<?php
namespace Sodino\Services;

use Sodino\Repositories\EventRepository;
use Sodino\Repositories\RuleRepository;

class AnalyticsService {
    private $eventRepository;
    private $ruleRepository;

    public function __construct(EventRepository $eventRepository, RuleRepository $ruleRepository) {
        $this->eventRepository = $eventRepository;
        $this->ruleRepository = $ruleRepository;
    }

    public function primeCache() {
        $cache_keys = [
            'sodino_dashboard_summary',
            'sodino_dashboard_sales_chart',
            'sodino_dashboard_rule_performance',
            'sodino_dashboard_user_behavior',
        ];

        foreach ($cache_keys as $key) {
            delete_transient($key);
        }
    }

    public function getDashboardData(array $filters = []) {
        $cache_key = 'sodino_dashboard_' . md5(wp_json_encode($filters));
        $cached = get_transient($cache_key);
        if ($cached !== false) {
            return $cached;
        }

        $range = $this->getDateRange($filters['range'] ?? '7d', $filters['start_date'] ?? '', $filters['end_date'] ?? '');
        $filters['from'] = $range['start'];
        $filters['to'] = $range['end'];

        if (!empty($filters['category_id'])) {
            $filters['product_ids'] = $this->getProductIdsByCategory($filters['category_id']);
        }

        $summary = $this->getSummary($filters);
        $salesChart = $this->getSalesChart($filters);
        $rulePerformance = $this->getRulePerformance($filters);
        $roiReport = $this->getRoiReport($filters);
        $upsellPerformance = $this->getUpsellPerformance($filters);
        $bannerPerformance = $this->getBannerPerformance($filters, $summary);
        $userBehavior = $this->getUserBehavior($filters);
        $insights = $this->getInsights($summary, $filters, $roiReport);

        $result = [
            'summary' => $summary,
            'sales_chart' => $salesChart,
            'rule_performance' => $rulePerformance,
            'roi_report' => $roiReport,
            'upsell_performance' => $upsellPerformance,
            'banner_performance' => $bannerPerformance,
            'user_behavior' => $userBehavior,
            'insights' => $insights,
        ];

        set_transient($cache_key, $result, 10 * MINUTE_IN_SECONDS);
        return $result;
    }

    public function getSummary(array $filters = []) {
        $purchaseFilters = array_merge($filters, ['event_type' => 'purchase']);
        $discountFilters = array_merge($filters, ['event_type' => 'discount_applied']);

        $purchaseCount = $this->eventRepository->getCount($purchaseFilters);
        $totalRevenue = $this->eventRepository->getSum('value', $purchaseFilters);
        $totalDiscount = $this->eventRepository->getSum('discount_value', $discountFilters);

        $productViewCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'product_view']));
        $addToCartCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'add_to_cart']));
        $checkoutStartCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'checkout_start']));

        $conversionRate = 0;
        if ($checkoutStartCount > 0) {
            $conversionRate = round(($purchaseCount / $checkoutStartCount) * 100, 2);
        } elseif ($addToCartCount > 0) {
            $conversionRate = round(($purchaseCount / $addToCartCount) * 100, 2);
        }

        $addToCartRate = 0;
        if ($productViewCount > 0) {
            $addToCartRate = round(($addToCartCount / $productViewCount) * 100, 2);
        }

        $bestRule = $this->getBestRule($filters);

        return [
            'total_revenue' => $totalRevenue,
            'total_discount' => $totalDiscount,
            'purchase_count' => $purchaseCount,
            'conversion_rate' => $conversionRate,
            'add_to_cart_rate' => $addToCartRate,
            'best_rule' => $bestRule,
        ];
    }

    public function getSalesChart(array $filters = []) {
        $filters = array_merge($filters, $this->getDateRange($filters['range'] ?? '7d', $filters['start_date'] ?? '', $filters['end_date'] ?? ''));

        if (!empty($filters['category_id'])) {
            $filters['product_ids'] = $this->getProductIdsByCategory($filters['category_id']);
        }

