import pymupdf
from fastapi import APIRouter, HTTPException
from fastapi.responses import Response
from pydantic import BaseModel

from app.config import settings

router = APIRouter(prefix="/debug", tags=["Debug"])

class VerifyCoordsRequest(BaseModel):
    document_id: str
    page: int
    x: float
    y: float
    width: float
    height: float

@router.post("/verify-coords")
async def verify_coords(req: VerifyCoordsRequest):
    """
    Test endpoint for cross-engine coordinate verification.
    Takes a canonical rect, draws it on the PDF using PyMuPDF,
    and returns the flattened PDF.
    """
    filepath = settings.PDF_STORAGE_PATH / f"{req.document_id}.pdf"
    if not filepath.exists():
        raise HTTPException(status_code=404, detail="Document not found")

    try:
        doc = pymupdf.open(filepath)
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

    if req.page < 0 or req.page >= len(doc):
        doc.close()
        raise HTTPException(status_code=400, detail="Invalid page number")

    page = doc[req.page]
    
    # Canonical space is defined as relative to the unrotated CropBox.
    # PyMuPDF naturally draws relative to the current rotation.
    # By temporarily setting rotation to 0, we can draw directly using canonical coordinates.
    original_rotation = page.rotation
    if original_rotation != 0:
        page.set_rotation(0)
    
    rect = pymupdf.Rect(req.x, req.y, req.x + req.width, req.y + req.height)
    page.draw_rect(rect, color=(1, 0, 0), width=2, fill=(1, 0, 0), fill_opacity=0.3)
    
    if original_rotation != 0:
        page.set_rotation(original_rotation)
    
    pdf_bytes = doc.write()
    doc.close()

    return Response(content=pdf_bytes, media_type="application/pdf")