from fastapi import APIRouter, HTTPException, Depends, File, UploadFile, Form, Path, Request, status, Query, Response, Body
from fastapi.responses import JSONResponse
from typing import List, Dict, Any, Optional
import logging
import json

# Import auth module
from modules.auth import limiter, getCurrentUser

# Import interfaces
import modules.interfaces.interfaceDbComponentObjects as interfaceDbComponentObjects
from modules.datamodels.datamodelFiles import FileItem, FilePreview
from modules.shared.attributeUtils import getModelAttributeDefinitions
from modules.datamodels.datamodelUam import User
from modules.datamodels.datamodelPagination import PaginationParams, PaginatedResponse, PaginationMetadata, normalize_pagination_dict

# Configure logger
logger = logging.getLogger(__name__)

# Model attributes for FileItem
fileAttributes = getModelAttributeDefinitions(FileItem)

# Create router for file endpoints
router = APIRouter(
    prefix="/api/files",
    tags=["Manage Files"],
    responses={
        404: {"description": "Not found"}, 
        400: {"description": "Bad request"},
        401: {"description": "Unauthorized"},
        403: {"description": "Forbidden"},
        500: {"description": "Internal server error"}
    }
)

@router.get("/list", response_model=PaginatedResponse[FileItem])
@limiter.limit("30/minute")
async def get_files(
    request: Request,
    pagination: Optional[str] = Query(None, description="JSON-encoded PaginationParams object"),
    currentUser: User = Depends(getCurrentUser)
) -> PaginatedResponse[FileItem]:
    """
    Get files with optional pagination, sorting, and filtering.
    
    Query Parameters:
    - pagination: JSON-encoded PaginationParams object, or None for no pagination
    
    Examples:
    - GET /api/files/list (no pagination - returns all items)
    - GET /api/files/list?pagination={"page":1,"pageSize":10,"sort":[]}
    - GET /api/files/list?pagination={"page":2,"pageSize":20,"sort":[{"field":"fileName","direction":"asc"}]}
    """
    try:
        # Parse pagination parameter
        paginationParams = None
        if pagination:
            try:
                paginationDict = json.loads(pagination)
                if paginationDict:
                    # Normalize pagination dict (handles top-level "search" field)
                    paginationDict = normalize_pagination_dict(paginationDict)
                    paginationParams = PaginationParams(**paginationDict)
            except (json.JSONDecodeError, ValueError) as e:
                raise HTTPException(
                    status_code=400,
                    detail=f"Invalid pagination parameter: {str(e)}"
                )
        
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        result = managementInterface.getAllFiles(pagination=paginationParams)
        
        # If pagination was requested, result is PaginatedResult
        # If no pagination, result is List[FileItem]
        if paginationParams:
            return PaginatedResponse(
                items=result.items,
                pagination=PaginationMetadata(
                    currentPage=paginationParams.page,
                    pageSize=paginationParams.pageSize,
                    totalItems=result.totalItems,
                    totalPages=result.totalPages,
                    sort=paginationParams.sort,
                    filters=paginationParams.filters
                )
            )
        else:
            return PaginatedResponse(
                items=result,
                pagination=None
            )
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error getting files: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to get files: {str(e)}"
        )

@router.post("/upload", status_code=status.HTTP_201_CREATED)
@limiter.limit("10/minute")
async def upload_file(
    request: Request,
    file: UploadFile = File(...),
    workflowId: Optional[str] = Form(None),
    currentUser: User = Depends(getCurrentUser)
) -> JSONResponse:
    # Add fileName property to UploadFile for consistency with backend model
    file.fileName = file.filename
    """Upload a file"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Read file
        fileContent = await file.read()
        
        # Check size limits
        maxSize = int(interfaceDbComponentObjects.APP_CONFIG.get("File_Management_MAX_UPLOAD_SIZE_MB")) * 1024 * 1024  # in bytes
        if len(fileContent) > maxSize:
            raise HTTPException(
                status_code=status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
                detail=f"File too large. Maximum size: {interfaceDbComponentObjects.APP_CONFIG.get('File_Management_MAX_UPLOAD_SIZE_MB')}MB"
            )
        
        # Save file via LucyDOM interface in the database
        fileItem, duplicateType = managementInterface.saveUploadedFile(fileContent, file.filename)
        
        # Determine response message based on duplicate type
        if duplicateType == "exact_duplicate":
            message = f"File '{file.filename}' already exists with identical content. Reusing existing file."
        elif duplicateType == "name_conflict":
            message = f"File '{file.filename}' already exists with different content. Uploaded as '{fileItem.fileName}'."
        else:  # new_file
            message = "File uploaded successfully"
        
        # If workflowId is provided, update the file information
        if workflowId:
            updateData = {"workflowId": workflowId}
            managementInterface.updateFile(fileItem.id, updateData)
            fileItem.workflowId = workflowId
        
        # Convert FileItem to dictionary for JSON response
        fileMeta = fileItem.model_dump()
        
        # Response with duplicate information
        return JSONResponse({
            "message": message,
            "file": fileMeta,
            "duplicateType": duplicateType,
            "originalFileName": file.filename,
            "storedFileName": fileItem.fileName,
            "isDuplicate": duplicateType != "new_file"
        })
        
    except interfaceDbComponentObjects.FileStorageError as e:
        logger.error(f"Error during file upload (storage): {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, 
            detail=str(e)
        )
    except Exception as e:
        logger.error(f"Error during file upload: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error during file upload: {str(e)}"
        )

