<?php
require_once __DIR__ . '/db/config.php';

/**
 * Fetches the upline for a given user.
 *
 * @param int $userId The ID of the user.
 * @param int $levels The number of levels to fetch.
 * @return array The upline users.
 */
function get_upline($userId, $levels = 10) {
    $upline = [];
    $currentUser = $userId;

    for ($i = 0; $i < $levels; $i++) {
        $db = db();
        $stmt = $db->prepare("SELECT sponsor_id FROM users WHERE id = :id");
        $stmt->execute([':id' => $currentUser]);
        $sponsor = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($sponsor && $sponsor['sponsor_id']) {
            $upline[] = $sponsor['sponsor_id'];
            $currentUser = $sponsor['sponsor_id'];
        } else {
            break;
        }
    }

    return $upline;
}

/**
 * Calculates and distributes commissions for a given booking.
 *
 * @param int $bookingId The ID of the booking.
 */
function calculate_commissions($bookingId) {
    $db = db();
    $db->beginTransaction();

    try {
        // 1. Get booking details
        $stmt = $db->prepare("SELECT user_id, amount FROM bookings WHERE id = :booking_id AND status = 'approved'");
        $stmt->execute([':booking_id' => $bookingId]);
        $booking = $stmt->fetch(PDO::FETCH_ASSOC);

        if (!$booking) {
            throw new Exception("Booking not found or not approved.");
        }

        $bookingAmount = $booking['amount'];
        $bookingUserId = $booking['user_id'];

        // 2. Get upline
        $upline = get_upline($bookingUserId, 10);

        if (empty($upline)) {
            // No upline, nothing to do
            $db->commit();
            return;
        }

        // 3. Direct Commission (Level 10)
        $directCommission = $bookingAmount * 0.10;
        $directSponsorId = $upline[0];

        // Insert transaction for direct commission
        $stmt = $db->prepare(
            "INSERT INTO transactions (user_id, amount, type, description, related_booking_id, related_user_id) VALUES (:user_id, :amount, 'commission_direct', :description, :booking_id, :related_user_id)"
        );
        $stmt->execute([
            ':user_id' => $directSponsorId,
            ':amount' => $directCommission,
            ':description' => 'Direct commission for booking #' . $bookingId,
            ':booking_id' => $bookingId,
            ':related_user_id' => $bookingUserId
        ]);
        $directCommissionTransactionId = $db->lastInsertId();

        // Schedule passive income for the sponsor
        schedule_passive_income($directCommissionTransactionId, $directSponsorId, $directCommission, $db);

        // Update sponsor's wallet and income
        $stmt = $db->prepare("UPDATE users SET wallet_balance = wallet_balance + :amount, total_direct_income = total_direct_income + :amount WHERE id = :user_id");
        $stmt->execute([':amount' => $directCommission, ':user_id' => $directSponsorId]);

        // 4. Team Commissions (Levels 9 down to 1)
        $previousLevelCommission = $directCommission;
        for ($i = 1; $i < count($upline); $i++) {
            $teamCommission = $previousLevelCommission * 0.50;
            $uplineMemberId = $upline[$i];

            // Insert transaction for team commission
            $stmt = $db->prepare(
                "INSERT INTO transactions (user_id, amount, type, description, related_booking_id, related_user_id) VALUES (:user_id, :amount, 'commission_team', :description, :booking_id, :related_user_id)"
            );
            $stmt->execute([
                ':user_id' => $uplineMemberId,
                ':amount' => $teamCommission,
                ':description' => 'Team commission (Level ' . (10 - ($i + 1) + 1) . ') for booking #' . $bookingId,
                ':booking_id' => $bookingId,
                ':related_user_id' => $bookingUserId
            ]);

            // Update user's wallet and income
            $stmt = $db->prepare("UPDATE users SET wallet_balance = wallet_balance + :amount, total_team_income = total_team_income + :amount WHERE id = :user_id");
            $stmt->execute([':amount' => $teamCommission, ':user_id' => $uplineMemberId]);

            $previousLevelCommission = $teamCommission;
        }

        // 5. Calculate Leg Match Bonus
        calculate_leg_match_bonus($bookingUserId, $db);

        $db->commit();
        echo "Commissions calculated and distributed successfully for booking #$bookingId.";

    } catch (Exception $e) {
        $db->rollBack();
        error_log("Commission calculation failed for booking #$bookingId: " . $e->getMessage());
        // Handle or log the error appropriately
    }
}

/**
 * Calculates and distributes leg match bonuses.
 */
/**
 * Recursively calculates the total booking volume for a given user and their entire downline.
 *
 * @param int $userId The ID of the user at the top of the leg.
 * @param PDO $db The database connection.
 * @return float The total volume of the leg.
 */
function get_leg_volume($userId, $db) {
    $totalVolume = 0.0;

    // Get the user's own contribution
    $stmt = $db->prepare("SELECT cumulative_bookings FROM users WHERE id = :user_id");
    $stmt->execute([':user_id' => $userId]);
    $user = $stmt->fetch(PDO::FETCH_ASSOC);
    if ($user) {
        $totalVolume += $user['cumulative_bookings'];
    }

