"""
Backup System API Router
REST endpoints for backup management
"""

import logging
from typing import List, Optional
from datetime import datetime, date, timedelta
from pathlib import Path
from fastapi import APIRouter, HTTPException, Query, UploadFile, File
from pydantic import BaseModel, Field

from app.core.database import execute_query, execute_update, execute_insert
from app.core.config import settings
from app.backups.backend.service import backup_service
from app.backups.backend.notifications import notifications

logger = logging.getLogger(__name__)

router = APIRouter()


# Pydantic Models
class BackupCreate(BaseModel):
    """Request model for creating a new backup"""
    job_type: str = Field(..., description="Type of backup: database, files, or full")
    is_monthly: bool = Field(False, description="Create monthly backup (uses SQL format)")


class BackupJob(BaseModel):
    """Response model for backup job"""
    id: int
    job_type: str
    status: str
    backup_format: str
    file_path: Optional[str]
    file_size_bytes: Optional[int]
    checksum_sha256: Optional[str]
    is_monthly: bool
    includes_uploads: bool
    includes_logs: bool
    includes_data: bool
    started_at: Optional[datetime]
    completed_at: Optional[datetime]
    error_message: Optional[str]
    retention_until: Optional[date]
    offsite_uploaded_at: Optional[datetime]
    offsite_retry_count: int
    notification_sent: bool
    created_at: datetime
    updated_at: datetime


class RestoreRequest(BaseModel):
    """Request model for restoring from backup"""
    confirmation: bool = Field(..., description="Must be true to confirm restore operation")
    message: Optional[str] = Field(None, description="Optional restore reason/notes")


class MaintenanceStatus(BaseModel):
    """Response model for maintenance mode status"""
    maintenance_mode: bool
    maintenance_message: str
    maintenance_eta_minutes: Optional[int]
    updated_at: datetime


class NotificationRecord(BaseModel):
    """Response model for notification record"""
    id: int
    backup_job_id: Optional[int]
    event_type: str
    message: str
    sent_at: datetime
    acknowledged: bool
    acknowledged_at: Optional[datetime]


class StorageStats(BaseModel):
    """Response model for storage statistics"""
    total_size_bytes: int
    total_size_gb: float
    max_size_gb: int
    usage_pct: float
    file_count: int
    warning: bool


# API Endpoints

@router.post("/backups", response_model=dict, tags=["Backups"])
async def create_backup(backup: BackupCreate):
    """
    Create a new backup manually
    
    - **job_type**: database, files, or full
    - **is_monthly**: Use plain SQL format for database (monthly backups)
    """
    if not settings.BACKUP_ENABLED:
        raise HTTPException(status_code=503, detail="Backup system is disabled (BACKUP_ENABLED=false)")
    
    logger.info("📦 Manual backup requested: type=%s, monthly=%s", backup.job_type, backup.is_monthly)
    
    try:
        if backup.job_type == 'database':
            job_id = await backup_service.create_database_backup(is_monthly=backup.is_monthly)
            if job_id:
                return {"success": True, "job_id": job_id, "message": "Database backup created successfully"}
            else:
                raise HTTPException(status_code=500, detail="Database backup failed - check logs")
        
        elif backup.job_type == 'files':
            job_id = await backup_service.create_files_backup()
            if job_id:
                return {"success": True, "job_id": job_id, "message": "Files backup created successfully"}
            else:
                raise HTTPException(status_code=500, detail="Files backup failed - check logs")
        
        elif backup.job_type == 'full':
            db_job_id, files_job_id = await backup_service.create_full_backup(is_monthly=backup.is_monthly)
            if db_job_id and files_job_id:
                return {
                    "success": True,
                    "db_job_id": db_job_id,
                    "files_job_id": files_job_id,
                    "message": "Full backup created successfully"
                }
            else:
                raise HTTPException(status_code=500, detail=f"Full backup partially failed: db={db_job_id}, files={files_job_id}")
        
        else:
            raise HTTPException(status_code=400, detail="Invalid job_type. Must be: database, files, or full")
    
    except Exception as e:
        logger.error("❌ Manual backup error: %s", str(e), exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))


