<?php

namespace App\Services\BusinessPlan;

use App\User;
use stdClass;
use Carbon\Carbon;
use App\Models\UserBusinessStructure;
use Illuminate\Support\Facades\Log;
use Illuminate\Contracts\Logging\Log as LogContract;

/**
 * Optimierte Version der TreeCalcBot Klasse
 * 
 * Verbesserungen:
 * - Trennung von Datenzugriff (Repository Pattern)
 * - Trennung von HTML-Rendering (Renderer Pattern)
 * - Optimierte Datenbankabfragen (N+1 Problem gelöst)
 * - Memory-effiziente Verarbeitung großer Datenmengen
 * - Robuste Fehlerbehandlung mit Logging
 * - Dependency Injection für bessere Testbarkeit
 */
class TreeCalcBotOptimized
{
    private stdClass $date;
    private string $initFrom;
    private array $businessUsers = [];
    private array $parentless = [];
    private ?BusinessUserItem $businessUser = null;
    private ?BusinessUserItem $sponsor = null;
    private array $processedUserIds = [];

    private BusinessUserRepository $repository;
    private TreeHtmlRenderer $renderer;
    private LogContract $logger;

    public function __construct(
        int $month, 
        int $year, 
        string $initFrom = 'member',
        ?BusinessUserRepository $repository = null,
        ?TreeHtmlRenderer $renderer = null,
        ?LogContract $logger = null
    ) {
        $this->validateInput($month, $year);
        $this->initializeDate($month, $year);
        $this->initFrom = $initFrom;
        
        // Dependency Injection mit Fallback
        $this->repository = $repository ?? new BusinessUserRepository($month, $year);
        $this->renderer = $renderer ?? new TreeHtmlRenderer($initFrom);
        $this->logger = $logger ?? app(LogContract::class);
    }

    /**
     * Initialisiert die Business-Struktur für Admin-Ansicht
     */
    public function initStructureAdmin(bool $check = true): void
    {
        try {
            $storedStructure = null;
            
            if ($check) {
                $storedStructure = $this->repository->getStoredStructure();
            }

            if ($storedStructure) {
                $this->logger->info("Loading stored business structure for {$this->date->month}/{$this->date->year}");
                $this->loadStoredStructure($storedStructure);
            } else {
                $this->logger->info("Building fresh business structure for {$this->date->month}/{$this->date->year}");
                $this->buildFreshStructure();
            }

        } catch (\Exception $e) {
            $this->logger->error("Error initializing admin structure: " . $e->getMessage());
            throw $e;
        }
    }

    /**
     * Initialisiert die Struktur für einen spezifischen User
     */
    public function initStructureUser(int $userId): void
    {
        try {
            $this->logger->info("Initializing structure for user: {$userId}");
            
            $user = $this->repository->getUserWithRelations($userId);
            if (!$user) {
                $this->logger->warning("User not found: {$userId}");
                return;
            }

            $businessUserItem = new BusinessUserItemOptimized($this->date);
            $businessUserItem->makeUserFromModel($user); // ✅ Nutzt bereits geladene Relations
            $this->addUserIdToProcessed($userId);
            $this->businessUsers[] = $businessUserItem;

            $storedStructure = $this->repository->getStoredStructure();
            if ($storedStructure) {
                $this->loadStoredParentsUsers($storedStructure);
                if (isset($this->businessUsers[0]) && $this->businessUsers[0]->sponsor) {
                    $this->loadStoredSponsorUser($this->businessUsers[0]->sponsor->user_id);
                }
            } else {
                $this->loadParentsUsers();
                $this->loadSponsorUser($userId);
            }

        } catch (\Exception $e) {
            $this->logger->error("Error initializing user structure for {$userId}: " . $e->getMessage());
            throw $e;
        }
    }

    /**
     * Initialisiert detaillierte Business-User-Informationen
     */
    public function initBusinesslUserDetail(User $user): void
    {
        try {
            $this->logger->info("Initializing business user details for: {$user->id}");
            
            $this->businessUser = new BusinessUserItemOptimized($this->date);
            $this->businessUser->makeUserFromModel($user); // ✅ Nutzt bereits User-Objekt
            $this->businessUser->checkSponsor($user);
            
            if (!$this->businessUser->isSave()) {
                // Aufbau der Struktur für den User in die unendliche Tiefe
                $this->businessUser->readParentsBusinessUsers();
                
                // Calculate Points in Lines (optimiert für Memory-Effizienz)
                if (count($this->businessUser->businessUserItems) > 0) {
                    $this->calculateUserPointsOptimized($this->businessUser->businessUserItems, 1);
                }
                
