<?php
/**
 * Fixes for the biggest leak that the store owner can apply from the
 * dashboard, and that then measure themselves.
 *
 * A fix is either a setting this plugin can change (with Undo, recorded in
 * the change log) or a link to the WooCommerce screen where it is done. When a
 * fix is applied, or the owner says they just did it, the rate it should move
 * (carts that reach checkout, or checkouts that become orders) is stored for
 * the 14 days before. After 14 more days the dashboard shows before and after.
 *
 * Stored in the aiflt_fixes option: key => at, change_id, metric, before, after.
 */
if (!defined('ABSPATH')) {
    exit;
}

class AIFLT_Fixes {

    const OPTION = 'aiflt_fixes';
    const MEASURE_DAYS = 14;
    /** Fewer shoppers than this on either side and the result is not shown as a number. */
    const MIN_SAMPLE = 10;

    public static function init() {
        add_action('admin_post_aiflt_fix', [__CLASS__, 'handle']);
        add_action('admin_post_aiflt_reassurance_text', [__CLASS__, 'handle_reassurance_text']);
        if (function_exists('aiflt_is_woocommerce_active') && aiflt_is_woocommerce_active()) {
            add_action('woocommerce_before_cart', [__CLASS__, 'print_free_shipping_notice']);
            add_action('woocommerce_before_checkout_form', [__CLASS__, 'print_free_shipping_notice'], 5);
            add_filter('render_block', [__CLASS__, 'block_free_shipping_notice'], 10, 2);
            // A short reassurance line under the Place order button (classic and block checkout).
            add_action('woocommerce_review_order_after_submit', [__CLASS__, 'print_reassurance']);
            add_filter('render_block_woocommerce/checkout-actions-block', [__CLASS__, 'block_reassurance'], 10, 1);
        }
    }

    /**
     * Every fix the dashboard knows.
     *
     * @return array key => stage (cart|checkout), metric, todo, done, options (setting fixes) or url (link fixes)
     */
    public static function all() {
        $fields = class_exists('AIFLT_Funnel_Analyzer_Logic') ? (int) (AIFLT_Funnel_Analyzer_Logic::get_checkout_field_data()['count'] ?? 0) : 0;
        return [
            'shipping_calc' => [
                'stage' => 'cart',
                'metric' => 'cart_to_checkout',
                'todo' => __('Show the delivery cost on the cart page', 'ai-flash-tune'),
                'done' => __('The cart page shows the delivery cost', 'ai-flash-tune'),
                'options' => ['woocommerce_enable_shipping_calc' => 'yes', 'woocommerce_shipping_cost_requires_address' => 'no'],
            ],
            'free_shipping_setup' => [
                'stage' => 'cart',
                'metric' => 'cart_to_checkout',
                'todo' => __('Offer free shipping above an order value', 'ai-flash-tune'),
                'done' => __('Free shipping is set up', 'ai-flash-tune'),
                'url' => admin_url('admin.php?page=wc-settings&tab=shipping'),
            ],
            'save_box' => [
                'stage' => 'cart',
                'metric' => null,
                'todo' => __('Ask for an email on the cart page ("Save my cart")', 'ai-flash-tune'),
                'done' => __('The cart page offers to email the cart', 'ai-flash-tune'),
                'url' => aiflt_admin_url('carts') . '#aiflt-catch-emails',
            ],
            'free_shipping_notice' => [
                'stage' => 'cart',
                'metric' => 'cart_to_checkout',
                'todo' => __('Tell shoppers how close they are to free shipping', 'ai-flash-tune'),
                'done' => __('Shoppers see how close they are to free shipping', 'ai-flash-tune'),
                'options' => ['aiflt_free_shipping_notice' => 'yes'],
            ],
            'checkout_fields' => [
                'stage' => 'checkout',
                'metric' => 'checkout_to_order',
                'todo' => $fields > 15
                    /* translators: %d: number of checkout fields */
                    ? sprintf(__('Hide checkout fields you don\'t need (%d now)', 'ai-flash-tune'), $fields)
                    : __('Keep the checkout short', 'ai-flash-tune'),
                'done' => __('Checkout has a reasonable number of fields', 'ai-flash-tune'),
                'url' => aiflt_admin_url('checkout'),
                'fields' => $fields,
            ],
            'guest_checkout' => [
                'stage' => 'checkout',
                'metric' => 'checkout_to_order',
                'todo' => __('Let guests check out without an account', 'ai-flash-tune'),
                'done' => __('Guests can check out without an account', 'ai-flash-tune'),
                'options' => ['woocommerce_enable_guest_checkout' => 'yes'],
            ],
            // The next three show on the Checkout page only (page_only), not in the dashboard list.
            'hide_company' => [
                'stage' => 'checkout',
                'page_only' => true,
                'metric' => 'checkout_to_order',
                'todo' => __('Hide the Company field', 'ai-flash-tune'),
                'done' => __('The Company field is hidden', 'ai-flash-tune'),
                'options' => ['woocommerce_checkout_company_field' => 'hidden'],
            ],
            'phone_optional' => [
                'stage' => 'checkout',
                'page_only' => true,
                'metric' => 'checkout_to_order',
                'todo' => __('Make the Phone field optional', 'ai-flash-tune'),
                'done' => __('The Phone field is optional', 'ai-flash-tune'),
                'options' => ['woocommerce_checkout_phone_field' => 'optional'],
            ],
            'reassurance' => [
                'stage' => 'checkout',
                'page_only' => true,
                'metric' => 'checkout_to_order',
                'todo' => __('Add a reassurance line under the Place order button', 'ai-flash-tune'),
                'done' => __('A reassurance line shows under the Place order button', 'ai-flash-tune'),
                'options' => ['aiflt_checkout_reassurance' => 'yes'],
            ],
            'reminders' => [
                'stage' => 'any',
                'metric' => null,
                'todo' => __('Remind shoppers who gave their email', 'ai-flash-tune'),
                'done' => __('Cart reminders are on', 'ai-flash-tune'),
                'url' => aiflt_admin_url('carts') . '#aiflt-reminders',
            ],
        ];
    }

