# Copyright (c) 2025 Patrick Motsch
# All rights reserved.
"""
Datenbank Export-Tool für Migration.

Dieses Script exportiert alle Daten aus ALLEN PowerOn PostgreSQL-Datenbanken
in eine JSON-Datei, die als Migrationsdatensatz verwendet werden kann.

Datenbanken:
    - poweron_app        (User, Mandate, RBAC, Features, etc.)
    - poweron_chat       (Chat-Konversationen und Nachrichten)
    - poweron_management (Workflows, Prompts, Connections, etc.)
    - poweron_realestate (Real Estate Daten)
    - poweron_trustee    (Trustee Daten)

Verwendung:
    python tool_db_export_migration.py [--output <pfad>] [--pretty]

Optionen:
    --output, -o    Pfad zur Ausgabedatei (Standard: migration_export_<timestamp>.json)
    --pretty, -p    JSON formatiert ausgeben (für bessere Lesbarkeit)
    --exclude       Komma-getrennte Liste von Tabellen, die ausgeschlossen werden sollen
    --include-meta  System-Metadaten (_createdAt, _modifiedAt, etc.) beibehalten
    --db            Nur bestimmte Datenbank(en) exportieren (komma-getrennt)
"""

import os
import sys
import json
import argparse
import logging
from datetime import datetime
from typing import Dict, List, Any, Optional
from pathlib import Path

import psycopg2
import psycopg2.extras

# Logging konfigurieren
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S'
)
logger = logging.getLogger(__name__)

# Alle PowerOn Datenbanken
ALL_DATABASES = [
    "poweron_app",        # Haupt-App: User, Mandate, RBAC, Features
    "poweron_chat",       # Chat-Konversationen
    "poweron_management", # Workflows, Prompts, Connections
    "poweron_realestate", # Real Estate
    "poweron_trustee",    # Trustee
]


def _loadEnvConfig() -> Dict[str, str]:
    """Lädt die Konfiguration direkt aus der .env Datei."""
    config = {}
    envPath = Path(__file__).parent / '.env'
    
    if not envPath.exists():
        logger.warning(f"Environment file not found at {envPath}")
        return config
    
    # Versuche verschiedene Encodings
    encodings = ['utf-8', 'utf-8-sig', 'latin-1', 'cp1252']
    
    for encoding in encodings:
        try:
            with open(envPath, 'r', encoding=encoding) as f:
                for line in f:
                    line = line.strip()
                    if not line or line.startswith('#'):
                        continue
                    if '=' in line:
                        key, value = line.split('=', 1)
                        config[key.strip()] = value.strip()
            # Erfolgreich geladen
            return config
        except UnicodeDecodeError:
            continue
        except Exception as e:
            logger.error(f"Error loading .env file with {encoding}: {e}")
            continue
    
    logger.error(f"Could not load .env file with any encoding")
    return config


# Globale Konfiguration laden
_ENV_CONFIG = _loadEnvConfig()


def _getConfigValue(key: str, default: str = None) -> str:
    """Holt einen Konfigurationswert."""
    return _ENV_CONFIG.get(key, os.environ.get(key, default))


def _databaseExists(dbDatabase: str) -> bool:
    """Prüft ob eine Datenbank existiert."""
    dbHost = _getConfigValue("DB_HOST", "localhost")
    dbUser = _getConfigValue("DB_USER")
    dbPassword = _getConfigValue("DB_PASSWORD_SECRET")
    dbPort = int(_getConfigValue("DB_PORT", "5432"))
    
    try:
        # Verbinde zur postgres Datenbank um zu prüfen
        conn = psycopg2.connect(
            host=dbHost,
            port=dbPort,
            database="postgres",
            user=dbUser,
            password=dbPassword
        )
        conn.autocommit = True
        
        with conn.cursor() as cursor:
            cursor.execute(
                "SELECT 1 FROM pg_database WHERE datname = %s",
                (dbDatabase,)
            )
            exists = cursor.fetchone() is not None
        
        conn.close()
        return exists
    except Exception as e:
        logger.error(f"Fehler beim Prüfen der Datenbank {dbDatabase}: {e}")
        return False


