import os
import base64
import io
import logging
from openai import AsyncOpenAI
from dotenv import load_dotenv
from PIL import Image
from backend.schemas import ExtractionResponse

load_dotenv()

# Setup logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

client = AsyncOpenAI(api_key=os.getenv("OPENAI_API_KEY"))

MAX_IMAGE_SIZE = (2000, 2000)
IMAGE_QUALITY = 85

def compress_image(image_content: bytes) -> bytes:
    """Resizes and compresses the image to reduce upload size."""
    img = Image.open(io.BytesIO(image_content))
    
    # Convert to RGB if necessary (to save as JPEG)
    if img.mode in ("RGBA", "P"):
        img = img.convert("RGB")
    
    # Resize if larger than max dimensions
    img.thumbnail(MAX_IMAGE_SIZE, Image.Resampling.LANCZOS)
    
    # Save to bytes
    output_buffer = io.BytesIO()
    img.save(output_buffer, format="JPEG", quality=IMAGE_QUALITY, optimize=True)
    return output_buffer.getvalue()

async def extract_receipt_data(image_content: bytes, user_name: str, department: str) -> ExtractionResponse:
    # 1. Compress Image
    compressed_content = compress_image(image_content)
    base64_image = base64.b64encode(compressed_content).decode("utf-8")
    
    # 2. Refined Prompt
    prompt = (
        f"You are a cautious auditor helping an HR department in Malaysia. "
        f"Extract the requested fields from the provided medical receipt image. "
        f"The employee submitting this is {user_name} from {department}. "
        f"IMPORTANT: The context is Malaysia (MYR). "
        f"For the fields `receipt_ref_no` and `clinic_reg_no`, only provide a value if you can read it clearly without any guessing or inference. If the text is smudged, handwritten, or ambiguous, return `null`. "
        f"Map the clinic/services to a `claim_category` from: [General, Dental, Optical, Specialist] based on the clinic name or invoice items. "
        f"Provide a 1-sentence `diagnosis_brief` summarizing the services seen (e.g. 'Fever consultation and medicine'). "
        f"Set `needs_manual_review` to `true` and provide a low `confidence_score` if: "
        f"1. The 'Total' does not match the sum of the individual items. "
        f"2. The receipt looks hand-written and lacks an official stamp. "
        f"3. The provider name is missing or the amount looks altered. "
        f"4. The user's name ({user_name}) is not clearly visible on the receipt. "
        f"IMPORTANT: Fill the `ai_reasoning` field with a 1-sentence explanation of how you identified the clinic and category."
    )
    
    # 3. Async Extraction
    completion = await client.beta.chat.completions.parse(
        model="gpt-4o-mini",
        messages=[
            {
                "role": "system",
                "content": "You are an HR data entry assistant. Extract medical receipt data accurately into structured JSON."
            },
            {
                "role": "user",
                "content": [
                    {"type": "text", "text": prompt},
                    {
                        "type": "image_url",
                        "image_url": {"url": f"data:image/jpeg;base64,{base64_image}"},
                    },
                ],
            }
        ],
        response_format=ExtractionResponse,
    )
    
    result = completion.choices[0].message.parsed
    
    # 4. Logging for Demo
    if result:
        logger.info(f"Extraction complete for {user_name}. Confidence Score: {result.confidence_score}")
        if result.needs_manual_review:
            logger.warning(f"Manual review required for receipt submitted by {user_name}")
            
    return result