    /** Whether a fix is in place now, whoever made the change. */
    public static function is_done($key, array $fix) {
        switch ($key) {
            case 'free_shipping_setup':
                return self::has_free_shipping();
            case 'free_shipping_notice':
                return get_option('aiflt_free_shipping_notice') === 'yes';
            case 'checkout_fields':
                return (int) ($fix['fields'] ?? 0) > 0 && (int) $fix['fields'] <= 15;
            case 'reminders':
                return class_exists('AIFLT_Cart_Recovery') && AIFLT_Cart_Recovery::is_enabled();
            case 'save_box':
                return class_exists('AIFLT_Cart_Recovery') && AIFLT_Cart_Recovery::save_cart_enabled('box');
        }
        foreach ((array) ($fix['options'] ?? []) as $name => $value) {
            if ((string) get_option($name, '') !== (string) $value) {
                return false;
            }
        }
        return !empty($fix['options']);
    }

    /** Whether a fix makes sense on this store (the free shipping note needs a free shipping minimum). */
    private static function applies($key) {
        if ($key === 'free_shipping_notice') {
            return self::free_shipping_min() > 0 || get_option('aiflt_free_shipping_notice') === 'yes';
        }
        if ($key === 'shipping_calc') {
            return function_exists('wc_shipping_enabled') ? wc_shipping_enabled() : true;
        }
        return true;
    }

    public static function records() {
        $records = get_option(self::OPTION, []);
        return is_array($records) ? $records : [];
    }

    private static function save_records(array $records) {
        update_option(self::OPTION, $records, false);
    }

    /**
     * The fixes for one leak, plus any fix that is being measured, ready for the
     * dashboard.
     *
     * @return array list of key, text, url, external, done, kind (setting|link), record, result, actions
     */
    public static function for_stage($stage, array $only = []) {
        $records = self::records();
        $out = [];
        foreach (self::all() as $key => $fix) {
            $wanted = $only
                ? in_array($key, $only, true)
                : ($fix['stage'] === $stage || $fix['stage'] === 'any') && empty($fix['page_only']);
            if ((!$wanted && !isset($records[$key])) || !self::applies($key)) {
                continue;
            }
            $done = self::is_done($key, $fix);
            $record = $records[$key] ?? null;
            $is_setting = !empty($fix['options']);
            if ($record && !empty($record['change_id']) && !$done) {
                // Undone from the change log: nothing left to measure.
                unset($records[$key]);
                self::save_records($records);
                $record = null;
                if (!$wanted) {
                    continue;
                }
            }
            $actions = [];
            if ($is_setting && !$done) {
                $actions[] = 'apply';
            }
            if ($record && !empty($record['change_id']) && $done) {
                $actions[] = 'undo';
            }
            if ($done && !$record && !empty($fix['metric'])) {
                $actions[] = 'mark';
            }
            if ($record && empty($record['change_id'])) {
                $actions[] = 'forget';
            }
            $out[] = [
                'key' => $key,
                'text' => $done ? $fix['done'] : $fix['todo'],
                'url' => $fix['url'] ?? '',
                'external' => false,
                'done' => $done,
                'kind' => $is_setting ? 'setting' : 'link',
                'record' => $record,
                'result' => $record ? self::result($key, $record) : '',
                'actions' => $actions,
            ];
        }
        return $out;
    }