def _getDbConnection(dbDatabase: str):
    """Erstellt eine Verbindung zu einer spezifischen PostgreSQL-Datenbank."""
    # Erst prüfen ob Datenbank existiert
    if not _databaseExists(dbDatabase):
        logger.warning(f"Datenbank '{dbDatabase}' existiert nicht - übersprungen")
        return None
    
    dbHost = _getConfigValue("DB_HOST", "localhost")
    dbUser = _getConfigValue("DB_USER")
    dbPassword = _getConfigValue("DB_PASSWORD_SECRET")
    dbPort = int(_getConfigValue("DB_PORT", "5432"))
    
    try:
        conn = psycopg2.connect(
            host=dbHost,
            port=dbPort,
            database=dbDatabase,
            user=dbUser,
            password=dbPassword,
            cursor_factory=psycopg2.extras.RealDictCursor
        )
        conn.set_client_encoding('UTF8')
        return conn
    except Exception as e:
        logger.error(f"Datenbankverbindung zu {dbDatabase} fehlgeschlagen: {e}")
        raise


def _getTables(conn) -> List[str]:
    """Gibt alle Tabellennamen in der Datenbank zurück."""
    with conn.cursor() as cursor:
        cursor.execute("""
            SELECT table_name 
            FROM information_schema.tables 
            WHERE table_schema = 'public' 
            AND table_type = 'BASE TABLE'
            ORDER BY table_name
        """)
        tables = [row["table_name"] for row in cursor.fetchall()]
    return tables


def _getTableData(conn, tableName: str, includeMeta: bool = False) -> List[Dict[str, Any]]:
    """Liest alle Daten aus einer Tabelle."""
    with conn.cursor() as cursor:
        cursor.execute(f'SELECT * FROM "{tableName}"')
        rows = cursor.fetchall()
        
        records = []
        for row in rows:
            record = dict(row)
            
            # Optional: System-Metadaten entfernen
            if not includeMeta:
                metaFields = ["_createdAt", "_modifiedAt", "_createdBy", "_modifiedBy"]
                for field in metaFields:
                    record.pop(field, None)
            
            # Konvertiere JSONB-Felder (sind bereits als Dict/List von psycopg2)
            for key, value in record.items():
                if isinstance(value, (int, float)):
                    record[key] = float(value) if isinstance(value, float) else int(value)
            
            records.append(record)
        
        return records


def _getTableRowCount(conn, tableName: str) -> int:
    """Zählt die Anzahl der Zeilen in einer Tabelle."""
    with conn.cursor() as cursor:
        cursor.execute(f'SELECT COUNT(*) as count FROM "{tableName}"')
        result = cursor.fetchone()
        return result["count"] if result else 0


def _exportSingleDatabase(
    dbDatabase: str,
    excludeTables: List[str],
    includeMeta: bool
) -> Optional[Dict[str, Any]]:
    """Exportiert eine einzelne Datenbank."""
    conn = _getDbConnection(dbDatabase)
    
    if conn is None:
        return None
    
    try:
        allTables = _getTables(conn)
        
        # System-Tabellen ausschliessen
        systemTables = ["_system"]
        tablesToExport = [
            t for t in allTables 
            if t not in systemTables and t not in excludeTables
        ]
        
        dbExport = {
            "tables": {},
            "summary": {},
            "tableCount": len(tablesToExport),
            "totalRecords": 0
        }
        
        for tableName in tablesToExport:
            try:
                records = _getTableData(conn, tableName, includeMeta)
                rowCount = len(records)
                dbExport["totalRecords"] += rowCount
                
                dbExport["tables"][tableName] = records
                dbExport["summary"][tableName] = {"recordCount": rowCount}
                
                if rowCount > 0:
                    logger.info(f"    {tableName}: {rowCount} Datensätze")
                
            except Exception as e:
                logger.error(f"    Fehler bei Tabelle {tableName}: {e}")
                dbExport["tables"][tableName] = []
                dbExport["summary"][tableName] = {"recordCount": 0, "error": str(e)}
        
        return dbExport
        
    finally:
        conn.close()


def exportDatabase(
    outputPath: Optional[str] = None,
    prettyPrint: bool = False,
    excludeTables: Optional[List[str]] = None,
    includeMeta: bool = False,
    onlyDatabases: Optional[List[str]] = None
) -> str:
    """
    Exportiert alle Datenbanken in eine JSON-Datei.
    
