from fastapi import APIRouter, Header, HTTPException, UploadFile, File, Form, Request
from pydantic import BaseModel
from typing import Optional, Dict, Any
from api.mcp_clients.rag_client import RAGClient
from api.services.document_ingestion import (
    prepare_ingestion_payload,
    process_ingestion,
    detect_source_type,
    normalize_text,
    extract_text_from_file_bytes
)
from ..utils.access_control import require_api_permission

router = APIRouter()
rag_client = RAGClient()


class IngestRequest(BaseModel):
    """Legacy simple ingestion request"""
    content: str


class DocumentIngestRequest(BaseModel):
    """Enhanced ingestion request matching the system prompt specification"""
    action: str = "ingest_document"
    tenant_id: Optional[str] = None  # Can come from header
    source_type: Optional[str] = None  # pdf | docx | txt | url | raw_text | markdown
    content: str
    metadata: Optional[Dict[str, Any]] = None


class SearchRequest(BaseModel):
    query: str


@router.post("/search")
async def rag_search(
    req: SearchRequest,
    x_tenant_id: str = Header(None)
):
    """
    Search tenant knowledge base using the RAG MCP server.
    """

    if not x_tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")

    try:
        results = await rag_client.search(req.query, x_tenant_id)
        return {
            "tenant_id": x_tenant_id,
            "query": req.query,
            "results": results
        }
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/ingest")
async def rag_ingest(
    req: IngestRequest,
    x_tenant_id: str = Header(None),
    x_user_role: str = Header("viewer")
):
    """
    Legacy ingestion endpoint - simple content ingestion.
    Ingest content into tenant knowledge base using the RAG MCP server.
    """

    if not x_tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")
    require_api_permission(x_user_role, "ingest_documents")

    try:
        result = await rag_client.ingest(req.content, x_tenant_id)
        return {
            "tenant_id": x_tenant_id,
            "status": "ok",
            **result
        }
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/ingest-document")
async def rag_ingest_document(
    req: DocumentIngestRequest,
    request: Request,
    x_tenant_id: Optional[str] = Header(None),
    x_user_role: str = Header("viewer")
):
    """
    Enhanced document ingestion endpoint matching the system prompt specification.
    
    Supports:
    - PDF, DOCX, TXT, Markdown files
    - URLs (fetches content automatically)
    - Raw text
    - Metadata (filename, url, doc_id)
    
    Expected payload:
    {
        "action": "ingest_document",
        "tenant_id": "...",
        "source_type": "pdf | docx | txt | url | raw_text",
        "content": "...",
        "metadata": {
            "filename": "...",
            "url": "...",
            "doc_id": "..."
        }
    }
    """
    # Use tenant_id from header if not in body (for backward compatibility)
    tenant_id = req.tenant_id or x_tenant_id
    if not tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")
    
    import sys
    # Debug: Check actual headers received
    all_headers = dict(request.headers)
    print(f"🔍 DEBUG: All headers received: {list(all_headers.keys())}", file=sys.stderr)
    print(f"🔍 DEBUG: x-user-role header value: '{all_headers.get('x-user-role', 'NOT FOUND')}'", file=sys.stderr)
    print(f"🔍 DEBUG: x-user-role header value (case-insensitive): '{all_headers.get('X-User-Role', all_headers.get('x-user-role', 'NOT FOUND'))}'", file=sys.stderr)
    print(f"🔍 DEBUG: Backend received x_user_role parameter='{x_user_role}' (type: {type(x_user_role)})", file=sys.stderr)
    print(f"🔍 DEBUG: x_tenant_id header='{x_tenant_id}'", file=sys.stderr)
    
    require_api_permission(x_user_role, "ingest_documents")

    content_length = len(req.content) if req.content else 0
    print(f"📥 Ingestion request received: tenant_id={tenant_id}, source_type={req.source_type}, content_length={content_length}", file=sys.stderr)
    
    # Validate content is not too short
    if not req.content or not req.content.strip():
        raise HTTPException(status_code=400, detail="Content cannot be empty. Please provide text to ingest.")
    
    if content_length < 10:
        print(f"⚠️ Warning: Content is very short ({content_length} chars). This may result in no chunks being created.", file=sys.stderr)

    try:
        print("🔧 Step 1: Preparing ingestion payload...", file=sys.stderr)
        # Prepare ingestion payload (async for URL fetching)
        try:
            payload = await prepare_ingestion_payload(
                tenant_id=tenant_id,
                content=req.content,
                source_type=req.source_type,
                filename=req.metadata.get("filename") if req.metadata else None,
                url=req.metadata.get("url") if req.metadata else None,
                doc_id=req.metadata.get("doc_id") if req.metadata else None,
                metadata=req.metadata
            )
            print(f"✅ Step 1 complete: payload prepared", file=sys.stderr)
        except Exception as prep_err:
            print(f"❌ Step 1 FAILED (prepare_ingestion_payload): {prep_err}", file=sys.stderr)
            import traceback
            print(traceback.format_exc(), file=sys.stderr)
            raise
        