@router.get("/backups/jobs", response_model=List[BackupJob], tags=["Backups"])
async def list_backups(
    status: Optional[str] = Query(None, description="Filter by status: pending, running, completed, failed"),
    job_type: Optional[str] = Query(None, description="Filter by type: database, files, full"),
    limit: int = Query(50, ge=1, le=500),
    offset: int = Query(0, ge=0)
):
    """
    List backup jobs with optional filtering and pagination
    """
    # Build query
    query = "SELECT * FROM backup_jobs WHERE 1=1"
    params = []
    
    if status:
        query += " AND status = %s"
        params.append(status)
    
    if job_type:
        query += " AND job_type = %s"
        params.append(job_type)
    
    query += " ORDER BY created_at DESC LIMIT %s OFFSET %s"
    params.extend([limit, offset])
    
    backups = execute_query_single(query, tuple(params))
    
    return backups if backups else []


@router.get("/backups/jobs/{job_id}", response_model=BackupJob, tags=["Backups"])
async def get_backup(job_id: int):
    """Get details of a specific backup job"""
    backup = execute_query(
        "SELECT * FROM backup_jobs WHERE id = %s",
        (job_id,))
    
    if not backup:
        raise HTTPException(status_code=404, detail=f"Backup job {job_id} not found")
    
    return backup


@router.post("/backups/upload", response_model=dict, tags=["Backups"])
async def upload_backup(
    file: UploadFile = File(...),
    backup_type: str = Query(..., description="Type: database or files"),
    is_monthly: bool = Query(False, description="Mark as monthly backup")
):
    """
    Upload a previously downloaded backup file
    
    Validates file format and creates backup job record
    """
    if settings.BACKUP_READ_ONLY:
        raise HTTPException(
            status_code=403,
            detail="Upload blocked: BACKUP_READ_ONLY=true"
        )
    
    logger.info("📤 Backup upload: filename=%s, type=%s, size=%d bytes",
               file.filename, backup_type, file.size if hasattr(file, 'size') else 0)
    
    # Validate file type
    allowed_extensions = {
        'database': ['.dump', '.sql', '.sql.gz'],
        'files': ['.tar.gz', '.tgz']
    }
    
    if backup_type not in allowed_extensions:
        raise HTTPException(status_code=400, detail="Invalid backup_type. Must be: database or files")
    
    file_ext = ''.join(Path(file.filename).suffixes)
    if file_ext not in allowed_extensions[backup_type]:
        raise HTTPException(
            status_code=400,
            detail=f"Invalid file extension '{file_ext}' for type '{backup_type}'. Allowed: {allowed_extensions[backup_type]}"
        )
    
    try:
        # Determine storage path and format
        backup_dir = Path(settings.BACKUP_STORAGE_PATH)
        
        if backup_type == 'database':
            target_dir = backup_dir / "database"
            backup_format = 'dump' if file_ext == '.dump' else 'sql'
        else:
            target_dir = backup_dir / "files"
            backup_format = 'tar.gz'
        
        target_dir.mkdir(parents=True, exist_ok=True)
        
        # Generate unique filename with timestamp
        timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
        original_name = Path(file.filename).stem
        new_filename = f"{original_name}_uploaded_{timestamp}{file_ext}"
        target_path = target_dir / new_filename
        
        # Save uploaded file
        logger.info("💾 Saving upload to: %s", target_path)
        
        content = await file.read()
        with open(target_path, 'wb') as f:
            f.write(content)
        
        file_size = target_path.stat().st_size
        
        # Calculate checksum
        import hashlib
        checksum = hashlib.sha256(content).hexdigest()
        
        logger.info("✅ File saved: %d bytes, checksum=%s", file_size, checksum[:16])
        
        # Calculate retention date
        if is_monthly:
            retention_until = datetime.now() + timedelta(days=settings.MONTHLY_KEEP_MONTHS * 30)
        else:
            retention_until = datetime.now() + timedelta(days=settings.RETENTION_DAYS)
        