    Args:
        outputPath: Pfad zur Ausgabedatei (optional)
        prettyPrint: JSON formatiert ausgeben
        excludeTables: Liste von Tabellen, die ausgeschlossen werden sollen
        includeMeta: System-Metadaten beibehalten
        onlyDatabases: Nur diese Datenbanken exportieren
        
    Returns:
        Pfad zur erstellten Exportdatei
    """
    excludeTables = excludeTables or []
    
    # Welche Datenbanken exportieren?
    databasesToExport = onlyDatabases if onlyDatabases else ALL_DATABASES
    
    # Standard-Ausgabepfad generieren (im Log-Ordner)
    if not outputPath:
        timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
        logDir = _getConfigValue("APP_LOGGING_LOG_DIR")
        if logDir and os.path.isabs(logDir):
            outputDir = logDir
        else:
            outputDir = os.path.join(os.path.dirname(__file__), "local", "logs")
        os.makedirs(outputDir, exist_ok=True)
        outputPath = os.path.join(outputDir, f"migration_export_{timestamp}.json")
    
    logger.info(f"Starte Export von {len(databasesToExport)} Datenbank(en)...")
    logger.info(f"Datenbanken: {', '.join(databasesToExport)}")
    
    # Export-Struktur erstellen
    exportData = {
        "meta": {
            "exportedAt": datetime.utcnow().isoformat() + "Z",
            "exportedFrom": _getConfigValue("APP_ENV_LABEL", "unknown"),
            "version": "1.0",
            "databaseCount": 0,
            "totalTables": 0,
            "totalRecords": 0,
            "excludedTables": excludeTables,
            "includesMeta": includeMeta
        },
        "databases": {}
    }
    
    # Jede Datenbank exportieren
    for dbName in databasesToExport:
        logger.info(f"Exportiere Datenbank: {dbName}")
        
        dbExport = _exportSingleDatabase(dbName, excludeTables, includeMeta)
        
        if dbExport is not None:
            exportData["databases"][dbName] = dbExport
            exportData["meta"]["databaseCount"] += 1
            exportData["meta"]["totalTables"] += dbExport["tableCount"]
            exportData["meta"]["totalRecords"] += dbExport["totalRecords"]
            logger.info(f"  -> {dbExport['tableCount']} Tabellen, {dbExport['totalRecords']} Datensätze")
        else:
            logger.info(f"  -> Übersprungen (existiert nicht)")
    
    # JSON-Datei schreiben
    logger.info(f"Schreibe Exportdatei: {outputPath}")
    
    with open(outputPath, "w", encoding="utf-8") as f:
        if prettyPrint:
            json.dump(exportData, f, indent=2, ensure_ascii=False, default=str)
        else:
            json.dump(exportData, f, ensure_ascii=False, default=str)
    
    # Dateigrösse berechnen
    fileSize = os.path.getsize(outputPath)
    fileSizeStr = _formatFileSize(fileSize)
    
    logger.info(f"Export abgeschlossen!")
    logger.info(f"  Datenbanken: {exportData['meta']['databaseCount']}")
    logger.info(f"  Tabellen: {exportData['meta']['totalTables']}")
    logger.info(f"  Datensätze: {exportData['meta']['totalRecords']}")
    logger.info(f"  Dateigrösse: {fileSizeStr}")
    logger.info(f"  Ausgabedatei: {outputPath}")
    
    return outputPath


def _formatFileSize(sizeBytes: int) -> str:
    """Formatiert Dateigrösse in lesbares Format."""
    for unit in ['B', 'KB', 'MB', 'GB']:
        if sizeBytes < 1024:
            return f"{sizeBytes:.2f} {unit}"
        sizeBytes /= 1024
    return f"{sizeBytes:.2f} TB"


def printDatabaseSummary():
    """Zeigt eine Zusammenfassung aller Datenbanken an."""
    print("\n" + "=" * 70)
    print("DATENBANK ZUSAMMENFASSUNG - ALLE POWEREON DATENBANKEN")
    print("=" * 70)
    print(f"Umgebung: {_getConfigValue('APP_ENV_LABEL', 'unknown')}")
    print(f"Host: {_getConfigValue('DB_HOST', 'localhost')}")
    print("=" * 70)
    
