $changes = self::couponChanges($args, $existing);
        if ($existing !== null && $changes['after'] === $changes['before']) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        return [
            'after' => self::describeCoupon($changes['after']),
            'before' => $existing !== null ? self::describeCoupon($changes['before']) : '',
            'summary' => sprintf(
                $existing !== null
                    /* translators: %s: the coupon code. */
                    ? __('Change the coupon %s', 'sarcio')
                    /* translators: %s: the coupon code. */
                    : __('Create the coupon %s', 'sarcio'),
                (string) $args['code'],
            ),
        ];
    }

    /** @param array<string,mixed> $fields */
    private static function writeCoupon(array $fields): array
    {
        $coupon = new \WC_Coupon((int) ($fields['id'] ?? 0));
        $coupon->set_code((string) $fields['code']);
        $coupon->set_discount_type((string) $fields['type']);
        $coupon->set_amount((string) $fields['amount']);
        $coupon->set_description(sanitize_textarea_field((string) $fields['description']));
        $coupon->set_date_expires($fields['expiry'] !== '' ? (string) $fields['expiry'] : null);
        $coupon->set_free_shipping((bool) $fields['freeShipping']);
        $coupon->set_minimum_amount((string) $fields['minimumSpend']);
        $coupon->set_usage_limit((int) $fields['usageLimit']);
        $coupon->set_usage_limit_per_user((int) ($fields['usageLimitPerUser'] ?? 0));
        $id = (int) $coupon->save();
        if ($id <= 0) {
            return ['error' => __('WooCommerce could not save the coupon.', 'sarcio')];
        }
        return ['id' => $id];
    }

    /**
     * @param array<string,mixed> $before
     * @param array<string,mixed> $after
     */
    private static function undoCoupon(array $before, array $after): array
    {
        if ($before === []) {
            $id = (int) ($after['id'] ?? 0);
            if ($id > 0 && get_post($id) !== null) {
                wp_trash_post($id);
            }
            return ['code' => (string) ($after['code'] ?? ''), 'trashed' => true];
        }
        return self::writeCoupon($before) + ['restored' => true];
    }

    /** @param array<string,mixed> $coupon */
    private static function describeCoupon(array $coupon): string
    {
        $amount = (string) $coupon['amount'];
        $lines = [
            $coupon['type'] === 'percent'
                ? sprintf(
                    /* translators: %s: the percentage. */
                    __('%s%% off', 'sarcio'),
                    $amount,
                )
                : sprintf(
                    /* translators: %s: the amount. */
                    __('%s off', 'sarcio'),
                    $amount,
                ),
        ];
        if ((string) $coupon['expiry'] !== '') {
            $lines[] = sprintf(
                /* translators: %s: the expiry date. */
                __('expires %s', 'sarcio'),
                (string) $coupon['expiry'],
            );
        }
        if ((int) $coupon['usageLimit'] > 0) {
            $lines[] = sprintf(
                /* translators: %d: how many uses in total. */
                _n('%d use in total', 'up to %d uses in total', (int) $coupon['usageLimit'], 'sarcio'),
                (int) $coupon['usageLimit'],
            );
        }
        if ((int) ($coupon['usageLimitPerUser'] ?? 0) > 0) {
            $lines[] = sprintf(
                /* translators: %d: how many uses per customer. */
                _n('%d use per customer', 'up to %d uses per customer', (int) $coupon['usageLimitPerUser'], 'sarcio'),
                (int) $coupon['usageLimitPerUser'],
            );
        }
        if (!empty($coupon['freeShipping'])) {
            $lines[] = __('free shipping', 'sarcio');
        }
        if ((string) $coupon['minimumSpend'] !== '') {
            $lines[] = sprintf(
                /* translators: %s: the minimum spend. */
                __('minimum spend %s', 'sarcio'),
                (string) $coupon['minimumSpend'],
            );
        }
        return implode(', ', $lines);
    }
}