        print("🔧 Step 2: Processing ingestion with RAG client...", file=sys.stderr)
        # Process ingestion with metadata extraction
        extract_metadata = req.metadata.get("extract_metadata", True) if req.metadata else True
        try:
            result = await process_ingestion(payload, rag_client, extract_metadata=extract_metadata, user_role=x_user_role)
            print(f"✅ Step 2 complete: chunks_stored={result.get('chunks_stored', 0) if isinstance(result, dict) else 'N/A'}", file=sys.stderr)
        except HTTPException:
            # Re-raise HTTP exceptions (like 403 permission errors) as-is
            raise
        except Exception as proc_err:
            # Check if it's a permission error with status_code attribute
            if hasattr(proc_err, 'status_code') and proc_err.status_code == 403:
                raise HTTPException(status_code=403, detail=getattr(proc_err, 'detail', str(proc_err)))
            
            print(f"❌ Step 2 FAILED (process_ingestion): {proc_err}", file=sys.stderr)
            import traceback
            print(traceback.format_exc(), file=sys.stderr)
            raise
        
        # Check if ingestion actually succeeded
        # First check if the result itself indicates an error
        if isinstance(result, dict) and result.get('status') == 'error':
            error_msg = result.get('message') or result.get('error') or "Unknown error from RAG server"
            error_type = result.get('error_type', 'unknown')
            print(f"❌ RAG server returned error ({error_type}): {error_msg}", file=sys.stderr)
            
            # If it's a permission error, return 403
            if 'permission' in error_msg.lower() or 'not permitted' in error_msg.lower() or error_type == 'validation_error':
                raise HTTPException(
                    status_code=403,
                    detail=f"Permission denied: {error_msg}\n\nPlease change your role to 'editor', 'admin', or 'owner' in the User Role dropdown."
                )
            else:
                raise HTTPException(status_code=500, detail=f"RAG server error: {error_msg}")
        
        chunks_stored = result.get('chunks_stored', 0)
        print(f"🔍 Debug: result keys={list(result.keys()) if isinstance(result, dict) else 'not a dict'}, chunks_stored={chunks_stored}", file=sys.stderr)
        
        if chunks_stored == 0:
            # Get more details about why no chunks were stored
            error_detail = result.get('error') or result.get('warnings') or result.get('message') or "No chunks were stored"
            warnings = result.get('warnings')
            
            error_msg = f"Ingestion failed: {error_detail}"
            if warnings:
                error_msg += f"\nWarnings: {warnings}"
            error_msg += (
                "\n\nPossible causes:\n"
                "1. Content too short or empty (minimum text required)\n"
                "2. Database connection issue (check POSTGRESQL_URL in RAG server)\n"
                "3. RAG MCP server error (check RAG server logs)\n"
                "4. Database table 'documents' doesn't exist"
            )
            
            print(f"❌ No chunks stored. Error detail: {error_detail}", file=sys.stderr)
            raise HTTPException(status_code=500, detail=error_msg)
        
        # Build response message
        message = f"Document ingested successfully. {chunks_stored} chunk(s) stored."
        if result.get("extracted_metadata"):
            metadata_info = result["extracted_metadata"]
            if metadata_info.get("title"):
                message += f" Title: {metadata_info['title']}"
            if metadata_info.get("quality_score"):
                message += f" Quality: {metadata_info['quality_score']:.2f}"
        
        return {
            "status": "ok",
            "message": message,
            **result
        }
    except HTTPException:
        # Re-raise HTTP exceptions as-is
        raise
    except ValueError as e:
        import traceback
        print(f"❌ Ingestion ValueError: {e}")
        print(traceback.format_exc())
        raise HTTPException(status_code=400, detail=f"Validation error: {str(e)}")
    except Exception as e:
        import traceback
        import sys
        error_detail = str(e)
        error_type = type(e).__name__
        full_traceback = traceback.format_exc()
        
        # Log to console with full details (use both stderr and stdout to ensure visibility)
        error_log = f"❌ Ingestion Error ({error_type}): {error_detail}\nFull traceback:\n{full_traceback}"
        print(error_log, file=sys.stderr)
        print(error_log)  # Also print to stdout for uvicorn logs
        
        # Provide helpful error message
        if "POSTGRESQL_URL" in error_detail or "database" in error_detail.lower() or "connection" in error_detail.lower():
            error_msg = (
                f"Database connection error: {error_detail}\n\n"
                f"Please check:\n"
                f"1. POSTGRESQL_URL is set correctly in your .env file\n"
                f"2. Database is accessible\n"
                f"3. The 'documents' table exists (run initialize_database() if needed)"
            )
        elif "RAG" in error_detail or "rag" in error_detail.lower() or "mcp" in error_detail.lower():
            error_msg = (
                f"RAG server error: {error_detail}\n\n"
                f"Please check:\n"
                f"1. RAG_MCP_URL is set correctly (default: http://localhost:8900/rag)\n"
                f"2. RAG MCP server is running\n"
                f"3. Database connection (POSTGRESQL_URL) is configured in the RAG server"
            )
        else:
            # For unknown errors, include the full error message
            error_msg = f"Ingestion failed ({error_type}): {error_detail}"
            # If it's a long traceback, include just the first few lines
            if len(error_detail) > 500:
                error_msg = f"Ingestion failed ({error_type}): {error_detail[:500]}...\n\nSee server logs for full traceback."
        