        # Create backup job record
        job_id = execute_insert(
            """INSERT INTO backup_jobs 
               (job_type, status, backup_format, file_path, file_size_bytes, 
                checksum_sha256, is_monthly, started_at, completed_at, retention_until)
               VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)""",
            (backup_type, 'completed', backup_format, str(target_path), file_size,
             checksum, is_monthly, datetime.now(), datetime.now(), retention_until.date())
        )
        
        logger.info("✅ Backup upload registered: job_id=%s", job_id)
        
        return {
            "success": True,
            "job_id": job_id,
            "message": f"Backup uploaded successfully: {new_filename}",
            "file_size_mb": round(file_size / 1024 / 1024, 2),
            "checksum": checksum
        }
    
    except Exception as e:
        logger.error("❌ Upload failed: %s", str(e), exc_info=True)
        # Clean up partial file
        if target_path.exists():
            target_path.unlink()
        raise HTTPException(status_code=500, detail=f"Upload failed: {str(e)}")


@router.post("/backups/restore/{job_id}", response_model=dict, tags=["Backups"])
async def restore_backup(job_id: int, request: RestoreRequest):
    """
    Restore from a backup (database or files)
    
    **WARNING**: This will enable maintenance mode and temporarily shut down the system
    """
    if not request.confirmation:
        raise HTTPException(
            status_code=400,
            detail="Restore operation requires confirmation=true"
        )
    
    if settings.BACKUP_READ_ONLY:
        raise HTTPException(
            status_code=403,
            detail="Restore blocked: BACKUP_READ_ONLY=true. Update configuration to enable restores."
        )
    
    # Get backup job
    backup = execute_query_single(
        "SELECT * FROM backup_jobs WHERE id = %s",
        (job_id,))
    
    if not backup:
        raise HTTPException(status_code=404, detail=f"Backup job {job_id} not found")
    
    if backup['status'] != 'completed':
        raise HTTPException(status_code=400, detail=f"Cannot restore from backup with status: {backup['status']}")
    
    logger.warning("🔧 Restore initiated: job_id=%s, type=%s, user_message=%s",
                  job_id, backup['job_type'], request.message)
    
    try:
        # Send notification
        await notifications.send_restore_started(
            job_id=job_id,
            backup_name=backup['file_path'].split('/')[-1],
            eta_minutes=5
        )
        
        # Perform restore based on type
        if backup['job_type'] == 'database':
            success = await backup_service.restore_database(job_id)
        elif backup['job_type'] == 'files':
            success = await backup_service.restore_files(job_id)
        elif backup['job_type'] == 'full':
            # Restore both database and files
            db_success = await backup_service.restore_database(job_id)
            files_success = await backup_service.restore_files(job_id)
            success = db_success and files_success
        else:
            raise HTTPException(status_code=400, detail=f"Unknown backup type: {backup['job_type']}")
        
        if success:
            logger.info("✅ Restore completed successfully: job_id=%s", job_id)
            return {"success": True, "message": "Restore completed successfully"}
        else:
            logger.error("❌ Restore failed: job_id=%s", job_id)
            raise HTTPException(status_code=500, detail="Restore operation failed - check logs")
    
    except Exception as e:
        logger.error("❌ Restore error: %s", str(e), exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/backups/jobs/{job_id}", response_model=dict, tags=["Backups"])
async def delete_backup(job_id: int):
    """
    Delete a backup job and its associated file
    """
    # Get backup job
    backup = execute_query_single(
        "SELECT * FROM backup_jobs WHERE id = %s",
        (job_id,))
    
    if not backup:
        raise HTTPException(status_code=404, detail=f"Backup job {job_id} not found")
    
    logger.info("🗑️ Deleting backup: job_id=%s, file=%s", job_id, backup['file_path'])
    
    try:
        # Delete file if exists
        from pathlib import Path
        if backup['file_path']:
            file_path = Path(backup['file_path'])
            if file_path.exists():
                file_path.unlink()
                logger.info("✅ Deleted backup file: %s", file_path.name)
        