                // Qualifikation nach qual_kp (KundenPoints) und qual_pp (PaylinePoints)
                $this->businessUser->calcQualPP();
            }

        } catch (\Exception $e) {
            $this->logger->error("Error initializing business user details for {$user->id}: " . $e->getMessage());
            throw $e;
        }
    }

    /**
     * Gibt Growth Bonus zurück (ab Linie 6)
     */
    public function getGrowthBonus(): array
    {
        if (!$this->businessUser || !$this->businessUser->business_lines) {
            return [];
        }

        if (count($this->businessUser->business_lines) > 6) {
            $bLines = $this->businessUser->business_lines->toArray();
            return array_slice($bLines, 6);
        }
        
        return [];
    }

    /**
     * Gibt Wert für spezifische Linie zurück
     */
    public function getKeybyLine(int $line, string $key)
    {
        if (!$this->businessUser || !$this->businessUser->business_lines) {
            return 0;
        }

        $bLines = $this->businessUser->business_lines;
        if (!isset($bLines[$line])) {
            return 0;
        }

        $lineData = $bLines[$line];
        
        if ($lineData instanceof stdClass) {
            return $lineData->{$key} ?? 0;
        }
        
        if (is_array($lineData)) {
            return $lineData[$key] ?? 0;
        }

        return 0;
    }

    /**
     * HTML-Rendering Methoden (Delegation an Renderer)
     */
    public function makeHtmlTree(): string
    {
        return $this->renderer->renderTree($this->businessUsers);
    }

    public function makeParentlessHtml(): string
    {
        return $this->renderer->renderParentless($this->parentless);
    }

    public function makeSponsorHtml(): string
    {
        return $this->renderer->renderSponsor($this->sponsor);
    }

    /**
     * Getter-Methoden (Rückwärtskompatibilität)
     */
    public function getItems(): array
    {
        return $this->businessUsers;
    }

    public function isParentless(): bool
    {
        return !empty($this->parentless);
    }

    /**
     * Static Methoden (Rückwärtskompatibilität)
     */
    public static function isFromStored(int $month, int $year): ?UserBusinessStructure
    {
        $structure = UserBusinessStructure::where('year', $year)
            ->where('month', $month)
            ->first();

        return ($structure && $structure->completed) ? $structure : null;
    }

    public static function addUserID(int $id): void
    {
        // Deprecated: Wird durch Instanz-Methode ersetzt
        // Bleibt für Rückwärtskompatibilität erhalten
    }

    // ===== Private Methoden =====

    /**
     * Validiert Eingabeparameter
     */
    private function validateInput(int $month, int $year): void
    {
        if ($month < 1 || $month > 12) {
            throw new \InvalidArgumentException("Invalid month: {$month}");
        }

        $currentYear = (int) date('Y');
        if ($year < 2020 || $year > $currentYear + 1) {
            throw new \InvalidArgumentException("Invalid year: {$year}");
        }
    }

    /**
     * Initialisiert Datums-Objekt
     */
    private function initializeDate(int $month, int $year): void
    {
        $this->date = new stdClass();
        $date = Carbon::parse($year . '-' . $month . '-1');
        $this->date->month = $month;
        $this->date->year = $year;
        $this->date->start_date = $date->format('Y-m-d H:i:s');
        $this->date->end_date = $date->endOfMonth()->format('Y-m-d H:i:s');
    }

    /**
     * Lädt gespeicherte Struktur
     */
    private function loadStoredStructure(UserBusinessStructure $structure): void
    {
        $this->loadStoredRootUsers($structure);
        $this->loadStoredParentsUsers($structure);
        $this->loadStoredParentlessUsers($structure);
    }

    /**
     * Baut frische Struktur auf
     */
    private function buildFreshStructure(): void
    {
        $this->loadRootUsers();
        $this->loadParentsUsers();
        $this->loadParentlessUsers();
    }

    /**
     * Lädt Root-Users (optimiert mit Memory-Monitoring)
     */
    private function loadRootUsers(): void
    {
        $startMemory = memory_get_usage();
        $users = $this->repository->getRootUsers();
        
        foreach ($users as $user) {
            // Memory-Check vor jeder User-Verarbeitung
            $this->checkMemoryUsage('loadRootUsers', $user->id);
            
            $businessUserItem = new BusinessUserItemOptimized($this->date);
            $businessUserItem->makeUserFromModel($user); // ✅ Nutzt bereits geladene Relations
            $this->addUserIdToProcessed($user->id);
            $this->businessUsers[] = $businessUserItem;
        }