        $start = new \DateTime($filters['start']);
        $end = new \DateTime($filters['end']);
        $days = [];
        $series = [ 'before' => [], 'after' => [], 'labels' => [] ];

        while ($start <= $end) {
            $date = $start->format('Y-m-d');
            $series['labels'][] = $date;
            $dayFilters = array_merge($filters, ['from' => $date . ' 00:00:00', 'to' => $date . ' 23:59:59']);
            $purchases = $this->eventRepository->getEvents(array_merge($dayFilters, ['event_type' => 'purchase']));
            $dayRevenue = 0;
            $dayDiscount = 0;
            foreach ($purchases as $purchase) {
                $dayRevenue += floatval($purchase['value']);
            }
            $discountEvents = $this->eventRepository->getEvents(array_merge($dayFilters, ['event_type' => 'discount_applied']));
            foreach ($discountEvents as $discount) {
                $dayDiscount += floatval($discount['discount_value']);
            }
            $series['after'][] = round($dayRevenue, 2);
            $series['before'][] = round($dayRevenue + $dayDiscount, 2);
            $start->modify('+1 day');
        }

        return $series;
    }

    public function getRulePerformance(array $filters = []) {
        $rules = $this->ruleRepository->getAll();
        $result = [];

        foreach ($rules as $rule) {
            $ruleFilters = array_merge($filters, ['event_type' => 'discount_applied', 'rule_id' => $rule->id]);
            $count = $this->eventRepository->getCount($ruleFilters);
            $revenue = $this->eventRepository->getSum('value', $ruleFilters);
            $totalDiscount = $this->eventRepository->getSum('discount_value', $ruleFilters);

            if ($count > 0) {
                $result[] = [
                    'name' => $rule->name,
                    'count' => $count,
                    'revenue' => round($revenue, 2),
                    'discount' => round($totalDiscount, 2),
                ];
            }
        }

        return $result;
    }

    public function getRoiReport(array $filters = []) {
        $orders = $this->getOrdersInRange($filters);
        $attributedRevenue = 0;
        $attributedDiscount = 0;
        $attributedOrders = [];
        $ruleRows = [];
        $upsellRows = [];

        foreach ($orders as $order) {
            $orderId = $order->get_id();
            foreach ($order->get_items() as $item) {
                $lineRevenue = (float) $item->get_total();
                $ruleIds = $this->parseIdList($item->get_meta('_sodino_rule_ids', true));
                $ruleDiscount = (float) $item->get_meta('_sodino_rule_discount', true);
                $upsellId = (int) $item->get_meta('_sodino_upsell_id', true);

                if (!empty($ruleIds) || $upsellId > 0) {
                    $attributedRevenue += $lineRevenue;
                    $attributedDiscount += $ruleDiscount;
                    $attributedOrders[$orderId] = true;
                }

                foreach ($ruleIds as $ruleId) {
                    if (!isset($ruleRows[$ruleId])) {
                        $ruleRows[$ruleId] = [
                            'rule_id' => $ruleId,
                            'name' => $this->getRuleName($ruleId),
                            'orders' => [],
                            'revenue' => 0,
                            'discount' => 0,
                        ];
                    }

                    $allocation = count($ruleIds) > 0 ? $lineRevenue / count($ruleIds) : $lineRevenue;
                    $discountAllocation = count($ruleIds) > 0 ? $ruleDiscount / count($ruleIds) : $ruleDiscount;
                    $ruleRows[$ruleId]['orders'][$orderId] = true;
                    $ruleRows[$ruleId]['revenue'] += $allocation;
                    $ruleRows[$ruleId]['discount'] += $discountAllocation;
                }

                if ($upsellId > 0) {
                    if (!isset($upsellRows[$upsellId])) {
                        $upsellRows[$upsellId] = [
                            'upsell_id' => $upsellId,
                            'title' => $this->getUpsellTitle($upsellId),
                            'orders' => [],
                            'revenue' => 0,
                        ];
                    }

                    $upsellRows[$upsellId]['orders'][$orderId] = true;
                    $upsellRows[$upsellId]['revenue'] += $lineRevenue;
                }
            }
        }

        $ruleRows = array_map(function ($row) {
            $row['order_count'] = count($row['orders']);
            unset($row['orders']);
            $row['revenue'] = round($row['revenue'], 2);
            $row['discount'] = round($row['discount'], 2);
            return $row;
        }, array_values($ruleRows));

        usort($ruleRows, function ($a, $b) {
            return $b['revenue'] <=> $a['revenue'];
        });