    grandTotalRecords = 0
    grandTotalTables = 0
    
    for dbName in ALL_DATABASES:
        print(f"\n{dbName}")
        print("-" * 70)
        
        conn = _getDbConnection(dbName)
        if conn is None:
            print("  (Datenbank existiert nicht)")
            continue
        
        try:
            tables = _getTables(conn)
            dbTotalRecords = 0
            
            print(f"  {'Tabelle':<45} {'Datensätze':>15}")
            print(f"  {'-' * 45} {'-' * 15}")
            
            for tableName in tables:
                if tableName.startswith("_"):
                    continue  # System-Tabellen überspringen
                count = _getTableRowCount(conn, tableName)
                dbTotalRecords += count
                if count > 0:  # Nur nicht-leere Tabellen anzeigen
                    print(f"  {tableName:<45} {count:>15}")
            
            print(f"  {'-' * 45} {'-' * 15}")
            print(f"  {'Gesamt':<45} {dbTotalRecords:>15}")
            
            grandTotalRecords += dbTotalRecords
            grandTotalTables += len([t for t in tables if not t.startswith("_")])
            
        finally:
            conn.close()
    
    print("\n" + "=" * 70)
    print(f"GESAMTÜBERSICHT")
    print(f"  Datenbanken: {len(ALL_DATABASES)}")
    print(f"  Tabellen: {grandTotalTables}")
    print(f"  Datensätze: {grandTotalRecords}")
    print("=" * 70 + "\n")


def main():
    parser = argparse.ArgumentParser(
        description="Exportiert alle PowerOn Datenbank-Daten für Migration",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Datenbanken:
  poweron_app        - User, Mandate, RBAC, Features
  poweron_chat       - Chat-Konversationen
  poweron_management - Workflows, Prompts, Connections
  poweron_realestate - Real Estate Daten
  poweron_trustee    - Trustee Daten

Beispiele:
  python tool_db_export_migration.py
  python tool_db_export_migration.py --pretty
  python tool_db_export_migration.py -o backup.json --pretty
  python tool_db_export_migration.py --db poweron_app,poweron_chat
  python tool_db_export_migration.py --exclude Token,AuthEvent --include-meta
  python tool_db_export_migration.py --summary
        """
    )
    
    parser.add_argument(
        "-o", "--output",
        help="Pfad zur Ausgabedatei",
        type=str,
        default=None
    )
    
    parser.add_argument(
        "-p", "--pretty",
        help="JSON formatiert ausgeben",
        action="store_true"
    )
    
    parser.add_argument(
        "--exclude",
        help="Komma-getrennte Liste von Tabellen zum Ausschliessen",
        type=str,
        default=""
    )
    
    parser.add_argument(
        "--include-meta",
        help="System-Metadaten (_createdAt, etc.) beibehalten",
        action="store_true"
    )
    
    parser.add_argument(
        "--db",
        help="Nur bestimmte Datenbank(en) exportieren (komma-getrennt)",
        type=str,
        default=""
    )
    
    parser.add_argument(
        "--summary",
        help="Nur Zusammenfassung anzeigen (kein Export)",
        action="store_true"
    )
    
    args = parser.parse_args()
    
    # Nur Zusammenfassung anzeigen
    if args.summary:
        printDatabaseSummary()
        return
    
    # Exclude-Liste parsen
    excludeTables = []
    if args.exclude:
        excludeTables = [t.strip() for t in args.exclude.split(",") if t.strip()]
    
    # Datenbank-Liste parsen
    onlyDatabases = None
    if args.db:
        onlyDatabases = [db.strip() for db in args.db.split(",") if db.strip()]
    
    # Export durchführen
    try:
        outputPath = exportDatabase(
            outputPath=args.output,
            prettyPrint=args.pretty,
            excludeTables=excludeTables,
            includeMeta=args.include_meta,
            onlyDatabases=onlyDatabases
        )
        print(f"\n Export erfolgreich: {outputPath}\n")
        
    except Exception as e:
        logger.error(f"Export fehlgeschlagen: {e}")
        sys.exit(1)


if __name__ == "__main__":
    main()