        # Delete database record
        execute_update("DELETE FROM backup_jobs WHERE id = %s", (job_id,))
        
        return {"success": True, "message": f"Backup {job_id} deleted successfully"}
    
    except Exception as e:
        logger.error("❌ Delete backup error: %s", str(e), exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/backups/offsite/{job_id}", response_model=dict, tags=["Backups"])
async def upload_offsite(job_id: int):
    """
    Manually trigger offsite upload for a specific backup
    """
    if not settings.OFFSITE_ENABLED:
        raise HTTPException(status_code=503, detail="Offsite uploads are disabled (OFFSITE_ENABLED=false)")
    
    logger.info("☁️ Manual offsite upload requested: job_id=%s", job_id)
    
    try:
        success = await backup_service.upload_offsite(job_id)
        
        if success:
            return {"success": True, "message": f"Backup {job_id} uploaded to offsite successfully"}
        else:
            raise HTTPException(status_code=500, detail="Offsite upload failed - check logs")
    
    except Exception as e:
        logger.error("❌ Manual offsite upload error: %s", str(e), exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))


@router.get("/backups/maintenance", response_model=MaintenanceStatus, tags=["System"])
async def get_maintenance_status():
    """
    Get current maintenance mode status
    
    Used by frontend to display maintenance overlay
    """
    status = execute_query_single(
        "SELECT * FROM system_status WHERE id = 1")
    
    if not status:
        # Return default status if not found
        return {
            "maintenance_mode": False,
            "maintenance_message": "",
            "maintenance_eta_minutes": None,
            "updated_at": datetime.now()
        }
    
    return status


@router.get("/backups/notifications", response_model=List[NotificationRecord], tags=["Backups"])
async def list_notifications(
    acknowledged: Optional[bool] = Query(None, description="Filter by acknowledged status"),
    limit: int = Query(50, ge=1, le=200),
    offset: int = Query(0, ge=0)
):
    """
    List backup notifications (alerts, warnings, errors)
    """
    query = "SELECT * FROM backup_notifications WHERE 1=1"
    params = []
    
    if acknowledged is not None:
        query += " AND acknowledged = %s"
        params.append(acknowledged)
    
    query += " ORDER BY sent_at DESC LIMIT %s OFFSET %s"
    params.extend([limit, offset])
    
    notifications_list = execute_query(query, tuple(params))
    
    return notifications_list if notifications_list else []


@router.post("/backups/notifications/{notification_id}/acknowledge", response_model=dict, tags=["Backups"])
async def acknowledge_notification(notification_id: int):
    """
    Acknowledge a notification (mark as read)
    """
    execute_update(
        """UPDATE backup_notifications 
           SET acknowledged = true, acknowledged_at = %s
           WHERE id = %s""",
        (datetime.now(), notification_id)
    )
    
    return {"success": True, "message": f"Notification {notification_id} acknowledged"}


@router.get("/backups/storage", response_model=StorageStats, tags=["System"])
async def get_storage_stats():
    """
    Get backup storage usage statistics
    """
    stats = await backup_service.check_storage_usage()
    return stats


@router.get("/backups/scheduler/status", response_model=dict, tags=["System"])
async def get_scheduler_status():
    """
    Get backup scheduler status and job information
    """
    from app.backups.backend.scheduler import backup_scheduler
    
    if not backup_scheduler.running:
        return {
            "enabled": settings.BACKUP_ENABLED,
            "running": False,
            "message": "Backup scheduler is not running"
        }
    
    jobs = []
    for job in backup_scheduler.scheduler.get_jobs():
        jobs.append({
            "id": job.id,
            "name": job.name,
            "next_run": job.next_run_time.isoformat() if job.next_run_time else None,
        })
    
    return {
        "enabled": settings.BACKUP_ENABLED,
        "running": backup_scheduler.running,
        "jobs": jobs
    }