    // ------------------------------------------------------------------
    // Measuring
    // ------------------------------------------------------------------

    /**
     * The rate a fix should move, between two site-local dates.
     *
     * @return array{rate: float|null, base: int}
     */
    public static function rate($metric, $start, $end) {
        $f = AIFLT_Funnel_Analyzer_Logic::get_funnel_data('all', $start, $end);
        if ($metric === 'checkout_to_order') {
            $base = (int) ($f['checkout_starts'] ?? 0);
            $hits = (int) ($f['sales'] ?? $f['completed_sessions'] ?? 0);
        } else {
            $base = (int) ($f['cart_entries'] ?? 0);
            $hits = (int) ($f['checkout_starts'] ?? 0);
        }
        return ['rate' => $base > 0 ? round(100 * min($hits, $base) / $base, 1) : null, 'base' => $base];
    }

    /** Before and after in words, or how far the measuring has got. */
    public static function result($key, array &$record) {
        $metric = (string) ($record['metric'] ?? '');
        if ($metric === '') {
            return '';
        }
        $at = strtotime((string) $record['at']);
        $days = (int) floor((current_time('timestamp') - $at) / DAY_IN_SECONDS);
        if ($days < self::MEASURE_DAYS) {
            /* translators: 1: days so far, 2: days in total */
            return sprintf(__('Measuring the effect: day %1$s of %2$s.', 'ai-flash-tune'), number_format_i18n(max(0, $days)), number_format_i18n(self::MEASURE_DAYS));
        }
        if (empty($record['after'])) {
            $record['after'] = self::rate($metric, wp_date('Y-m-d', $at + DAY_IN_SECONDS, new DateTimeZone('UTC')), wp_date('Y-m-d', $at + self::MEASURE_DAYS * DAY_IN_SECONDS, new DateTimeZone('UTC')));
            $records = self::records();
            if (isset($records[$key])) {
                $records[$key]['after'] = $record['after'];
                self::save_records($records);
            }
        }
        $before = (array) ($record['before'] ?? []);
        $after = (array) $record['after'];
        if ((int) ($before['base'] ?? 0) < self::MIN_SAMPLE || (int) ($after['base'] ?? 0) < self::MIN_SAMPLE || ($before['rate'] ?? null) === null || ($after['rate'] ?? null) === null) {
            return __('Too few shoppers in the two weeks before and after to tell a difference.', 'ai-flash-tune');
        }
        $diff = (float) $after['rate'] - (float) $before['rate'];
        $what = $metric === 'checkout_to_order'
            ? __('of checkouts became orders', 'ai-flash-tune')
            : __('of carts reached checkout', 'ai-flash-tune');
        /* translators: 1: rate before, 2: rate after, 3: what was measured, 4: change in points such as "+4.2" */
        return sprintf(__('Two weeks before: %1$s%%. Two weeks after: %2$s%% %3$s (%4$s points).', 'ai-flash-tune'), number_format_i18n((float) $before['rate'], 1), number_format_i18n((float) $after['rate'], 1), $what, ($diff >= 0 ? '+' : '') . number_format_i18n($diff, 1));
    }

    private static function start_record($key, array $fix, $change_id = 0) {
        $now = current_time('timestamp');
        $records = self::records();
        $records[$key] = [
            'at' => current_time('mysql'),
            'change_id' => (int) $change_id,
            'metric' => (string) ($fix['metric'] ?? ''),
            'before' => !empty($fix['metric'])
                ? self::rate($fix['metric'], wp_date('Y-m-d', $now - self::MEASURE_DAYS * DAY_IN_SECONDS, new DateTimeZone('UTC')), wp_date('Y-m-d', $now - DAY_IN_SECONDS, new DateTimeZone('UTC')))
                : [],
            'by' => get_current_user_id(),
        ];
        self::save_records($records);
    }