@router.get("/{fileId}", response_model=FileItem)
@limiter.limit("30/minute")
async def get_file(
    request: Request,
    fileId: str = Path(..., description="ID of the file"),
    currentUser: User = Depends(getCurrentUser)
) -> FileItem:
    """Get a file"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Get file via LucyDOM interface from the database
        fileData = managementInterface.getFile(fileId)
        if not fileData:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"File with ID {fileId} not found"
            )
            
        return fileData
            
    except interfaceDbComponentObjects.FileNotFoundError as e:
        logger.warning(f"File not found: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=str(e)
        )
    except interfaceDbComponentObjects.FilePermissionError as e:
        logger.warning(f"No permission for file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail=str(e)
        )
    except interfaceDbComponentObjects.FileError as e:
        logger.error(f"Error retrieving file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=str(e)
        )
    except Exception as e:
        logger.error(f"Unexpected error retrieving file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error retrieving file: {str(e)}"
        )

@router.put("/{fileId}", response_model=FileItem)
@limiter.limit("10/minute")
async def update_file(
    request: Request,
    fileId: str = Path(..., description="ID of the file to update"),
    file_info: Dict[str, Any] = Body(...),
    currentUser: User = Depends(getCurrentUser)
) -> FileItem:
    """Update file info"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Get the file from the database
        file = managementInterface.getFile(fileId)
        if not file:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"File with ID {fileId} not found"
            )
            
        # Check if user has access to the file using RBAC
        if not managementInterface.checkRbacPermission(FileItem, "update", fileId):
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail="Not authorized to update this file"
            )
            
        # Update the file
        result = managementInterface.updateFile(fileId, file_info)
        if not result:
            raise HTTPException(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                detail="Failed to update file"
            )
            
        # Get updated file
        updatedFile = managementInterface.getFile(fileId)
        return updatedFile
        
    except HTTPException as he:
        raise he
    except Exception as e:
        logger.error(f"Error updating file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=str(e)
        )

@router.delete("/{fileId}", response_model=Dict[str, Any])
@limiter.limit("10/minute")
async def delete_file(
    request: Request,
    fileId: str = Path(..., description="ID of the file to delete"),
    currentUser: User = Depends(getCurrentUser)
) -> Dict[str, Any]:
    """Delete a file"""
    managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
    
    # Check if the file exists
    existingFile = managementInterface.getFile(fileId)
    if not existingFile:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"File with ID {fileId} not found"
        )
    
    success = managementInterface.deleteFile(fileId)
    if not success:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Error deleting the file"
        )
    
    return {"message": f"File with ID {fileId} successfully deleted"}

@router.get("/stats", response_model=Dict[str, Any])
@limiter.limit("30/minute")
async def get_file_stats(
    request: Request,
    currentUser: User = Depends(getCurrentUser)
) -> Dict[str, Any]:
    """Returns statistics about the stored files"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Get all files - metadata only
        allFiles = managementInterface.getAllFiles()
        
        # Calculate statistics
        totalFiles = len(allFiles)
        totalSize = sum(file.fileSize for file in allFiles)
        
        # Group by file type
        fileTypes = {}
        for file in allFiles:
            fileType = file.mimeType.split("/")[0]
            if fileType not in fileTypes:
                fileTypes[fileType] = 0
            fileTypes[fileType] += 1
        
        return {
            "totalFiles": totalFiles,
            "totalSizeBytes": totalSize,
            "fileTypes": fileTypes
        }
        
    except Exception as e:
        logger.error(f"Error retrieving file statistics: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error retrieving file statistics: {str(e)}"
        )

@router.get("/{fileId}/download")
@limiter.limit("30/minute")
async def download_file(
    request: Request,
    fileId: str = Path(..., description="ID of the file to download"),
    currentUser: User = Depends(getCurrentUser)
) -> Response:
    """Download a file"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Get file data
        fileData = managementInterface.getFile(fileId)
        if not fileData:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"File with ID {fileId} not found"
            )
            
        # Get file content
        fileContent = managementInterface.getFileData(fileId)
        if not fileContent:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"File content not found for ID {fileId}"
            )
        
        # Return file as response
        # Properly encode filename for Content-Disposition header to handle Unicode characters
        import urllib.parse
        encoded_filename = urllib.parse.quote(fileData.fileName)
        
        return Response(
            content=fileContent,
            media_type=fileData.mimeType,
            headers={
                "Content-Disposition": f"attachment; filename*=UTF-8''{encoded_filename}"
            }
        )
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error downloading file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error downloading file: {str(e)}"
        )

@router.get("/{fileId}/preview", response_model=FilePreview)
@limiter.limit("30/minute")
async def preview_file(
    request: Request,
    fileId: str = Path(..., description="ID of the file to preview"),
    currentUser: User = Depends(getCurrentUser)
) -> FilePreview:
    """Preview a file's content"""
    try:
        managementInterface = interfaceDbComponentObjects.getInterface(currentUser)
        
        # Get file preview using the correct method
        preview = managementInterface.getFileContent(fileId)
        if not preview:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"File with ID {fileId} not found or no content available"
            )
        
        return preview
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error previewing file: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Error previewing file: {str(e)}"
        )