        $upsellRows = array_map(function ($row) {
            $row['order_count'] = count($row['orders']);
            unset($row['orders']);
            $row['revenue'] = round($row['revenue'], 2);
            return $row;
        }, array_values($upsellRows));

        usort($upsellRows, function ($a, $b) {
            return $b['revenue'] <=> $a['revenue'];
        });

        return [
            'attributed_revenue' => round($attributedRevenue, 2),
            'attributed_discount' => round($attributedDiscount, 2),
            'attributed_order_count' => count($attributedOrders),
            'rule_rows' => $ruleRows,
            'upsell_rows' => $upsellRows,
        ];
    }

    public function getUpsellPerformance(array $filters = []) {
        $roi = $this->getRoiReport($filters);
        $orderRows = [];
        foreach ($roi['upsell_rows'] as $row) {
            $orderRows[(int) $row['upsell_id']] = $row;
        }

        $repository = new \Sodino\Repositories\UpsellRepository();
        $rows = [];
        foreach ($repository->getAll() as $upsell) {
            $orderRow = $orderRows[(int) $upsell->id] ?? null;
            $impressions = max(0, (int) $upsell->impressions);
            $addToCartConversions = max(0, (int) $upsell->conversions);
            $orderCount = $orderRow ? (int) $orderRow['order_count'] : 0;
            $revenue = $orderRow ? (float) $orderRow['revenue'] : 0;

            $rows[] = [
                'id' => (int) $upsell->id,
                'title' => $upsell->title,
                'impressions' => $impressions,
                'add_to_cart' => $addToCartConversions,
                'orders' => $orderCount,
                'revenue' => round($revenue, 2),
                'cart_conversion_rate' => $impressions > 0 ? round(($addToCartConversions / $impressions) * 100, 2) : 0,
                'order_conversion_rate' => $impressions > 0 ? round(($orderCount / $impressions) * 100, 2) : 0,
            ];
        }

        usort($rows, function ($a, $b) {
            return $b['revenue'] <=> $a['revenue'];
        });

        return $rows;
    }

    public function getBannerPerformance(array $filters = [], array $summary = []) {
        $repository = new \Sodino\Repositories\BannerRepository();
        $purchaseCount = (int) ($summary['purchase_count'] ?? $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'purchase'])));
        $clickTotal = 0;
        foreach ($repository->getAll() as $banner) {
            $clickTotal += max(0, (int) $banner->clicks);
        }

        $rows = [];
        foreach ($repository->getAll() as $banner) {
            $impressions = max(0, (int) $banner->impressions);
            $clicks = max(0, (int) $banner->clicks);
            $estimatedOrders = $clickTotal > 0 ? round(($clicks / $clickTotal) * $purchaseCount, 2) : 0;

            $rows[] = [
                'id' => (int) $banner->id,
                'title' => $banner->title,
                'impressions' => $impressions,
                'clicks' => $clicks,
                'ctr' => $impressions > 0 ? round(($clicks / $impressions) * 100, 2) : 0,
                'estimated_orders' => $estimatedOrders,
            ];
        }

        usort($rows, function ($a, $b) {
            return $b['clicks'] <=> $a['clicks'];
        });

        return $rows;
    }

    public function getUserBehavior(array $filters = []) {
        $productViewCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'product_view']));
        $addToCartCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'add_to_cart']));
        $checkoutStartCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'checkout_start']));
        $purchaseCount = $this->eventRepository->getCount(array_merge($filters, ['event_type' => 'purchase']));

        return [
            'product_views' => $productViewCount,
            'add_to_cart' => $addToCartCount,
            'checkout_start' => $checkoutStartCount,
            'purchases' => $purchaseCount,
        ];
    }

    private function getBestRule(array $filters = []) {
        $performance = $this->getRulePerformance($filters);
        if (empty($performance)) {
            return null;
        }

        usort($performance, function ($a, $b) {
            return $b['revenue'] <=> $a['revenue'];
        });

        return $performance[0]['name'] ?? null;
    }

    private function getInsights(array $summary, array $filters = [], array $roiReport = []) {
        $insights = [];

        if (!empty($roiReport['attributed_revenue'])) {
            $insights[] = sprintf(
                __('سودینو %s فروش اثرگرفته ثبت کرده است.', 'sodino'),
                wp_strip_all_tags(wc_price((float) $roiReport['attributed_revenue']))
            );
        }

