"""
Patent upload and management endpoints
"""

from fastapi import APIRouter, UploadFile, File, HTTPException
from fastapi.responses import FileResponse
from pathlib import Path
import uuid
import shutil
from datetime import datetime
from typing import List, Dict
from loguru import logger

router = APIRouter()

UPLOAD_DIR = Path("uploads/patents")
UPLOAD_DIR.mkdir(parents=True, exist_ok=True)

@router.post("/upload", response_model=Dict)
async def upload_patent(file: UploadFile = File(...)):
    """
    Upload a patent PDF for analysis.

    Args:
        file: PDF file to upload

    Returns:
        Patent metadata including unique ID
    """
    logger.info(f"Received upload request for: {file.filename}")

    # Validate file type
    if not file.filename.endswith('.pdf'):
        raise HTTPException(
            status_code=400,
            detail="Only PDF files are supported. Please upload a .pdf file."
        )

    # Validate file size (max 50MB)
    file.file.seek(0, 2)  # Seek to end
    file_size = file.file.tell()
    file.file.seek(0)  # Reset to beginning

    if file_size > 50 * 1024 * 1024:  # 50MB
        raise HTTPException(
            status_code=400,
            detail="File too large. Maximum size is 50MB."
        )

    try:
        # Generate unique ID
        patent_id = str(uuid.uuid4())

        # Save file
        file_path = UPLOAD_DIR / f"{patent_id}.pdf"
        with file_path.open("wb") as buffer:
            shutil.copyfileobj(file.file, buffer)

        # Store metadata in app state
        from api.main import app_state

        metadata = {
            "id": patent_id,
            "filename": file.filename,
            "path": str(file_path),
            "size": file_size,
            "uploaded_at": datetime.utcnow().isoformat(),
            "status": "uploaded",
            "workflow_id": None
        }

        app_state["patents"][patent_id] = metadata

        logger.success(f"✅ Patent uploaded: {patent_id} ({file.filename})")

        return {
            "patent_id": patent_id,
            "filename": file.filename,
            "size": file_size,
            "uploaded_at": metadata["uploaded_at"],
            "message": "Patent uploaded successfully"
        }

    except Exception as e:
        logger.error(f"❌ Upload failed: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Upload failed: {str(e)}"
        )

@router.get("/{patent_id}", response_model=Dict)
async def get_patent(patent_id: str):
    """
    Get patent metadata by ID.

    Args:
        patent_id: Unique patent identifier

    Returns:
        Patent metadata
    """
    from api.main import app_state

    if patent_id not in app_state["patents"]:
        raise HTTPException(
            status_code=404,
            detail=f"Patent not found: {patent_id}"
        )

    return app_state["patents"][patent_id]

@router.get("/", response_model=List[Dict])
async def list_patents(
    status: str = None,
    limit: int = 100,
    offset: int = 0
):
    """
    List all uploaded patents.

    Args:
        status: Filter by status (uploaded, analyzing, analyzed, failed)
        limit: Maximum number of results
        offset: Pagination offset

    Returns:
        List of patent metadata
    """
    from api.main import app_state

    patents = list(app_state["patents"].values())

    # Filter by status if provided
    if status:
        patents = [p for p in patents if p["status"] == status]

    # Sort by upload time (newest first)
    patents.sort(key=lambda x: x["uploaded_at"], reverse=True)

    # Pagination
    patents = patents[offset:offset + limit]

    return patents

@router.delete("/{patent_id}")
async def delete_patent(patent_id: str):
    """
    Delete a patent and its associated files.

    Args:
        patent_id: Unique patent identifier

    Returns:
        Success message
    """
    from api.main import app_state

    if patent_id not in app_state["patents"]:
        raise HTTPException(
            status_code=404,
            detail=f"Patent not found: {patent_id}"
        )

    try:
        patent = app_state["patents"][patent_id]

        # Delete file if exists
        file_path = Path(patent["path"])
        if file_path.exists():
            file_path.unlink()

        # Remove from state
        del app_state["patents"][patent_id]

        logger.info(f"Deleted patent: {patent_id}")

        return {"message": "Patent deleted successfully"}

    except Exception as e:
        logger.error(f"Delete failed: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Delete failed: {str(e)}"
        )

@router.get("/{patent_id}/download")
async def download_patent(patent_id: str):
    """
    Download the original patent PDF.

    Args:
        patent_id: Unique patent identifier

    Returns:
        PDF file
    """
    from api.main import app_state

    if patent_id not in app_state["patents"]:
        raise HTTPException(
            status_code=404,
            detail=f"Patent not found: {patent_id}"
        )

    patent = app_state["patents"][patent_id]
    file_path = Path(patent["path"])

    if not file_path.exists():
        raise HTTPException(
            status_code=404,
            detail="Patent file not found on disk"
        )

    return FileResponse(
        path=file_path,
        media_type="application/pdf",
        filename=patent["filename"]
    )