    // ------------------------------------------------------------------
    // Actions from the dashboard
    // ------------------------------------------------------------------

    public static function handle() {
        if (!current_user_can('manage_woocommerce') && !current_user_can('manage_options')) {
            wp_die(esc_html__('Permission denied.', 'ai-flash-tune'));
        }
        check_admin_referer('aiflt_fix');
        $key = sanitize_key(wp_unslash($_POST['fix'] ?? ''));
        $do = sanitize_key(wp_unslash($_POST['do'] ?? ''));
        $all = self::all();
        $flag = 'none';
        if (isset($all[$key])) {
            $fix = $all[$key];
            if ($do === 'apply') {
                $flag = self::apply($key, $fix) ? 'applied' : 'none';
            } elseif ($do === 'undo') {
                $flag = self::undo($key) ? 'undone' : 'none';
            } elseif ($do === 'mark' && self::is_done($key, $fix)) {
                self::start_record($key, $fix);
                $flag = 'measuring';
            } elseif ($do === 'forget') {
                $records = self::records();
                unset($records[$key]);
                self::save_records($records);
                $flag = 'forgotten';
            }
        }
        $back = isset($_POST['redirect_to']) ? wp_validate_redirect(esc_url_raw(wp_unslash($_POST['redirect_to'])), '') : '';
        if ($back === '' || strpos($back, admin_url()) !== 0) {
            $back = aiflt_admin_url('leak-scan') . '#aiflt-dash-leak';
        }
        $anchor = strpos($back, '#') !== false ? substr($back, strpos($back, '#')) : '';
        $back = $anchor !== '' ? substr($back, 0, strpos($back, '#')) : $back;
        wp_safe_redirect(add_query_arg(['aiflt_fix' => $flag, 'aiflt_fix_key' => $key], $back) . $anchor);
        exit;
    }

    /** Change the settings, log the change for Undo, and start measuring. */
    public static function apply($key, array $fix) {
        if (empty($fix['options']) || self::is_done($key, $fix)) {
            return false;
        }
        $before = [];
        foreach ($fix['options'] as $name => $value) {
            $old = get_option($name, null);
            $before[$name] = $old === false ? null : $old;
            update_option($name, $value);
        }
        $change_id = 0;
        if (class_exists('AIFLT_World_Class_Tools')) {
            $change_id = (int) AIFLT_World_Class_Tools::log_change('fix_' . $key, [
                'object_type' => 'option',
                'label' => $fix['todo'],
                'before_data' => ['options' => $before],
                'after_data' => ['options' => $fix['options']],
                'source' => 'fix',
            ]);
        }
        self::start_record($key, $fix, $change_id);
        return true;
    }

    public static function undo($key) {
        $records = self::records();
        $record = $records[$key] ?? null;
        if (!$record || empty($record['change_id']) || !class_exists('AIFLT_World_Class_Tools')) {
            return false;
        }
        $ok = AIFLT_World_Class_Tools::rollback_change((int) $record['change_id']);
        if ($ok) {
            unset($records[$key]);
            self::save_records($records);
        }
        return $ok;
    }

    /** Settings a fix may change, so the change log's Undo can put them back. */
    public static function undoable_options() {
        $names = [];
        foreach (self::all() as $fix) {
            $names = array_merge($names, array_keys((array) ($fix['options'] ?? [])));
        }
        return array_values(array_unique($names));
    }

    // ------------------------------------------------------------------
    // Free shipping
    // ------------------------------------------------------------------