        $endMemory = memory_get_usage();
        $memoryUsed = $this->formatBytes($endMemory - $startMemory);
        
        $this->logger->info("Loaded " . count($users) . " root users with optimized relations. Memory used: {$memoryUsed}");
    }

    /**
     * Lädt Parent-Users für alle Business-Users
     */
    private function loadParentsUsers(): void
    {
        foreach ($this->businessUsers as $businessUser) {
            $businessUser->readParentsBusinessUsers();
        }
    }

    /**
     * Lädt parentlose Users (Memory-optimiert)
     */
    private function loadParentlessUsers(): void
    {
        $count = 0;
        $excludeIds = array_keys($this->processedUserIds);
        
        foreach ($this->repository->getParentlessUsers($excludeIds) as $user) {
            $businessUserItem = new BusinessUserItemOptimized($this->date);
            $businessUserItem->makeUserFromModel($user); // ✅ Nutzt bereits geladene Relations
            $this->parentless[] = $businessUserItem;
            $count++;
        }

        $this->logger->info("Loaded {$count} parentless users with optimized relations");
    }

    /**
     * Lädt Sponsor für User
     */
    private function loadSponsorUser(int $userId): void
    {
        try {
            $sponsorUser = $this->repository->getSponsorForUser($userId);
            
            if ($sponsorUser) {
                $this->sponsor = new BusinessUserItem($this->date);
                $this->sponsor->makeUser($sponsorUser->id);
                $this->logger->info("Loaded sponsor {$sponsorUser->id} for user {$userId}");
            }
        } catch (\Exception $e) {
            $this->logger->warning("Could not load sponsor for user {$userId}: " . $e->getMessage());
        }
    }

    /**
     * Gespeicherte Root-Users laden
     */
    private function loadStoredRootUsers(UserBusinessStructure $structure): void
    {
        if (!$structure->structure) {
            return;
        }

        foreach ($structure->structure as $obj) {
            $businessUserItem = new BusinessUserItem($this->date);
            $businessUserItem->makeUser($obj->user_id);
            $this->addUserIdToProcessed($obj->user_id);
            $this->businessUsers[] = $businessUserItem;
        }
    }

    /**
     * Gespeicherte Parent-Users laden
     */
    private function loadStoredParentsUsers(UserBusinessStructure $structure): void
    {
        foreach ($this->businessUsers as $businessUser) {
            $businessUser->readStoredParentsBusinessUsers($structure->structure);
        }
    }

    /**
     * Gespeicherte parentlose Users laden
     */
    private function loadStoredParentlessUsers(UserBusinessStructure $structure): void
    {
        if (!$structure->parentless) {
            return;
        }

        foreach ($structure->parentless as $obj) {
            if (!isset($this->processedUserIds[$obj->user_id])) {
                $businessUserItem = new BusinessUserItem($this->date);
                $businessUserItem->makeUser($obj->user_id);
                $this->parentless[] = $businessUserItem;
            }
        }
    }

    /**
     * Gespeicherten Sponsor laden
     */
    private function loadStoredSponsorUser(int $userId): void
    {
        $this->sponsor = new BusinessUserItem($this->date);
        $this->sponsor->makeUser($userId);
    }

    /**
     * Optimierte Punkte-Berechnung (Stack-basiert mit korrekter Depth-First Reihenfolge)
     * 
     * KRITISCH: Stack muss gleiche Reihenfolge wie Original-Rekursion produzieren
     * Original: Depth-First Traversierung (erst tief, dann Punkte addieren)
     * Stack: Muss umgekehrt arbeiten - erst alle Kinder sammeln, dann von tief zu flach verarbeiten
     */
    private function calculateUserPointsOptimized(array $businessUserItems, int $startLine): void
    {
        $processingStack = [];
        $collectionStack = []; // Sammelt Items in korrekter Reihenfolge
        
        // Phase 1: Sammle alle Items in Depth-First Reihenfolge
        foreach ($businessUserItems as $item) {
            $collectionStack[] = ['item' => $item, 'line' => $startLine, 'depth' => 0];
        }

        // Expandiere alle Kinder (Depth-First)
        $processedItems = [];
        while (!empty($collectionStack)) {
            $current = array_shift($collectionStack); // FIFO für Breadth-First Sammlung
            $item = $current['item'];
            $line = $current['line'];
            $depth = $current['depth'];
            
            // Markiere für Verarbeitung (mit Tiefe für spätere Sortierung)
            $processingStack[] = [
                'item' => $item, 
                'line' => $line, 
                'depth' => $depth,
                'id' => $item->user_id ?? uniqid()
            ];