        # Ensure error message is not too long for HTTP response
        if len(error_msg) > 2000:
            error_msg = error_msg[:2000] + "...\n\n(Error message truncated. See server logs for full details.)"
        
        raise HTTPException(status_code=500, detail=error_msg)


@router.post("/ingest-file")
async def rag_ingest_file(
    file: UploadFile = File(...),
    x_tenant_id: Optional[str] = Header(None),
    tenant_id: Optional[str] = Form(None),
    x_user_role: str = Header("viewer")
):
    """
    File upload endpoint for binary files (PDF, DOCX, TXT, MD).
    Extracts text server-side and ingests into knowledge base.
    
    Usage:
        POST /rag/ingest-file
        Headers:
            x-tenant-id: <tenant_id>
        Form Data:
            file: <binary file>
            tenant_id: <optional, can use header instead>
    """
    # Use tenant_id from form or header
    tenant_id_value = tenant_id or x_tenant_id
    if not tenant_id_value:
        raise HTTPException(status_code=400, detail="Missing tenant ID")
    require_api_permission(x_user_role, "ingest_documents")

    try:
        # Read file bytes
        file_bytes = await file.read()
        if not file_bytes:
            raise HTTPException(status_code=400, detail="File is empty")

        # Extract text from binary file
        try:
            extracted_text = extract_text_from_file_bytes(file_bytes, file.filename or "unknown")
        except ValueError as e:
            raise HTTPException(status_code=400, detail=str(e))

        if not extracted_text or not extracted_text.strip():
            raise HTTPException(status_code=400, detail="No text could be extracted from file")

        # Prepare ingestion payload
        payload = await prepare_ingestion_payload(
            tenant_id=tenant_id_value,
            content=extracted_text,
            source_type=None,  # Auto-detect from filename
            filename=file.filename,
            url=None,
            doc_id=None,
            metadata=None
        )
        
        # Process ingestion with metadata extraction
        result = await process_ingestion(payload, rag_client, extract_metadata=True)
        
        # Build response message
        message = f"File '{file.filename}' ingested successfully. {result.get('chunks_stored', 0)} chunk(s) stored."
        if result.get("extracted_metadata"):
            metadata_info = result["extracted_metadata"]
            if metadata_info.get("title"):
                message += f" Title: {metadata_info['title']}"
            if metadata_info.get("quality_score"):
                message += f" Quality: {metadata_info['quality_score']:.2f}"
        
        return {
            "status": "ok",
            "message": message,
            **result
        }
    except HTTPException:
        raise
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.get("/list")
async def rag_list(
    limit: int = 1000,
    offset: int = 0,
    x_tenant_id: str = Header(None)
):
    """
    List all documents in tenant knowledge base.
    """

    if not x_tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")

    try:
        result = await rag_client.list_documents(x_tenant_id, limit=limit, offset=offset)
        return result
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/delete/{document_id}")
async def rag_delete(
    document_id: int,
    x_tenant_id: str = Header(None),
    x_user_role: str = Header("viewer")
):
    """
    Delete a specific document by ID from tenant knowledge base.
    """
    if not x_tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")
    require_api_permission(x_user_role, "delete_documents")

    try:
        result = await rag_client.delete_document(x_tenant_id, document_id, user_role=x_user_role)
        if "error" in result:
            # Check if it's a connection error (500) or not found (404)
            error_msg = result["error"]
            if "Cannot connect" in error_msg:
                raise HTTPException(status_code=503, detail=error_msg)
            elif "not found" in error_msg.lower() or "access denied" in error_msg.lower():
                raise HTTPException(status_code=404, detail=error_msg)
            else:
                raise HTTPException(status_code=500, detail=error_msg)
        return result
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/delete-all")
async def rag_delete_all(
    x_tenant_id: str = Header(None),
    x_user_role: str = Header("viewer")
):
    """
    Delete all documents for a tenant.
    """
    if not x_tenant_id:
        raise HTTPException(status_code=400, detail="Missing tenant ID")
    require_api_permission(x_user_role, "delete_documents")

    try:
        result = await rag_client.delete_all_documents(x_tenant_id, user_role=x_user_role)
        if "error" in result:
            error_msg = result["error"]
            # Check if it's a connection error (503) or other error
            if "Cannot connect" in error_msg:
                raise HTTPException(status_code=503, detail=error_msg)
            else:
                raise HTTPException(status_code=500, detail=error_msg)
        return result
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))