        if (!empty($summary['best_rule'])) {
            $insights[] = sprintf('%s %s', __('قانون برتر:', 'sodino'), esc_html($summary['best_rule']));
        }

        if ($summary['total_discount'] > 0 && $summary['total_revenue'] > 0) {
            $discountShare = round(($summary['total_discount'] / ($summary['total_revenue'] + $summary['total_discount'])) * 100, 2);
            $insights[] = sprintf(
                '%s %s%% %s',
                __('تخفیف‌ها باعث ایجاد', 'sodino'),
                esc_html($discountShare),
                __('درصد از درآمد شده‌اند.', 'sodino')
            );
        }

        if ($summary['conversion_rate'] > 0) {
            $insights[] = sprintf('%s %s%% %s', __('نرخ تبدیل تقریبی', 'sodino'), esc_html($summary['conversion_rate']), __('است.', 'sodino'));
        }

        if (empty($insights)) {
            $insights[] = __('هیچ دادهٔ قابل تحلیلی هنوز ثبت نشده است.', 'sodino');
        }

        return $insights;
    }

    private function getDateRange($range, $start, $end) {
        $today = current_time('Y-m-d');
        $result = [
            'start' => date('Y-m-d', strtotime($today . ' -6 days')),
            'end' => $today,
        ];

        if ($range === '30d') {
            $result['start'] = date('Y-m-d', strtotime($today . ' -29 days'));
            $result['end'] = $today;
        }

        if ($range === 'custom' && !empty($start) && !empty($end)) {
            $startTimestamp = strtotime($start);
            $endTimestamp = strtotime($end);

            if ($startTimestamp && $endTimestamp) {
                if ($endTimestamp < $startTimestamp) {
                    $endTimestamp = $startTimestamp;
                }

                $result['start'] = date('Y-m-d', $startTimestamp);
                $result['end'] = date('Y-m-d', $endTimestamp);
            }
        }

        return $result;
    }

    private function getOrdersInRange(array $filters = []) {
        if (!function_exists('wc_get_orders')) {
            return [];
        }

        $range = $this->getDateRange($filters['range'] ?? '7d', $filters['start_date'] ?? '', $filters['end_date'] ?? '');
        $start = $filters['from'] ?? $range['start'];
        $end = $filters['to'] ?? $range['end'];

        return wc_get_orders([
            'limit' => -1,
            'status' => ['completed', 'processing'],
            'date_created' => $start . '...' . $end,
            'return' => 'objects',
        ]);
    }

    private function parseIdList($value) {
        $ids = [];
        foreach (explode(',', (string) $value) as $id) {
            $id = absint(trim($id));
            if ($id > 0) {
                $ids[] = $id;
            }
        }

        return array_values(array_unique($ids));
    }

    private function getRuleName($ruleId) {
        $rule = $this->ruleRepository->getById((int) $ruleId);
        return $rule ? $rule->name : sprintf(__('قانون #%d', 'sodino'), (int) $ruleId);
    }

    private function getUpsellTitle($upsellId) {
        $repository = new \Sodino\Repositories\UpsellRepository();
        $upsell = $repository->getById((int) $upsellId);
        return $upsell ? $upsell->title : sprintf(__('آپسل #%d', 'sodino'), (int) $upsellId);
    }

    public function getProductIdsByCategory($category_id) {
        $products = get_posts([
            'post_type' => 'product',
            'numberposts' => -1,
            'fields' => 'ids',
            'tax_query' => [
                [
                    'taxonomy' => 'product_cat',
                    'field' => 'term_id',
                    'terms' => intval($category_id),
                ],
            ],
        ]);

        return $products ?: [];
    }

    public function getProductOptions() {
        $products = get_posts([
            'post_type' => 'product',
            'numberposts' => -1,
            'fields' => 'ids',
            'orderby' => 'title',
            'order' => 'ASC',
        ]);

        $options = [];
        foreach ($products as $product_id) {
            $options[] = [
                'id' => $product_id,
                'name' => get_the_title($product_id),
            ];
        }

        return $options;
    }

    public function getCategoryOptions() {
        $categories = get_terms(['taxonomy' => 'product_cat', 'hide_empty' => false]);
        $options = [];

        if (!is_wp_error($categories)) {
            foreach ($categories as $category) {
                $options[] = [
                    'id' => $category->term_id,
                    'name' => $category->name,
                ];
            }
        }

        return $options;
    }
}