            // Füge Kinder hinzu (werden später verarbeitet = Depth-First)
            if (isset($item->businessUserItems) && count($item->businessUserItems) > 0) {
                // Kinder in umgekehrter Reihenfolge hinzufügen für korrekte Stack-Verarbeitung
                $children = array_reverse($item->businessUserItems);
                foreach ($children as $childItem) {
                    array_unshift($collectionStack, [
                        'item' => $childItem, 
                        'line' => $line + 1, 
                        'depth' => $depth + 1
                    ]);
                }
            }
        }

        // Phase 2: Sortiere nach Tiefe (tiefste zuerst, wie bei Rekursion)
        usort($processingStack, function($a, $b) {
            return $b['depth'] <=> $a['depth']; // Tiefste zuerst
        });

        // Phase 3: Verarbeite in korrekter Reihenfolge (von tief zu flach)
        foreach ($processingStack as $current) {
            $item = $current['item'];
            $line = $current['line'];

            try {
                // Business Line initialisieren falls nötig
                if (!isset($this->businessUser->business_lines[$line])) {
                    $obj = new stdClass();
                    $obj->points = 0;
                    $this->businessUser->addBusinessLineToUser($line, $obj);
                }

                // Punkte hinzufügen (mit Validierung)
                $points = (float) ($item->sales_volume_points_TP_sum ?? 0);
                if ($points > 0) {
                    $this->businessUser->addBusinessLinePoints($line, $points);
                    $this->businessUser->addTotalTP($points);
                }

                $this->logger->debug("Processed user {$current['id']} at line {$line} with {$points} points");

            } catch (\Exception $e) {
                $this->logger->error("Error processing user points for {$current['id']}: " . $e->getMessage());
            }
        }

        $this->logger->info("Processed " . count($processingStack) . " business user items in depth-first order");
    }

    /**
     * User-ID zu verarbeiteten IDs hinzufügen
     */
    private function addUserIdToProcessed(int $id): void
    {
        $this->processedUserIds[$id] = true;
    }

    /**
     * Prüft ob User bereits verarbeitet wurde
     */
    private function isUserProcessed(int $id): bool
    {
        return isset($this->processedUserIds[$id]);
    }

    /**
     * Memory-Monitoring Methoden
     */
    private function checkMemoryUsage(string $operation, $identifier = null): void
    {
        $currentMemory = memory_get_usage();
        $memoryLimit = $this->parseMemoryLimit(ini_get('memory_limit'));
        $memoryPercent = ($currentMemory / $memoryLimit) * 100;

        if ($memoryPercent > 80) {
            $currentFormatted = $this->formatBytes($currentMemory);
            $limitFormatted = $this->formatBytes($memoryLimit);
            
            $this->logger->warning("High memory usage detected in {$operation}", [
                'identifier' => $identifier,
                'current_memory' => $currentFormatted,
                'memory_limit' => $limitFormatted,
                'usage_percent' => round($memoryPercent, 2)
            ]);

            // Garbage Collection bei hohem Memory-Verbrauch
            if ($memoryPercent > 90) {
                $this->logger->warning("Critical memory usage - forcing garbage collection");
                gc_collect_cycles();
            }
        }
    }

    private function parseMemoryLimit(string $limit): int
    {
        $limit = trim($limit);
        $last = strtolower($limit[strlen($limit)-1]);
        $number = (int) $limit;

        switch($last) {
            case 'g': $number *= 1024;
            case 'm': $number *= 1024;
            case 'k': $number *= 1024;
        }

        return $number;
    }

    private function formatBytes(int $bytes, int $precision = 2): string
    {
        $units = array('B', 'KB', 'MB', 'GB', 'TB');

        for ($i = 0; $bytes > 1024 && $i < count($units) - 1; $i++) {
            $bytes /= 1024;
        }

        return round($bytes, $precision) . ' ' . $units[$i];
    }

    /**
     * Public Properties für Rückwärtskompatibilität
     */
    public function __get(string $name)
    {
        switch ($name) {
            case 'date':
                return $this->date;
            case 'business_user':
                return $this->businessUser;
            case 'business_users':
                return $this->businessUsers;
            case 'parentless':
                return $this->parentless;
            default:
                throw new \InvalidArgumentException("Property {$name} does not exist");
        }
    }

    public function __set(string $name, $value)
    {
        switch ($name) {
            case 'business_users':
                $this->businessUsers = $value;
                break;
            case 'parentless':
                $this->parentless = $value;
                break;
            default:
                throw new \InvalidArgumentException("Property {$name} cannot be set");
        }
    }
}