<?php

namespace App\Services;

use Exception;

abstract class BaseSyncService
{
    protected \PDO $pdo;
    protected array $source;
    protected int $sourceId;

    protected $logFileHandle;
    protected $logFilePath;

    public function __construct(\PDO $pdo, array $source, ?int $existingSyncLogId = null)
    {
        $this->pdo = $pdo;
        $this->source = $source;

        if (!isset($source['id']) || empty($source['id'])) {
            throw new \Exception('Source ID is required for sync service');
        }

        $this->sourceId = (int) $source['id'];
        $this->currentSyncLogId = $existingSyncLogId;

        // Create log file for this sync operation
        $this->initializeLogFile();
    }

    private function initializeLogFile(): void
    {
        $timestamp = date('Y-m-d_H-i-s');
        $sourceName = strtolower($this->source['name'] ?? 'unknown');
        $this->logFilePath = "logs/{$sourceName}_sync_{$timestamp}.log";

        // Create logs directory if it doesn't exist
        $logDir = dirname($this->logFilePath);
        if (!is_dir($logDir)) {
            mkdir($logDir, 0755, true);
        }

        $this->logFileHandle = fopen($this->logFilePath, 'w');
        if ($this->logFileHandle) {
            $this->logProgress("=== Starting {$sourceName} sync at " . date('Y-m-d H:i:s') . " ===");
        }
    }

    public function __destruct()
    {
        if ($this->logFileHandle) {
            $this->logProgress("=== Sync completed at " . date('Y-m-d H:i:s') . " ===");
            fclose($this->logFileHandle);
        }
    }

    public function startSync(string $syncType = 'full'): int
    {
        // Set higher limits for long-running syncs
        ini_set('max_execution_time', 3600); // 1 hour
        ini_set('memory_limit', '512M');

        // Use existing sync log ID if provided, otherwise create a new one
        if ($this->currentSyncLogId) {
            $syncLogId = $this->currentSyncLogId;
            // Update the existing log to 'started' status
            $this->updateSyncLog($syncLogId, 'started', [
                'sync_type' => $syncType,
                'started_at' => date('Y-m-d H:i:s')
            ]);
        } else {
            // Create sync log entry
            $syncLogId = $this->createSyncLog($syncType, 'started');
        }

        $this->currentSyncLogId = $syncLogId;

        try {
            $this->logProgress("Starting {$syncType} sync for source: " . ($this->source['display_name'] ?? $this->source['name']));

            $this->executeSync($syncType);

            // Update sync log as completed
            $this->updateSyncLog($syncLogId, 'completed', [
                'processed_items' => $this->getProcessedCount(),
                'new_items' => $this->getNewCount(),
                'updated_items' => $this->getUpdatedCount(),
                'deleted_items' => $this->getDeletedCount(),
                'message' => "Successfully completed sync"
            ]);

            $this->logProgress("Sync completed successfully");

        } catch (Exception $e) {
            // Log the full error details
            $errorMessage = $e->getMessage();
            $errorFile = $e->getFile();
            $errorLine = $e->getLine();
            $errorTrace = $e->getTraceAsString();

            $this->logProgress("CRITICAL ERROR - Sync failed: {$errorMessage}");
            $this->logProgress("Error location: {$errorFile}:{$errorLine}");
            $this->logProgress("Stack trace: {$errorTrace}");

            // Update sync log as failed with full error details
            $this->updateSyncLog($syncLogId, 'failed', [
                'message' => $errorMessage,
                'errors' => [
                    $errorMessage,
                    "File: {$errorFile}:{$errorLine}",
                    "Stack: " . substr($errorTrace, 0, 1000) // Limit trace size
                ]
            ]);

            throw $e;
        }

        return $syncLogId;
    }

    private function createSyncLog(string $syncType, string $status): int
    {
        $data = [
            'source_id' => $this->sourceId,
            'sync_type' => $syncType,
            'status' => $status,
            'total_items' => 0,
            'processed_items' => 0,
            'new_items' => 0,
            'updated_items' => 0,
            'deleted_items' => 0,
            'started_at' => date('Y-m-d H:i:s')
        ];

        $columns = array_keys($data);
        $placeholders = array_map(fn($col) => ":$col", $columns);
        $sql = "INSERT INTO sync_logs (" . implode(', ', $columns) . ") VALUES (" . implode(', ', $placeholders) . ")";

        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($data);

        return (int) $this->pdo->lastInsertId();
    }

    protected function updateSyncLog(int $syncLogId, string $status, array $stats = []): bool
    {
        $data = [
            'status' => $status,
            'processed_items' => $stats['processed_items'] ?? 0,
            'new_items' => $stats['new_items'] ?? 0,
            'updated_items' => $stats['updated_items'] ?? 0,
            'deleted_items' => $stats['deleted_items'] ?? 0,
            'completed_at' => date('Y-m-d H:i:s')
        ];

        if (!empty($stats['errors'])) {
            $data['errors'] = json_encode($stats['errors']);
        }

        if (!empty($stats['message'])) {
            $data['message'] = $stats['message'];
        }

        $setClause = array_map(fn($col) => "$col = :$col", array_keys($data));
        $sql = "UPDATE sync_logs SET " . implode(', ', $setClause) . " WHERE id = :id";
        $data['id'] = $syncLogId;

        $stmt = $this->pdo->prepare($sql);
        return $stmt->execute($data);
    }

    abstract protected function executeSync(string $syncType): void;

    protected function getProcessedCount(): int
    {
        return 0; // Override in subclasses
    }

    protected function getNewCount(): int
    {
        return 0; // Override in subclasses
    }

    protected function getUpdatedCount(): int
    {
        return 0; // Override in subclasses
    }

    protected function getDeletedCount(): int
    {
        return 0; // Override in subclasses
    }

    protected $currentSyncLogId = null;

    protected function logProgress(string $message): void
    {
        $timestamp = date('H:i:s');
        $logMessage = "[{$timestamp}] {$message}\n";

        // Write to log file if available
        if ($this->logFileHandle) {
            fwrite($this->logFileHandle, $logMessage);
        }

        // Also write to error log for immediate visibility
        error_log($message);

        // Update sync log with progress message if we have a current sync log
        if ($this->currentSyncLogId) {
            $this->updateSyncLog($this->currentSyncLogId, 'running', [
                'message' => $message
            ]);
        }
    }

    public function getLogFilePath(): string
    {
        return $this->logFilePath ?? '';
    }
}