    public static function has_free_shipping() {
        if (!class_exists('WC_Shipping_Zones')) {
            return false;
        }
        $zones = WC_Shipping_Zones::get_zones();
        $zones[] = ['shipping_methods' => (new WC_Shipping_Zone(0))->get_shipping_methods(true)];
        foreach ($zones as $zone) {
            foreach ((array) ($zone['shipping_methods'] ?? []) as $method) {
                if ($method->id === 'free_shipping' && $method->is_enabled()) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * The order value for free shipping in the shopper's zone (or the store's
     * own country before an address is known); 0 when there is none.
     */
    public static function free_shipping_min() {
        if (!class_exists('WC_Shipping_Zones') || !function_exists('WC')) {
            return 0.0;
        }
        $customer = WC()->customer;
        $country = $customer && $customer->get_shipping_country() ? $customer->get_shipping_country() : WC()->countries->get_base_country();
        $zone = WC_Shipping_Zones::get_zone_matching_package([
            'destination' => [
                'country' => $country,
                'state' => $customer ? $customer->get_shipping_state() : '',
                'postcode' => $customer ? $customer->get_shipping_postcode() : '',
            ],
        ]);
        $min = 0.0;
        foreach ($zone->get_shipping_methods(true) as $method) {
            if ($method->id === 'free_shipping' && in_array($method->get_option('requires'), ['min_amount', 'either', 'both'], true)) {
                $amount = (float) $method->get_option('min_amount');
                if ($amount > 0 && ($min <= 0 || $amount < $min)) {
                    $min = $amount;
                }
            }
        }
        return $min;
    }

    public static function handle_reassurance_text() {
        if (!current_user_can('manage_woocommerce') && !current_user_can('manage_options')) {
            wp_die(esc_html__('Permission denied.', 'ai-flash-tune'));
        }
        check_admin_referer('aiflt_reassurance_text');
        $text = isset($_POST['text']) ? sanitize_text_field(wp_unslash($_POST['text'])) : '';
        update_option('aiflt_checkout_reassurance_text', mb_substr($text, 0, 200), false);
        wp_safe_redirect(aiflt_admin_url('checkout') . '#aiflt-checkout-fixes');
        exit;
    }

    /** The reassurance line: the owner's own text, or a plain default. */
    public static function reassurance_html() {
        if (get_option('aiflt_checkout_reassurance') !== 'yes') {
            return '';
        }
        $text = trim((string) get_option('aiflt_checkout_reassurance_text', ''));
        if ($text === '') {
            $text = __('Secure checkout. Your payment details are handled by the payment provider you choose.', 'ai-flash-tune');
        }
        return '<p class="aiflt-reassurance" style="margin:12px 0 0;font-size:0.9em;opacity:0.85;">' . esc_html($text) . '</p>';
    }

    public static function print_reassurance() {
        echo self::reassurance_html(); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- Escaped in reassurance_html().
    }

    public static function block_reassurance($content) {
        return $content . self::reassurance_html();
    }

    /** "Add ₨500 more for free shipping" on the classic cart and checkout. */
    public static function print_free_shipping_notice() {
        $message = self::free_shipping_message(true);
        if ($message !== '') {
            wc_print_notice(esc_html($message), 'notice');
        }
    }

    /**
     * On the block cart and checkout the totals change without a page load, so
     * the note says the threshold instead of the amount still missing.
     */
    public static function block_free_shipping_notice($content, $block) {
        $name = (string) ($block['blockName'] ?? '');
        if (($name !== 'woocommerce/cart' && $name !== 'woocommerce/checkout') || is_admin()) {
            return $content;
        }
        $message = self::free_shipping_message(false);
        if ($message === '') {
            return $content;
        }
        return '<div class="wc-block-components-notice-banner is-info" role="status"><div class="wc-block-components-notice-banner__content">' . esc_html($message) . '</div></div>' . $content;
    }

    private static function free_shipping_message($exact) {
        if (get_option('aiflt_free_shipping_notice') !== 'yes' || !function_exists('WC') || !WC()->cart || WC()->cart->is_empty()) {
            return '';
        }
        $min = self::free_shipping_min();
        if ($min <= 0) {
            return '';
        }
        $price = static function ($amount) {
            return html_entity_decode(wp_strip_all_tags(wc_price($amount)), ENT_QUOTES, 'UTF-8');
        };
        if (!$exact) {
            /* translators: %s: order value */
            return sprintf(__('Free shipping on orders over %s.', 'ai-flash-tune'), $price($min));
        }
        $left = $min - ((float) WC()->cart->get_displayed_subtotal() - (float) WC()->cart->get_discount_total());
        return $left > 0
            /* translators: %s: amount still needed */
            ? sprintf(__('Add %s more to your cart for free shipping.', 'ai-flash-tune'), $price($left))
            : __('Your order qualifies for free shipping.', 'ai-flash-tune');
    }
}