    // Get all directly sponsored users
    $stmt = $db->prepare("SELECT id FROM users WHERE sponsor_id = :sponsor_id");
    $stmt->execute([':sponsor_id' => $userId]);
    $downline = $stmt->fetchAll(PDO::FETCH_ASSOC);

    foreach ($downline as $downlineUser) {
        $totalVolume += get_leg_volume($downlineUser['id'], $db);
    }

    return $totalVolume;
}

/**
 * Calculates and distributes leg match bonuses.
 *
 * @param int $bookingUserId The user who made the original booking.
 * @param PDO $db The database connection.
 */
function calculate_leg_match_bonus($bookingUserId, $db) {
    // A leg match bonus is paid to the SPONSOR of the user who made the booking,
    // based on the performance of their OTHER legs.
    // The spec is "5% leg-match paid to user for every INR 10,00,000 leg milestone".
    // This implies we check the sponsor's legs.

    // Get the sponsor of the person who made the booking
    $stmt = $db->prepare("SELECT sponsor_id FROM users WHERE id = :id");
    $stmt->execute([':id' => $bookingUserId]);
    $sponsor = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$sponsor || !$sponsor['sponsor_id']) {
        return; // No sponsor, no bonus to calculate
    }
    $sponsorId = $sponsor['sponsor_id'];

    // Get all the direct downlines of the SPONSOR (these are the legs)
    $stmt = $db->prepare("SELECT id FROM users WHERE sponsor_id = :sponsor_id");
    $stmt->execute([':sponsor_id' => $sponsorId]);
    $legs = $stmt->fetchAll(PDO::FETCH_ASSOC);

    $milestoneAmount = 1000000.00;
    $bonusPercentage = 0.05;
    $bonusAmount = $milestoneAmount * $bonusPercentage;

    foreach ($legs as $leg) {
        $legUserId = $leg['id'];
        $legVolume = get_leg_volume($legUserId, $db);

        // Find out how many milestones this leg has already been paid for
        $stmt = $db->prepare("SELECT COUNT(*) as count FROM leg_milestones WHERE user_id = :user_id AND leg_user_id = :leg_user_id");
        $stmt->execute([':user_id' => $sponsorId, ':leg_user_id' => $legUserId]);
        $paidMilestonesCount = $stmt->fetch(PDO::FETCH_ASSOC)['count'];

        $achievedMilestones = floor($legVolume / $milestoneAmount);

        if ($achievedMilestones > $paidMilestonesCount) {
            $newMilestones = $achievedMilestones - $paidMilestonesCount;
            for ($i = 0; $i < $newMilestones; $i++) {
                $currentMilestoneNumber = $paidMilestonesCount + $i + 1;
                $currentMilestoneValue = $currentMilestoneNumber * $milestoneAmount;

                // 1. Pay the bonus
                $stmt = $db->prepare(
                    "INSERT INTO transactions (user_id, amount, type, description, related_user_id) VALUES (:user_id, :amount, 'leg_match_bonus', :description, :related_user_id)"
                );
                $stmt->execute([
                    ':user_id' => $sponsorId,
                    ':amount' => $bonusAmount,
                    ':description' => "Leg match bonus for leg of user #$legUserId reaching milestone ₹" . number_format($currentMilestoneValue),
                    ':related_user_id' => $legUserId
                ]);

                // 2. Update wallet
                $stmt = $db->prepare("UPDATE users SET wallet_balance = wallet_balance + :amount, total_leg_match_income = total_leg_match_income + :amount WHERE id = :user_id");
                $stmt->execute([':amount' => $bonusAmount, ':user_id' => $sponsorId]);

                // 3. Record the milestone payment
                $stmt = $db->prepare("INSERT INTO leg_milestones (user_id, leg_user_id, milestone_amount, bonus_amount) VALUES (:user_id, :leg_user_id, :milestone_amount, :bonus_amount)");
                $stmt->execute([
                    ':user_id' => $sponsorId,
                    ':leg_user_id' => $legUserId,
                    ':milestone_amount' => $currentMilestoneValue,
                    ':bonus_amount' => $bonusAmount
                ]);
            }
        }
    }
}

/**
 * Schedules passive income payments.
 */
function schedule_passive_income($directCommissionTransactionId, $userId, $directCommissionAmount, $db) {
    $passiveIncomeAmount = $directCommissionAmount * 0.005;
    $startDate = new DateTime();

    for ($i = 1; $i <= 12; $i++) {
        $paymentDate = clone $startDate;
        $paymentDate->add(new DateInterval("P{$i}M"));

        $stmt = $db->prepare(
            "INSERT INTO passive_income_schedule (transaction_id, user_id, amount, payment_date, status) VALUES (:transaction_id, :user_id, :amount, :payment_date, 'pending')"
        );
        $stmt->execute([
            ':transaction_id' => $directCommissionTransactionId,
            ':user_id' => $userId,
            ':amount' => $passiveIncomeAmount,
            ':payment_date' => $paymentDate->format('Y-m-d')
        ]);
    }
}