from __future__ import annotations

from fastapi import FastAPI, UploadFile, File, HTTPException, Query
from fastapi.responses import JSONResponse
from typing import Optional

from pathlib import Path
import tempfile
import requests

from .reviewer import PDFReviewer

app = FastAPI(title="TMLR Reviewer PDF API", description="Generate reviews for uploaded PDFs")

reviewer = PDFReviewer()


@app.post("/review")
async def review_pdf(
    file: Optional[UploadFile] = File(None),
    url: Optional[str] = Query(None, description="URL of PDF to review"),
    test: bool = Query(False, description="Return mock data for testing")
):
    """Upload a PDF file and return the structured review as JSON.
    
    You can either:
    - Upload a file directly
    - Provide a URL to a PDF
    - Use test=true for mock data
    """
    # Return mock data if test mode is enabled
    if test:
        return JSONResponse(content={
            "contributions": "Test contribution summary",
            "strengths": "- Test strength 1\n- Test strength 2",
            "weaknesses": "- Test weakness 1\n- Test weakness 2",
            "requested_changes": "- Test change 1\n- Test change 2",
            "impact_concerns": "No concerns for test",
            "claims_and_evidence": "yes",
            "audience_interest": "yes"
        })
    
    # Check if either file or URL is provided
    if not file and not url:
        raise HTTPException(status_code=400, detail="Either file upload or URL is required")
    
    if file and url:
        raise HTTPException(status_code=400, detail="Please provide either file or URL, not both")
    
    # Handle URL download
    if url:
        try:
            # Download PDF from URL
            response = requests.get(url, timeout=30)
            response.raise_for_status()
            
            # Verify it's a PDF
            content_type = response.headers.get('content-type', '')
            if 'application/pdf' not in content_type.lower():
                raise HTTPException(status_code=400, detail=f"URL does not point to a PDF. Content-Type: {content_type}")
            
            # Save to temporary file
            with tempfile.NamedTemporaryFile(delete=False, suffix=".pdf") as tmp:
                tmp.write(response.content)
                tmp_path = Path(tmp.name)
                
        except requests.RequestException as e:
            raise HTTPException(status_code=400, detail=f"Failed to download PDF from URL: {str(e)}")
    
    # Handle file upload
    else:
        if file.content_type != "application/pdf":
            raise HTTPException(status_code=400, detail="Only PDF files are supported")

        # Save to temporary location
        suffix = Path(file.filename).suffix or ".pdf"
        with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
            content = await file.read()
            tmp.write(content)
            tmp_path = Path(tmp.name)

    try:
        review_result = reviewer.review_pdf(tmp_path)
    except Exception as exc:
        raise HTTPException(status_code=500, detail=str(exc))
    finally:
        tmp_path.unlink(missing_ok=True)

    return JSONResponse(content=review_result)